Ground-water and surface-water elevations in the Fairbanks International Airport area, Alaska, 1990-96, and selected geohydrologic report references

USGS Publications Warehouse

Claar, David V.; Lilly, Michael R.

1997-01-01

Ground-water and surface-water elevation data were collected at 61 sites from 1990 to 1996 by the U.S. Geological Survey in cooperation with the Alaska Department of Transportation and Public Facilities, Fairbanks International Airport. Water-surface elevations were measured in 41 ground-water observation wells and at 20 surface-water sites to help characterize the geohydrology of the Fairbanks International Airport area. From 1990 to 1993, data were collected in the vicinity of the former fire-training area at the airport. From 1993 to 1996, the data-collection area was expanded to include the entire airport area. The total number of data-collection sites varied each year because of changing project objectives and increased understanding of the geohydrology in the area.

Complete Soil-Structure Interaction (SSI) Analyses of I-walls Embedded in Level Ground During Flood Loading

DTIC Science & Technology

2012-09-01

at the ground surface el 0 ft versus water elevation...sheet pile at the ground surface . ................ 62  Figure 3.24. Total displacements for a water elevation of 16.5 ft and a gap tip elevation of -11...103  Figure 4.19. Relative horizontal displacements of the sheet pile at the ground surface

Combining slope stability and groundwater flow models to assess stratovolcano collapse hazard

NASA Astrophysics Data System (ADS)

Ball, J. L.; Taron, J.; Reid, M. E.; Hurwitz, S.; Finn, C.; Bedrosian, P.

2016-12-01

Flank collapses are a well-documented hazard at volcanoes. Elevated pore-fluid pressures and hydrothermal alteration are invoked as potential causes for the instability in many of these collapses. Because pore pressure is linked to water saturation and permeability of volcanic deposits, hydrothermal alteration is often suggested as a means of creating low-permeability zones in volcanoes. Here, we seek to address the question: What alteration geometries will produce elevated pore pressures in a stratovolcano, and what are the effects of these elevated pressures on slope stability? We initially use a finite element groundwater flow model (a modified version of OpenGeoSys) to simulate `generic' stratovolcano geometries that produce elevated pore pressures. We then input these results into the USGS slope-stability code Scoops3D to investigate the effects of alteration and magmatic intrusion on potential flank failure. This approach integrates geophysical data about subsurface alteration, water saturation and rock mechanical properties with data about precipitation and heat influx at Cascade stratovolcanoes. Our simulations show that it is possible to maintain high-elevation water tables in stratovolcanoes given specific ranges of edifice permeability (ideally between 10-15 and 10-16 m2). Low-permeability layers (10-17 m2, representing altered pyroclastic deposits or altered breccias) in the volcanoes can localize saturated regions close to the surface, but they may actually reduce saturation, pore pressures, and water table levels in the core of the volcano. These conditions produce universally lower factor-of-safety (F) values than at an equivalent dry edifice with the same material properties (lower values of F indicate a higher likelihood of collapse). When magmatic intrusions into the base of the cone are added, near-surface pore pressures increase and F decreases exponentially with time ( 7-8% in the first year). However, while near-surface impermeable layers create elevated water tables and pore pressures, they do not necessarily produce the largest or deepest collapses. This suggests that mechanical properties of both the edifice and layers still exert a significant control, and collapse volumes depend on a complex interplay of mechanical factors and layering.

Using computational modeling of river flow with remotely sensed data to infer channel bathymetry

USGS Publications Warehouse

Nelson, Jonathan M.; McDonald, Richard R.; Kinzel, Paul J.; Shimizu, Y.

2012-01-01

As part of an ongoing investigation into the use of computational river flow and morphodynamic models for the purpose of correcting and extending remotely sensed river datasets, a simple method for inferring channel bathymetry is developed and discussed. The method is based on an inversion of the equations expressing conservation of mass and momentum to develop equations that can be solved for depth given known values of vertically-averaged velocity and water-surface elevation. The ultimate goal of this work is to combine imperfect remotely sensed data on river planform, water-surface elevation and water-surface velocity in order to estimate depth and other physical parameters of river channels. In this paper, the technique is examined using synthetic data sets that are developed directly from the application of forward two-and three-dimensional flow models. These data sets are constrained to satisfy conservation of mass and momentum, unlike typical remotely sensed field data sets. This provides a better understanding of the process and also allows assessment of how simple inaccuracies in remotely sensed estimates might propagate into depth estimates. The technique is applied to three simple cases: First, depth is extracted from a synthetic dataset of vertically averaged velocity and water-surface elevation; second, depth is extracted from the same data set but with a normally-distributed random error added to the water-surface elevation; third, depth is extracted from a synthetic data set for the same river reach using computed water-surface velocities (in place of depth-integrated values) and water-surface elevations. In each case, the extracted depths are compared to the actual measured depths used to construct the synthetic data sets (with two- and three-dimensional flow models). Errors in water-surface elevation and velocity that are very small degrade depth estimates and cannot be recovered. Errors in depth estimates associated with assuming water-surface velocities equal to depth-integrated velocities are substantial, but can be reduced with simple corrections.

Using Selective Drainage Methods to Extract Continuous Surface Flow from 1-Meter Lidar-Derived Digital Elevation Data

USGS Publications Warehouse

Poppenga, Sandra K.; Worstell, Bruce B.; Stoker, Jason M.; Greenlee, Susan K.

2010-01-01

Digital elevation data commonly are used to extract surface flow features. One source for high-resolution elevation data is light detection and ranging (lidar). Lidar can capture a vast amount of topographic detail because of its fine-scale ability to digitally capture the surface of the earth. Because elevation is a key factor in extracting surface flow features, high-resolution lidar-derived digital elevation models (DEMs) provide the detail needed to consistently integrate hydrography with elevation, land cover, structures, and other geospatial features. The U.S. Geological Survey has developed selective drainage methods to extract continuous surface flow from high-resolution lidar-derived digital elevation data. The lidar-derived continuous surface flow network contains valuable information for water resource management involving flood hazard mapping, flood inundation, and coastal erosion. DEMs used in hydrologic applications typically are processed to remove depressions by filling them. High-resolution DEMs derived from lidar can capture much more detail of the land surface than courser elevation data. Therefore, high-resolution DEMs contain more depressions because of obstructions such as roads, railroads, and other elevated structures. The filling of these depressions can significantly affect the DEM-derived surface flow routing and terrain characteristics in an adverse way. In this report, selective draining methods that modify the elevation surface to drain a depression through an obstruction are presented. If such obstructions are not removed from the elevation data, the filling of depressions to create continuous surface flow can cause the flow to spill over an obstruction in the wrong location. Using this modified elevation surface improves the quality of derived surface flow and retains more of the true surface characteristics by correcting large filled depressions. A reliable flow surface is necessary for deriving a consistently connected drainage network, which is important in understanding surface water movement and developing applications for surface water runoff, flood inundation, and erosion. Improved methods are needed to extract continuous surface flow features from high-resolution elevation data based on lidar.

A summary of measured hydraulic data for the series of steady and unsteady flow experiments over patterned roughness

USGS Publications Warehouse

Collins, Dannie L.; Flynn, Kathleen M.

1979-01-01

This report summarizes and makes available to other investigators the measured hydraulic data collected during a series of experiments designed to study the effect of patterned bed roughness on steady and unsteady open-channel flow. The patterned effect of the roughness was obtained by clear-cut mowing of designated areas of an otherwise fairly dense coverage of coastal Bermuda grass approximately 250 mm high. All experiments were conducted in the Flood Plain Simulation Facility during the period of October 7 through December 12, 1974. Data from 18 steady flow experiments and 10 unsteady flow experiments are summarized. Measured data included are ground-surface elevations, grass heights and densities, water-surface elevations and point velocities for all experiments. Additional tables of water-surface elevations and measured point velocities are included for the clear-cut areas for most experiments. One complete set of average water-surface elevations and one complete set of measured point velocities are tabulated for each steady flow experiment. Time series data, on a 2-minute time interval, are tabulated for both water-surface elevations and point velocities for each unsteady flow experiment. All data collected, including individual records of water-surface elevations for the steady flow experiments, have been stored on computer disk storage and can be retrieved using the computer programs listed in the attachment to this report. (Kosco-USGS)

30 CFR 77.217 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) Area-capacity curves means graphic curves which readily show the reservoir water surface area, in acres, at different elevations from the bottom of the reservoir to the maximum water surface, and the capacity or volume, in acre-feet, of the water contained in the reservoir at various elevations. (c...

30 CFR 77.217 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

...) Area-capacity curves means graphic curves which readily show the reservoir water surface area, in acres, at different elevations from the bottom of the reservoir to the maximum water surface, and the capacity or volume, in acre-feet, of the water contained in the reservoir at various elevations. (c...

Water Resources Data, Florida, Water Year 2003, Volume 1A: Northeast Florida Surface Water

USGS Publications Warehouse

,

2004-01-01

Water resources data for the 2003 water year in Florida consist of continuous or daily discharge for 385 streams, periodic discharge for 13 streams, continuous or daily stage for 255 streams, periodic stage for 13 streams, peak stage and discharge for 36 streams; continuous or daily elevations for 13 lakes, periodic elevations for 46 lakes; continuous ground-water levels for 441 wells, periodic ground-water levels for 1,227 wells; quality-of-water data for 133 surface-water sites and 308 wells. The data for northeast Florida include continuous or daily discharge for 138 streams, periodic discharge for 3 streams, continuous or daily stage for 61 streams, periodic stage for 0 streams; peak stage and discharge for 0 streams; continuous or daily elevations for 9 lakes, periodic elevations for 20 lakes; continuous ground water levels for 73 wells, periodic groundwater levels for 543 wells; quality-of-water data for 43 surface-water sites and 115 wells. These data represent the National Water Data System records collected by the U.S. Geological Survey and cooperating local, State and Federal agencies in Florida.

Verification and transfer of thermal pollution model. Volume 3: Verification of 3-dimensional rigid-lid model

NASA Technical Reports Server (NTRS)

Lee, S. S.; Sengupta, S.; Nwadike, E. V.; Sinha, S. K.

1982-01-01

The six-volume report: describes the theory of a three dimensional (3-D) mathematical thermal discharge model and a related one dimensional (1-D) model, includes model verification at two sites, and provides a separate user's manual for each model. The 3-D model has two forms: free surface and rigid lid. The former, verified at Anclote Anchorage (FL), allows a free air/water interface and is suited for significant surface wave heights compared to mean water depth; e.g., estuaries and coastal regions. The latter, verified at Lake Keowee (SC), is suited for small surface wave heights compared to depth (e.g., natural or man-made inland lakes) because surface elevation has been removed as a parameter. These models allow computation of time-dependent velocity and temperature fields for given initial conditions and time-varying boundary conditions. The free-surface model also provides surface height variations with time.

Development of a Trajectory Model for the Analysis of Stratospheric Water Vapor

NASA Astrophysics Data System (ADS)

Koby, Timothy Robert

To study stratospheric water vapor, a new trajectory model was created. The model is built from first principles specific to stratospheric motion and can run on any gridded dataset, making it more versatile than current solutions. The design of a new model was motivated by measurements of elevated stratospheric water vapor, which in situ isotopic measurements have determined to be tropospheric in origin. A moist stratosphere has substantial feedbacks in the climate system including radiative, chemical, and biological effects. Additionally, elevated stratospheric water vapor is theorized as an important coupling in the historical transition to the Eocene, 56 million years ago, as well as emergence from the Eocene 40 million years ago. This transition mirrors modern climate change, both in surface temperature and carbon dioxide increase. However, the historical transition became much more extreme and settled to a state of warm temperatures from the equator to the poles with little variation in between. The lack of latitudinal gradient in temperature is associated with a moist stratosphere, which provides additional motivation for thoroughly understanding the effects of adding water vapor to the stratosphere in a climatological context. The time evolution of water vapor enhancements from convective injection is analyzed by initializing trajectories over satellite-measured water vapor enhancements. The model runs show water vapor concentrations that remain elevated over the background concentrations for several days and often over a week, which is of the timescale that warrants concern over increased halogen catalyzed ozone loss and the subsequent risk to public health. By analyzing stratospheric winds during the summer months over North America using normalized angular momentum, a pattern of frequent stratospheric anticyclonic activity over North America emerges as a unique feature of the region. This provides a mechanism for the modeled persistent elevated water vapor and validates observations. In a climate like today's with increasing surface radiative forcing, the magnitude and frequency of convective injection may increase, with dramatic consequences on the climate system and human health.

Using Profiles of Water Vapor Flux to Characterize Turbulence in the Convective Boundary Layer

NASA Astrophysics Data System (ADS)

Weber, Kristy Jane

The 2015 Plains Elevated Convection at Night (PECAN) field campaign sought to increase understanding of mechanisms for nocturnal severe weather in the Great Plains of the United States. A collection of instruments from this field campaign, including a water vapor Differential LiDAR (Light Detection Imaging And Ranging) (DIAL) and 449 MHz radar wind profiler were used to measure water vapor flux in regions between 300 m and the convective boundary layer. Methods to properly sample eddies using eddy-covariance were established, where analysis showed that a 90-minute Reynold's averaging period was optimal to sample most eddies. Additionally, a case study was used to demonstrate the additional atmospheric parameters which can be calculated from profiles of water vapor flux, such as the water vapor flux convergence/divergence. Flux footprints calculated at multiple heights within the convective boundary layer also show how a surface based instrument is sampling a completely different source than one taking measurements above 300 m. This result is important, as it shows how measurements above the surface layer will not be expected to match with those taken within a few meters of the surface, especially if average surface features such as land use type and roughness length are significantly different. These calculated water vapor flux profile measurements provide a new tool to analyze boundary layer dynamics during the PECAN field campaign, and their relationships to PECAN's study areas such as mesoscale convective systems (MCSs), nocturnal low-level jets (NLLJs), elevated convective initiation, and the propagation of bores or wavelike features from nocturnal convective systems.

A geospatial framework for improving the vertical accuracy of elevation models in Florida's coastal Everglades

NASA Astrophysics Data System (ADS)

Cooper, H.; Zhang, C.; Sirianni, M.

2016-12-01

South Florida relies upon the health of the Everglades, the largest subtropical wetland in North America, as a vital source of water. Since the late 1800's, this imperiled ecosystem has been highly engineered to meet human needs of flood control and water use. The Comprehensive Everglades Restoration Plan (CERP) was initiated in 2000 to restore original water flows to the Everglades and improve overall ecosystem health, while also aiming to achieve balance with human water usage. Due to subtle changes in the Everglades terrain, better vertical accuracy elevation data are needed to model groundwater and surface water levels that are integral to monitoring the effects of restoration under impacts such as sea-level rise. The current best available elevation datasets for the coastal Everglades include High Accuracy Elevation Data (HAED) and Florida Department of Emergency Management (FDEM) Light Detection and Ranging (LiDAR). However, the horizontal resolution of the HAED data is too coarse ( 400 m) for fine scale mapping, and the LiDAR data does not contain an accuracy assessment for coastal Everglades' vegetation communities. The purpose of this study is to develop a framework for generating better vertical accuracy and horizontal resolution Digital Elevation Models in the Flamingo District of Everglades National Park. In the framework, field work is conducted to collect RTK GPS and total station elevation measurements for mangrove swamp, coastal prairies, and freshwater marsh, and the proposed accuracy assessment and elevation modeling methodology is integrated with a Geographical Information System (GIS). It is anticipated that this study will provide more accurate models of the soil substrate elevation that can be used by restoration planners to better predict the future state of the Everglades ecosystem.

Water Resources Data, Florida, Water Year 2003, Volume 3A: Southwest Florida Surface Water

USGS Publications Warehouse

Kane, R.L.; Fletcher, W.L.

2004-01-01

Water resources data for the 2003 water year in Florida consist of continuous or daily discharges for 385 streams, periodic discharge for 13 streams, continuous daily stage for 255 streams, periodic stage for 13 streams, peak stage for 36 streams and peak discharge for 36 streams, continuous or daily elevations for 13 lakes, periodic elevations for 46 lakes; continuous ground-water levels for 441 wells, periodic ground-water levels for 1,227 wells, and quality-of-water data for 133 surface-water sites and 308 wells. The data for Southwest Florida include records of stage, discharge, and water quality of streams; stage, contents, water quality of lakes and reservoirs, and water levels and water quality of ground-water wells. Volume 3A contains continuous or daily discharge for 103 streams, periodic discharge for 7 streams, continuous or daily stage for 67 streams, periodic stage for 13 streams, peak stage and discharge for 8 streams, continuous or daily elevations for 2 lakes, periodic elevations for 26 lakes, and quality-of-water data for 62 surface-water sites. These data represent the national Water Data System records collected by the U.S. Geological Survey and cooperating local, state, and federal agencies in Florida.

Documentation of programs used to determine a wetlands hydroperiod from model-simulated water-surface elevations

USGS Publications Warehouse

Sonenshein, R.S.

1996-01-01

A technique has been developed to determine a wetlands hydroperiod by comparing simulated water levels from a ground-water flow model and land- surface elevation data through a geographic information system. The simulated water levels are compared with the land-surface elevation data to determine the height of the water surface above or below land surface for the area of interest. Finally, the hydroperiod is determined for established time periods using criteria specified by the user. The program application requires the use of geographic information system software (ARC/INFO), including the TIN and GRID subsystems of the software. The application consists of an ANSI compatible C program to translate ground- water data output from the U.S. Geological Survey modular three-dimensional, finite-difference, ground-water flow model (MODFLOW) into a format that can be used as input for the geographic information system programs (AML's). The application uses ARC/INFO AML programs and ARC/INFO menu interface programs to create digital spatial data layers of the land surface and water surface and to determine the hydroperiod. The technique can be used to evaluate and manage wetlands hydrology.

Field and laboratory determination of water-surface elevation and velocity using noncontact measurements

USGS Publications Warehouse

Nelson, Jonathan M.; Kinzel, Paul J.; Schmeeckle, Mark Walter; McDonald, Richard R.; Minear, Justin T.

2016-01-01

Noncontact methods for measuring water-surface elevation and velocity in laboratory flumes and rivers are presented with examples. Water-surface elevations are measured using an array of acoustic transducers in the laboratory and using laser scanning in field situations. Water-surface velocities are based on using particle image velocimetry or other machine vision techniques on infrared video of the water surface. Using spatial and temporal averaging, results from these methods provide information that can be used to develop estimates of discharge for flows over known bathymetry. Making such estimates requires relating water-surface velocities to vertically averaged velocities; the methods here use standard relations. To examine where these relations break down, laboratory data for flows over simple bumps of three amplitudes are evaluated. As anticipated, discharges determined from surface information can have large errors where nonhydrostatic effects are large. In addition to investigating and characterizing this potential error in estimating discharge, a simple method for correction of the issue is presented. With a simple correction based on bed gradient along the flow direction, remotely sensed estimates of discharge appear to be viable.

Presenting the Rain-Sea Interaction Facility

NASA Technical Reports Server (NTRS)

Bliven, Larry F.; Elfouhaily, Tonas M.

1993-01-01

The new Rain-Sea Interaction Facility (RSIF) was established at GSFC/WFF and the first finds are presented. The unique feature of this laboratory is the ability to systematically study microwave scattering from a water surface roughened by artificial rain, for which the droplets are at terminal velocity. The fundamental instruments and systems (e.g., the rain simulator, scatterometers, and surface elevation probes) were installed and evaluated during these first experiments - so the majority of the data were obtained with the rain simulator at 1 m above the water tank. From these initial experiments, three new models were proposed: the square-root function for NCS vs. R, the log Gaussian model for ring-wave elevation frequency spectrum, and the Erland probability density distribution for back scattered power. Rain rate is the main input for these models, although the coefficients may be dependent upon other factors (drop-size distribution, fall velocity, radar configuration, etc.). The facility is functional and we foresee collaborative studies with investigators who are engaged in measuring and modeling rain-sea interaction processes.

Method to identify wells that yield water that will be replaced by Colorado River water in Arizona, California, Nevada, and Utah

USGS Publications Warehouse

Wilson, Richard P.; Owen-Joyce, Sandra J.

1994-01-01

Accounting for the use of Colorado River water is required by the U.S. Supreme Court decree, 1964, Arizona v. California. Water pumped from wells on the flood plain and from certain wells on alluvial slopes outside the flood plain is presumed to be river water and is accounted for as Colorado River water. A method was developed to identify wells outside the f1ood plain of the lower Colorado River that yield water that will be replaced by water from the river. The method provides a uniform criterion of identification for all users pumping water from wells. Wells that have a static water-level elevation equal to or below the accounting surface are presumed to yield water that will be replaced by water from the river. Wells that have a static water-level elevation above the accounting surface are presumed to yield water that will be replaced by water from precipitation and inflow from tributary valleys. The method is based on the concept of a river aquifer and an accounting surface within the river aquifer. The river aquifer consists of permeable, partly saturated sediments and sedimentary rocks that are hydraulically connected to the Colorado River so that water can move between the river and the aquifer in response to withdrawal of water from the aquifer or differences in water-level elevations between the river and the aquifer. The accounting surface represents the elevation and slope of the unconfined static water table in the river aquifer outside the flood plain and reservoirs that would exist if the river were the only source of water to the river aquifer. Maps at a scale of 1:100,000 show the extent and elevation of the accounting surface from the area surrounding Lake Mead to Laguna Dam near Yuma, Arizona.

Water Resources Data, Florida, Water Year 2003 Volume 2A: South Florida Surface Water

USGS Publications Warehouse

Price, C.; Woolverton, J.; Overton, K.

2004-01-01

Water resources data for 2003 water year in Florida consists of continuous or daily discharge for 385 streams, periodic discharge for 13 streams, continuous or daily stage for 255 streams, periodic stage for 13 stream, peak discharge for 36 streams, and peak stage for 36 streams, continuous or daily elevations for 13 lakes, periodic elevations for 46 lakes, continuous ground-water levels for 441 wells, periodic ground-water levels for 1227 wells, quality of water data for 133 surface-water sites, and 308 wells. The data for South Florida included continuous or daily discharge for 72 streams, continuous or daily stage for 50 streams, no peak stage discharge for streams, 1 continuous elevation for lake, continuous ground-water levels for 237 wells, periodic ground-water levels for 248 wells, water quality for 25 surface-water sites, and 161 wells. These data represent the National Water Data System records collected by the U.S. Geological Survey and cooperation with local, state, and federal agencies in Florida.

Noncontact methods for measuring water-surface elevations and velocities in rivers: Implications for depth and discharge extraction

USGS Publications Warehouse

Nelson, Jonathan M.; Kinzel, Paul J.; McDonald, Richard R.; Schmeeckle, Mark

2016-01-01

Recently developed optical and videographic methods for measuring water-surface properties in a noninvasive manner hold great promise for extracting river hydraulic and bathymetric information. This paper describes such a technique, concentrating on the method of infrared videog- raphy for measuring surface velocities and both acoustic (laboratory-based) and laser-scanning (field-based) techniques for measuring water-surface elevations. In ideal laboratory situations with simple flows, appropriate spatial and temporal averaging results in accurate water-surface elevations and water-surface velocities. In test cases, this accuracy is sufficient to allow direct inversion of the governing equations of motion to produce estimates of depth and discharge. Unlike other optical techniques for determining local depth that rely on transmissivity of the water column (bathymetric lidar, multi/hyperspectral correlation), this method uses only water-surface information, so even deep and/or turbid flows can be investigated. However, significant errors arise in areas of nonhydrostatic spatial accelerations, such as those associated with flow over bedforms or other relatively steep obstacles. Using laboratory measurements for test cases, the cause of these errors is examined and both a simple semi-empirical method and computational results are presented that can potentially reduce bathymetric inversion errors.

Changes in micro-relief during different water erosive stages of purple soil under simulated rainfall.

PubMed

Luo, Jian; Zheng, Zicheng; Li, Tingxuan; He, Shuqin

2018-02-22

This study investigated the variation characteristics of micro-topography during successive erosive stages of water erosion: splash erosion (SpE), sheet erosion (ShE), and rill erosion (RE). Micro-topography was quantified using surface elevation change, soil roughness (SR) and multifractal model. Results showed that the area of soil surface elevation decay increased gradually with the development of water erosion. With rainfall, the combined effects of the detachment by raindrop impact and the transport of runoff decreased SR, whereas rill erosion contributed to increase SR. With the increase in slope gradient, soil erosion area gradually decreased at the splash erosion stage. By contrast, soil erosion area initially decreased and then increased at the sheet and rill erosion stages. The width of the D q spectra (ΔD) values increased at the splash erosion stage and then decreased at the sheet and rill erosion stages on the 10° slope, opposite to that on the 15° slope. The ΔD values decreased with the evolution of water erosive stages on the 20° slope. The slope had an enhancing effect on the evolution of water erosion. In this study, we clarified the essence of micro-topography and laid a theoretical foundation for further understanding diverse hydrological processes.

Water movement in glass bead porous media: 1. Experiments of capillary rise and hysteresis

NASA Astrophysics Data System (ADS)

Lu, T. X.; Biggar, J. W.; Nielsen, D. R.

1994-12-01

Experimental observations of capillary rise and hysteresis of water or ethanol in glass beads are presented to improve our understanding of those physical processes in porous media. The results provide evidence that capillary rise into porous media cannot be fully explained by a model of cylinders. They further demonstrate that the "Ink bottle" model does not provide an adequate explanation of hysteresis. Glass beads serving as a model for ideal soil are enclosed in a rectangular glass chamber model. A TV camera associated with a microscope was used to record the processes of capillary rise and drainage. It is clearly shown during capillary rise that the fluid exhibits a "jump" behavior at the neck of the pores in an initially dry profile or at the bottom of the water film in an initially wet profile. Under an initially dry condition, the jump initiates at the particle with smallest diameter. The jump process continues to higher elevations until at equilibrium the surface tensile force is balanced by the hydrostatic force. The wetting front at that time is readily observed as flat and saturated. Under an initially wet condition, capillary rise occurs as a water film thickening process associated with the jump process. Trapped air behind the wetting front renders the wetting front irregular and unsaturated. The capillary rise into an initially wet porous medium can be higher than that into an initially dry profile. During the drying process, large surface areas associated with the gas-liquid interface develop, allowing the porous medium to retain more water than during the wetting process at the same pressure. That mechanism explains better the hysteresis phenomenon in porous media in contrast to other mechanisms that now prevail.

Comparison of Surface Flow Features from Lidar-Derived Digital Elevation Models with Historical Elevation and Hydrography Data for Minnehaha County, South Dakota

USGS Publications Warehouse

Poppenga, Sandra K.; Worstell, Bruce B.; Stoker, Jason M.; Greenlee, Susan K.

2009-01-01

The U.S. Geological Survey (USGS) has taken the lead in the creation of a valuable remote sensing product by incorporating digital elevation models (DEMs) derived from Light Detection and Ranging (lidar) into the National Elevation Dataset (NED), the elevation layer of 'The National Map'. High-resolution lidar-derived DEMs provide the accuracy needed to systematically quantify and fully integrate surface flow including flow direction, flow accumulation, sinks, slope, and a dense drainage network. In 2008, 1-meter resolution lidar data were acquired in Minnehaha County, South Dakota. The acquisition was a collaborative effort between Minnehaha County, the city of Sioux Falls, and the USGS Earth Resources Observation and Science (EROS) Center. With the newly acquired lidar data, USGS scientists generated high-resolution DEMs and surface flow features. This report compares lidar-derived surface flow features in Minnehaha County to 30- and 10-meter elevation data previously incorporated in the NED and ancillary hydrography datasets. Surface flow features generated from lidar-derived DEMs are consistently integrated with elevation and are important in understanding surface-water movement to better detect surface-water runoff, flood inundation, and erosion. Many topographic and hydrologic applications will benefit from the increased availability of accurate, high-quality, and high-resolution surface-water data. The remotely sensed data provide topographic information and data integration capabilities needed for meeting current and future human and environmental needs.

Near-field Oblique Remote Sensing of Stream Water-surface Elevation, Slope, and Surface Velocity

NASA Astrophysics Data System (ADS)

Minear, J. T.; Kinzel, P. J.; Nelson, J. M.; McDonald, R.; Wright, S. A.

2014-12-01

A major challenge for estimating discharges during flood events or in steep channels is the difficulty and hazard inherent in obtaining in-stream measurements. One possible solution is to use near-field remote sensing to obtain simultaneous water-surface elevations, slope, and surface velocities. In this test case, we utilized Terrestrial Laser Scanning (TLS) to remotely measure water-surface elevations and slope in combination with surface velocities estimated from particle image velocimetry (PIV) obtained by video-camera and/or infrared camera. We tested this method at several sites in New Mexico and Colorado using independent validation data consisting of in-channel measurements from survey-grade GPS and Acoustic Doppler Current Profiler (ADCP) instruments. Preliminary results indicate that for relatively turbid or steep streams, TLS collects tens of thousands of water-surface elevations and slopes in minutes, much faster than conventional means and at relatively high precision, at least as good as continuous survey-grade GPS measurements. Estimated surface velocities from this technique are within 15% of measured velocity magnitudes and within 10 degrees from the measured velocity direction (using extrapolation from the shallowest bin of the ADCP measurements). Accurately aligning the PIV results into Cartesian coordinates appears to be one of the main sources of error, primarily due to the sensitivity at these shallow oblique look angles and the low numbers of stationary objects for rectification. Combining remotely-sensed water-surface elevations, slope, and surface velocities produces simultaneous velocity measurements from a large number of locations in the channel and is more spatially extensive than traditional velocity measurements. These factors make this technique useful for improving estimates of flow measurements during flood flows and in steep channels while also decreasing the difficulty and hazard associated with making measurements in these conditions.

Summary of water-surface-elevation data for 116 U.S. Geological Survey lake and reservoir stations in Texas and comparison to data for water year 2006

USGS Publications Warehouse

Asquith, William H.; Vrabel, Joseph; Roussel, Meghan C.

2007-01-01

The U.S. Geological Survey (USGS), in cooperation with numerous Federal, State, municipal, and local agencies, currently (2007) collects data for more than 120 lakes and reservoirs in Texas through a realtime, data-collection network. The National Water Information System that processes and archives water-resources data for the Nation provides a central source for retrieval of real-time as well as historical data. This report provides a brief description of the real-time, data-collection network and graphically summarizes the period-of-record daily mean water-surface elevations for 116 active and discontinued USGS lake and reservoir stations in Texas. The report also graphically depicts selected statistics (minimum, maximum, and mean) of daily mean water-surface-elevation data. The data for water year 2006 are compared to the selected statistics.

Initial characterization of the groundwater system near the Lower Colorado Water Supply Project, Imperial Valley, California

USGS Publications Warehouse

Coes, Alissa L.; Land, Michael; Densmore, Jill N.; Landrum, Michael T.; Beisner, Kimberly R.; Kennedy, Jeffrey R.; Macy, Jamie P.; Tillman, Fred D.

2015-01-01

During and after lining the All-American Canal (2007–11), groundwater elevations in the Lower Colorado Water Supply Project area declined, while total dissolved solids concentrations remained relatively constant. The total dissolved solids concentrations in well LCWSP-2 ranged from 650 to 800 milligrams per liter during this study. Depth-specific water-quality and isotope sampling at well LCWSP-2 indicated the groundwater pumped from the deeper part of the screened interval (240–280 feet below land surface) contained a greater proportion of historical groundwater than the groundwater pumped from the shallower part of the screened interval (350–385 feet below land surface). Age-tracer data at well LCWSP-2 indicated that all depths of the screened interval had received recent recharge from seepage of Colorado River water from the All-American Canal.

Worlddem - a Novel Global Foundation Layer

NASA Astrophysics Data System (ADS)

Riegler, G.; Hennig, S. D.; Weber, M.

2015-03-01

Airbus Defence and Space's WorldDEM™ provides a global Digital Elevation Model of unprecedented quality, accuracy, and coverage. The product will feature a vertical accuracy of 2m (relative) and better than 6m (absolute) in a 12m x 12m raster. The accuracy will surpass that of any global satellite-based elevation model available. WorldDEM is a game-changing disruptive technology and will define a new standard in global elevation models. The German radar satellites TerraSAR-X and TanDEM-X form a high-precision radar interferometer in space and acquire the data basis for the WorldDEM. This mission is performed jointly with the German Aerospace Center (DLR). Airbus DS refines the Digital Surface Model (e.g. editing of acquisition, processing artefacts and water surfaces) or generates a Digital Terrain Model. Three product levels are offered: WorldDEMcore (output of the processing, no editing is applied), WorldDEM™ (guarantees a void-free terrain description and hydrological consistency) and WorldDEM DTM (represents bare Earth elevation). Precise elevation data is the initial foundation of any accurate geospatial product, particularly when the integration of multi-source imagery and data is performed based upon it. Fused data provides for improved reliability, increased confidence and reduced ambiguity. This paper will present the current status of product development activities including methodologies and tool to generate these, like terrain and water bodies editing and DTM generation. In addition, the studies on verification & validation of the WorldDEM products will be presented.

Verification and transfer of thermal pollution model. Volume 5: Verification of 2-dimensional numerical model

NASA Technical Reports Server (NTRS)

Lee, S. S.; Sengupta, S.; Nwadike, E. V.

1982-01-01

The six-volume report: describes the theory of a three dimensional (3-D) mathematical thermal discharge model and a related one dimensional (1-D) model, includes model verification at two sites, and provides a separate user's manual for each model. The 3-D model has two forms: free surface and rigid lid. The former, verified at Anclote Anchorate (FL), allows a free air/water interface and is suited for significant surface wave heights compared to mean water depth; e.g., estuaries and coastal regions. The latter, verified at Lake Keowee (SC), is suited for small surface wave heights compared to depth (e.g., natural or man-made inland lakes) because surface elevation has been removed as a parameter. These models allow computation of time dependent velocity and temperature fields for given initial conditions and time-varying boundary conditions.

An Investigation into Groundwater Recharge Dynamics and Hydrologic Connectivity in an Alpine/Subalpine Mountainous Headwater Catchment, Colorado, USA

NASA Astrophysics Data System (ADS)

Dailey, K. R.; Hughes, H.; Williams, M. W.

2015-12-01

Geochemical surface and groundwater data were used to examine groundwater recharge dynamics and hydrologic connectivity in the dominantly subalpine Como Creek headwater catchment within the Boulder Creek Watershed in the Colorado Front Range. Streamwater chemistry along an elevational gradient of Como Creek showed strong responses to variations in precipitation inputs spanning 2011-2014. Elevation effects on δ18O were apparent, with more depleted values indicative of snowmelt influence observed at the higher elevation sites. Results from one-way ANOVA indicated that the highest elevation stream site, situated right below treeline, was significantly different from the lower three sites with regards to DOC, δ18O, and Ca2+ (p < 0.05) over May-October 2011-2014. Additionally, the second highest site in elevation was found to be significantly different from all other sites with respect to Ca2+ concentrations. Soil moisture sensor and geochemical data from soil tension lysimeters co-located with subalpine groundwater wells revealed a disconnect between soil and surface water chemistry during snowmelt and that of deeper, underlying groundwater. The initial results of this study provide insight on where groundwater recharge and discharge may be occurring in the catchment and help us to evaluate the large September 2013 rain event in the Colorado Front Range, a once in a 1000 year event. Water isotopes were enriched, Ca2+ decreased, and DOC was enriched, showing that new event water had flowed through near-surface soils but not deeper, recharging groundwater, with all values returning to normal within six months. The event was also observable compared to a long-term geochemical and stream stage record at the stream site near the catchment outlet, with the most enriched δ18O value on record of -13.41‰ corresponding to the flood. Remaining questions concerning groundwater dynamics in the catchment include constraining the tradeoffs between forest ET, groundwater recharge, and streamflow under a warming climate in order to forecast future water yield from the catchment. Further research quantifying where and when groundwater is recharging in the catchment will be conducted to determine how hydrological resilience of the catchment will change under varying climatic conditions.

Bathymetric Surveys of Lake Arthur and Raccoon Lake, Pennsylvania, June 2007

USGS Publications Warehouse

Hittle, Clinton D.; Ruby, A. Thomas

2008-01-01

In spring of 2007, bathymetric surveys of two Pennsylvania State Park lakes were performed to collect accurate data sets of lake-bed elevations and to develop methods and techniques to conduct similar surveys across the state. The lake-bed elevations and associated geographical position data can be merged with land-surface elevations acquired through Light Detection and Ranging (LIDAR) techniques. Lake Arthur in Butler County and Raccoon Lake in Beaver County were selected for this initial data-collection activity. In order to establish accurate water-surface elevations during the surveys, benchmarks referenced to NAVD 88 were established on land at each lake by use of differential global positioning system (DGPS) surveys. Bathymetric data were collected using a single beam, 210 kilohertz (kHz) echo sounder and were coupled with the DGPS position data utilizing a computer software package. Transects of depth data were acquired at predetermined intervals on each lake, and the shoreline was delineated using a laser range finder and compass module. Final X, Y, Z coordinates of the geographic positions and lake-bed elevations were referenced to NAD 83 and NAVD 88 and are available to create bathymetric maps of the lakes.

23 CFR 650.117 - Content of design studies.

Code of Federal Regulations, 2013 CFR

2013-04-01

... BRIDGES, STRUCTURES, AND HYDRAULICS Location and Hydraulic Design of Encroachments on Flood Plains § 650... probability of exceedance and, at appropriate locations, the water surface elevations associated with the overtopping flood or the flood of § 650.115(a)(1)(ii), and (2) The magnitude and water surface elevation of...

23 CFR 650.117 - Content of design studies.

Code of Federal Regulations, 2014 CFR

2014-04-01

... BRIDGES, STRUCTURES, AND HYDRAULICS Location and Hydraulic Design of Encroachments on Flood Plains § 650... probability of exceedance and, at appropriate locations, the water surface elevations associated with the overtopping flood or the flood of § 650.115(a)(1)(ii), and (2) The magnitude and water surface elevation of...

23 CFR 650.117 - Content of design studies.

Code of Federal Regulations, 2012 CFR

2012-04-01

... BRIDGES, STRUCTURES, AND HYDRAULICS Location and Hydraulic Design of Encroachments on Flood Plains § 650... probability of exceedance and, at appropriate locations, the water surface elevations associated with the overtopping flood or the flood of § 650.115(a)(1)(ii), and (2) The magnitude and water surface elevation of...

23 CFR 650.117 - Content of design studies.

Code of Federal Regulations, 2011 CFR

2011-04-01

... BRIDGES, STRUCTURES, AND HYDRAULICS Location and Hydraulic Design of Encroachments on Flood Plains § 650... probability of exceedance and, at appropriate locations, the water surface elevations associated with the overtopping flood or the flood of § 650.115(a)(1)(ii), and (2) The magnitude and water surface elevation of...

23 CFR 650.117 - Content of design studies.

Code of Federal Regulations, 2010 CFR

2010-04-01

... BRIDGES, STRUCTURES, AND HYDRAULICS Location and Hydraulic Design of Encroachments on Flood Plains § 650... probability of exceedance and, at appropriate locations, the water surface elevations associated with the overtopping flood or the flood of § 650.115(a)(1)(ii), and (2) The magnitude and water surface elevation of...

Building Daily 30-meter Spatial Resolution Maps of Surface Water Bodies from MODIS Data Using a Novel Technique for Transferring Information Across Space and Time

NASA Astrophysics Data System (ADS)

Khandelwal, A.; Karpatne, A.; Kumar, V.

2017-12-01

In this paper, we present novel methods for producing surface water maps at 30 meter spatial resolution at a daily temporal resolution. These new methods will make use of the MODIS spectral data from Terra (available daily since 2000) to produce daily maps at 250 meter and 500 meter resolution, and then refine them using the relative elevation ordering of pixels at 30 meter resolution. The key component of these methods is the use of elevation structure (relative elevation ordering) of a water body. Elevation structure is not explicitly available at desired resolution for most water bodies in the world and hence it will be estimated using our previous work that uses the history of imperfect labels. In this paper, we will present a new technique that uses elevation structure (unlike existing pixel based methods) to enforce temporal consistency in surface water extents (lake area on nearby dates is likely to be very similar). This will greatly improve the quality of the MODIS scale land/water labels since daily MODIS data can have a large amount of missing (or poor quality) data due to clouds and other factors. The quality of these maps will be further improved using elevation based resolution refinement approach that will make use of elevation structure estimated at Landsat scale. With the assumption that elevation structure does not change over time, it provides a very effective way to transfer information between datasets even when they are not observed concurrently. In this work, we will derive elevation structure at Landsat scale from monthly water extent maps spanning 1984-2015, publicly available through a joint effort of Google Earth Engine and the European Commission's Joint Research Centre (JRC). This elevation structure will then be used to refine spatial resolution of Modis scale maps from 2000 onwards. We will present the analysis of these methods on a large and diverse set of water bodies across the world.

Water Resources Data, Florida, Water Year 2003, Volume 1B: Northeast Florida Ground Water

USGS Publications Warehouse

George, H.G.; Nazarian, A.P.; Dickerson, S.M.

2004-01-01

Water resources data for the 2003 water year in Florida consist of continuous or daily discharge for 385 streams, periodic discharge for 13 streams, continuous or daily stage for 255 streams, periodic stage for 13 streams, peak stage and discharge for 36 streams; continuous or daily elevations for 13 lakes, periodic elevations for 46 lakes; continuous ground-water levels for 441 wells, periodic ground-water levels for 1,227 wells; quality-of-water data for 133 surface-water sites and 308 wells. The data for northeast Florida include continuous or daily discharge for 138 streams, periodic discharge for 3 streams, continuous or daily stage for 61 streams, periodic stage for 0 streams; peak stage and discharge for 0 streams; continuous or daily elevations for 9 lakes, periodic elevations for 20 lakes; continuous ground water levels for 73 wells, periodic groundwater levels for 543 wells; quality-of-water data for 43 surface-water sites and 115 wells. These data represent the National Water Data System records collected by the U.S. Geological Survey and cooperating local, State and Federal agencies in Florida.

Interpolations of groundwater table elevation in dissected uplands.

PubMed

Chung, Jae-won; Rogers, J David

2012-01-01

The variable elevation of the groundwater table in the St. Louis area was estimated using multiple linear regression (MLR), ordinary kriging, and cokriging as part of a regional program seeking to assess liquefaction potential. Surface water features were used to determine the minimum water table for MLR and supplement the principal variables for ordinary kriging and cokriging. By evaluating the known depth to the water and the minimum water table elevation, the MLR analysis approximates the groundwater elevation for a contiguous hydrologic system. Ordinary kriging and cokriging estimate values in unsampled areas by calculating the spatial relationships between the unsampled and sampled locations. In this study, ordinary kriging did not incorporate topographic variations as an independent variable, while cokriging included topography as a supporting covariable. Cross validation suggests that cokriging provides a more reliable estimate at known data points with less uncertainty than the other methods. Profiles extending through the dissected uplands terrain suggest that: (1) the groundwater table generated by MLR mimics the ground surface and elicits a exaggerated interpolation of groundwater elevation; (2) the groundwater table estimated by ordinary kriging tends to ignore local topography and exhibits oversmoothing of the actual undulations in the water table; and (3) cokriging appears to give the realistic water surface, which rises and falls in proportion to the overlying topography. The authors concluded that cokriging provided the most realistic estimate of the groundwater surface, which is the key variable in assessing soil liquefaction potential in unconsolidated sediments. © 2011, The Author(s). Ground Water © 2011, National Ground Water Association.

Two-dimensional streamflow simulations of the Jordan River, Midvale and West Jordan, Utah

USGS Publications Warehouse

Kenney, Terry A.; Freeman, Michael L.

2011-01-01

The Jordan River in Midvale and West Jordan, Utah, flows adjacent to two U.S. Environmental Protection Agency Superfund sites: Midvale Slag and Sharon Steel. At both sites, geotechnical caps extend to the east bank of the river. The final remediation tasks for these sites included the replacement of a historic sheet-pile dam and the stabilization of the river banks adjacent to the Superfund sites. To assist with these tasks, two hydraulic modeling codes contained in the U.S. Geological Survey (USGS) Multi-Dimensional Surface-Water Modeling System (MD_SWMS), System for Transport and River Modeling (SToRM) and Flow and Sediment Transport and Morphological Evolution of Channels (FaSTMECH), were used to provide predicted water-surface elevations, velocities, and boundary shear-stress values throughout the study reach of the Jordan River. A SToRM model of a 0.7 mile subreach containing the sheet-pile dam was used to compare water-surface elevations and velocities associated with the sheet-pile dam and a proposed replacement structure. Maps showing water-surface elevation and velocity differences computed from simulations of the historic sheet-pile dam and the proposed replacement structure topographies for streamflows of 500 and 1,000 cubic feet per second (ft3/s) were created. These difference maps indicated that the velocities associated with the proposed replacement structure topographies were less than or equal to those associated with the historic sheet-pile dam. Similarly, water-surface elevations associated with the proposed replacement structure topographies were all either greater than or equal to water-surface elevations associated with the sheet-pile dam. A FaSTMECH model was developed for the 2.5-mile study reach to aid engineers in bank stabilization designs. Predicted water-surface elevations, velocities and shear-stress values were mapped on an aerial photograph of the study reach to place these parameters in a spatial context. Profile plots of predicted cross-stream average water-surface elevations and cross-stream maximum and average velocities showed how these parameters change along the study reach for two simulated discharges of 1,040 ft3/s and 2,790 ft3/s. The profile plots for the simulated streamflow of 1,040 ft3/s show that the highest velocities are associated with the constructed sheet-pile replacement structure. Results for the simulated streamflow of 2,790 ft3/s indicate that the geometry of the 7800 South Bridge causes more backwater and higher velocities than the constructed sheet-pile replacement structure.

Hydrologic and Hydraulic Analyses of Selected Streams in Lorain County, Ohio, 2003

USGS Publications Warehouse

Jackson, K. Scott; Ostheimer, Chad J.; Whitehead, Matthew T.

2003-01-01

Hydrologic and hydraulic analyses were done for selected reaches of nine streams in Lorain County Ohio. To assess the alternatives for flood-damage mitigation, the Lorain County Engineer and the U.S. Geological Survey (USGS) initiated a cooperative study to investigate aspects of the hydrology and hydraulics of the nine streams. Historical streamflow data and regional regression equations were used to estimate instantaneous peak discharges for floods having recurrence intervals of 2, 5, 10, 25, 50, and 100 years. Explanatory variables used in the regression equations were drainage area, main-channel slope, and storage area. Drainage areas of the nine stream reaches studied ranged from 1.80 to 19.3 square miles. The step-backwater model HEC-RAS was used to determine water-surface-elevation profiles for the 10-year-recurrence-interval (10-year) flood along a selected reach of each stream. The water-surface pro-file information was used then to generate digital mapping of flood-plain boundaries. The analyses indicate that at the 10-year flood elevation, road overflow results at numerous hydraulic structures along the nine streams.

Water-surface elevation and discharge measurement data for the Red River of the North and its tributaries near Fargo, North Dakota, water years 2014–15

USGS Publications Warehouse

Damschen, William C.; Galloway, Joel M.

2016-08-25

The U.S. Geological Survey, in cooperation with the Fargo Diversion Board of Authority, collected water-surface elevations during a range of discharges needed for calibration of hydrologic and hydraulic models for specific reaches of interest in water years 2014–15. These water-surface elevation and discharge measurement data were collected for design planning of diversion structures on the Red River of the North and Wild Rice River and the aqueduct/diversion structures on the Sheyenne and Maple Rivers. The Red River of the North and Sheyenne River reaches were surveyed six times, and discharges ranged from 276 to 6,540 cubic feet per second and from 166 to 2,040 cubic feet per second, respectively. The Wild Rice River reach also was surveyed six times during 2014 and 2015, and discharges ranged from 13 to 1,550 cubic feet per second. The Maple River reach was surveyed four times, and discharges ranged from 16.4 to 633 cubic feet per second. Water-surface elevation differences from upstream to downstream in the reaches ranged from 0.33 feet in the Red River of the North reach to 9.4 feet in the Maple River reach.

Tidally-driven Surface Flow in a Georgia Estuarine Saltmarsh

NASA Astrophysics Data System (ADS)

Young, D.; Bruder, B. L.; Haas, K. A.; Webster, D. R.

2016-02-01

Estuarine saltmarshes are diverse, valuable, and productive ecosystems. Vegetation dampens wave and current energy, thereby allowing the estuaries to serve as a nursery habitat for shellfish and fish species. Tidally-driven flow transports nutrients into and out of the estuary, nourishing inshore and offshore vegetation and animals. The effects of vegetation on the marsh hydrodynamics and on the estuary creek and channel flow are, unfortunately, poorly understood, and the knowledge that does exist primarily originates from modeling studies. Field studies addressing marsh surface flows are limited due to the difficulty of accurately measuring the water surface elevation and acquiring concurrent velocity measurements in the dense marsh vegetation. This study partially bridges the gap between the model observations of marsh flow driven by water surface elevation gradients and flume studies of flow through vegetation. Three current meters and three pressure transducers were deployed for three days along a transect perpendicular to the main channel (Little Ogeechee River) in a saltmarsh adjacent to Rose Dhu Island (Savannah, Georgia, USA). The pressure transducer locations were surveyed daily with static GPS yielding highly accurate water surface elevation data. During flood and ebb tide, water surface elevation differences between the marsh and Little Ogeechee River were observed up to 15 cm and pressure gradients were observed up to 0.0017 m of water surface elevation drop per m of linear distance. The resulting channel-to-saltmarsh pressure gradients substantially affected tidal currents at all current meters. At one current meter, the velocity was nearly perpendicular to the Little Ogeechee River bank. The velocity at this location was effectively modeled as a balance between the pressure gradient and marsh vegetation-induced drag force using the Darcy-Weisbach/Lindner's equations developed for flow-through-vegetation analysis in open channel flow.

Simulation of Water-Surface Elevations and Velocity Distributions at the U.S. Highway 13 Bridge over the Tar River at Greenville, North Carolina, Using One- and Two-Dimensional Steady-State Hydraulic Models

USGS Publications Warehouse

Wagner, Chad R.

2007-01-01

The use of one-dimensional hydraulic models currently is the standard method for estimating velocity fields through a bridge opening for scour computations and habitat assessment. Flood-flow contraction through bridge openings, however, is hydrodynamically two dimensional and often three dimensional. Although there is awareness of the utility of two-dimensional models to predict the complex hydraulic conditions at bridge structures, little guidance is available to indicate whether a one- or two-dimensional model will accurately estimate the hydraulic conditions at a bridge site. The U.S. Geological Survey, in cooperation with the North Carolina Department of Transportation, initiated a study in 2004 to compare one- and two-dimensional model results with field measurements at complex riverine and tidal bridges in North Carolina to evaluate the ability of each model to represent field conditions. The field data consisted of discharge and depth-averaged velocity profiles measured with an acoustic Doppler current profiler and surveyed water-surface profiles for two high-flow conditions. For the initial study site (U.S. Highway 13 over the Tar River at Greenville, North Carolina), the water-surface elevations and velocity distributions simulated by the one- and two-dimensional models showed appreciable disparity in the highly sinuous reach upstream from the U.S. Highway 13 bridge. Based on the available data from U.S. Geological Survey streamgaging stations and acoustic Doppler current profiler velocity data, the two-dimensional model more accurately simulated the water-surface elevations and the velocity distributions in the study reach, and contracted-flow magnitudes and direction through the bridge opening. To further compare the results of the one- and two-dimensional models, estimated hydraulic parameters (flow depths, velocities, attack angles, blocked flow width) for measured high-flow conditions were used to predict scour depths at the U.S. Highway 13 bridge by using established methods. Comparisons of pier-scour estimates from both models indicated that the scour estimates from the two-dimensional model were as much as twice the depth of the estimates from the one-dimensional model. These results can be attributed to higher approach velocities and the appreciable flow angles at the piers simulated by the two-dimensional model and verified in the field. Computed flood-frequency estimates of the 10-, 50-, 100-, and 500-year return-period floods on the Tar River at Greenville were also simulated with both the one- and two-dimensional models. The simulated water-surface profiles and velocity fields of the various return-period floods were used to compare the modeling approaches and provide information on what return-period discharges would result in road over-topping and(or) pressure flow. This information is essential in the design of new and replacement structures. The ability to accurately simulate water-surface elevations and velocity magnitudes and distributions at bridge crossings is essential in assuring that bridge plans balance public safety with the most cost-effective design. By compiling pertinent bridge-site characteristics and relating them to the results of several model-comparison studies, the framework for developing guidelines for selecting the most appropriate model for a given bridge site can be accomplished.

Storage Capacity and Water Quality of Lake Ngardok, Babeldaob Island, Republic of Palau, 1996-98

USGS Publications Warehouse

Yeung, Chiu Wang; Wong, Michael F.

1999-01-01

A bathymetric survey conducted during March and April, 1996, determined the total storage capacity Lake Ngardok to be between 90 and 168 acre-feet. Elevation-surface area and elevation-capacity curves summarizing the current relations among elevation, surface area, and storage capacity were created from the bathymetric map. Rainfall and lake-elevation data collected from April 1996 to March 1998 indicated that lake levels correlated to rainfall values with lake elevation rising rapidly in response to heavy rainfall and then returning to normal levels within a few days. Mean lake elevation for the 22 month period of data was 59.5 feet which gives a mean storage capacity of 107 acre-feet and a mean surface area of 24.1 acre. A floating mat of reeds, which covered 58 percent of the lake surface area at the time of the bathymetric survey, makes true storage capacity difficult to estimate. Water-quality sampling during April 1996 and November 1997 indicated that no U.S. Environmental Protection Agency primary drinking-water standards were violated for analyzed organic and inorganic compounds and radionuclides. With suitable biological treatment, the lake water could be used for drinking-water purposes. Temperature and dissolved oxygen measurements indicated that Lake Ngardok is stratified. Given that air temperature on Palau exhibits little seasonal variation, it is likely that this pattern of stratification is persistent. As a result, complete mixing of the lake is probably rare. Near anaerobic conditions exist at the lake bottom. Low dissolved oxygen (3.2 milligrams per liter) measured at the outflow indicated that water flowing past the outflow was from the deep oxygen-depleted depths of the lake.

Algae metabolism and organic carbon in sediments determining arsenic mobilisation in ground- and surface water. A field study in Doñana National Park, Spain.

PubMed

Kohfahl, Claus; Navarro, Daniel Sánchez-Rodas; Mendoza, Jorge Armando; Vadillo, Iñaki; Giménez-Forcada, Elena

2016-02-15

A study has been performed to explore the origin, spatiotemporal behaviour and mobilisation mechanism of the elevated arsenic (As) concentrations found in ground water and drinking ponds of the Doñana National Park, Southern Spain. At a larger scale, 13 piezometers and surface water samples of about 50 artificial drinking ponds and freshwater lagoons throughout the National Park were collected and analysed for major ions, metals and trace elements. At a smaller scale, 5 locations were equipped with piezometers and groundwater was sampled up to 4 times for ambient parameters, major ions, metals, trace elements and iron (Fe) speciation. As was analysed for inorganic and organic speciation. Undisturbed sediment samples were analysed for physical parameters, mineralogy, geochemistry as well as As species. Sediment analyses yielded total As between 0.1 and 18 mg/kg and are not correlated with As concentration in water. Results of the surface- and groundwater sampling revealed elevated concentration of As up to 302 μg/L within a restricted area of the National Park. Results of groundwater sampling reveals strong correlation of As with Fe(2+) pointing to As mobilisation due to reductive dissolution of hydroferric oxides (HFO) in areas of locally elevated amounts of organic matter within the sediments. High As concentrations in surface water ponds are correlated with elevated alkalinity and pH attributed to algae metabolism, leading to As desorption from HFO. The algae metabolism is responsible for the presence of methylated arsenic species in surface water, in contrast to ground water in which only inorganic As species was found. Temporal variations in surface water and groundwater are also related to changes in pH and alkalinity as a result of enhanced algae metabolism in surface water or related to changes in the redox level in the case of groundwater. Copyright © 2015 Elsevier B.V. All rights reserved.

Water Resources Data, Florida, Water Year 2003 Volume 2B: South Florida Ground Water

USGS Publications Warehouse

Prinos, S.; Irvin, R.; Byrne, M.

2004-01-01

Water resources data for 2003 water year in Florida consists of continuous or daily discharge for 385 streams, periodic discharge for 13 streams, continuous or daily stage for 255 streams, periodic stage for 13 stream, peak discharge for 36 streams, and peak stage for 36 streams, continuous or daily elevations for 13 lakes, periodic elevations for 46 lakes, continuous ground-water levels for 441 wells, periodic ground-water levels for 1227 wells, quality of water data for 133 surface-water sites, and 308 wells. The data for South Florida included continuous or daily discharge for 72 streams, continuous or daily stage for 50 streams, no peak stage discharge for streams, 1 continuous elevation for lake, continuous ground-water levels for 237 wells, periodic ground-water levels for 248 wells, water quality for 25 surface-water sites, and 161 wells. These data represent the National Water Data System records collected by the U.S. Geological Survey and cooperation with local, state, and federal agencies in Florida.

Multi-temporal AirSWOT elevations on the Willamette river: error characterization and algorithm testing

NASA Astrophysics Data System (ADS)

Tuozzolo, S.; Frasson, R. P. M.; Durand, M. T.

2017-12-01

We analyze a multi-temporal dataset of in-situ and airborne water surface measurements from the March 2015 AirSWOT field campaign on the Willamette River in Western Oregon, which included six days of AirSWOT flights over a 75km stretch of the river. We examine systematic errors associated with dark water and layover effects in the AirSWOT dataset, and test the efficacies of different filtering and spatial averaging techniques at reconstructing the water surface profile. Finally, we generate a spatially-averaged time-series of water surface elevation and water surface slope. These AirSWOT-derived reach-averaged values are ingested in a prospective SWOT discharge algorithm to assess its performance on SWOT-like data collected from a borderline SWOT-measurable river (mean width = 90m).

Geogenic fluoride and arsenic contamination in the groundwater environments in Tanzania

NASA Astrophysics Data System (ADS)

Bhattacharya, Prosun; Lesafi, Fina; Filemon, Regina; Ligate, Fanuel; Ijumulana, Julian; Mtalo, Felix

2016-04-01

Adequate, safe and accessible drinking water is an important aspect to human health worldwide. Understanding this importance, the Tanzanian Government has initiated a number of programmes to ensure access to high quality water by the citizens. However, elevated concentration of geochemical pollutants in many drinking water sources pose a serious challenge to water suppliers and users in the country. Fluoride is a widespread drinking water contaminant of geogenic origin occuring in both surface- and groundwater around volcanic mountains and many parts within the East African Rift Valley in regions including Arusha (10 mg/L), Shinyanga (2.9 mg/L) and Singida (1.8 mg/L). An estimated 90% of the population living along the Rift Valley region are affected by dental or skeletal fluorosis and bone crippling because of long term exposure to very high levels of fluoride in drinking water sources. In the mining areas within Lake Victoria basin, groundwater wit elevated concentrations of arsenic has been discovered over an extended area. Most of these geochemical and naturally occurring drinking water pollutants are patchy with uncertainities in their spatial and temporal distribution patterns. The adverse health effects of skin disorder and cancer due to an elevated As concentration are reported from the North Mara gold and Geita mining areas in the Lake Victoria basin. About 30% of the water sources used for drinking in Tanzania exceed the WHO guideline values of fluoride (1.5 mg/L) and arsenic (10 μg/L). There is a scarcity of baseline information on the water quality data especially on geogenic contaminants in the groundwater and surface water as potable sources. This information is crucial in exploring sources of safe drinking water aquifers, associated human health risks of fluoride and arsenic pollution. using Laboratory based studies during the past two decades have shown promising results on the removal of fluoride and arsenic using locally available adsorbent materials such as pumice, bauxite, ferralsols and bone char. Developing innovative technologies, pilot-scale implementation and scaling-up water purification based on the locally available adsorbents is thus necessary to safeguard the public health for communities exposed to high levels of fluoride and arsenic in drinking water.

Land subsidence and recovery in the Albuquerque Basin, New Mexico, 1993–2014

USGS Publications Warehouse

Driscoll, Jessica M.; Brandt, Justin T.

2017-08-14

The Albuquerque Bernalillo County Water Utility Authority (ABCWUA) drinking water supply was almost exclusively sourced from groundwater from within the Albuquerque Basin before 2008. In 2008, the San Juan-Chama Drinking Water Project (SJCDWP) provided surface-water resources to augment the groundwater supply, allowing for a reduction in groundwater pumping in the Albuquerque Basin. In 2013, the U.S. Geological Survey, in cooperation with the ABCWUA, began a study to measure and compare aquifer-system and land-surface elevation change before and after the SJCDWP in 2008. Three methods of data collection with different temporal and spatial resolutions were used for this study: (1) aquifer-system compaction data collected continuously at a single extensometer from 1994 to 2013; (2) land-surface elevation change from Global Positioning System (GPS) surveys of a network of monuments collected in 1994–95, 2005, and 2014; and (3) spatially distributed Interferometric Synthetic Aperture Radar (InSAR) satellite data from 1993 to 2010. Collection of extensometer data allows for direct and continuous measurement of aquifer-system compaction at the extensometer location. The GPS surveys of a network of monuments allow for periodic measurements of land-surface elevation change at monument locations. Interferograms are limited in time by lifespan of the satellite, orbital pattern, and data quality but allow for measurement of gridded land-surface elevation change over the study area. Each of these methods was employed to provide a better understanding of aquifer-system compaction and land-surface elevation change for the Albuquerque Basin.Results do not show large magnitudes of subsidence in the Albuquerque Basin. High temporal-resolution but low spatial-resolution data measurements of aquifer-system compaction at the Albuquerque extensometer show elastic aquifer-system response to recovering groundwater levels. Results from the GPS survey of the network of monuments show inconsistent land-surface elevation changes over the Albuquerque Basin, likely because of the lack of significant change and the complexity of subsurface stratigraphy in addition to the spatial and temporal heterogeneity of groundwater withdrawals over the study period. Results from the InSAR analysis show areas of land-surface elevation increase after 2008, which could be attributed to elastic recovery of the aquifer system. The spatial extent to which elastic recovery of the aquifer system has resulted in recovery of land-surface elevation is limited to the in-situ measurements at the extensometer. Examination of spatially distributed InSAR data relative to limited spatial extent of the complex heterogeneity subsurface stratigraphy may explain some of the heterogeneity of land-surface elevation changes over this study period.

Bathymetry of Lake Manatee, Manatee County, Florida, 2009

USGS Publications Warehouse

Bellino, Jason C.; Pfeiffer, William R.

2010-01-01

Lake Manatee, located in central Manatee County, Florida, is the principal drinking-water source for Manatee and Sarasota Counties. The drainage basin of Lake Manatee encompasses about 120 square miles, and the reservoir covers a surface area of about 1,450 acres at an elevation of 38.8 feet above NAVD 88 or 39.7 feet above NGVD 29. The full pool water-surface elevation is 39.1 feet above NAVD 88 (40.0 feet above NGVD 29), and the estimated minimum usable elevation is 25.1 feet above NAVD 88 (26.0 feet above NGVD 29). The minimum usable elevation is based on the elevation of water intake structures. Manatee County has used the stage/volume relation that was developed from the original survey in the 1960s to estimate the volume of water available for consumption. Concerns about potential changes in storage capacity of the Lake Manatee reservoir, coupled with a recent drought, led to this bathymetry mapping effort.

The dynamic response of Kennicott Glacier, Alaska, USA, to the Hidden Creek Lake outburst flood

USGS Publications Warehouse

Anderson, R. Scott; Walder, J.S.; Anderson, S.P.; Trabant, D.C.; Fountain, A.G.

2005-01-01

Glacier sliding is commonly linked with elevated water pressure at the glacier bed. Ice surface motion during a 3 week period encompassing an outburst of ice-dammed Hidden Creek Lake (HCL) at Kennicott Glacier, Alaska, USA, showed enhanced sliding during the flood. Two stakes, 1.2 km from HCL, revealed increased speed in two episodes, both associated with uplift of the ice surface relative to the trajectory of bed-parallel motion. Uplift of the surface began 12 days before the flood, initially stabilizing at a value of 0.25 m. Two days after lake drainage began, further uplift (reaching 0.4 m) occurred while surface speed peaked at 1.2 m d-1. Maximum surface uplift coincided with peak discharge from HCL, high water level in a down-glacier ice-marginal basin, and low solute concentrations in the Kennicott River. Each of these records is consistent with high subglacial water pressure. We interpret the ice surface motion as arising from sliding up backs of bumps on the bed, which enlarges cavities and produces bed separation. The outburst increased water pressure over a broad region, promoting sliding, inhibiting cavity closure, and blocking drainage of solute-rich water from the distributed system. Pressure drop upon termination of the outburst drained water from and depressurized the distributed system, reducing sliding speeds. Expanded cavities then collapsed with a 1 day time-scale set by the local ice thickness.

Network global navigation satellite system survey to harmonize water-surface elevation data for the Rainy River Basin

USGS Publications Warehouse

Ziegeweid, Jeffrey R.; Silliker, R. Jason; Densmore, Brenda K.; Krahulik, Justin

2016-08-15

Continuously recording water-level streamgages in Rainy Lake and Namakan Reservoir are used to regulate water levels according to rule curves established in 2000 by the International Joint Commission; however, water levels at streamgages were referenced to a variety of vertical datums, confounding efforts to model the flow of water through the system, regulate water levels during periods of high inflow, and evaluate the effectiveness of the rule curves. In October 2014, the U.S. Geological Survey, Natural Resources Canada, International Joint Commission, and National Park Service began a joint field study with the goal of obtaining precise elevations referenced to a uniform vertical datum for all reference marks used to set water levels at streamgages throughout Rainy Lake and Namakan Reservoir. This report was prepared by the U.S. Geological Survey in cooperation with Natural Resources Canada, International Joint Commission, and National Park Service.Three field crews deployed Global Navigation Satellite System receivers statically over 16 reference marks colocated with active and discontinued water-level streamgages throughout Rainy River, Rainy Lake, Namakan Reservoir, and select tributaries of Rainy Lake and Namakan Reservoir. A Global Navigation Satellite System receiver also was deployed statically over a National Geodetic Survey cooperative base network control station for use as a quality-control reference mark. Satellite data were collected simultaneously during a 5-day period and processed independently by the U.S. Geological Survey and Natural Resources Canada to obtain accurate positioning and elevations for the 17 surveyed reference marks. Processed satellite data were used to convert published water levels to elevations above sea level referenced to the Canadian Geodetic Vertical Datum of 2013 in order to compare water-surface elevations referenced to a uniform vertical datum throughout the study area. In this report, an “offset” refers to the correction applied to published data from a particular streamgage to produce elevation data referenced to a specified vertical datum.Offsets were applied to water-level data from surveyed streamgages to further evaluate the accuracy and utility of updated reference mark elevations presented in this report. Daily mean water levels from active streamgages surveyed in this study were converted to water-surface elevations referenced to the Canadian Geodetic Vertical Datum of 2013. Graphical comparisons of water-surface elevations for streamgages in Namakan Reservoir, Rainy Lake, and selected rivers are presented (referencing the Canadian Geodetic Vertical Datum of 2013). Offsets presented in this report can be used in the evaluation of rule curves and in flood damage curves that fully assess the benefits of one regulation approach over another. In addition, offsets may be used to calibrate hydraulic models developed for four narrows that connect lakes of Namakan Reservoir, refine digital elevation models, and support modeling studies designed to assess the effects of rule curves on aquatic vegetation, benthic invertebrates, northern pike, and walleye.

Land Capability Potential Index (LCPI) for the Lower Missouri River Valley

USGS Publications Warehouse

Jacobson, Robert B.; Chojnacki, Kimberly A.; Reuter, Joanna M.

2007-01-01

The Land Capability Potential Index (LCPI) was developed to serve as a relatively coarse-scale index to delineate broad land capability classes in the valley of the Lower Missouri River. The index integrates fundamental factors that determine suitability of land for various uses, and may provide a useful mechanism to guide land-management decisions. The LCPI was constructed from integration of hydrology, hydraulics, land-surface elevations, and soil permeability (or saturated hydraulic conductivity) datasets for an area of the Lower Missouri River, river miles 423–670. The LCPI estimates relative wetness based on intersecting water-surface elevations, interpolated from measurements or calculated from hydraulic models, with a high-resolution land-surface elevation dataset. The potential for wet areas to retain or drain water is assessed using soil-drainage classes that are estimated from saturated hydraulic conductivity of surface soils. Terrain mapping that delineates areas with convex, concave, and flat parts of the landscape provides another means to assess tendency of landscape patches to retain surface water.

Development of wave and surge atlases for the design and protection of coastal bridges in South Louisiana.

DOT National Transportation Integrated Search

2011-05-01

The objectives of this proposed research are to: 1. Develop a 100-year design. a. maximum water surface elevation and associated wave height, b. maximum wave height and associated water elevation atlases for South Louisiana coastal waters. 2. Obtain ...

An assessment of The Effects of Elevation and Aspect on Deposition of Airborne Pollution and Water Quality in an Alpine Critical Zone: San Juan Mountains, Colorado, USA

NASA Astrophysics Data System (ADS)

Price, A.; Giardino, J. R.; Marcantonio, F.

2015-12-01

The alpine critical zone is affected by various inputs, storages, pathways, and outputs. Unfortunately, many of these processes distribute the pollutants beyond the immediate area and into the surrounding biological and anthropogenic communities. Years of mining and improper disposal of the tailings and acid-mine drainage have degraded the quality of surface water within the San Juan Mountains. However, mining may not be the only factor significantly affecting the surface water quality in this high-elevation environment. As a high elevation system, this area is a fragile ecosystem with inputs ranging from local mining to atmospheric transport and deposition. Studies from around the world have shown atmospheric transport and deposition affect high-elevation systems. Thus, a significant question arises: does elevation or aspect affect the volume and rate of atmospheric deposition of pollutants? We assume atmospheric deposition occurs on the slopes in addition to in streams, lakes, and ponds. Deposition on slopes can be transported to nearby surface waters and increase the impact of the atmospheric pollutants along with residence time. Atmospheric deposition data were collected for aluminum, iron, manganese, nitrate, phosphate, and sulfate. Water chemistry data were collected for the same constituents as the atmospheric deposition with the addition of temperature, dissolved oxygen, pH, and specific conductance. Deposition samples were collected on a five-day sampling regime during two summers. Water quality samples were collected in-stream adjacent to the deposition-ample collectors. Collection sites were located on opposite sides of Red Mountain at five equal elevations providing two different aspects. The north side is drained by Red Mountain Creek and the south side is drained by Mineral Creek. Differences in atmospheric deposition and water quality at different elevations and aspects suggest there is a relationship between aspect and elevation on atmospheric pollution deposition. It is suggested that degradation of water quality in the San Juan Mountains is affected by atmospheric deposition along with the damage sustained from local mining activities. These results facilitate a better understanding of this high-elevation critical-zone system.

Use of inexpensive pressure transducers for measuring water levels in wells

USGS Publications Warehouse

Keeland, B.D.; Dowd, J.F.; Hardegree, W.S.

1997-01-01

Frequent measurement of below ground water levels at multiple locations is an important component of many wetland ecosystem studies. These measurements, however, are usually time consuming, labor intensive, and expensive. This paper describes a water-level sensor that is inexpensive and easy to construct. The sensor is placed below the expected low water level in a shallow well and, when connected to a datalogger, uses a pressure transducer to detect groundwater or surface water elevations. Details of pressure transducer theory, sensor construction, calibration, and examples of field installations are presented. Although the transducers must be individually calibrated, the sensors have a linear response to changing water levels (r2 ??? .999). Measurement errors resulting from temperature fluctuations are shown to be about 4 cm over a 35??C temperature range, but are minimal when the sensors are installed in groundwater wells where temperatures are less variable. Greater accuracy may be obtained by incorporating water temperature data into the initial calibration (0.14 cm error over a 35??C temperature range). Examples of the utility of these sensors in studies of groundwater/surface water interactions and the effects of water level fluctuations on tree growth are provided. ?? 1997 Kluwer Academic Publishers.

Complementary effects of surface water and groundwater on soil moisture dynamics in a degraded coastal floodplain forest

NASA Astrophysics Data System (ADS)

Kaplan, D.; Muñoz-Carpena, R.

2011-02-01

SummaryRestoration of degraded floodplain forests requires a robust understanding of surface water, groundwater, and vadose zone hydrology. Soil moisture is of particular importance for seed germination and seedling survival, but is difficult to monitor and often overlooked in wetland restoration studies. This research hypothesizes that the complex effects of surface water and shallow groundwater on the soil moisture dynamics of floodplain wetlands are spatially complementary. To test this hypothesis, 31 long-term (4-year) hydrological time series were collected in the floodplain of the Loxahatchee River (Florida, USA), where watershed modifications have led to reduced freshwater flow, altered hydroperiod and salinity, and a degraded ecosystem. Dynamic factor analysis (DFA), a time series dimension reduction technique, was applied to model temporal and spatial variation in 12 soil moisture time series as linear combinations of common trends (representing shared, but unexplained, variability) and explanatory variables (selected from 19 additional candidate hydrological time series). The resulting dynamic factor models yielded good predictions of observed soil moisture series (overall coefficient of efficiency = 0.90) by identifying surface water elevation, groundwater elevation, and net recharge (cumulative rainfall-cumulative evapotranspiration) as important explanatory variables. Strong and complementary linear relationships were found between floodplain elevation and surface water effects (slope = 0.72, R2 = 0.86, p < 0.001), and between elevation and groundwater effects (slope = -0.71, R2 = 0.71, p = 0.001), while the effect of net recharge was homogenous across the experimental transect (slope = 0.03, R2 = 0.05, p = 0.242). This study provides a quantitative insight into the spatial structure of groundwater and surface water effects on soil moisture that will be useful for refining monitoring plans and developing ecosystem restoration and management scenarios in degraded coastal floodplains.

Gross decontamination experiment report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mason, R.; Kinney, K.; Dettorre, J.

1983-07-01

A Gross Decontamination Experiment was conducted on various levels and surfaces of the TMI - Unit 2 reactor building in March 1982. The polar crane, D-rings, missile shields, refueling canals, refueling bridges, equipment, and elevations 305' and 347'-6'' were flushed with low pressure water. Additionally, floor surfaces on elevation 305' and floor surfaces and major pieces of equipment on elevation 347'-6'' were sprayed with high pressure water. Selective surfaces were decontaminated with a mechanical scrubber and chemicals. Strippable coating was tested and evaluated on equipment and floor surfaces. The effectiveness, efficiency, and safety of several decontamination techniques were established formore » the large, complex decontamination effort. Various decontamination equipment was evaluated and its effectiveness was documented. Decontamination training and procedures were documented and evaluated, as were the support system and organization for the experiment.« less

Subglacial efficiency and storage modified by the temporal pattern of high-elevation meltwater input

NASA Astrophysics Data System (ADS)

Andrews, L. C.; Dow, C. F.; Poinar, K.; Nowicki, S.

2017-12-01

Ice flow in marginal region of the Greenland Ice Sheet dynamically responds to summer melting as surface meltwater is routed through the supraglacial hydrologic system to the bed of the ice sheet via crevasses and moulins. Given the expected increases in surface melt production and extent, and the potential for high elevation surface-to-bed connections, it is imperative to understand how meltwater delivered to the bed from different high-elevation supraglacial storage features affects the evolution of the subglacial hydrologic system and associated ice dynamics. Here, we use the two-dimensional subglacial hydrologic model, GLaDS, which includes distributed and channelized water flow, to test how the subglacial system of an idealized outlet glacier responds to cases of high-elevation firn-aquifer-type and supraglacial-lake-type englacial drainage over the course of 5 years. Model outputs driven by these high elevation drainage types are compared to steady-state model results, where the subglacial system only receives the 1980-2016 mean MERRA-2 runoff via low-elevation moulins. Across all experiments, the subglacial hydrologic system displays inter-annual memory, resulting in multiyear declines in subglacial pressure during the onset of seasonal melting and growth of subglacial channels. The gradual addition of water in firn-aquifer-type drainage scenarios resulted in small increases in subglacial water storage but limited changes in subglacial efficiency and channelization. Rapid, supraglacial-lake-type drainage resulted in short-term local increases in subglacial water pressure and storage, which gave way to spatially extensive decreases in subglacial pressure and downstream channelization. These preliminary results suggest that the character of high-elevation englacial drainage can have a strong, and possibly outsized, control on subglacial efficiency throughout the ablation zone. Therefore, understanding both how high elevation meltwater is stored supraglacially and the probability of crevassing at high elevations will play an important role in how the subglacial system, proglacial discharge and ice motion will respond to future increases in surface melt production and runoff.

Subglacial efficiency and storage modified by the temporal pattern of high-elevation meltwater input

NASA Astrophysics Data System (ADS)

Ackley, S. F.; Maksym, T.; Stammerjohn, S. E.; Gao, Y.; Weissling, B.

2016-12-01

Ice flow in marginal region of the Greenland Ice Sheet dynamically responds to summer melting as surface meltwater is routed through the supraglacial hydrologic system to the bed of the ice sheet via crevasses and moulins. Given the expected increases in surface melt production and extent, and the potential for high elevation surface-to-bed connections, it is imperative to understand how meltwater delivered to the bed from different high-elevation supraglacial storage features affects the evolution of the subglacial hydrologic system and associated ice dynamics. Here, we use the two-dimensional subglacial hydrologic model, GLaDS, which includes distributed and channelized water flow, to test how the subglacial system of an idealized outlet glacier responds to cases of high-elevation firn-aquifer-type and supraglacial-lake-type englacial drainage over the course of 5 years. Model outputs driven by these high elevation drainage types are compared to steady-state model results, where the subglacial system only receives the 1980-2016 mean MERRA-2 runoff via low-elevation moulins. Across all experiments, the subglacial hydrologic system displays inter-annual memory, resulting in multiyear declines in subglacial pressure during the onset of seasonal melting and growth of subglacial channels. The gradual addition of water in firn-aquifer-type drainage scenarios resulted in small increases in subglacial water storage but limited changes in subglacial efficiency and channelization. Rapid, supraglacial-lake-type drainage resulted in short-term local increases in subglacial water pressure and storage, which gave way to spatially extensive decreases in subglacial pressure and downstream channelization. These preliminary results suggest that the character of high-elevation englacial drainage can have a strong, and possibly outsized, control on subglacial efficiency throughout the ablation zone. Therefore, understanding both how high elevation meltwater is stored supraglacially and the probability of crevassing at high elevations will play an important role in how the subglacial system, proglacial discharge and ice motion will respond to future increases in surface melt production and runoff.

The Surface Water and Ocean Topography Satellite Mission - An Assessment of Swath Altimetry Measurements of River Hydrodynamics

NASA Technical Reports Server (NTRS)

Wilson, Matthew D.; Durand, Michael; Alsdorf, Douglas; Chul-Jung, Hahn; Andreadis, Konstantinos M.; Lee, Hyongki

2012-01-01

The Surface Water and Ocean Topography (SWOT) satellite mission, scheduled for launch in 2020 with development commencing in 2015, will provide a step-change improvement in the measurement of terrestrial surface water storage and dynamics. In particular, it will provide the first, routine two-dimensional measurements of water surface elevations, which will allow for the estimation of river and floodplain flows via the water surface slope. In this paper, we characterize the measurements which may be obtained from SWOT and illustrate how they may be used to derive estimates of river discharge. In particular, we show (i) the spatia-temporal sampling scheme of SWOT, (ii) the errors which maybe expected in swath altimetry measurements of the terrestrial surface water, and (iii) the impacts such errors may have on estimates of water surface slope and river discharge, We illustrate this through a "virtual mission" study for a approximately 300 km reach of the central Amazon river, using a hydraulic model to provide water surface elevations according to the SWOT spatia-temporal sampling scheme (orbit with 78 degree inclination, 22 day repeat and 140 km swath width) to which errors were added based on a two-dimension height error spectrum derived from the SWOT design requirements. Water surface elevation measurements for the Amazon mainstem as may be observed by SWOT were thereby obtained. Using these measurements, estimates of river slope and discharge were derived and compared to those which may be obtained without error, and those obtained directly from the hydraulic model. It was found that discharge can be reproduced highly accurately from the water height, without knowledge of the detailed channel bathymetry using a modified Manning's equation, if friction, depth, width and slope are known. Increasing reach length was found to be an effective method to reduce systematic height error in SWOT measurements.

Unmanned aerial vehicle observations of water surface elevation and bathymetry in the cenotes and lagoons of the Yucatan Peninsula, Mexico

NASA Astrophysics Data System (ADS)

Bandini, Filippo; Lopez-Tamayo, Alejandro; Merediz-Alonso, Gonzalo; Olesen, Daniel; Jakobsen, Jakob; Wang, Sheng; Garcia, Monica; Bauer-Gottwein, Peter

2018-04-01

Observations of water surface elevation (WSE) and bathymetry of the lagoons and cenotes of the Yucatán Peninsula (YP) in southeast Mexico are of hydrogeological interest. Observations of WSE (orthometric water height above mean sea level, amsl) are required to inform hydrological models, to estimate hydraulic gradients and groundwater flow directions. Measurements of bathymetry and water depth (elevation of the water surface above the bed of the water body) improve current knowledge on how lagoons and cenotes connect through the complicated submerged cave systems and the diffuse flow in the rock matrix. A novel approach is described that uses unmanned aerial vehicles (UAVs) to monitor WSE and bathymetry of the inland water bodies on the YP. UAV-borne WSE observations were retrieved using a radar and a global navigation satellite system on-board a multi-copter platform. Water depth was measured using a tethered floating sonar controlled by the UAV. This sonar provides depth measurements also in deep and turbid water. Bathymetry (wet-bed elevation amsl) can be computed by subtracting water depth from WSE. Accuracy of the WSE measurements is better than 5-7 cm and accuracy of the water depth measurements is estimated to be 3.8% of the actual water depth. The technology provided accurate measurements of WSE and bathymetry in both wetlands (lagoons) and cenotes. UAV-borne technology is shown to be a more flexible and lower cost alternative to manned aircrafts. UAVs allow monitoring of remote areas located in the jungle of the YP, which are difficult to access by human operators.

PHYSICAL MODELING OF CONTRACTED FLOW.

USGS Publications Warehouse

Lee, Jonathan K.

1987-01-01

Experiments on steady flow over uniform grass roughness through centered single-opening contractions were conducted in the Flood Plain Simulation Facility at the U. S. Geological Survey's Gulf Coast Hydroscience Center near Bay St. Louis, Miss. The experimental series was designed to provide data for calibrating and verifying two-dimensional, vertically averaged surface-water flow models used to simulate flow through openings in highway embankments across inundated flood plains. Water-surface elevations, point velocities, and vertical velocity profiles were obtained at selected locations for design discharges ranging from 50 to 210 cfs. Examples of observed water-surface elevations and velocity magnitudes at basin cross-sections are presented.

Optimization of Malachite Green Removal from Water by TiO₂ Nanoparticles under UV Irradiation.

PubMed

Ma, Yongmei; Ni, Maofei; Li, Siyue

2018-06-13

TiO₂ nanoparticles with surface porosity were prepared by a simple and efficient method and presented for the removal of malachite green (MG), a representative organic pollutant, from aqueous solution. Photocatalytic degradation experiments were systematically conducted to investigate the influence of TiO₂ dosage, pH value, and initial concentrations of MG. The kinetics of the reaction were monitored via UV spectroscopy and the kinetic process can be well predicted by the pseudo first-order model. The rate constants of the reaction kinetics were found to decrease as the initial MG concentration increased; increased via elevated pH value at a certain amount of TiO₂ dosage. The maximum efficiency of photocatalytic degradation was obtained when the TiO₂ dosage, pH value and initial concentrations of MG were 0.6 g/L, 8 and 10 −5 mol/L (M), respectively. Results from this study provide a novel optimization and an efficient strategy for water pollutant treatment.

Flood of April 2007 in Southern Maine

USGS Publications Warehouse

Lombard, Pamela J.

2009-01-01

Up to 8.5 inches of rain fell from April 15 through 18, 2007, in southern Maine. The rain - in combination with up to an inch of water from snowmelt - resulted in extensive flooding. York County, Maine, was declared a presidential disaster area following the event. The U.S. Geological Survey, in cooperation with the Federal Emergency Management Agency (FEMA), determined peak streamflows and recurrence intervals at 24 locations and peak water-surface elevations at 63 sites following the April 2007 flood. Peak streamflows were determined with data from continuous-record streamflow-gaging stations where available and through hydraulic models where station data were not available. The flood resulted in peak streamflows with recurrence intervals greater than 100 years throughout most of York County, and recurrence intervals up to 50 years in Cumberland County. Peak flows for selected recurrence intervals varied from less than 10 percent to greater than 100 percent different than those in the current FEMA flood-insurance studies due to additional data or newer regression equations. Water-surface elevations observed during the April 2007 flood were bracketed by elevation profiles in FEMA flood-insurance studies with the same recurrence intervals as the recurrence intervals bracketing the observed peak streamflows at seven sites, with higher elevation-profile recurrence intervals than streamflow recurrence intervals at six sites, and with lower elevation-profile recurrence intervals than streamflow recurrence intervals at one site. The April 2007 flood resulted in higher peak flows and water-surface elevations than the flood of May 2006 in coastal locations in York County, and lower peak flows and water-surface elevations than the May 2006 flood further from the coast and in Cumberland County. The Mousam River watershed with over 13 dams and reservoirs was severely impacted by both events. Analyses indicate that the April 2007 peak streamflows in the Mousam River watershed occurred despite the fact that up to 287 million ft3 of runoff was stored by 13 dams and reservoirs.

Spatial and Temporal Mapping of Distributed Surface and Groundwater Stable Isotopes Enables New insights into Hydrologic Processes Operating at the Catchment Scale

NASA Astrophysics Data System (ADS)

Cole, A.; Boutt, D. F.

2017-12-01

Isotopic analyses of d18O and d2H of water transiting the hydrologic cycle have allowed hydrologists to better understand the portioning of water between the different components of the water cycle. Isoscapes on a large spatial scale have been created to show isotopic variation in waters as a function of elevation, temperature, distance to coast and precipitation. This has not been done on a 10,000 sq mi area, sub-regional scale or for that matter exhaustively sampled the important components of the terrestrial hydrologic cycle (groundwater, surface water and soil waters). We present the spatial and temporal isotopic results of an ongoing study across Massachusetts, USA, to establish an isotopic baseline for the region. Our current database consists of water samples from 50 precipitation sites, 333 ground water sites and 421 surface water sites. The isotopic signature of d18O and d2H of the samples are measured by a wavelength scanned cavity ring-down spectrometry on un-acidified water samples by a Picarro Cavity Ring Down Spectrometer (L2120-I) analyzer. Our results show that groundwater ranges from -11 to -1 ‰ δ18O across Massachusetts. Wells show a correlation with elevation; at higher elevations groundwater is more depleted in the heavy isotopes than compared with wells located at a lower elevation. Surface, groundwater and precipitation depict a seasonal evaporative enrichment, with waters being lighter during the months and heavier during the summer months. Based on Massachusetts location relative to the coast, there is a large variability in the mean d18O of precipitation with rain being heavy near the coast and lighter with increasing distance from the coast. HYSPLIT trajectory models will be used to determine how source affects isotopic composition. Within Massachusetts the isotopic composition of groundwater in till, glacial fluvial and bedrock aquifers are distinct which indicates the potential for surface and groundwater interaction. Our data also indicates groundwater enrichment in the heavy isotopes. In order to further determine the interrelationship between surface and groundwater we will measure chloride on both surface and groundwater and relate the results. This dataset will become an important tool for water management and water resources.

Effect of water-column pH on sediment-phosphorus release rates in Upper Klamath Lake, Oregon, 2001

USGS Publications Warehouse

Fisher, Lawrence H.; Wood, Tamara M.

2004-01-01

Sediment-phosphorus release rates as a function of pH were determined in laboratory experiments for sediment and water samples collected from Shoalwater Bay in Upper Klamath Lake, Oregon, in 2001. Aerial release rates for a stable sediment/water interface that is representative of the sediment surface area to water column volume ratio (1:3) observed in the lake and volumetric release rates for resuspended sediment events were determined at three different pH values (8.1, 9.2, 10.2). Ambient water column pH (8.1) was maintained by sparging study columns with atmospheric air. Elevation of the water column pH to 9.2 was achieved through the removal of dissolved carbon dioxide by sparging with carbon dioxide-reduced air, partially simulating water chemistry changes that occur during algal photosynthesis. Further elevation of the pH to 10.2 was achieved by the addition of sodium hydroxide, which doubled average alkalinities in the study columns from about 1 to 2 milliequivalents per liter. Upper Klamath Lake sediments collected from the lake bottom and then placed in contact with lake water, either at a stable sediment/water interface or by resuspension, exhibited an initial capacity to take up soluble reactive phosphorus (SRP) from the water column rather than release phosphorus to the water column. At a higher pH this initial uptake of phosphorus is slowed, but not stopped. This initial phase was followed by a reversal in which the sediments began to release SRP back into the water column. The release rate of phosphorus 30 to 40 days after suspension of sediments in the columns was 0.5 mg/L/day (micrograms per liter per day) at pH 8, and 0.9 mg/L/day at pH 10, indicating that the higher pH increased the rate of phosphorus release by a factor of about two. The highest determined rate of release was approximately 10% (percent) of the rate required to explain the annual internal loading to Upper Klamath Lake from the sediments as calculated from a lake-wide mass balance and observed in total phosphorus data collected at individual locations.

Water Resources Data, Florida, Water Year 2003, Volume 3B: Southwest Florida Ground Water

USGS Publications Warehouse

Kane, Richard L.; Fletcher, William L.; Lane, Susan L.

2004-01-01

Water resources data for the 2003 water year in Florida consist of continuous or daily discharges for 385 streams, periodic discharge for 13 streams, continuous daily stage for 255 streams, periodic stage for 13 streams, peak stage for 36 streams and peak discharge for 36 streams, continuous or daily elevations for 13 lakes, periodic elevations for 46 lakes; continuous ground-water levels for 441 wells, periodic ground-water levels for 1,227 wells, and quality-of-water data for 133 surface-water sites and 308 wells. The data for Southwest Florida include records of stage, discharge, and water quality of streams; stage, contents, water quality of lakes and reservoirs, and water levels and water quality of ground-water wells. Volume 3B contains records for continuous ground-water elevations for 128 wells; periodic ground-water elevations at 31 wells; miscellaneous ground-water elevations at 405 wells; and water quality at 32 ground-water sites. These data represent the national Water Data System records collected by the U.S. Geological Survey and cooperating local, state, and federal agencies in Florida.

The Enhancement of Water Ice Content in the Local Area Northeast of Arcadia Planitia: Evidence from Neutron Data from HEND (Mars Odyssey) and Elevation from MOLA (MGS)

NASA Technical Reports Server (NTRS)

Sanin, A. B.; Mitrofanov, I. G.; Kozyrev, A. S.; Litvak, M. L.; Tretyakov, V.; Smith, D. E.; Zuber, M. T.; Boynton, W.; Saunders, R. S.

2003-01-01

The first year of neutron mapping measurements from the Mars Odyssey spacecraft revealed enormous hydrogen-rich regions in the southern and northern hemispheres of the Martian crust that imply significant amounts of near surface water ice. The hydrogen-rich areas of the southern and northern regions appear generally comparable in spatial extent and water ice content. This observation is interesting in light of topography measured by the Mars Orbiter Laser Altimeter (MOLA) on the Mars Global Surveyor (MGS) spacecraft, which shows a significant difference in elevation between northern lowlands and southern highlands that could imply a difference in seasonal CO2 condensation. In this study we correlate the high energy neutron flux observed by HEND (Mars Odyssey) and surface elevation measured by MOLA in order to interpret the seasonal change in epithermal neutron flux in terms near-surface water ice content.

Flood of April and May 2008 in Northern Maine

USGS Publications Warehouse

Lombard, Pamela J.

2010-01-01

Severe flooding occurred in Aroostook and Penobscot Counties in northern Maine between April 28 and May 1, 2008, and was most extreme in the town of Fort Kent. Peak streamflows in northern Aroostook County were the result of a persistent heavy snowpack that caused high streamflows when it quickly melted during the third week of April 2008. Snowmelt was followed by from two to four inches of rainfall over a 2-day period in northern Maine. Peak water-surface elevations resulting from the flood were obtained from 13 continuous-record streamgages and 63 surveyed high-water marks in Aroostook and Penobscot Counties. Peak streamflows were obtained from 20 sites on 15 streams through stage/discharge rating curves or hydraulic flow models. Peak water-surface elevations and streamflows were the highest ever recorded at seven continuous-record streamgages, which had between 25 and 84 years of record in northern Aroostook County. The annual exceedance probability (the percent chance of exceeding the streamflow recorded during the April/May 2008 flood during any given year) at six streamgages in northern Maine was equal to or less than 1 percent. Data from flood-insurance studies published by the Federal Emergency Management Agency were available for five of the locations analyzed for the April/May 2008 flood and were compared to streamflows and observed peak water-surface elevations from the 2008 flood. Water-surface elevations that would be expected given the observed flow as applied to the effective flood insurance studies ranged from between 1 and 4 feet from the water-surface elevations observed during the 2008 flood. Differences were likely the result of up to 30 years of additional data for the calculation of recurrence intervals and the fact that hydraulic models used for the models had not previously been calibrated to a flood of this magnitude.

Use of upscaled elevation and surface roughness data in two-dimensional surface water models

USGS Publications Warehouse

Hughes, J.D.; Decker, J.D.; Langevin, C.D.

2011-01-01

In this paper, we present an approach that uses a combination of cell-block- and cell-face-averaging of high-resolution cell elevation and roughness data to upscale hydraulic parameters and accurately simulate surface water flow in relatively low-resolution numerical models. The method developed allows channelized features that preferentially connect large-scale grid cells at cell interfaces to be represented in models where these features are significantly smaller than the selected grid size. The developed upscaling approach has been implemented in a two-dimensional finite difference model that solves a diffusive wave approximation of the depth-integrated shallow surface water equations using preconditioned Newton–Krylov methods. Computational results are presented to show the effectiveness of the mixed cell-block and cell-face averaging upscaling approach in maintaining model accuracy, reducing model run-times, and how decreased grid resolution affects errors. Application examples demonstrate that sub-grid roughness coefficient variations have a larger effect on simulated error than sub-grid elevation variations.

Effect of surface texture and structure on the development of stable fluvial armors

NASA Astrophysics Data System (ADS)

Bertin, Stephane; Friedrich, Heide

2018-04-01

Stable fluvial armors are found in river systems under conditions of partial sediment transport and limited sediment supply, a common occurrence in nature. Stable armoring is also readily recreated in experimental flumes. Initially, this bed stabilizing phenomenon was examined for different flow discharges and solely related to surface coarsening and bedload transport reduction. The models developed suggest a specific armor composition (i.e., texture) dependent on the parent bed material and formative discharge. Following developments in topographic remote sensing, recent research suggests that armor structure is an important control on bed stability and roughness. In this paper, replicated flume runs during which digital elevation models (DEMs) were collected from both exposed and flooded gravel beds are used to interpret armoring manifestations and to assess their replicability. A range of methodologies was used for the analysis, providing information on (i) surface grain size and orientation, (ii) bed-elevation distributions, (iii) the spatial coherence of the elevations at the grain-scale, (iv) surface slope and aspect, (v) grain imbrication and (vi) the spatial variability in DEM properties. The bed-surface topography was found to be more responsive than bed-material size to changes in flow strength. Our experimental results also provide convincing evidence that gravel-beds' response to water-work during parallel degradation is unique (i.e., replicable) given the formative parameters. Based on this finding, relationships between the armors' properties and formative parameters are proposed, and are supported by adding extensive data from previous research.

River analysis and floodplain modeling using HEC-GeoRAS/RAS, GIS and ArcGIS: a case study for the Salinas River

NASA Astrophysics Data System (ADS)

Mishra, P. K.; Bernini Campos, H. E.

2016-12-01

The lower portion of the Salinas River in Monterey bay, California has a history of flood, lots of study has been made ab out the water quality since the river provides water for the crops around, but is still in need a detailed study about the river behavior and flood analysis. The floods did significant damage, affecting valuable landing farms, residences and businesses in Monterey County. The first step for this study is comprehend and collect the river bathymetry and surroundings and then analyze the discharge and how it is going to change with time. This thesis develops a model about the specific site, recruiting real data from GIS and performing a flow simulation according to flow data provided by USGS, to verify water surface elevation and floodplain. The ArcMap, developed by ESRI, was used along with an extension (HEC-GeoRAS) because it was indeed the most appropriate model to work with the Digital Elevation Model, develop the floodplain and characterizing the land surface accurately in the study site. The HEC-RAS software, developed by US Army Corp of Engineers, was used to compute one-dimension steady flow and two-dimension unsteady flow, providing flow velocity, water surface elevation and profiles, total surface area, head and friction loss and other characteristics, allowing the analysis of the flow. A mean discharge, a mean peak streamflow and a peak discharge were used for the steady flow and a Hydrograph was used for the unsteady flow, both are based on the 1995 flood and discharge history. This study provides important information about water surface elevation and water flow, allowing stakeholders and the government to analyze solutions to avoid damage to the society and landowners.

Surface contamination artificially elevates initial sweat mineral concentrations

USDA-ARS?s Scientific Manuscript database

During exercise in the heat, sweat is initially concentrated in minerals, but serial sweat samples appear more dilute. Possible causes include reduced dermal mineral concentrations or flushing of surface contamination. PURPOSE: To simultaneously sample mineral concentrations in transdermal fluid (T...

Delineation and Characterization of Furnace Brook Watershed in Marshfield, Massachusetts: A Study of Effects upon Conjunctive Water Use within a Watershed

NASA Astrophysics Data System (ADS)

Croll, E. D.; Enright, R.

2012-12-01

An understanding of conjunctive use between surface and ground water is essential to resource management both for sustained public use and watershed conservation practices. The Furnace Brook watershed in Marshfield, Massachusetts supplies a coastal community of 25,132 residents with nearly 50% of the town water supply. As with many other coastal communities, development pressure has increased creating a growing demand for freshwater extraction. It has been observed, however, that portions of the stream and Furnace Pond disappear entirely. This has created a conflict between protection of the designated wetland areas and meeting public pressure for water resources, even within what is traditionally viewed as a humid region. Questions have arisen as to whether the town water extraction is influencing this losing behavior by excessively lowering water-table elevations and potentially endangering the health of the stream. This study set out to initially characterize these behaviors and identify possible influences of anthropogenic and natural sources acting upon the watershed including stream flow obstructions, water extraction, and geologic conditions. The initial characterization was conducted utilizing simple, low-cost and minimally intrusive methods as outlined by Lee and Cherry (1978), Rosenberry and LaBaugh (2008) and others during a six week period. Five monitoring stations were established along a 3.0 mile reach of the basin consisting of mini-piezometers, seepage meters, survey elevation base-lines, and utilizing a Marsh-McBirney flow velocity meter. At each station stream discharge, seepage flux rates and hydraulic gradients were determined to develop trends of stream behavior. This methodology had the benefit of demonstrating the efficacy of an intrinsically low-expense, minimally intrusive initial approach to characterizing interactions between surface and ground water resources. The data was correlated with town pumping information, previous geologic surveys and meteorological data. Early data analysis indicated that the stream behaved in an anomalous manner decreasing in discharge with downstream flow despite normal precipitation inputs. The behavior within this particular watershed appeared to be influenced by four primary factors resulting in the stream "running dry" during the June-August period. These factors included: (1) A losing gradient induced by well pumping (2) Obstructions to stream flow reduced contribution from upper reaches to lower reaches (3) A highly anisotropic layer of lower conductivity material regulated infiltration rates and (4) Evapotranspiration effects are such that during this period the basin is in a deficit situation even without additional losses. Additionally, relationships between well pumping and decreasing discharge, seepage flux loss rates and hydraulic gradients have demonstrated that even within humid region watersheds it cannot be assumed aquifer recharge is sufficient to avoid conflict between surface water protection and ground water utilization. Timing of precipitation events combined with geological governance of aquifer recharge play critical roles in managing the conjunctive use of water resources and cannot be assumed to have a negligible effect, even within relatively humid regions.

A prototype data assimilation framework for generating spatiotemporally continuous SWOT data products

NASA Astrophysics Data System (ADS)

Andreadis, K.; Margulis, S. A.; Li, D.; Lettenmaier, D. P.

2017-12-01

The Surface Water and Ocean Topography (SWOT) satellite will provide critical surface water observations for the hydrologic community. However, production of key SWOT variables, such as river discharge and surface inundation, as well as lake, reservoir, and wetland storage change will be complicated by the discontinuity of the observations in space and time. A methodology that generates products with spatially and temporally continuous fields based on SWOT observables would be highly desirable. Data assimilation provides a mechanism for merging observations from SWOT with model predictions in order to produce estimates of quantities such as river discharge, storage change, and water heights for locations and times when there is no satellite overpass or other constraints (such as layover) render the measurement unusable. We describe here a prototype assimilation system with application to the Upper Mississippi basin, implemented using synthetic SWOT observations. We use a hydrologic model (VIC) coupled with a hydrodynamic model (LISFLOOD-FP) which generates "true" fields of surface water variables. The true fields are then used to generate synthetic SWOT observations using the SWOT Instrument Simulator. We also perform a "first-guess" (or open-loop) simulation with the coupled model using a configuration that contains errors representative of the imperfect knowledge of parameters and input data, including channel topography, bankfull widths and depths, and inflows, to create an ensemble of 20 model trajectories. Subsequently we assimilate the synthetic SWOT observations into the open-loop model results to estimate water surface elevation, discharge, and storage change. Our preliminary results using three data assimilation strategies show that all improve the water surface elevation estimate accuracy by 25% - 35% for a river reach of the upper Mississippi River. Ongoing work is examining whether the improved water surface elevation estimates propagate to improvements in river discharge.

The influence of vegetation on the transport pathways and residence time of surface water on the deltaic islands of Wax Lake Delta, LA

NASA Astrophysics Data System (ADS)

Olliver, E. A.; Edmonds, D. A.; Shaw, J.

2017-12-01

The coastal deltas of the world are vital ecosystems that disproportionately support the world's population and biological productivity. Recent studies indicate vegetation may have significant influence on the development and structure of the deltaic islands composing these deltas. However, there is little convincing data drawn from natural systems. Here we present a 2D numerical modeling study of the interaction of surface water flow and vegetation on Wax lake Delta, LA, USA. We use a seamless digital elevation model (DEM) of the Wax Lake Delta (WLD) as the initial topographic condition. The deltaic island elevation data for the DEM is derived from LiDAR data, while the channel and delta front bathymetry is derived from single and multi-beam data. The upstream boundary conditions are set by discharge data from the USGS gauge located in the Wax Lake Outlet at Calumet, LA and the downstream water level boundary condition comes from tidal data from the NOAA gauge located in the Atchafalaya Delta at Amerada Pass, LA. The deltaic islands in our seamless DEM are populated by two general vegetation communities of different canopy density and height: a subaerial-intermediate community and a subaqueous community. In our study we explore how variations in discharge coming into the delta and extent of the general vegetation communities at different times of the year influence the transport pathways and residence time of surface water on the levees and within the interdistributary wetlands of the deltaic islands. A better understanding of vegetation's influence on these elements of deltaic island development and organization could prove valuable for informing design of wetland restoration projects.

Sustainable land cover and terrain modification to enhance convection and precipitation in the arid region of the United Arab Emirates

NASA Astrophysics Data System (ADS)

Wulfmeyer, V.; Branch, O.; Adebabseh, A.; Temimi, M.

2017-12-01

Irrigated plantations and modified terrain can provide a sustainable means of enhancing convective rainfall in arid regions like the United Arab Emirates, or UAE, and can be used to aid ongoing cloud seeding operations through the geographic-localization of seedable cloud formation. The first method, the planting of vast irrigated plantations of hardy desert shrubs, can lead to wind convergence and vertical mixing through increased roughness and modified radiative balances. When upper-air atmospheric instability is present, these phenomena can initiate convection. The second method, increasing the elevation of moderate-sized mountains, is based on the correlation between elevation and the number of summertime convection initiation events observed in the mountains of the UAE and Oman. This augmentation of existing orographic features should therefore increase the likelihood and geographic range of convection initiation events. High-resolution simulations provide a powerful means of assessing the likely impacts of land surface modifications. Previous convection-permitting simulations have yielded some evidential support for these hypotheses, but higher resolutions down to 1 km provide more detail regarding convective processes and land surface representation. Using seasonal simulations with the WRF-NOAHMP land-atmosphere model at a 2.5 km resolution, we identify frequent zones of convergence and atmospheric instability in the UAE and select interesting cases. Using these results, as well as an agricultural feasibility study, we identify optimal plantation positions within the UAE. We then run realistic plantation scenarios for single case studies at 1 km resolution. Using the same cases, we simulate the impact of augmenting mountain elevations on convective processes, with the augmentation being achieved through GIS-based modification of the terrain data. For both methods, we assess the impacts quantitatively and qualitatively, and assess key processes and dependencies. If we can demonstrate that convective rainfall would be enhanced through feasible agricultural and engineering methods, then land surface-based weather modification deserves serious consideration as a solution for water scarcity and anthropogenic climate change.

River stage influences on uranium transport in a hydrologically dynamic groundwater-surface water transition zone: U TRANSPORT IN A GROUNDWATER-SURFACE WATER TRANSITION ZONE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zachara, John M.; Chen, Xingyuan; Murray, Chris

A tightly spaced well-field within a groundwater uranium (U) plume in the groundwater-surface water transition zone was monitored for a three year period for groundwater elevation and dissolved solutes. The plume discharges to the Columbia River, which displays a dramatic spring stage surge resulting from mountain snowmelt. Groundwater exhibits a low hydrologic gradient and chemical differences with river water. River water intrudes the site in spring. Specific aims were to assess the impacts of river intrusion on dissolved uranium (Uaq), specific conductance (SpC), and other solutes, and to discriminate between transport, geochemical, and source term heterogeneity effects. Time series trendsmore » for Uaq and SpC were complex and displayed large temporal well-to well variability as a result of water table elevation fluctuations, river water intrusion, and changes in groundwater flow directions. The wells were clustered into subsets exhibiting common temporal behaviors resulting from the intrusion dynamics of river water and the location of source terms. Concentration hot spots were observed in groundwater that varied in location with increasing water table elevation. Heuristic reactive transport modeling with PFLOTRAN demonstrated that mobilized U was transported between wells and source terms in complex trajectories, and was diluted as river water entered and exited the groundwater system. While uranium time-series concentration trends varied significantly from year to year as a result of climate-caused differences in the spring hydrograph, common and partly predictable response patterns were observed that were driven by water table elevation, and the extent and duration of the river water intrusion event.« less

Levels at gaging stations

USGS Publications Warehouse

Kenney, Terry A.

2010-01-01

Operational procedures at U.S. Geological Survey gaging stations include periodic leveling checks to ensure that gages are accurately set to the established gage datum. Differential leveling techniques are used to determine elevations for reference marks, reference points, all gages, and the water surface. The techniques presented in this manual provide guidance on instruments and methods that ensure gaging-station levels are run to both a high precision and accuracy. Levels are run at gaging stations whenever differences in gage readings are unresolved, stations may have been damaged, or according to a pre-determined frequency. Engineer's levels, both optical levels and electronic digital levels, are commonly used for gaging-station levels. Collimation tests should be run at least once a week for any week that levels are run, and the absolute value of the collimation error cannot exceed 0.003 foot/100 feet (ft). An acceptable set of gaging-station levels consists of a minimum of two foresights, each from a different instrument height, taken on at least two independent reference marks, all reference points, all gages, and the water surface. The initial instrument height is determined from another independent reference mark, known as the origin, or base reference mark. The absolute value of the closure error of a leveling circuit must be less than or equal to ft, where n is the total number of instrument setups, and may not exceed |0.015| ft regardless of the number of instrument setups. Closure error for a leveling circuit is distributed by instrument setup and adjusted elevations are determined. Side shots in a level circuit are assessed by examining the differences between the adjusted first and second elevations for each objective point in the circuit. The absolute value of these differences must be less than or equal to 0.005 ft. Final elevations for objective points are determined by averaging the valid adjusted first and second elevations. If final elevations indicate that the reference gage is off by |0.015| ft or more, it must be reset.

GLORI: A GNSS-R Dual Polarization Airborne Instrument for Land Surface Monitoring

PubMed Central

Motte, Erwan; Zribi, Mehrez; Fanise, Pascal; Egido, Alejandro; Darrozes, José; Al-Yaari, Amen; Baghdadi, Nicolas; Baup, Frédéric; Dayau, Sylvia; Fieuzal, Remy; Frison, Pierre-Louis; Guyon, Dominique; Wigneron, Jean-Pierre

2016-01-01

Global Navigation Satellite System-Reflectometry (GNSS-R) has emerged as a remote sensing tool, which is complementary to traditional monostatic radars, for the retrieval of geophysical parameters related to surface properties. In the present paper, we describe a new polarimetric GNSS-R system, referred to as the GLObal navigation satellite system Reflectometry Instrument (GLORI), dedicated to the study of land surfaces (soil moisture, vegetation water content, forest biomass) and inland water bodies. This system was installed as a permanent payload on a French ATR42 research aircraft, from which simultaneous measurements can be carried out using other instruments, when required. Following initial laboratory qualifications, two airborne campaigns involving nine flights were performed in 2014 and 2015 in the Southwest of France, over various types of land cover, including agricultural fields and forests. Some of these flights were made concurrently with in situ ground truth campaigns. Various preliminary applications for the characterisation of agricultural and forest areas are presented. Initial analysis of the data shows that the performance of the GLORI instrument is well within specifications, with a cross-polarization isolation better than −15 dB at all elevations above 45°, a relative polarimetric calibration accuracy better than 0.5 dB, and an apparent reflectivity sensitivity better than −30 dB, thus demonstrating its strong potential for the retrieval of land surface characteristics. PMID:27213393

GLORI: A GNSS-R Dual Polarization Airborne Instrument for Land Surface Monitoring.

PubMed

Motte, Erwan; Zribi, Mehrez; Fanise, Pascal; Egido, Alejandro; Darrozes, José; Al-Yaari, Amen; Baghdadi, Nicolas; Baup, Frédéric; Dayau, Sylvia; Fieuzal, Remy; Frison, Pierre-Louis; Guyon, Dominique; Wigneron, Jean-Pierre

2016-05-20

Global Navigation Satellite System-Reflectometry (GNSS-R) has emerged as a remote sensing tool, which is complementary to traditional monostatic radars, for the retrieval of geophysical parameters related to surface properties. In the present paper, we describe a new polarimetric GNSS-R system, referred to as the GLObal navigation satellite system Reflectometry Instrument (GLORI), dedicated to the study of land surfaces (soil moisture, vegetation water content, forest biomass) and inland water bodies. This system was installed as a permanent payload on a French ATR42 research aircraft, from which simultaneous measurements can be carried out using other instruments, when required. Following initial laboratory qualifications, two airborne campaigns involving nine flights were performed in 2014 and 2015 in the Southwest of France, over various types of land cover, including agricultural fields and forests. Some of these flights were made concurrently with in situ ground truth campaigns. Various preliminary applications for the characterisation of agricultural and forest areas are presented. Initial analysis of the data shows that the performance of the GLORI instrument is well within specifications, with a cross-polarization isolation better than -15 dB at all elevations above 45°, a relative polarimetric calibration accuracy better than 0.5 dB, and an apparent reflectivity sensitivity better than -30 dB, thus demonstrating its strong potential for the retrieval of land surface characteristics.

Simulated effects of proposed Arkansas Valley Conduit on hydrodynamics and water quality for projected demands through 2070, Pueblo Reservoir, southeastern Colorado

USGS Publications Warehouse

Ortiz, Roderick F.

2013-01-01

The purpose of the Arkansas Valley Conduit (AVC) is to deliver water for municipal and industrial use within the boundaries of the Southeastern Colorado Water Conservancy District. Water supplied through the AVC would serve two needs: (1) to supplement or replace existing poor-quality water to communities downstream from Pueblo Reservoir; and (2) to meet a portion of the AVC participants’ projected water demands through 2070. The Bureau of Reclamation (Reclamation) initiated an Environmental Impact Statement (EIS) to address the potential environmental consequences associated with constructing and operating the proposed AVC, entering into a conveyance contract for the Pueblo Dam north-south outlet works interconnect (Interconnect), and entering into a long-term excess capacity master contract (Master Contract). Operational changes, as a result of implementation of proposed EIS alternatives, could change the hydrodynamics and water-quality conditions in Pueblo Reservoir. An interagency agreement was initiated between Reclamation and the U.S. Geological Survey to accurately simulate hydrodynamics and water quality in Pueblo Reservoir for projected demands associated with four of the seven proposed EIS alternatives. The four alternatives submitted to the USGS for scenario simulation included various combinations (action or no action) of the proposed Arkansas Valley Conduit, Master Contract, and Interconnect options. The four alternatives were the No Action, Comanche South, Joint Use Pipeline North, and Master Contract Only. Additionally, scenario simulations were done that represented existing conditions (Existing Conditions scenario) in Pueblo Reservoir. Water-surface elevations, water temperature, dissolved oxygen, dissolved solids, dissolved ammonia, dissolved nitrate, total phosphorus, total iron, and algal biomass (measured as chlorophyll-a) were simulated. Each of the scenarios was simulated for three contiguous water years representing a wet, average, and dry annual hydrologic cycle. Each selected simulation scenario also was evaluated for differences in direct/indirect effects and cumulative effects on a particular scenario. Analysis of the results for the direct/indirect- and cumulative-effects analyses indicated that, in general, the results were similar for most of the scenarios and comparisons in this report focused on results from the direct/indirect-effects analyses. Scenario simulations that represented existing conditions in Pueblo Reservoir were compared to the No Action scenario to assess changes in water quality from current demands (2006) to projected demands in 2070. Overall, comparisons of the results between the Existing Conditions and the No Action scenarios for water-surface elevations, water temperature, and dissolved oxygen, dissolved solids, dissolved ammonia, dissolved nitrate, total phosphorus, and total iron concentrations indicated that the annual median values generally were similar for all three simulated years. Additionally, algal groups and chlorophyll-a concentrations (algal biomass) were similar for the Existing Conditions and the No Action scenarios at site 7B in the epilimnion for the simulated period (Water Year 2000 through 2002). The No Action scenario also was compared individually to the Comanche South, Joint Use Pipeline North, and Master Contract Only scenarios. These comparisons were made to describe changes in the annual median, 85th percentile, or 15th percentile concentration between the No Action scenario and each of the other three simulation scenarios. Simulated water-surface elevations, water temperature, dissolved oxygen, dissolved solids, dissolved ammonia, dissolved nitrate, total phosphorus, total iron, algal groups, and chlorophyll-a concentrations in Pueblo Reservoir generally were similar between the No Action scenario and each of the other three simulation scenarios.

Modelling landscape evolution at the flume scale

NASA Astrophysics Data System (ADS)

Cheraghi, Mohsen; Rinaldo, Andrea; Sander, Graham C.; Barry, D. Andrew

2017-04-01

The ability of a large-scale Landscape Evolution Model (LEM) to simulate the soil surface morphological evolution as observed in a laboratory flume (1-m × 2-m surface area) was investigated. The soil surface was initially smooth, and was subjected to heterogeneous rainfall in an experiment designed to avoid rill formation. Low-cohesive fine sand was placed in the flume while the slope and relief height were 5 % and 20 cm, respectively. Non-uniform rainfall with an average intensity of 85 mm h-1 and a standard deviation of 26 % was applied to the sediment surface for 16 h. We hypothesized that the complex overland water flow can be represented by a drainage discharge network, which was calculated via the micro-morphology and the rainfall distribution. Measurements included high resolution Digital Elevation Models that were captured at intervals during the experiment. The calibrated LEM captured the migration of the main flow path from the low precipitation area into the high precipitation area. Furthermore, both model and experiment showed a steep transition zone in soil elevation that moved upstream during the experiment. We conclude that the LEM is applicable under non-uniform rainfall and in the absence of surface incisions, thereby extending its applicability beyond that shown in previous applications. Keywords: Numerical simulation, Flume experiment, Particle Swarm Optimization, Sediment transport, River network evolution model.

Expected Performance of the Upcoming Surface Water and Ocean Topography Mission Measurements of River Height, Width, and Slope

NASA Astrophysics Data System (ADS)

Wei, R.; Frasson, R. P. M.; Williams, B. A.; Rodriguez, E.; Pavelsky, T.; Altenau, E. H.; Durand, M. T.

2017-12-01

The upcoming Surface Water and Ocean Topography (SWOT) mission will measure river widths and water surface elevations of rivers wider than 100 m. In preparation for the SWOT mission, the Jet Propulsion Laboratory built the SWOT hydrology simulator with the intent of generating synthetic SWOT overpasses over rivers with realistic error characteristics. These synthetic overpasses can be used to guide the design of processing methods and data products, as well as develop data assimilation techniques that will incorporate the future SWOT data into hydraulic and hydrologic models as soon as the satellite becomes operational. SWOT simulator uses as inputs water depth, river bathymetry, and the surrounding terrain digital elevation model to create simulated interferograms of the study area. Next, the simulator emulates the anticipated processing of SWOT data by attempting to geolocate and classify the radar returns. The resulting cloud of points include information on water surface elevation, pixel area, and surface classification (land vs water). Finally, we process the pixel clouds by grouping pixels into equally spaced nodes located at the river centerline. This study applies the SWOT simulator to six different rivers: Sacramento River, Tanana River, Saint Lawrence River, Platte River, Po River, and Amazon River. This collection of rivers covers a range of size, slope, and planform complexity with the intent of evaluating the impact of river width, slope, planform complexity, and surrounding topography on the anticipated SWOT height, width, and slope error characteristics.

Estimation of Missing Water-Level Data for the Everglades Depth Estimation Network (EDEN)

USGS Publications Warehouse

Conrads, Paul; Petkewich, Matthew D.

2009-01-01

The Everglades Depth Estimation Network (EDEN) is an integrated network of real-time water-level gaging stations, ground-elevation models, and water-surface elevation models designed to provide scientists, engineers, and water-resource managers with current (2000-2009) water-depth information for the entire freshwater portion of the greater Everglades. The U.S. Geological Survey Greater Everglades Priority Ecosystems Science provides support for EDEN and their goal of providing quality-assured monitoring data for the U.S. Army Corps of Engineers Comprehensive Everglades Restoration Plan. To increase the accuracy of the daily water-surface elevation model, water-level estimation equations were developed to fill missing data. To minimize the occurrences of no estimation of data due to missing data for an input station, a minimum of three linear regression equations were developed for each station using different input stations. Of the 726 water-level estimation equations developed to fill missing data at 239 stations, more than 60 percent of the equations have coefficients of determination greater than 0.90, and 92 percent have an coefficient of determination greater than 0.70.

The distribution of organic material and its contribution to the micro-topography of particles from wettable and water repellent soils

NASA Astrophysics Data System (ADS)

Bryant, Rob; Cheng, Shuying; Doerr, Stefan H.; Wright, Chris J.; Bayer, Julia V.; Williams, Rhodri P.

2010-05-01

Organic coatings on mineral particles will mask the physic-chemical properties of the underlying mineral surface. Surface images and force measurements obtained using atomic force microscopy (AFM) provide information about the nature of and variability in surfaces properties at the micro- to nano-scale. As AFM technology and data processing advance it is anticipated that a significant amount of information will be obtained simultaneously from individual contacts made at high frequency in non-contact or tapping mode operation. For present purposes the surfaces of model materials (smooth glass surfaces and acid-washed sand (AWS)) provide an indication of the dependency of the so-called AFM phase image on the topographic image (which is obtained synoptically). Pixel wise correlation of these images reveals how the modulation of an AFM probe is affected when topographic features are encountered. Adsorption of soil-derived humic acid (HA) or lecithin (LE), used here as an example for natural organic material, on these surfaces provides a soft and compliant, albeit partial, covering on the mineral which modifies the topography and the response of an AFM tip as it partially indents the soft regions (which contributes depth to the phase image). This produces a broadening on the data domain in the topographic/phase scatter diagram. Two dimensional classifications of these data, together with those obtained from sand particles drawn from water repellent and wettable soils, suggest that these large adsorbate molecules appear to have little preference to attach to particular topographic features or elevations. It appears that they may effectively remain on the surface at the point of initial contact. If organic adsorbates present a hydrophobic outer surface, then it seems possible that elevated features will not be immune from this and provide scope for a local, albeit, small contribution to the expression of super-hydrophobicity. It is therefore speculated here that the water repellency of a soil is the result of not only of particle surface chemistry and soil pore space geometry, but also of the micro-topography generated by organic material adsorbed on particle surfaces.

The Effect of Firn-Aquifer Drainage on the Greenland Subglacial System or Subglacial Efficiency and Storage Modified by the Temporal Pattern of High-Elevation Meltwater Input

NASA Technical Reports Server (NTRS)

Andrews, Lauren C.; Poinar, Kristin; Dow, Christine F.; Nowicki, Sophie M.

2017-01-01

Ice flow in marginal region of the Greenland Ice Sheet dynamically responds to summer melting as surface meltwater is routed through the supraglacial hydrologic system to the bed of the ice sheet via crevasses and moulins. Given the expected increases in surface melt production and extent, and the potential for high elevation surface-to-bed connections, it is imperative to understand how meltwater delivered to the bed from different high-elevation supraglacial storage features affects the evolution of the subglacial hydrologic system and associated ice dynamics. Here, we use the two-dimensional subglacial hydrologic model, GLaDS, which includes distributed and channelized water flow, to test how the subglacial system of an idealized outlet glacier responds to cases of high-elevation firn-aquifer-type and supraglacial-lake-type englacial drainage over the course of 5 years. Model outputs driven by these high elevation drainage types are compared to steady-state model results, where the subglacial system only receives the 1980- 2016 mean MERRA-2 runoff via low-elevation moulins. Across all experiments, the subglacial hydrologic system displays inter-annual memory, resulting in multiyear declines in subglacial pressure during the onset of seasonal melting and growth of subglacial channels. The gradual addition of water in firn-aquifer-type drainage scenarios resulted in small increases in subglacial water storage but limited changes in subglacial efficiency and channelization. Rapid, supraglacial- lake-type drainage resulted in short-term local increases in subglacial water pressure and storage, which gave way to spatially extensive decreases in subglacial pressure and downstream channelization. These preliminary results suggest that the character of high-elevation englacial drainage can have a strong, and possibly outsized, control on subglacial efficiency throughout the ablation zone. Therefore, understanding both how high elevation meltwater is stored supraglacially and the probability of crevassing at high elevations will play an important role in how the subglacial system, proglacial discharge and ice motion will respond to future increases in surface melt production and runoff.

Geostatistical applications in ground-water modeling in south-central Kansas

USGS Publications Warehouse

Ma, T.-S.; Sophocleous, M.; Yu, Y.-S.

1999-01-01

This paper emphasizes the supportive role of geostatistics in applying ground-water models. Field data of 1994 ground-water level, bedrock, and saltwater-freshwater interface elevations in south-central Kansas were collected and analyzed using the geostatistical approach. Ordinary kriging was adopted to estimate initial conditions for ground-water levels and topography of the Permian bedrock at the nodes of a finite difference grid used in a three-dimensional numerical model. Cokriging was used to estimate initial conditions for the saltwater-freshwater interface. An assessment of uncertainties in the estimated data is presented. The kriged and cokriged estimation variances were analyzed to evaluate the adequacy of data employed in the modeling. Although water levels and bedrock elevations are well described by spherical semivariogram models, additional data are required for better cokriging estimation of the interface data. The geostatistically analyzed data were employed in a numerical model of the Siefkes site in the project area. Results indicate that the computed chloride concentrations and ground-water drawdowns reproduced the observed data satisfactorily.This paper emphasizes the supportive role of geostatistics in applying ground-water models. Field data of 1994 ground-water level, bedrock, and saltwater-freshwater interface elevations in south-central Kansas were collected and analyzed using the geostatistical approach. Ordinary kriging was adopted to estimate initial conditions for ground-water levels and topography of the Permian bedrock at the nodes of a finite difference grid used in a three-dimensional numerical model. Cokriging was used to estimate initial conditions for the saltwater-freshwater interface. An assessment of uncertainties in the estimated data is presented. The kriged and cokriged estimation variances were analyzed to evaluate the adequacy of data employed in the modeling. Although water levels and bedrock elevations are well described by spherical semivariogram models, additional data are required for better cokriging estimation of the interface data. The geostatistically analyzed data were employed in a numerical model of the Siefkes site in the project area. Results indicate that the computed chloride concentrations and ground-water drawdowns reproduced the observed data satisfactorily.

River Discharge and Bathymetry Estimation from Hydraulic Inversion of Surface Currents and Water Surface Elevation Observations

NASA Astrophysics Data System (ADS)

Simeonov, J.; Holland, K. T.

2015-12-01

We developed an inversion model for river bathymetry and discharge estimation based on measurements of surface currents, water surface elevation and shoreline coordinates. The model uses a simplification of the 2D depth-averaged steady shallow water equations based on a streamline following system of coordinates and assumes spatially uniform bed friction coefficient and eddy viscosity. The spatial resolution of the predicted bathymetry is related to the resolution of the surface currents measurements. The discharge is determined by minimizing the difference between the predicted and the measured streamwise variation of the total head. The inversion model was tested using in situ and remote sensing measurements of the Kootenai River east of Bonners Ferry, ID. The measurements were obtained in August 2010 when the discharge was about 223 m3/s and the maximum river depth was about 6.5 m. Surface currents covering a 10 km reach with 8 m spatial resolution were estimated from airborne infrared video and were converted to depth-averaged currents using acoustic Doppler current profiler (ADCP) measurements along eight cross-stream transects. The streamwise profile of the water surface elevation was measured using real-time kinematic GPS from a drifting platform. The value of the friction coefficient was obtained from forward calibration simulations that minimized the difference between the predicted and measured velocity and water level along the river thalweg. The predicted along/cross-channel water depth variation was compared to the depth measured with a multibeam echo sounder. The rms error between the measured and predicted depth along the thalweg was found to be about 60cm and the estimated discharge was 5% smaller than the discharge measured by the ADCP.

Update of the Accounting Surface Along the Lower Colorado River

USGS Publications Warehouse

Wiele, Stephen M.; Leake, Stanley A.; Owen-Joyce, Sandra J.; McGuire, Emmet H.

2008-01-01

The accounting-surface method was developed in the 1990s by the U.S. Geological Survey, in cooperation with the Bureau of Reclamation, to identify wells outside the flood plain of the lower Colorado River that yield water that will be replaced by water from the river. This method was needed to identify which wells require an entitlement for diversion of water from the Colorado River and need to be included in accounting for consumptive use of Colorado River water as outlined in the Consolidated Decree of the United States Supreme Court in Arizona v. California. The method is based on the concept of a river aquifer and an accounting surface within the river aquifer. The study area includes the valley adjacent to the lower Colorado River and parts of some adjacent valleys in Arizona, California, Nevada, and Utah and extends from the east end of Lake Mead south to the southerly international boundary with Mexico. Contours for the original accounting surface were hand drawn based on the shape of the aquifer, water-surface elevations in the Colorado River and drainage ditches, and hydrologic judgment. This report documents an update of the original accounting surface based on updated water-surface elevations in the Colorado River and drainage ditches and the use of simple, physically based ground-water flow models to calculate the accounting surface in four areas adjacent to the free-flowing river.

Development of a GNSS Buoy for Monitoring Water Surface Elevations in Estuaries and Coastal Areas.

PubMed

Lin, Yen-Pin; Huang, Ching-Jer; Chen, Sheng-Hsueh; Doong, Dong-Jiing; Kao, Chia Chuen

2017-01-18

In this work, a Global Navigation Satellite System (GNSS) buoy that utilizes a Virtual Base Station (VBS) combined with the Real-Time Kinematic (RTK) positioning technology was developed to monitor water surface elevations in estuaries and coastal areas. The GNSS buoy includes a buoy hull, a RTK GNSS receiver, data-transmission devices, a data logger, and General Purpose Radio Service (GPRS) modems for transmitting data to the desired land locations. Laboratory and field tests were conducted to test the capability of the buoy and verify the accuracy of the monitored water surface elevations. For the field tests, the GNSS buoy was deployed in the waters of Suao (northeastern part of Taiwan). Tide data obtained from the GNSS buoy were consistent with those obtained from the neighboring tide station. Significant wave heights, zero-crossing periods, and peak wave directions obtained from the GNSS buoy were generally consistent with those obtained from an accelerometer-tilt-compass (ATC) sensor. The field tests demonstrate that the developed GNSS buoy can be used to obtain accurate real-time tide and wave data in estuaries and coastal areas.

Development of a GNSS Buoy for Monitoring Water Surface Elevations in Estuaries and Coastal Areas

PubMed Central

Lin, Yen-Pin; Huang, Ching-Jer; Chen, Sheng-Hsueh; Doong, Dong-Jiing; Kao, Chia Chuen

2017-01-01

In this work, a Global Navigation Satellite System (GNSS) buoy that utilizes a Virtual Base Station (VBS) combined with the Real-Time Kinematic (RTK) positioning technology was developed to monitor water surface elevations in estuaries and coastal areas. The GNSS buoy includes a buoy hull, a RTK GNSS receiver, data-transmission devices, a data logger, and General Purpose Radio Service (GPRS) modems for transmitting data to the desired land locations. Laboratory and field tests were conducted to test the capability of the buoy and verify the accuracy of the monitored water surface elevations. For the field tests, the GNSS buoy was deployed in the waters of Suao (northeastern part of Taiwan). Tide data obtained from the GNSS buoy were consistent with those obtained from the neighboring tide station. Significant wave heights, zero-crossing periods, and peak wave directions obtained from the GNSS buoy were generally consistent with those obtained from an accelerometer-tilt-compass (ATC) sensor. The field tests demonstrate that the developed GNSS buoy can be used to obtain accurate real-time tide and wave data in estuaries and coastal areas. PMID:28106763

Modeling the Dynamic Water Resource Needs of California's Coastal Watersheds

NASA Astrophysics Data System (ADS)

Alford, C.

2009-12-01

Many watersheds face formidable water supply challenges when it comes to managing water availability to meet diverse water supply and ecosystem management objectives. California’s central coast watersheds are no exception, and both the scarcity of water resources during drier water years and mandates to establish minimum instream flows for salmon habitat have prompted interests in reassessing water management strategies for several of these watersheds. Conventional supply-oriented hydrologic models, however, are not adequate to fully investigate and describe the reciprocal implications of surface water demands for human use and the maintenance of instream flows for salmon habitat that vary both temporally and spatially within a watershed. In an effort to address this issue I developed a coastal watershed management model based on the San Gregorio watershed utilizing the Water Evaluation and Planning (WEAP) system, which permits demand-side prioritization at a time step interval and spatial resolution that captures functional supply and demand relationships. Physiographic input data such as soil type, land cover, elevation, habitat, and water demand sites were extrapolated at a sub-basin level in a GIS. Time-series climate data were collected and processed utilizing the Berkeley Water Center Data Cube at daily time steps for the period 1952 through September 2009. Recent synoptic flow measurements taken at seven tributary sites during the 2009 water year, water depth measured by pressure transducers at six sites within the watershed from September 2005 through September 2009, and daily gauge records from temporary gauges installed in 1981 were used to assess the hydrologic patterns of sub-basins and supplement historic USGS gauge flow records. Empirical functions were used to describe evapotranspiration, surface runoff, sub-surface runoff, and deep percolation. Initial model simulations carried out under both dry and wet water year scenarios were able to capture representative hydrological conditions in both the sample watershed case and an initial test case that utilized base data from a watershed with minimal land disturbance. Results from this study provide valuable insight into the effects of water use through a variety of climactic conditions and provide potential strategies for policy makers, regulators, and stakeholders to strengthen adaptive capacity to achieve sustainable water use within coastal watersheds.

Evaluation of ERTS data for certain oceanographic uses. [sunglint, algal bloom, water temperature, upwelling, and turbidity of Great Lakes waters

NASA Technical Reports Server (NTRS)

Strong, A. E. (Principal Investigator)

1973-01-01

The author has identified the following significant results. (1) Sunglint effects over water can be expected in ERTS-1 images whenever solar elevations exceed 55 deg. (2) Upwellings were viewed coincidently by ERTS-1 and NOAA-2 in Lake Michigan on two occasions during August 1973. (3) A large oil slick was identified 100 km off the Maryland coast in the Atlantic Ocean. Volume of the oil was estimated to be least 200,000 liters (50,000 gallons). (4) ERTS-1 observations of turbidity patterns in Lake St. Clair provide circulation information that correlates well with physical model studies made 10 years ago. (5) Good correlation has been established between ERTS-1 water color densities and NOAA-2 thermal infrared surface temperature measurements. Initial comparisons have been made in Lake Erie during March 1973.

Biogeochemistry of Lakes in Western Papua, Indonesia - First Results of a Pilot Study.

NASA Astrophysics Data System (ADS)

Kallmeyer, J.; Nomosatryo, S.; Henny, C.; Kopalit, H.

2016-12-01

Despite years of exploration for mineral and hydrocarbon resources, the lakes of Western Papua have received very little attention from a limnogeologic perspective. In some cases not even the maximum water depth of the lakes is published. The only research carried out so far focused on the fish and invertebrate fauna of the lakes, because the macrofauna of Papuan Lakes is significantly different from other islands of western Indonesia. Most lakes harbor numerous endemic species. We carried out a first limnogeologic pilot campaign in spring 2016 to measure water column profiles and take short (max 80 cm long) sediment cores.Lake Sentani is seated in Mesozoic mafic bedrock and consists of four separate basins with maximum water depths of 30 to 40 m. Three basins are connected by shallow sills and one by a natural canal. Although all four basins share almost identical surface water chemistry and exhibit sub- to anoxic bottom waters, each basin has its distinct water column stratification and sediment geochemistry. Despite its coastal location and minimal elevation we could not identify an influx of seawater into the lake. Lake Ayamaru is located further inland on a densely forested karstified carbonate platform. The lake level has dropped significantly in recent years due to water loss into the karst, further reduction of open water surface is caused by massive growth of Pistia. Currently the lake has a maximum depth of around 2 m. Its sediment is mainly composed of carbonate minerals and methane saturated. Due to the carbonate bedrock the lake is highly alkaline (up to 20 meq/L) despite its very low salinity. The initial analyses show that these lakes offer unique biogeochemical conditions that require further in-depth studies.Our research will expand to lakes Anggi Giji and Anggi Gida, which are at almost 2000 m elevation. They have maximum depths of around 200 m and much colder surface waters (12-20°C) compared to the other two lakes that have about 30°C throughout the year.

[Temporal and Spatial Characteristics of Lake Taihu Surface Albedo and Its Impact Factors].

PubMed

Cao, Chang; Li, Xu-hui; Zhang, Mi; Liu, Shou-dong; Xiao, Wei; Xiao, Qi-tao; Xu, Jia-ping

2015-10-01

Lake surface albedo determines energy balance of water-atmospheric interface and water physical environment. Solar elevation angle, cloudiness, wind speed, water quality and other factors can affect lake surface albedo. Using solar radiation, wind speed, and water quality data (turbidity and chlorophyll-a concentration) which were observed in four eddy covariance sites (Meiliangwan, Dapukou, Bifenggang and Xiaoleishan i. e. MLW, DPK, BFG and XLS) in Lake Taihu and clearness index (k(t)), the influence of these factors on Lake Taihu surface albedo and the reasons that led to its spatial difference were investigated. The results showed that solar elevation angle played a leading role in the diurnal and seasonal change of lake surface albedo; lake surface albedo reached two peaks in 0 < k(t) < 0.1 and 0.4 < k(t) < 0.6 respectively, when solar elevation angle was below 35 degrees. The surface albedo increased with the increasing wind speed, turbidity and chlorophyll-a concentration. However, wind could indirectly affect surface albedo through leading to the changes in sediment resuspension and chlorophyll-a distribution. The sequence of albedo in the four sites was XLS > BFG > DPK > MLW. XLS and BFG belonged to the higher albedo group, while DPK and MLW belonged to the lower albedo group. The different biological environments caused by aquatic macrophytes and algae resulting in the spatial variation of Lake Taihu surface albedo. The relationship between albedo and chlorophyll-a concentration was not a very sensitive factor for indicating the outbreak of algae. This study can provide theoretical reference for lake albedo parameterization.

Refraction of microwave signals by water vapor

NASA Technical Reports Server (NTRS)

Goldfinger, A. D.

1980-01-01

Tropospheric water vapor causes a refractive path length effect which is typically 5-10% of the 'dry' tropospheric effect and as large as several meters at elevation angles below 5 deg. The vertical water vapor profile is quite variable, and measurements of intensive atmospheric parameters such as temperature and humidity limited to the surface do not adequately predict the refractive effect. It is suggested that a water vapor refraction model that is a function of the amount of precipitable water alone can be successful at low elevation angles. From an extensive study of numerical ray tracings through radiosonde balloon data, such a model has been constructed. The model predicts the effect at all latitudes and elevation angles between 2 and 10 deg to an accuracy of better than 4% (11 cm at 3 deg elevation angle).

Recent and historic drivers of landscape change in the Everglades ridge, slough, and Tree Island mosaic

USGS Publications Warehouse

Larsen, Laurel G.; Nicholas Aumen,; Bernhardt, Christopher E.; Vic Engel,; Givnish, Thomas J.; S Hagerthey, P McCormick; Harvey, Judson; Lynn Leonard,; McCormick, P.; McVoy, Christopher; Noe, Gregory; Nungesser, Martha K.; Rutchey, K.; Sklar, Fred; Troxler, Tiffany G.; Volin, John C.; Willard, Debra A.

2011-01-01

More than half of the original Everglades extent formed a patterned peat mosaic of elevated ridges, lower and more open sloughs, and tree islands aligned parallel to the dominant flow direction. This ecologically important landscape structure remained in a dynamic equilibrium for millennia prior to rapid degradation over the past century in response to human manipulation of the hydrologic system. Restoration of the patterned landscape structure is one of the primary objectives of the Everglades restoration effort. Recent research has revealed that three main drivers regulated feedbacks that initiated and maintained landscape structure: the spatial and temporal distribution of surface water depths, surface and subsurface flow, and phosphorus supply. Causes of recent degradation include but are not limited to perturbations to these historically important controls; shifts in mineral and sulfate supply may have also contributed to degradation. Restoring predrainage hydrologic conditions will likely preserve remaining landscape pattern structure, provided a sufficient supply of surface water with low nutrient and low total dissolved solids content exists to maintain a rainfall-driven water chemistry. However, because of hysteresis in landscape evolution trajectories, restoration of areas with a fully degraded landscape could require additional human intervention.

Water Resources Data, Florida, Water Year 2003, Volume 4. Northwest Florida

USGS Publications Warehouse

prepared by Blum, Darlene A.; Alvarez, A. Ernie

2004-01-01

The U.S. Geological Survey (USGS), in cooperation with Federal, State, and local agencies, obtains a large amount of data on the water resources of the State of Florida each water year. These data, accumulated during many water years, constitute a valuable database that is used by water-resources managers, emergency-management officials, and many others to develop an improved understanding of water resources within the State. This report series for the 2003 water year for the state of Florida consists of records for continuous or daily discharge for 385 streams, periodic discharge for 13 streams, continuous or daily stage for 255 streams, periodic stage for 13 streams, peak stage and discharge for 36 streams, continuous or daily elevations for 13 lakes, periodic elevations for 46 lakes, continuous ground-water levels for 441 wells, periodic ground-water levels for 1,227 wells, and quality-of-water for 133 surface-water sites and 308 wells. This volume (Volume 4, Northwest Florida)contains records of continuous or daily discharge for 72 streams, periodic discharge for 3 stream, continuous or daily stage for 13 streams, periodic stage for 0 stream, peak stage and discharge for 28 streams, continuous or daily elevations for 1 lake, periodic elevations for 0 lakes, continuous ground-water levels for 3 wells, periodic ground-water levels for 0 wells, and quality-of-water for 3 surface-water sites and 0 wells. These data represent the National Water Data System records collected by the U.S. Geological Survey and cooperating local, State, and Federal agencies in Florida.

Processes regulating watershed chemical export during snowmelt, fraser experimental forest, Colorado

USGS Publications Warehouse

Stottlemyer, R.

2001-01-01

In the Central Rocky Mountains, snowfall dominates precipitation. Airborne contaminants retained in the snowpack can affect high elevation surface water chemistry during snowmelt. At the Fraser Experimental Forest (FEF), located west of the Continental Divide in Central Colorado, snowmelt dominates the annual hydrograph, and accounts for >95% of annual stream water discharge. During the winters of 1989-1993, we measured precipitation inputs, snowpack water equivalent (SWE) and ion content, and stream water chemistry every 7-10 days along a 3150-3500 m elevation gradient in the subalpine and alpine Lexen Creek watershed. The study objectives were to (1) quantify the distribution of SWE and snowpack chemical content with elevation and aspect, (2) quantify snowmelt rates, temperature of soil, snowpack, and air with elevation and aspect, and (3) use change in upstream-downstream water chemistry during snowmelt to better define alpine and subalpine flowpaths. The SWE increased with elevation (P - 3??C) temperatures throughout winter which resulted in significant snowpack ion loss. By snowpack PWE in mid May, the snowpack had lost almost half the cumulative precipitation H+, NH4+, and SO42- inputs and a third of the NO3- input. Windborne soil particulate inputs late in winter increased snowpack base cation content. Variation in subalpine SWE and snowpack ion content with elevation and aspect, and wind redistribution of snowfall in the alpine resulted in large year-to-year differences in the timing and magnitude of SWE, PWE, and snowpack ion content. The alpine stream water ion concentrations changed little during snowmelt indicating meltwater passed quickly through surface porous soils and was well mixed before entering the stream. Conversely, subalpine stream water chemistry was diluted during snowmelt suggesting much melt water moved to the stream as shallow subsurface lateral flow. Published by Elsevier Science B.V.

Echelon approach to areas of concern in synoptic regional monitoring

USGS Publications Warehouse

Myers, Wayne; Patil, Ganapati P.; Joly, Kyle

1997-01-01

Echelons provide an objective approach to prospecting for areas of potential concern in synoptic regional monitoring of a surface variable. Echelons can be regarded informally as stacked hill forms. The strategy is to identify regions of the surface which are elevated relative to surroundings (Relative ELEVATIONS or RELEVATIONS). These are areas which would continue to expand as islands with receding (virtual) floodwaters. Levels where islands would merge are critical elevations which delimit echelons in the vertical dimension. Families of echelons consist of surface sectors constituting separate islands for deeper waters that merge as water level declines. Pits which would hold water are disregarded in such a progression, but a complementary analysis of pits is obtained using the surface as a virtual mould to cast a counter-surface (bathymetric analysis). An echelon tree is a family tree of echelons with peaks as terminals and the lowest level as root. An echelon tree thus provides a dendrogram representation of surface topology which enables graph theoretic analysis and comparison of surface structures. Echelon top view maps show echelon cover sectors on the base plane. An echelon table summarizes characteristics of echelons as instances or cases of hill form surface structure. Determination of echelons requires only ordinal strength for the surface variable, and is thus appropriate for environmental indices as well as measurements. Since echelons are inherent in a surface rather than perceptual, they provide a basis for computer-intelligent understanding of surfaces. Echelons are given for broad-scale mammalian species richness in Pennsylvania.

Impact on the Columbia River of an outburst of Spirit Lake

USGS Publications Warehouse

Sikonia, W.G.

1985-01-01

A one-dimensional sediment-transport computer model was used to study the effects of an outburst of Spirit Lake on the Columbia River. According to the model, flood sediment discharge to the Columbia from the Cowlitz would form a blockage to a height of 44 feet above the current streambed of the Columbia River, corresponding to a new streambed elevation of -3 feet, that would impound the waters of the Columbia River. For an average flow of 233,000 cubic feet in that river, water surface elevations would continue to increase for 16 days after the blockage had been formed. The river elevation at the Trojan nuclear power plant, 5 miles upstream of the Cowlitz River, would rise to 32 feet, compared to a critical elevation of 45 feet, above which the plant would be flooded. For comparison, the Columbia River at average flow without the blockage has an elevation at this location of 6 feet. Correspondingly high water surface elevations would occur along the river to Bonneville Dam , with that at Portland, Oregon, for example, rising also to 32 feet, compared to 10 feet without the blockage. (USGS)

Water-elevation, stream-discharge, and ground-water quality data in the Alaska Railroad Industrial Area, Fairbanks, Alaska, May 1993 to May 1995

USGS Publications Warehouse

Kriegler, A.T.; Lilly, M.R.

1995-01-01

From May 1993 to May 1995, the U.S. Geological Survey in cooperation with the Alaska Department of Natural Resources, Division of Mining and Water Management collected data on ground-water and surface-water elevations, stream discharge, and ground-water quality in the Alaska Railroad Industrial area in Fairbanks, Alaska. The data- collection efforts were coordinated with environmental efforts being made in the study area by the Alaska Railroad Corporation. These data were collected as part of an effort to characterize the hydrogeology of the Alaska Railroad Industrial area and to define the extent of petroleum hydrocarbons in the area. Ground-water data were collected at 52 observation wells, surface-water data at 12 sites, stream discharge data at 9 sites, and chemical water-quality data at 32 observation wells.

Correlation between lead levels in drinking water and mothers' breast milk: Dakahlia, Egypt.

PubMed

Mandour, Raafat A; Ghanem, Abdel-Aziz; El-Azab, Somaia M

2013-04-01

This study was performed on fifty-two drinking tap water samples (surface and groundwater) collected from different districts of Dakahlia Governorate and fifty-two breast milk samples from lactating mothers hosted in Dakahlia Governorate hospitals. All these samples were subjected to lead analysis. Lead level in drinking groundwater showed higher levels than in drinking surface water. Also, an elevation of lead levels in breast milk of mothers drinking groundwater was noticed when compared with that of mothers drinking surface water. The comparison between mean lead levels in drinking water and mothers' breast milk samples showed positive relationship. Lead concentrations in breast milk of the studied samples were elevated by exposure to smoking. We conclude that prolonged contact with lead plumbing can increase the lead content in tap water with subsequent increase in lead burden in infant fed formula and infant blood. Also, we recommend that chemical analyses must be carried out periodically for the surface and groundwater to ensure the water suitability for drinking purposes. Passive exposure to smoking during lactation should be avoided. Capsule: Prolonged contact with lead plumbing can increase the lead content in tap water with subsequent increase in lead burden in infant fed formula and infant blood.

Everglades Depth Estimation Network (EDEN) Applications: Tools to View, Extract, Plot, and Manipulate EDEN Data

USGS Publications Warehouse

Telis, Pamela A.; Henkel, Heather

2009-01-01

The Everglades Depth Estimation Network (EDEN) is an integrated system of real-time water-level monitoring, ground-elevation data, and water-surface elevation modeling to provide scientists and water managers with current on-line water-depth information for the entire freshwater part of the greater Everglades. To assist users in applying the EDEN data to their particular needs, a series of five EDEN tools, or applications (EDENapps), were developed. Using EDEN's tools, scientists can view the EDEN datasets of daily water-level and ground elevations, compute and view daily water depth and hydroperiod surfaces, extract data for user-specified locations, plot transects of water level, and animate water-level transects over time. Also, users can retrieve data from the EDEN datasets for analysis and display in other analysis software programs. As scientists and managers attempt to restore the natural volume, timing, and distribution of sheetflow in the wetlands, such information is invaluable. Information analyzed and presented with these tools is used to advise policy makers, planners, and decision makers of the potential effects of water management and restoration scenarios on the natural resources of the Everglades.

Method for estimating potential wetland extent by utilizing streamflow statistics and flood-inundation mapping techniques: Pilot study for land along the Wabash River near Terre Haute, Indiana

USGS Publications Warehouse

Kim, Moon H.; Ritz, Christian T.; Arvin, Donald V.

2012-01-01

Potential wetland extents were estimated for a 14-mile reach of the Wabash River near Terre Haute, Indiana. This pilot study was completed by the U.S. Geological Survey in cooperation with the U.S. Department of Agriculture, Natural Resources Conservation Service (NRCS). The study showed that potential wetland extents can be estimated by analyzing streamflow statistics with the available streamgage data, calculating the approximate water-surface elevation along the river, and generating maps by use of flood-inundation mapping techniques. Planning successful restorations for Wetland Reserve Program (WRP) easements requires a determination of areas that show evidence of being in a zone prone to sustained or frequent flooding. Zone determinations of this type are used by WRP planners to define the actively inundated area and make decisions on restoration-practice installation. According to WRP planning guidelines, a site needs to show evidence of being in an "inundation zone" that is prone to sustained or frequent flooding for a period of 7 consecutive days at least once every 2 years on average in order to meet the planning criteria for determining a wetland for a restoration in agricultural land. By calculating the annual highest 7-consecutive-day mean discharge with a 2-year recurrence interval (7MQ2) at a streamgage on the basis of available streamflow data, one can determine the water-surface elevation corresponding to the calculated flow that defines the estimated inundation zone along the river. By using the estimated water-surface elevation ("inundation elevation") along the river, an approximate extent of potential wetland for a restoration in agricultural land can be mapped. As part of the pilot study, a set of maps representing the estimated potential wetland extents was generated in a geographic information system (GIS) application by combining (1) a digital water-surface plane representing the surface of inundation elevation that sloped in the downstream direction of flow and (2) land-surface elevation data. These map products from the pilot study will aid the NRCS and its partners with the onsite inundation-zone verification in agricultural land for a potential restoration and will assist in determining at what elevation to plant hardwood trees for increased survivability on ground above frequently flooded terraces.

A drifting GPS buoy for retrieving effective riverbed bathymetry

NASA Astrophysics Data System (ADS)

Hostache, R.; Matgen, P.; Giustarini, L.; Teferle, F. N.; Tailliez, C.; Iffly, J.-F.; Corato, G.

2015-01-01

Spatially distributed riverbed bathymetry information are rarely available but mandatory for accurate hydrodynamic modeling. This study aims at evaluating the potential of the Global Navigation Satellite System (GNSS), like for instance Global Positioning System (GPS), for retrieving such data. Drifting buoys equipped with navigation systems such as GPS enable the quasi-continuous measurement of water surface elevation, from virtually any point in the world. The present study investigates the potential of assimilating GNSS-derived water surface elevation measurements into hydraulic models in order to retrieve effective riverbed bathymetry. First tests with a GPS dual-frequency receiver show that the root mean squared error (RMSE) on the elevation measurement equals 30 cm provided that a differential post processing is performed. Next, synthetic observations of a drifting buoy were generated assuming a 30 cm average error of Water Surface Elevation (WSE) measurements. By assimilating the synthetic observation into a 1D-Hydrodynamic model, we show that the riverbed bathymetry can be retrieved with an accuracy of 36 cm. Moreover, the WSEs simulated by the hydrodynamic model using the retrieved bathymetry are in good agreement with the synthetic "truth", exhibiting an RMSE of 27 cm.

A Climatology of Nocturnal-Convection Initiation Over the Central Great Plains

NASA Astrophysics Data System (ADS)

Reif, D. W.; Bluestein, H. B.

2015-12-01

A nocturnal maximum in rainfall and thunderstorm activity over the central Great Plains is widely documented, but the mechanisms for understanding the development of thunderstorms over the region at night are still not well understood. Elevated convection, defined by Colman (1990) as storms formed through ascent above frontal surfaces, is one explanation, but our study shows that many thunderstorms can initiate at night without the presence of an elevated frontal inversion or nearby surface boundary. We address the following questions: Of all the events documented, what percentage fall under this definition of elevated convection, and what percentage fall outside of that definition? How do characteristics differ among the events that fall under that definition and the events that fall outside that definition? This study documents convection initiation (CI) events occurring at night over the central Great Plains from 1996 through 2014 during the months of April through July. Storm characteristics such as storm type (defined as linear, areal, or single cell), storm motion, initiation time and location, and others were documented. Once all of the cases were documented, surface data were examined to locate any nearby surface boundaries. The event's location relative to these boundaries (if they existed) was documented. Three main modes of CI were identified: formation on a surface boundary, formation on the cold side of a surface boundary, and formation without the presence of a surface boundary. A climatology of these events will be presented. There are many differences among the different modes of CI at night. One result is that there appears to be two main peaks of CI time at night: one early at night and one later at night. The later peak is likely due to the events that form in the absence of a nearby surface boundary.

Using a hybrid model to predict solute transfer from initially saturated soil into surface runoff with controlled drainage water.

PubMed

Tong, Juxiu; Hu, Bill X; Yang, Jinzhong; Zhu, Yan

2016-06-01

The mixing layer theory is not suitable for predicting solute transfer from initially saturated soil to surface runoff water under controlled drainage conditions. By coupling the mixing layer theory model with the numerical model Hydrus-1D, a hybrid solute transfer model has been proposed to predict soil solute transfer from an initially saturated soil into surface water, under controlled drainage water conditions. The model can also consider the increasing ponding water conditions on soil surface before surface runoff. The data of solute concentration in surface runoff and drainage water from a sand experiment is used as the reference experiment. The parameters for the water flow and solute transfer model and mixing layer depth under controlled drainage water condition are identified. Based on these identified parameters, the model is applied to another initially saturated sand experiment with constant and time-increasing mixing layer depth after surface runoff, under the controlled drainage water condition with lower drainage height at the bottom. The simulation results agree well with the observed data. Study results suggest that the hybrid model can accurately simulate the solute transfer from initially saturated soil into surface runoff under controlled drainage water condition. And it has been found that the prediction with increasing mixing layer depth is better than that with the constant one in the experiment with lower drainage condition. Since lower drainage condition and deeper ponded water depth result in later runoff start time, more solute sources in the mixing layer are needed for the surface water, and larger change rate results in the increasing mixing layer depth.

Potential and limitations of satellite laser altimetry for monitoring water surface dynamics: ICESat for US lakes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shu, Liu; Qigang, Jiang; Zhang, Xuesong

Elevation measurements from the Ice, Cloud and Land Elevation Satellite (ICESat) have been applied to monitor dynamics of lakes and other surface water bodies. Despite such potential, the true utility of ICESat--more generally, satellite laser altimetry--for tracking surface water dynamics over time has not been adequately assessed, especially in the continental or global contexts. Here, we analyzed ICESat elevation data for the conterminous United States and examined the potential and limitations of satellite laser altimetry in measuring water-level dynamics. Owing to a lack of spatially-explicit ground-based water-level data, we first resorted to high-fidelity land elevation data acquired by airborne lidarmore » to quantify ICESat’s ranging accuracy. We then performed trend and frequency analyses to evaluate how reliably ICESat could capture water-level dynamics over a range of temporal scales, as compared to in-situ gauge measurements. Our analyses showed that ICESat had a vertical ranging error of 0.16 m at the footprint level—a limit on the detectable range of water-level dynamics. The sparsity of data over time was identified as a major factor limiting the use of ICESat for water dynamics studies. Of all the US lakes, only 361 had quality ICESat measurements for more than two flight passes. Even for those lakes with sufficient temporal coverage, ICESat failed to capture the true interannual water-level dynamics in 68% of the cases. Our frequency analysis suggested that even with a repeat cycle of two months, ICESat could capture only 60% of the variations in water-level dynamics for at most 34 % of the US lakes. To capture 60% of the water-level variation for most of the US lakes, a weekly repeat cycle (e.g., less than 5 days) is needed – a requirement difficult to meet in current designs of spaceborne laser altimetry. Overall, our results highlight that current or near-future satellite laser missions, though with high ranging accuracies, are unlikely to fulfill the general needs in remotely monitoring water surface dynamics for lakes or reservoirs.« less

Water surface elevation from the upcoming SWOT mission under different flows conditions

NASA Astrophysics Data System (ADS)

Domeneghetti, Alessio; Schumann, Guy J. P.; Wei, Rui; Frasson, Renato P. M.; Durand, Michael; Pavelsky, Tamlin; Castellarin, Attilio; Brath, Armando

2017-04-01

The upcoming SWOT (Surface Water and Ocean Topography) satellite mission will provide unprecedented bi-dimensional observations of terrestrial water surface heights along rivers wider than 100m. Despite the literature reports several activities showing possible uses of SWOT products, potential and limitations of satellite observations still remain poorly understood and investigated. We present one of the first analyses regarding the spatial observation of water surface elevation expected from SWOT for a 140 km reach of the middle-lower portion of the Po River, in Northern Italy. The river stretch is characterized by a main channel varying from 100-500 m in width and a floodplain delimited by a system of major embankments that can be as wide as 5 km. The reconstruction of the hydraulic behavior of the Po River is performed by means of a quasi-2D model built with detailed topographic and bathymetric information (LiDAR, 2m resolution), while the simulation of remotely sensed hydrometric data is performed with a SWOT simulator that mimics the satellite sensor characteristics. Referring to water surface elevations associated with different flow conditions (maximum, minimum and average flow) this work characterizes the spatial observations provided by SWOT and highlights the strengths and limitations of the expected products. The analysis provides a robust reference for spatial water observations that will be available from SWOT and assesses possible effects of river embankments, river width and river topography under different hydraulic conditions. Results of the study characterize the expected accuracy of the upcoming SWOT mission and provide additional insights towards the appropriate exploitation of future hydrological observations.

Natural attenuation of chlorinated-hydrocarbon contamination at Fort Wainwright, Alaska; a hydrogeochemical and microbiological investigation workplan

USGS Publications Warehouse

McCarthy, Kathleen A.; Lilly, Michael R.; Braddock, Joan F.; Hinzman, Larry D.

1998-01-01

Natural attenuation processes include biological degradation, by which microorganisms break down contaminants into simpler product compounds; adsorption of contaminants to soil particles, which decreases the mass of contaminants dissolved in ground water; and dispersion, which decreases dissolved contaminant concentrations through dilution. The primary objectives of this study are to (1) assess the degree to which such natural processes are attenuating chlorinated-hydrocarbon contamination in ground water, and (2) evaluate the effects of ground-water/surface-water interactions on natural-attenuation processes in the area of the former East and West Quartermasters Fueling Systems for Fort Wainwright, Alaska. The study will include investigations of the hydrologic, geochemical, and microbiological processes occurring at this site that influence the transport and fate of chlorinated hydrocarbons in ground water. To accomplish these objectives, a data-collection program has been initiated that includes measurements of water-table elevations and the stage of the Chena River; measurements of vertical temperature profiles within the subsurface; characterization of moisture distribution and movement in the unsaturated zone; collection of ground-water samples for determination of both organic and inorganic chemical constituents; and collection of ground-water samples for enumeration of microorganisms and determination of their potential to mineralize contaminants. We will use results from the data-collection program described above to refine our conceptual model of hydrology and contaminant attenuation at this site. Measurements of water-table elevations and river stage will help us to understand the magnitude and direction of ground-water flow and how changes in the stage of the Chena River affect ground-water flow. Because ambient ground water and surface water typically have different temperature characteristics, temperature monitoring will likely provide further insight into ground-water/surface-water interactions in the subsurface. Characterization of the unsaturated zone will improve our understanding of interactions among ground water, the unsaturated zone, and the atmosphere. The interactions likely of importance to this study include the migration of water, dissolved contaminants, nutrients, and gases (oxygen, carbon dioxide, and methane) between the saturated and unsaturated zones. We will use the results of ground-water chemical analyses to determine the spatial and temporal distribution of (1) chlorinated-hydrocarbon contaminants and their degradation products, (2) oxidation-reduction indicators, (3) nutrients, and (4) major ground-water ions. These water-quality data will provide insight into ground-water flow directions, interactions between ground water and surface water, attenuation of contaminant concentrations caused by dispersion, and intrinsic microbiological processes. Microbiological analyses will indicate whether microorganisms at the site are capable of degrading the contaminants of interest, and will allow us to estimate their potential to attenuate existing contamination. Physical and chemical data interpreted as part of the analysis of ground water and surface water mixing will improve our understanding of the relationship between water quality and contaminant source mixing.

Swath-altimetry measurements of the main stem Amazon River: measurement errors and hydraulic implications

NASA Astrophysics Data System (ADS)

Wilson, M. D.; Durand, M.; Jung, H. C.; Alsdorf, D.

2015-04-01

The Surface Water and Ocean Topography (SWOT) mission, scheduled for launch in 2020, will provide a step-change improvement in the measurement of terrestrial surface-water storage and dynamics. In particular, it will provide the first, routine two-dimensional measurements of water-surface elevations. In this paper, we aimed to (i) characterise and illustrate in two dimensions the errors which may be found in SWOT swath measurements of terrestrial surface water, (ii) simulate the spatio-temporal sampling scheme of SWOT for the Amazon, and (iii) assess the impact of each of these on estimates of water-surface slope and river discharge which may be obtained from SWOT imagery. We based our analysis on a virtual mission for a ~260 km reach of the central Amazon (Solimões) River, using a hydraulic model to provide water-surface elevations according to SWOT spatio-temporal sampling to which errors were added based on a two-dimensional height error spectrum derived from the SWOT design requirements. We thereby obtained water-surface elevation measurements for the Amazon main stem as may be observed by SWOT. Using these measurements, we derived estimates of river slope and discharge and compared them to those obtained directly from the hydraulic model. We found that cross-channel and along-reach averaging of SWOT measurements using reach lengths greater than 4 km for the Solimões and 7.5 km for Purus reduced the effect of systematic height errors, enabling discharge to be reproduced accurately from the water height, assuming known bathymetry and friction. Using cross-sectional averaging and 20 km reach lengths, results show Nash-Sutcliffe model efficiency values of 0.99 for the Solimões and 0.88 for the Purus, with 2.6 and 19.1 % average overall error in discharge, respectively. We extend the results to other rivers worldwide and infer that SWOT-derived discharge estimates may be more accurate for rivers with larger channel widths (permitting a greater level of cross-sectional averaging and the use of shorter reach lengths) and higher water-surface slopes (reducing the proportional impact of slope errors on discharge calculation).

Stream profile analysis using a step backwater model for selected reaches in the Chippewa Creek basin in Medina, Wayne, and Summit Counties, Ohio

USGS Publications Warehouse

Straub, David E.; Ebner, Andrew D.

2011-01-01

The USGS, in cooperation with the Chippewa Subdistrict of the Muskingum Watershed Conservancy District, performed hydrologic and hydraulic analyses for selected reaches of three streams in Medina, Wayne, Stark, and Summit Counties in northeast Ohio: Chippewa Creek, Little Chippewa Creek, and River Styx. This study was done to facilitate assessment of various alternatives for mitigating flood hazards in the Chippewa Creek basin. StreamStats regional regression equations were used to estimate instantaneous peak discharges approximately corresponding to bankfull flows. Explanatory variables used in the regression equations were drainage area, main-channel slope, and storage area. Hydraulic models were developed to determine water-surface profiles along the three stream reaches studied for the bankfull discharges established in the hydrologic analyses. The HEC-RAS step-backwater hydraulic analysis model was used to determine water-surface profiles for the three streams. Starting water-surface elevations for all streams were established using normal depth computations in the HEC-RAS models. Cross-sectional elevation data, hydraulic-structure geometries, and roughness coefficients were collected in the field and (along with peak-discharge estimates) used as input for the models. Reach-averaged reductions in water-surface elevations ranged from 0.11 to 1.29 feet over the four roughness coefficient reduction scenarios.

The effects of elevated CO2 and eutrophication on surface elevation gain in a European salt marsh.

PubMed

Reef, Ruth; Spencer, Tom; Mӧller, Iris; Lovelock, Catherine E; Christie, Elizabeth K; McIvor, Anna L; Evans, Ben R; Tempest, James A

2017-02-01

Salt marshes can play a vital role in mitigating the effects of global environmental change by dissipating incident storm wave energy and, through accretion, tracking increasing water depths consequent upon sea level rise. Atmospheric CO 2 concentrations and nutrient availability are two key variables that can affect the biological processes that contribute to marsh surface elevation gain. We measured the effects of CO 2 concentrations and nutrient availability on surface elevation change in intact mixed-species blocks of UK salt marsh using six open-top chambers receiving CO 2 -enriched (800 ppm) or ambient (400 ppm) air. We found more rapid surface elevation gain in elevated CO 2 conditions: an average increase of 3.4 mm over the growing season relative to ambient CO 2 . Boosted regression analysis to determine the relative influence of different parameters on elevation change identified that a 10% reduction in microbial activity in elevated CO 2 -grown blocks had a positive influence on elevation. The biomass of Puccinellia maritima also had a positive influence on elevation, while other salt marsh species (e.g. Suaeda maritima) had no influence or a negative impact on elevation. Reduced rates of water use by the vegetation in the high CO 2 treatment could be contributing to elevation gain, either directly through reduced soil shrinkage or indirectly by decreasing microbial respiration rates due to lower redox levels in the soil. Eutrophication did not influence elevation change in either CO 2 treatment despite doubling aboveground biomass. The role of belowground processes (transpiration, root growth and decomposition) in the vertical adjustment of European salt marshes, which are primarily minerogenic in composition, could increase as atmospheric CO 2 concentrations rise and should be considered in future wetland models for the region. Elevated CO 2 conditions could enhance resilience in vulnerable systems such as those with low mineral sediment supply or where migration upwards within the tidal frame is constrained. © 2016 John Wiley & Sons Ltd.

On the Representation of Subgrid Microtopography Effects in Process-based Hydrologic Models

NASA Astrophysics Data System (ADS)

Jan, A.; Painter, S. L.; Coon, E. T.

2017-12-01

Increased availability of high-resolution digital elevation are enabling process-based hydrologic modeling on finer and finer scales. However, spatial variability in surface elevation (microtopography) exists below the scale of a typical hyper-resolution grid cell and has the potential to play a significant role in water retention, runoff, and surface/subsurface interactions. Though the concept of microtopographic features (depressions, obstructions) and the associated implications on flow and discharge are well established, representing those effects in watershed-scale integrated surface/subsurface hydrology models remains a challenge. Using the complex and coupled hydrologic environment of the Arctic polygonal tundra as an example, we study the effects of submeter topography and present a subgrid model parameterized by small-scale spatial heterogeneities for use in hyper-resolution models with polygons at a scale of 15-20 meters forming the surface cells. The subgrid model alters the flow and storage terms in the diffusion wave equation for surface flow. We compare our results against sub-meter scale simulations (acts as a benchmark for our simulations) and hyper-resolution models without the subgrid representation. The initiation of runoff in the fine-scale simulations is delayed and the recession curve is slowed relative to simulated runoff using the hyper-resolution model with no subgrid representation. Our subgrid modeling approach improves the representation of runoff and water retention relative to models that ignore subgrid topography. We evaluate different strategies for parameterizing subgrid model and present a classification-based method to efficiently move forward to larger landscapes. This work was supported by the Interoperable Design of Extreme-scale Application Software (IDEAS) project and the Next-Generation Ecosystem Experiments-Arctic (NGEE Arctic) project. NGEE-Arctic is supported by the Office of Biological and Environmental Research in the DOE Office of Science.

75 FR 63048 - Airworthiness Directives; Empresa Brasileira de Aeronautica S.A. (EMBRAER) Model EMB-500 Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-14

..., in general, agree with their substance. But we might have found it necessary to use different words...: It has been found that certain regions of the elevators, elevators trim tabs, and ailerons do not present drain holes to avoid water accumulation inside of these flight control surfaces. Internal water...

A Numerical Study of Currents, Water Surface Elevations, and Energy Dissipation in Chandeleur-Breton Sound, Louisiana.

DTIC Science & Technology

1978-02-01

Numerical methods in the form of a digital computer model were used to simulate and study the tide- and wind-induced circulation in Chandeleur -Breton...entrances through the Chandeleur Island chain, where speed reaches 50-60 cm/sec for short periods. Surface elevations were found to have an average tide range

Using surface water application to reduce 1,3-dichloropropene emission from soil fumigation.

PubMed

Gao, Suduan; Trout, Thomas J

2006-01-01

High emissions from soil fumigants increase the risk of detrimental impact on workers, bystanders, and the environment, and jeopardize future availability of fumigants. Efficient and cost-effective approaches to minimize emissions are needed. This study evaluated the potential of surface water application (or water seal) to reduce 1,3-dichloropropene (1,3-D) emissions from soil (Hanford sandy loam) columns. Treatments included dry soil (control), initial water application (8 mm of water just before fumigant application), initial plus a second water application (2.6 mm) at 12 h, initial plus two water applications (2.6 mm each time) at 12 and 24 h, standard high density polyethylene (HDPE) tarp, initial water application plus HDPE tarp, and virtually impermeable film (VIF) tarp. Emissions from the soil surface and distribution of 1,3-D in the soil-gas phase were monitored for 2 wk. Each water application abruptly reduced 1,3-D emission flux, which rebounded over a few hours. Peak emission rates were substantially reduced, but total emission reduction was small. Total fumigant emission was 51% of applied for the control, 46% for initial water application only, and 41% for the three intermittent water applications with the remaining water treatment intermediate. The HDPE tarp alone resulted in 45% emission, while initial water application plus HDPE tarp resulted in 38% emission. The most effective soil surface treatment was VIF tarp (10% emission). Surface water application can be as effective, and less expensive than, standard HDPE tarp. Frequent water application is required to substantially reduce emissions.

Experimental study of temporal evolution of waves under transient wind conditions

NASA Astrophysics Data System (ADS)

Zavadsky, Andrey; Shemer, Lev

2016-11-01

Temporal variation of the waves excited by nearly sudden wind forcing over an initially still water surface is studied in a small wind-wave flume at Tel Aviv University for variety of fetches and wind velocities. Simultaneous measurements of the surface elevation using a conventional capacitance wave-gauge and of the surface slope in along-wind and cross-wind directions by a laser slope gauge were performed. Variation with time of two components of instantaneous surface velocity was measured by particle tracking velocimetry. The size of the experimental facility and thus relatively short characteristic time scales of the phenomena under investigation, as well as an automated experimental procedure controlling the experiments made it possible to record a large amount of independent realizations for each wind-fetch condition. Sufficient data were accumulated to compute reliable ensemble averaged temporal variation of governing wave parameters. The essentially three-dimensional structure of wind-waves at all stages of evolution is demonstrated. The results obtained at each wind-fetch condition allowed to characterize the major stages of the evolution of the wind-wave field and to suggest a plausible scenario for the initial growth of the wind-waves.

Bathymetry of Ashokan, Cannonsville, Neversink, Pepacton, Rondout, and Schoharie Reservoirs, New York, 2013–15

USGS Publications Warehouse

Nystrom, Elizabeth A.

2018-02-01

Drinking water for New York City is supplied from several large reservoirs, including a system of reservoirs west of the Hudson River. To provide updated reservoir capacity tables and bathymetry maps of the City’s six West of Hudson reservoirs, bathymetric surveys were conducted by the U.S. Geological Survey from 2013 to 2015. Depths were surveyed with a single-beam echo sounder and real-time kinematic global positioning system along planned transects at predetermined intervals for each reservoir. A separate quality assurance dataset of echo sounder points was collected along transects at oblique angles to the main transects for accuracy assessment. Field-survey data were combined with water surface elevations in a geographic information system to create three-dimensional surfaces in the form of triangulated irregular networks (TINs) representing the elevations of the reservoir geomorphology. The TINs were linearly enforced to better represent geomorphic features within the reservoirs. The linearly enforced TINs were then used to create raster surfaces and 2-foot-interval contour maps of the reservoirs. Elevation-area-capacity tables were calculated at 0.01-foot intervals. The results of the surveys show that the total capacity of the West of Hudson reservoirs has decreased by 11.5 billion gallons (Ggal), or 2.3 percent, since construction, and the useable capacity (the volume above the minimum operating level required to deliver full flow for drinking water supply) has decreased by 7.9 Ggal (1.7 percent). The available capacity (the volume between the spillway elevation and the lowest intake or sill elevation used for drinking water supply) decreased by 9.6 Ggal (2.0 percent), and dead storage (the volume below the lowest intake or sill elevation) decreased by 1.9 Ggal (11.6 percent).

76 FR 69720 - Don Pedro Hydro, LLC; Moccasin Pumped Storage, LLC; Notice of Competing Preliminary Permit...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-09

... storage capacity of 25,000 acre-feet and a surface area of 241 acres at maximum normal water surface... penstocks; (4) a powerhouse with four 250 MW pump/turbines having an installed capacity of approximately... capacity of 25,000 acre-feet and a surface area of 240 acres at maximum normal water surface elevation of 1...

Biotransformation of gabapentin in surface water matrices under different redox conditions and the occurrence of one major TP in the aquatic environment.

PubMed

Henning, Nina; Kunkel, Uwe; Wick, Arne; Ternes, Thomas A

2018-06-15

Laboratory-scale incubation experiments in water/sediment systems were conducted to test the transformation behavior of the anticonvulsant gabapentin (GBP) under different environmental conditions (aerobic, anaerobic, with abiotic controls). GBP was transformed by biological processes as it was eliminated quickly under aerobic conditions (dissipation time 50% of initial concentration (DT 50 ): 2-7 days) whereas no decrease was observed under anaerobic conditions. Measurements via high resolution mass spectrometry (LC-Orbitrap-MS) revealed eight biological transformation products (TPs). Three of them were identified with reference standards (GBP-Lactam, TP186, TP213), while for the other five TPs tentative structures were proposed from information by MS 2 /MS 3 experiments. Furthermore, the quantitatively most relevant TP GBP-Lactam was formed via intramolecular amidation (up to 18% of initial GBP concentration). Incubation experiments with GBP-Lactam revealed a higher stability against biotic degradation (DT 50 : 12 days) in contrast to GBP, while it was stable under anaerobic and abiotic conditions. Besides GBP, GBP-Lactam was detected in surface water in the μg L -1 range. Finally, GBP and GBP-Lactam were found in potable water with concentrations up to 0.64 and 0.07 μg L -1 , respectively. According to the elevated environmental persistence of GBP-Lactam compared to GBP and its presumed enhanced toxicity, we recommend to involve GBP-Lactam into monitoring programs. Copyright © 2018 Elsevier Ltd. All rights reserved.

Effects of Whole-Ecosystem Warming on Porewater Chemistry and Hydrology in a Northern Peatland

NASA Astrophysics Data System (ADS)

Griffiths, N.; Sebestyen, S. D.

2016-12-01

Northern peatlands are carbon-rich ecosystems, and thus it is important to understand the effects of climate change on carbon cycle feedbacks in these vulnerable systems. An ecosystem-scale experiment is evaluating the effects of warming and elevated CO2 on an ombrotrophic bog in northern Minnesota, USA. Ten enclosures, each 12-m in diameter, were constructed in the peatland to allow for both above and belowground warming. Each enclosure receives one of five temperature treatments (+0 to +9°C), with half of the enclosures receiving elevated CO2 (+500ppm) and the other half ambient CO2. A belowground corral with a lateral drainage system surrounds each enclosure, and allows for measurements of lateral outflow volume and chemistry. Piezometers are used to sample porewater chemistry at different depths (0-3m) into the peat. We evaluated the effects of one year of whole-ecosystem warming on depth-specific porewater chemistry and outflow dynamics. Changes in porewater chemistry were observed upon initiation of whole-ecosystem warming. Total organic carbon (TOC) concentrations increased in near-surface porewater in the warmer enclosures, while concentrations were lower and similar to pre-treatment conditions in the ambient (+0°C) enclosures. The changes in TOC concentration measured in response to whole-ecosystem warming were initially limited to only the near-surface porewater (0 m); however, TOC concentrations began to increase at 0.3 m depth after several months of warming. These changes in TOC concentrations were also reflected in water draining from each enclosure, with generally higher TOC concentrations in water flowing from warmer enclosures. However, warmer treatments tended to have lower water outflow rates, possibly due to increased evapotranspiration, and thus TOC fluxes were generally lowest from the warmest enclosures. Overall, these initial results suggest that warming may increase porewater TOC concentrations, possibly due to increased mineralization rates of peat; however, due to the interaction with hydrology, export of this TOC to downstream ecosystems may be lower with warming. Continued measurements over the next 10 years will evaluate the long-term effects of warming on peatland chemistry and hydrology.

Hydrostratigraphy of Tree Island Cores from Water Conservation Area 3

USGS Publications Warehouse

McNeill, Donald F.; Cunningham, Kevin J.

2003-01-01

Cores and borehole-geophysical logs collected on and around two tree islands in Water Conservation Area 3 have been examined to develop a stratigraphic framework for these ecosystems. Especially important is the potential for the exchange of ground water and surface water within these features. The hydrostratigraphic results from this study document the lithologic nature of the foundation of the tree islands, the distribution of porous intervals, the potential for paleotopographic influence on their formation, and the importance of low-permeability, subaerial-exposure horizons on the vertical exchange of ground water and surface water. Figure 1. Location of Tree Islands 3AS3 and 3BS1. [larger image] Results from this hydrostratigraphic study indicate that subtle differences occur in lithofacies and topography between the on-island and off-island subsurface geologic records. Specifics are described herein. Firstly, at both tree-island sites, the top of the limestone bedrock is slightly elevated beneath the head of the tree islands relative to the off-island core sites and the tail of the tree islands, which suggests that bedrock 'highs' acted as 'seeds' for the development of the tree islands of this study and possibly many others. Secondly, examination of the recovered core and the caliper logs tentatively suggest that the elevated limestone beneath the tree islands may have a preferentially more porous framework relative to limestone beneath the adjacent areas, possibly providing a ground-water-to-surface-water connection that sustains the tree island system. Finally, because the elevation of the top of the limestone bedrock at the head of Tree Island 3AS3 is slightly higher than the surrounding upper surface of the peat, and because the wetland peats have a lower hydraulic conductivity than the limestone bedrock (Miami Limestone and Fort Thompson Formation), it is possible that there is a head difference between surface water of the wetlands and the ground water in underlying limestone bedrock.

Tidal wetland fluxes of dissolved organic carbon and sediment at Browns Island, California: initial evaluation

USGS Publications Warehouse

Ganju, N.K.; Bergamaschi, B.; Schoellhamer, D.H.

2003-01-01

Carbon and sediment fluxes from tidal wetlands are of increasing concern in the Sacramento-San Joaquin River Delta (Delta), because of drinking water issues and habitat restoration efforts. Certain forms of dissolved organic carbon (DOC) react with disinfecting chemicals used to treat drinking water, to form disinfection byproducts (DBPs), some of which are potential carcinogens. The contribution of DBP precursors by tidal wetlands is unknown. Sediment transport to and from tidal wetlands determines the potential for marsh accretion, thereby affecting habitat formation.Water, carbon, and sediment flux were measured in the main channel of Browns Island, a tidal wetland located at the confluence of Suisun Bay and the Delta. In-situ instrumentation were deployed between May 3 and May 21, 2002. Water flux was measured using acoustic Doppler current profilers and the index-velocity method. DOC concentrations were measured using calibrated ultraviolet absorbance and fluorescence instruments. Suspended-sediment concentrations were measured using a calibrated nephelometric turbidity sensor. Tidally averaged water flux through the channel was dependent on water surface elevations in Suisun Bay. Strong westerly winds resulted in higher water surface elevations in the area east of Browns Island, causing seaward flow, while subsiding winds reversed this effect. Peak ebb flow transported 36% more water than peak flood flow, indicating an ebb-dominant system. DOC concentrations were affected strongly by porewater drainage from the banks of the channel. Peak DOC concentrations were observed during slack after ebb, when the most porewater drained into the channel. Suspended-sediment concentrations were controlled by tidal currents that mobilized sediment from the channel bed, and stronger tides mobilized more sediment than the weaker tides. Sediment was transported mainly to the island during the 2-week monitoring period, though short periods of export occurred during the spring tide. Future deployments will characterize the seasonal variability of these fluxes.

Discharge of New Subglacial Lake on Whillians Ice Stream: Implication for Ice Stream Flow Dynamics.

NASA Astrophysics Data System (ADS)

Sergienko, O. V.; Fricker, H. A.; Bindschadler, R. A.; Vornberger, P. L.; Macayeal, D. R.

2006-12-01

One of the surprise discoveries made possible by the ICESat laser altimeter mission of 2004-2006 is the presence of a large subglacial lake below the grounding zone of Whillians Ice Stream (dubbed here `Lake Helen' after the discoverer, Helen Fricker). What is even more surprising is the fact that this lake discharged a substantial portion of its volume during the ICESat mission, and changes in lake volume and surface elevation of the ice stream are documented in exquisite detail [Fricker et al., in press]. The presence and apparent dynamism of large subglacial lakes in the grounding zone of a major ice stream raises questions about their effects on ice-stream dynamics. Being liquid and movable, water modifies basal friction spatially and temporally. Melting due to shear heating and geothermal flux reduces basal traction, making the ice stream move fast. However, when water collects in a depression to form a lake, it potentially deprives the surrounding bed of lubricating water, and additionally makes the ice surface flat, thereby locally decreasing the ice stream driving stress. We study the effect of formation and discharge of a subglacial lake at the mouth of and ice stream using a two dimensional, vertically integrated, ice-stream model. The model is forced by the basal friction, ice thickness and surface elevation. The basal friction is obtained by inversion of the ice surface velocity, ice thickness and surface elevation come from observations. To simulate the lake formation we introduce zero basal friction and "inflate" the basal elevation of the ice stream at the site of the lake. Sensitivity studies of the response of the surrounding ice stream and ice shelf flow are performed to delineate the influence of near-grounding-line subglacial water storage for ice streams in general.

Recent Hydrologic Developments in the SWOT Mission

NASA Astrophysics Data System (ADS)

Alsdorf, D. E.; Mognard, N. M.; Cretaux, J.; Calmant, S.; Lettenmaier, D. P.; Rodriguez, E.

2012-12-01

The Surface Water and Ocean Topography satellite mission (SWOT) is designed to measure the elevations of the world's water surfaces including both terrestrial surface waters and the oceans. CNES, NASA, and the CSA are partners in the mission as are hydrologists, oceanographers, and an international engineering team. Recent hydrologic and mission related advances include the following. (1) An airborne version of SWOT called AirSWOT has been developed to provide calibration and validation for the mission when on orbit as well as to support science and technology during mission development. AirSWOT flights are in the planning stage. (2) In early 2012, NASA and CNES issued calls for proposals to participate in the forthcoming SWOT Science Definition Team. Results are expected in time for a Fall 2012 start of the SDT. (3) A workshop held in June 2012 addressed the problem of estimating river discharge from SWOT measurements. SWOT discharge estimates will be developed for river reaches rather than individual cross-sections. Errors will result from algorithm unknowns of bathymetry and roughness, from errors in SWOT measurements of water surface height and inundation, from the incomplete temporal record dictated by the SWOT orbit, and from fluvial features such as unmeasured inflows and outflows within the reach used to estimate discharge. To overcome these issues, in-situ and airborne field data are required in order to validate and refine algorithms. (4) Two modeling methods are using the Amazon Basin as a test case for demonstrating the utility of SWOT observables for constraining water balances. In one case, parameters used to minimize differences between SWOT and model water surface elevations should be adjusted locally in space and time. In the other case, using actual altimetry data as a proxy for SWOT's water surface elevations, it was determined that model water surface elevations were less than 1.6m different from the altimetry measurements: a considerable match given the lack of channel bathymetric knowledge. (5) The influence of the world's managed reservoirs on the water cycle is difficult to assess given the abundance of dams and the relative lack of water level or storage change information. The downstream impacts, particularly for transboundary rivers, are similarly difficult to determine. The challenges for SWOT to overcome this lack hinge on the temporal sampling dictated by the mission's orbital repeat cycle, on the accuracy of the height measurements, on the surface area, and on topography causing radar layover. (6) While SWOT's orbit is designed to minimize errors from tidal aliasing, orbital sub-cycles can be adjusted to minimize hydrological errors. The impact of theses sub-cycles has been assessed using a hydrodynamic modeling of the last 1000 km reach of the Ob River, a West Siberian river draining a total area of around 3 million km2. Using a local ensemble Kalman smoother to assimilate virtual SWOT observations, similar results have been obtained for either a 1-day or 3-day sub-cycle when decreasing the differences between "true" and modeled water elevations. A key result is the necessity of using the smoother in the assimilation, at least for large rivers like the Ob.

Surface elevation dynamics in vegetated Spartina marshes versus unvegetated tidal ponds along the mid-Atlantic coast, USA, with implications to waterbirds

USGS Publications Warehouse

Erwin, R. Michael; Cahoon, Donald R.; Prosser, Diann J.; Sanders, Geoffrey; Hensel, Philippe

2006-01-01

Mid Atlantic coastal salt marshes contain a matrix of vegetation diversified by tidal pools, pannes, and creeks, providing habitats of varying importance to many species of breeding, migrating, and wintering waterbirds. We hypothesized that changes in marsh elevation were not sufficient to keep pace with those of sea level in both vegetated and unvegetated Spartina alterniflora sites at a number of mid lagoon marsh areas along the Atlantic coast. We also predicted that northern areas would suffer less of a deficit than would southern sites. Beginning in August 1998, we installed surface elevation tables at study sites on Cape Cod, Massachusetts, southern New Jersey, and two locations along Virginia's eastern shore. We compared these elevation changes over the 4-4.5 yr record with the long-term (> 50 yr) tidal records for each locale. We also collected data on waterbird use of these sites during all seasons of the year, based on ground surveys and replicated surveys from observation platforms. Three patterns of marsh elevation change were found. At Nauset Marsh, Cape Cod, the Spartina marsh surface tracked the pond surface, both keeping pace with regional sea-level rise rates. In New Jersey, the ponds are becoming deeper while marsh surface elevation remains unchanged from the initial reading. This may result in a submergence of the marsh in the future, assuming sea-level rise continues at current rates. Ponds at both Virginia sites are filling in, while marsh surface elevation rates do not seem to be keeping pace with local sea-level rise. An additional finding at all sites was that subsidence in the vegetated marsh surfaces was less than in unvegetated areas, reflecting the importance of the root mat in stabilizing sediments. The implications to migratory waterbirds are significant. Submergence of much of the lagoonal marsh area in Virginia and New Jersey over the next century could have major negative (i.e., flooding) effects on nesting populations of marsh-dependent seaside sparrows Ammodramus maritimus, saltmarsh sharp-tailed sparrows A. caudacutus, black rails Laterallus jamaicensis, clapper rails Rallus longirostris, Forster's terns Sterna forsteri, common terns Sterna hirundo, and gull-billed terns Sterna nilotica. Although short-term inundation of many lagoonal marshes may benefit some open-water feeding ducks, geese, and swans during winter, the long-term ecosystem effects may be detrimental, as wildlife resources will be lost or displaced. With the reduction in area of emergent marsh, estuarine secondary productivity and biotic diversity will also be reduced.

Characterizing water surface elevation under different flow conditions for the upcoming SWOT mission

NASA Astrophysics Data System (ADS)

Domeneghetti, A.; Schumann, G. J.-P.; Frasson, R. P. M.; Wei, R.; Pavelsky, T. M.; Castellarin, A.; Brath, A.; Durand, M. T.

2018-06-01

The Surface Water and Ocean Topography satellite mission (SWOT), scheduled for launch in 2021, will deliver two-dimensional observations of water surface heights for lakes, rivers wider than 100 m and oceans. Even though the scientific literature has highlighted several fields of application for the expected products, detailed simulations of the SWOT radar performance for a realistic river scenario have not been presented in the literature. Understanding the error of the most fundamental "raw" SWOT hydrology product is important in order to have a greater awareness about strengths and limits of the forthcoming satellite observations. This study focuses on a reach (∼140 km in length) of the middle-lower portion of the Po River, in Northern Italy, and, to date, represents one of the few real-case analyses of the spatial patterns in water surface elevation accuracy expected from SWOT. The river stretch is characterized by a main channel varying from 100 to 500 m in width and a large floodplain (up to 5 km) delimited by a system of major embankments. The simulation of the water surface along the Po River for different flow conditions (high, low and mean annual flows) is performed with inputs from a quasi-2D model implemented using detailed topographic and bathymetric information (LiDAR, 2 m resolution). By employing a simulator that mimics many SWOT satellite sensor characteristics and generates proxies of the remotely sensed hydrometric data, this study characterizes the spatial observations potentially provided by SWOT. We evaluate SWOT performance under different hydraulic conditions and assess possible effects of river embankments, river width, river topography and distance from the satellite ground track. Despite analyzing errors from the raw radar pixel cloud, which receives minimal processing, the present study highlights the promising potential of this Ka-band interferometer for measuring water surface elevations, with mean elevation errors of 0.1 cm and 21 cm for high and low flows, respectively. Results of the study characterize the expected performance of the upcoming SWOT mission and provide additional insights into potential applications of SWOT observations.

Illinois drainage water management demonstration project

USGS Publications Warehouse

Pitts, D.J.; Cooke, R.; Terrio, P.J.; ,

2004-01-01

Due to naturally high water tables and flat topography, there are approximately 4 million ha (10 million ac) of farmland artificially drained with subsurface (tile) systems in Illinois. Subsurface drainage is practiced to insure trafficable field conditions for farm equipment and to reduce crop stress from excess water within the root zone. Although drainage is essential for economic crop production, there have been some significant environmental costs. Tile drainage systems tend to intercept nutrient (nitrate) rich soil-water and shunt it to surface water. Data from numerous monitoring studies have shown that a significant amount of the total nitrate load in Illinois is being delivered to surface water from tile drainage systems. In Illinois, these drainage systems are typically installed without control mechanisms and allow the soil to drain whenever the water table is above the elevation of the tile outlet. An assessment of water quality in the tile drained areas of Illinois showed that approximately 50 percent of the nitrate load was being delivered through the tile systems during the fallow period when there was no production need for drainage to occur. In 1998, a demonstration project to introduce drainage water management to producers in Illinois was initiated by NRCS4 An initial aspect of the project was to identify producers that were willing to manage their drainage system to create a raised water table during the fallow (November-March) period. Financial assistance from two federal programs was used to assist producers in retrofitting the existing drainage systems with control structures. Growers were also provided guidance on the management of the structures for both water quality and production benefits. Some of the retrofitted systems were monitored to determine the effect of the practice on water quality. This paper provides background on the water quality impacts of tile drainage in Illinois, the status of the demonstration project, preliminary monitoring results, and other observations.

How well Can We Classify SWOT-derived Water Surface Profiles?

NASA Astrophysics Data System (ADS)

Frasson, R. P. M.; Wei, R.; Picamilh, C.; Durand, M. T.

2015-12-01

The upcoming Surface Water Ocean Topography (SWOT) mission will detect water bodies and measure water surface elevation throughout the globe. Within its continental high resolution mask, SWOT is expected to deliver measurements of river width, water elevation and slope of rivers wider than ~50 m. The definition of river reaches is an integral step of the computation of discharge based on SWOT's observables. As poorly defined reaches can negatively affect the accuracy of discharge estimations, we seek strategies to break up rivers into physically meaningful sections. In the present work, we investigate how accurately we can classify water surface profiles based on simulated SWOT observations. We assume that most river sections can be classified as either M1 (mild slope, with depth larger than the normal depth), or A1 (adverse slope with depth larger than the critical depth). This assumption allows the classification to be based solely on the second derivative of water surface profiles, with convex profiles being classified as A1 and concave profiles as M1. We consider a HEC-RAS model of the Sacramento River as a representation of the true state of the river. We employ the SWOT instrument simulator to generate a synthetic pass of the river, which includes our best estimates of height measurement noise and geolocation errors. We process the resulting point cloud of water surface heights with the RiverObs package, which delineates the river center line and draws the water surface profile. Next, we identify inflection points in the water surface profile and classify the sections between the inflection points. Finally, we compare our limited classification of simulated SWOT-derived water surface profile to the "exact" classification of the modeled Sacramento River. With this exercise, we expect to determine if SWOT observations can be used to find inflection points in water surface profiles, which would bring knowledge of flow regimes into the definition of river reaches.

Impacts of Agriculture on Nitrates in Soil and Groundwater in the Southeastern Coastal Plain

USDA-ARS?s Scientific Manuscript database

Nitrogen (N) contamination of surface and groundwater is a health concern for both humans and animals. Excess N in surface water bodies may contribute to eutrophication. Elevated nitrate (NO3-N) concentrations in drinking water have caused infant death from the disease methemoglobinemia. Nitrates...

Using in situ synchrotron radiation wide angle X-ray scattering (WAXS) to study CaCO3 scale formation at ambient and elevated temperature.

PubMed

Chen, Tao; Neville, Anne; Sorbie, Ken; Zhong, Zhong

2007-01-01

The formation of calcium carbonate mineral scale is a persistent and expensive problem in oil and gas production, water piping systems, power generator, and batch precipitation. The aim of this paper is to further the understanding of scale formation and inhibition by in situ probing of crystal growth by synchrotron radiation wide angle X-ray scattering (WAXS) at ambient and elevated temperature. This novel technique enables in situ study of mineral scale formation and inhibition and as such, information on the nucleation and growth processes are accessible. This technique studies bulk precipitation and surface deposition in the same system and will be of great benefit to the understanding of an industrial scaling system. It offers an exciting prospect for the study of scaling. It has been shown that the nucleation and growth of various calcareous polymorphs and their individual crystal planes can be followed in real-time and from this the following conclusions are reached. The process of scale deposition on the surface can be divided into an unstable phase and a stable phase. The initial phase of crystallization of calcium carbonate is characterized by instability with individual planes from various vaterite and aragonite polymorphs emerging and subsequently disappearing under the hydrodynamic conditions. After the initial unstable phase, various calcium carbonate crystal planes adhere on the surface and then grow on the surface. At 25 degrees C, the main plane of surface deposit is calcite and a strong (104) peak is detected. The other calcite planes (102), (006), (110) (113) and (202) are hardly detectable under this condition. At 80 degrees C, the main planes in the surface deposit are the (104), (113) and (110) planes of calcite. Stable planes of vaterite and aragonite are also observed. This paper will discuss how surface scale evolves--exploring the power of the synchrotron in situ methodology.

Greenland Subglacial Drainage Evolution Regulated by Weakly Connected Regions of the Bed

NASA Technical Reports Server (NTRS)

Hoffman, Matthew J.; Andrews, Lauren C.; Price, Stephen F.; Catania, Ginny A.; Neumann, Thomas A.; Luthi, Martin P.; Gulley, Jason; Ryser, Claudia; Hawley, Robert L.; Morriss, Blaine

2016-01-01

Penetration of surface meltwater to the bed of the Greenland Ice Sheet each summer causes an initial increase in ice speed due to elevated basal water pressure, followed by slowdown in late summer that continues into fall and winter. While this seasonal pattern is commonly explained by an evolution of the subglacial drainage system from an inefficient distributed to efficient channelized configuration, mounting evidence indicates that subglacial channels are unable to explain important aspects of hydrodynamic coupling in late summer and fall. Here we use numerical models of subglacial drainage and ice flow to show that limited, gradual leakage of water and lowering of water pressure in weakly connected regions of the bed can explain the dominant features in late and post melt season ice dynamics. These results suggest that a third weakly connected drainage component should be included in the conceptual model of subglacial hydrology.

Greenland subglacial drainage evolution regulated by weakly connected regions of the bed

PubMed Central

Hoffman, Matthew J.; Andrews, Lauren C.; Price, Stephen A.; Catania, Ginny A.; Neumann, Thomas A.; Lüthi, Martin P.; Gulley, Jason; Ryser, Claudia; Hawley, Robert L.; Morriss, Blaine

2016-01-01

Penetration of surface meltwater to the bed of the Greenland Ice Sheet each summer causes an initial increase in ice speed due to elevated basal water pressure, followed by slowdown in late summer that continues into fall and winter. While this seasonal pattern is commonly explained by an evolution of the subglacial drainage system from an inefficient distributed to efficient channelized configuration, mounting evidence indicates that subglacial channels are unable to explain important aspects of hydrodynamic coupling in late summer and fall. Here we use numerical models of subglacial drainage and ice flow to show that limited, gradual leakage of water and lowering of water pressure in weakly connected regions of the bed can explain the dominant features in late and post melt season ice dynamics. These results suggest that a third weakly connected drainage component should be included in the conceptual model of subglacial hydrology. PMID:27991518

Greenland subglacial drainage evolution regulated by weakly connected regions of the bed

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoffman, Matthew J.; Andrews, Lauren C.; Price, Stephen A.

Penetration of surface meltwater to the bed of the Greenland Ice Sheet each summer causes an initial increase in ice speed due to elevated basal water pressure, followed by slowdown in late summer that continues into fall and winter. While this seasonal pattern is commonly explained by an evolution of the subglacial drainage system from an inefficient distributed to efficient channelized configuration, mounting evidence indicates that subglacial channels are unable to explain important aspects of hydrodynamic coupling in late summer and fall. Here we use numerical models of subglacial drainage and ice flow to show that limited, gradual leakage ofmore » water and lowering of water pressure in weakly connected regions of the bed can explain the dominant features in late and post melt season ice dynamics. Finally, these results suggest that a third weakly connected drainage component should be included in the conceptual model of subglacial hydrology.« less

Greenland subglacial drainage evolution regulated by weakly connected regions of the bed.

PubMed

Hoffman, Matthew J; Andrews, Lauren C; Price, Stephen A; Catania, Ginny A; Neumann, Thomas A; Lüthi, Martin P; Gulley, Jason; Ryser, Claudia; Hawley, Robert L; Morriss, Blaine

2016-12-19

Penetration of surface meltwater to the bed of the Greenland Ice Sheet each summer causes an initial increase in ice speed due to elevated basal water pressure, followed by slowdown in late summer that continues into fall and winter. While this seasonal pattern is commonly explained by an evolution of the subglacial drainage system from an inefficient distributed to efficient channelized configuration, mounting evidence indicates that subglacial channels are unable to explain important aspects of hydrodynamic coupling in late summer and fall. Here we use numerical models of subglacial drainage and ice flow to show that limited, gradual leakage of water and lowering of water pressure in weakly connected regions of the bed can explain the dominant features in late and post melt season ice dynamics. These results suggest that a third weakly connected drainage component should be included in the conceptual model of subglacial hydrology.

Greenland subglacial drainage evolution regulated by weakly connected regions of the bed

DOE PAGES

Hoffman, Matthew J.; Andrews, Lauren C.; Price, Stephen A.; ...

2016-12-19

Penetration of surface meltwater to the bed of the Greenland Ice Sheet each summer causes an initial increase in ice speed due to elevated basal water pressure, followed by slowdown in late summer that continues into fall and winter. While this seasonal pattern is commonly explained by an evolution of the subglacial drainage system from an inefficient distributed to efficient channelized configuration, mounting evidence indicates that subglacial channels are unable to explain important aspects of hydrodynamic coupling in late summer and fall. Here we use numerical models of subglacial drainage and ice flow to show that limited, gradual leakage ofmore » water and lowering of water pressure in weakly connected regions of the bed can explain the dominant features in late and post melt season ice dynamics. Finally, these results suggest that a third weakly connected drainage component should be included in the conceptual model of subglacial hydrology.« less

Greenland subglacial drainage evolution regulated by weakly connected regions of the bed

NASA Astrophysics Data System (ADS)

Hoffman, Matthew J.; Andrews, Lauren C.; Price, Stephen A.; Catania, Ginny A.; Neumann, Thomas A.; Lüthi, Martin P.; Gulley, Jason; Ryser, Claudia; Hawley, Robert L.; Morriss, Blaine

2016-12-01

Penetration of surface meltwater to the bed of the Greenland Ice Sheet each summer causes an initial increase in ice speed due to elevated basal water pressure, followed by slowdown in late summer that continues into fall and winter. While this seasonal pattern is commonly explained by an evolution of the subglacial drainage system from an inefficient distributed to efficient channelized configuration, mounting evidence indicates that subglacial channels are unable to explain important aspects of hydrodynamic coupling in late summer and fall. Here we use numerical models of subglacial drainage and ice flow to show that limited, gradual leakage of water and lowering of water pressure in weakly connected regions of the bed can explain the dominant features in late and post melt season ice dynamics. These results suggest that a third weakly connected drainage component should be included in the conceptual model of subglacial hydrology.

Characterization of Missouri surface waters near point sources of pollution reveals potential novel atmospheric route of exposure for bisphenol A and wastewater hormonal activity pattern.

PubMed

Kassotis, Christopher D; Alvarez, David A; Taylor, Julia A; vom Saal, Frederick S; Nagel, Susan C; Tillitt, Donald E

2015-08-15

Surface water contamination by chemical pollutants increasingly threatens water quality around the world. Among the many contaminants found in surface water, there is growing concern regarding endocrine disrupting chemicals, based on their ability to interfere with some aspect of hormone action in exposed organisms, including humans. This study assessed water quality at several sites across Missouri (near wastewater treatment plants and airborne release sites of bisphenol A) based on hormone receptor activation potencies and chemical concentrations present in the surface water. We hypothesized that bisphenol A and ethinylestradiol would be greater in water near permitted airborne release sites and wastewater treatment plant inputs, respectively, and that these two compounds would be responsible for the majority of activities in receptor-based assays conducted with water collected near these sites. Concentrations of bisphenol A and ethinylestradiol were compared to observed receptor activities using authentic standards to assess contribution to total activities, and quantitation of a comprehensive set of wastewater compounds was performed to better characterize each site. Bisphenol A concentrations were found to be elevated in surface water near permitted airborne release sites, raising questions that airborne releases of BPA may influence nearby surface water contamination and may represent a previously underestimated source to the environment and potential for human exposure. Estrogen and androgen receptor activities of surface water samples were predictive of wastewater input, although the lower sensitivity of the ethinylestradiol ELISA relative to the very high sensitivity of the bioassay approaches did not allow a direct comparison. Wastewater-influenced sites also had elevated anti-estrogenic and anti-androgenic equivalence, while sites without wastewater discharges exhibited no antagonist activities. Published by Elsevier B.V.

Characterization of Missouri surface waters near point sources of pollution reveals potential novel atmospheric route of exposure for bisphenol A and wastewater hormonal activity pattern

USGS Publications Warehouse

Kassotis, Christopher D.; Alvarez, David A.; Taylor, Julia A.; vom Saal, Frederick S.; Nagel, Susan C.; Tillitt, Donald E.

2015-01-01

Surface water contamination by chemical pollutants increasingly threatens water quality around the world. Among the many contaminants found in surface water, there is growing concern regarding endocrine disrupting chemicals, based on their ability to interfere with some aspect of hormone action in exposed organisms, including humans. This study assessed water quality at several sites across Missouri (near wastewater treatment plants and airborne release sites of bisphenol A) based on hormone receptor activation potencies and chemical concentrationspresent in the surface water. We hypothesized that bisphenol A and ethinylestradiol would be greater in water near permitted airborne release sites and wastewater treatment plant inputs, respectively, and that these two compounds would be responsible for the majority of activities in receptor-based assays conducted with water collected near these sites. Concentrations of bisphenol A and ethinylestradiol were compared to observed receptor activities using authentic standards to assess contribution to total activities, and quantitation of a comprehensive set of wastewater compounds was performed to better characterize each site. Bisphenol A concentrations were found to be elevated in surface water near permitted airborne release sites, raising questions that airborne releases of BPA may influence nearby surface water contamination and may represent a previously underestimated source to the environment and potential for human exposure. Estrogen and androgen receptor activities of surface water samples were predictive of wastewater input, although the lower sensitivity of the ethinylestradiol ELISA relative to the very high sensitivity of the bioassay approaches did not allow a direct comparison. Wastewater-influenced sites also had elevated anti-estrogenic and anti-androgenic equivalence, while sites without wastewater discharges exhibited no antagonist activities.

Hurricane Katrina sediment slowed elevation loss in subsiding brackish marshes of the Mississippi River delta

USGS Publications Warehouse

McKee, K.L.; Cherry, J.A.

2009-01-01

Although hurricanes can damage or destroy coastal wetlands, they may play a beneficial role in reinvigorating marshes by delivering sediments that raise soil elevations and stimulate organic matter production. Hurricane Katrina altered elevation dynamics of two subsiding brackish marshes in the Mississippi River deltaic plain by adding 3 to 8 cm of sediment to the soil surface in August 2005. Soil elevations at both sites subsequently declined due to continued subsidence, but net elevation gain was still positive at both Pearl River (+1.7 cm) and Big Branch (+0.7 cm) marshes two years after the hurricane. At Big Branch where storm sediments had higher organic matter and water contents, post-storm elevation loss was more rapid due to initial compaction of the storm layer in combination with root-zone collapse. In contrast, elevation loss was slower at Pearl River where the storm deposit (high sand content) did not compact and the root zone did not collapse. Vegetation at both sites fully recovered within one year, and accumulation of root matter at Big Branch increased 10-fold from 2005 to 2006, suggesting that the hurricane stimulated belowground productivity. Results of this study imply that hurricane sediment may benefit subsiding marshes by slowing elevation loss. However, long-term effects of hurricane sediment on elevation dynamics will depend not only on the amount of sediment deposited, but on sediment texture and resistance to compaction as well as on changes in organic matter accumulation in the years following the hurricane.

Analysis of water-surface profiles in Leon County and the city of Tallahassee, Florida

USGS Publications Warehouse

Franklin, M.A.; Orr, R.A.

1987-01-01

Water surface profiles for the 10-, 25-, 50-, and 100-yr recurrence interval floods for most of the streams that drain developing areas of Leon County and the city of Tallahassee are presented. The principal streams studied are in the Lake Munson, Lake Lafayette, and Lake Jackson basins Peak discharges were computed from regression equations based on information gained from 15 streamflow stations in the area. Standard step-backwater procedures were used to determine the water-surface elevations for the streams. The flood elevations were generally higher than those in the Flood Insurance Studies for Tallahassee (1976) and Leon County (1982). The primary reason for the higher profiles is that peak discharges used in this report are larger than those used previously, largely due to changes in land use. The flood profiles for Bradford Brook, North Branch Gum Creek, and West Branch Gum Creek generally match those in the Leon County Flood Insurance Studies. Channel improvements in some areas would lower the flood elevation in that area, but would probably increase flooding downstream. (Lantz-PTT)

High resolution imaging of latent fingerprints by localized corrosion on brass surfaces.

PubMed

Goddard, Alex J; Hillman, A Robert; Bond, John W

2010-01-01

The Atomic Force Microscope (AFM) is capable of imaging fingerprint ridges on polished brass substrates at an unprecedented level of detail. While exposure to elevated humidity at ambient or slightly raised temperatures does not change the image appreciably, subsequent brief heating in a flame results in complete loss of the sweat deposit and the appearance of pits and trenches. Localized elemental analysis (using EDAX, coupled with SEM imaging) shows the presence of the constituents of salt in the initial deposits. Together with water and atmospheric oxygen--and with thermal enhancement--these are capable of driving a surface corrosion process. This process is sufficiently localized that it has the potential to generate a durable negative topographical image of the fingerprint. AFM examination of surface regions between ridges revealed small deposits (probably microscopic "spatter" of sweat components or transferred particulates) that may ultimately limit the level of ridge detail analysis.

Estimated Flood-Inundation Mapping for the Upper Blue River, Indian Creek, and Dyke Branch in Kansas City, Missouri, 2006-08

USGS Publications Warehouse

Kelly, Brian P.; Huizinga, Richard J.

2008-01-01

In the interest of improved public safety during flooding, the U.S. Geological Survey, in cooperation with the city of Kansas City, Missouri, completed a flood-inundation study of the Blue River in Kansas City, Missouri, from the U.S. Geological Survey streamflow gage at Kenneth Road to 63rd Street, of Indian Creek from the Kansas-Missouri border to its mouth, and of Dyke Branch from the Kansas-Missouri border to its mouth, to determine the estimated extent of flood inundation at selected flood stages on the Blue River, Indian Creek, and Dyke Branch. The results of this study spatially interpolate information provided by U.S. Geological Survey gages, Kansas City Automated Local Evaluation in Real Time gages, and the National Weather Service flood-peak prediction service that comprise the Blue River flood-alert system and are a valuable tool for public officials and residents to minimize flood deaths and damage in Kansas City. To provide public access to the information presented in this report, a World Wide Web site (http://mo.water.usgs.gov/indep/kelly/blueriver) was created that displays the results of two-dimensional modeling between Hickman Mills Drive and 63rd Street, estimated flood-inundation maps for 13 flood stages, the latest gage heights, and National Weather Service stage forecasts for each forecast location within the study area. The results of a previous study of flood inundation on the Blue River from 63rd Street to the mouth also are available. In addition the full text of this report, all tables and maps are available for download (http://pubs.usgs.gov/sir/2008/5068). Thirteen flood-inundation maps were produced at 2-foot intervals for water-surface elevations from 763.8 to 787.8 feet referenced to the Blue River at the 63rd Street Automated Local Evaluation in Real Time stream gage operated by the city of Kansas City, Missouri. Each map is associated with gages at Kenneth Road, Blue Ridge Boulevard, Kansas City (at Bannister Road), U.S. Highway 71, and 63rd Street on the Blue River, and at 103rd Street on Indian Creek. The National Weather Service issues peak stage forecasts for Blue Ridge Boulevard, Kansas City (at Bannister Road), U.S. Highway 71, and 63rd Street during floods. A two-dimensional depth-averaged flow model simulated flooding within a hydraulically complex, 5.6-mile study reach of the Blue River between Hickman Mills Drive and 63rd Street. Hydraulic simulation of the study reach provided information for the estimated flood-inundation maps and water-velocity magnitude and direction maps. Flood profiles of the upper Blue River between the U.S. Geological Survey streamflow gage at Kenneth Road and Hickman Mills Drive were developed from water-surface elevations calculated using Federal Emergency Management Agency flood-frequency discharges and 2006 stage-discharge ratings at U.S. Geological Survey streamflow gages. Flood profiles between Hickman Mills Drive and 63rd Street were developed from two-dimensional hydraulic modeling conducted for this study. Flood profiles of Indian Creek between the Kansas-Missouri border and the mouth were developed from water-surface elevations calculated using current stage-discharge ratings at the U.S. Geological Survey streamflow gage at 103rd Street, and water-surface slopes derived from Federal Emergency Management Agency flood-frequency stage-discharge relations. Mapped flood water-surface elevations at the mouth of Dyke Branch were set equal to the flood water-surface elevations of Indian Creek at the Dyke Branch mouth for all Indian Creek water-surface elevations; water-surface elevation slopes were derived from Federal Emergency Management Agency flood-frequency stage-discharge relations.

Deposition and accumulation of airborne organic contaminants in Yosemite National Park, Calfornia

USGS Publications Warehouse

Mast, Alisa M.; Alvarez, David A.; Zaugg, Steven D.

2012-01-01

Deposition and accumulation of airborne organic contaminants in Yosemite National Park were examined by sampling atmospheric deposition, lichen, zooplankton, and lake sediment at different elevations. Passive samplers were deployed in high-elevation lakes to estimate surface-water concentrations. Detected compounds included current-use pesticides chlorpyrifos, dacthal, and endosulfans and legacy compounds chlordane, dichlorodiphenyltrichloroethane-related compounds, dieldrin, hexachlorobenzene, and polychlorinated biphenyls. Concentrations in snow were similar among sites and showed little variation with elevation. Endosulfan concentrations in summer rain appeared to coincide with application rates in the San Joaquin Valley. More than 70% of annual pesticide inputs from atmospheric deposition occurred during the winter, largely because most precipitation falls as snow. Endosulfan and chlordane concentrations in lichen increased with elevation, indicating that mountain cold-trapping might be an important control on accumulation of these compounds. By contrast, chlorpyrifos concentrations were inversely correlated with elevation, indicating that distance from source areas was the dominant control. Sediment concentrations were inversely correlated with elevation, possibly because of the organic carbon content of sediments but also perhaps the greater mobility of organic contaminants at lower elevations. Surface-water concentrations inferred from passive samplers were at sub-parts-per-trillion concentrations, indicating minimal exposure to aquatic organisms from the water column. Concentrations in sediment generally were low, except for dichlorodiphenyldichloroethane in Tenaya Lake, which exceeded sediment guidelines for protection of benthic organisms.

Identification and management of microbial contaminations in a surface drinking water source.

PubMed

Aström, J; Pettersson, T J R; Stenström, T A

2007-01-01

Microbial contamination of surface waters constitutes a health risk for drinking water consumers which may be lowered by closing the raw water intake. We have evaluated microbial discharge events reported in the river Göta älv, which is used for raw water supply to the city of Göteborg. Elevated levels of faecal indicator bacteria were observed during periods of closed raw water intake. High bacteria levels were, however, also occasionally detected during periods of open intake, probably as a result of microbial discharge far upstream in the river which may be difficult to predict and manage by closing the intake. Accumulated upstream precipitations, resulting in surface runoff and wastewater contaminations in the catchment, correlated positively with the levels of total coliforms, E. coli, intestinal enterococci and sulfite-reducing clostridia. Levels of faecal indicator organisms were negatively correlated to the water temperature due to enhanced survival at lower temperatures. Wastewater discharges from a municipality located just upstream of the water intake resulted in elevated E. coli concentrations downstream at the raw water intake for Göteborg. To improve the prediction of microbial contaminations within the river Göta älv, monitoring data on turbidity and upstream precipitation are of particular importance.

Quantitative Campylobacter spp., antibiotic resistance genes, and veterinary antibiotics in surface and ground water following manure application: Influence of tile drainage control.

PubMed

Frey, Steven K; Topp, Edward; Khan, Izhar U H; Ball, Bonnie R; Edwards, Mark; Gottschall, Natalie; Sunohara, Mark; Lapen, David R

2015-11-01

This work investigated chlortetracycline, tylosin, and tetracycline (plus transformation products), and DNA-based quantitative Campylobacter spp. and Campylobacter tetracycline antibiotic resistant genes (tet(O)) in tile drainage, groundwater, and soil before and following a liquid swine manure (LSM) application on clay loam plots under controlled (CD) and free (FD) tile drainage. Chlortetracycline/tetracycline was strongly bound to manure solids while tylosin dominated in the liquid portion of manure. The chlortetracycline transformation product isochlortetracycline was the most persistent analyte in water. Rhodamine WT (RWT) tracer was mixed with manure and monitored in tile and groundwater. RWT and veterinary antibiotic (VA) concentrations were strongly correlated in water which supported the use of RWT as a surrogate tracer. While CD reduced tile discharge and eliminated application-induced VA movement (via tile) to surface water, total VA mass loading to surface water was not affected by CD. At both CD and FD test plots, the biggest 'flush' of VA mass and highest VA concentrations occurred in response to precipitation received 2d after application, which strongly influenced the flow abatement capacity of CD on account of highly elevated water levels in field initiating overflow drainage for CD systems (when water level <0.3m below surface). VA concentrations in tile and groundwater became very low within 10d following application. Both Campylobacter spp. and Campylobacter tet(O) genes were present in groundwater and soil prior to application, and increased thereafter. Unlike the VA compounds, Campylobacter spp. and Campylobacter tet(O) gene loadings in tile drainage were reduced by CD, in relation to FD. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.

Modeling Surface Water Flow in the Atchafalaya Basin

NASA Astrophysics Data System (ADS)

Liu, K.; Simard, M.

2017-12-01

While most of the Mississippi River Delta is sinking due to insufficient sediment supply and subsidence, the stable wetlands and the prograding delta systems in the Atchafalaya Basin provide a unique opportunity to study the constructive interactions between riverine and marine forcings and their impacts upon coastal morphology. To better understand the hydrodynamics in this region, we developed a numerical modeling system for the water flow through the river channel - deltas - wetlands networks in the Atchafalaya Basin. Determining spatially varying model parameters for a large area composed of such diverse land cover types poses a challenge to developing an accurate numerical model. For example, the bottom friction coefficient can not be measured directly and the available elevation maps for the wetlands in the basin are inaccurate. To overcome these obstacles, we developed the modeling system in three steps. Firstly, we modeled river bathymetry based on in situ sonar transects and developed a simplified 1D model for the Wax Lake Outlet using HEC-RAS. Secondly, we used a Bayesian approach to calibrate the model automatically and infer important unknown parameters such as riverbank elevation and bottom friction coefficient through Markov Chain Monte Carlo (MCMC) simulations. We also estimated the wetland elevation based on the distribution of different vegetation species in the basin. Thirdly, with the lessons learnt from the 1D model, we developed a depth-averaged 2D model for the whole Atchafalaya Basin using Delft3D. After calibrations, the model successfully reproduced the water levels measured at five gauges in the Wax Lake Outlet and the modeled water surface profile along the channel agreed reasonably well with our LIDAR measurements. In addition, the model predicted a one-hour delay in tidal phase from the Wax Lake Delta to the upstream gauge. In summary, this project presents a procedure to initialize hydrology model parameters that integrates field measurements, existing knowledge and model sensitivities. The numerical model provides a powerful tool to understand the complex patterns of water flow and exchange in the rivers, tributaries, and wetlands of the Atchafalaya Basin.

A (very) Simple Model for the Aspect Ratio of High-Order River Basins

NASA Astrophysics Data System (ADS)

Shelef, E.

2017-12-01

The structure of river networks dictates the distribution of elevation, water, and sediments across Earth's surface. Despite its intricate shape, the structure of high-order river networks displays some surprising regularities such as the consistent aspect ratio (i.e., basin's width over length) of river basins along linear mountain fronts. This ratio controls the spacing between high-order channels as well as the spacing between the depositional bodies they form. It is generally independent of tectonic and climatic conditions and is often attributed to the initial topography over which the network was formed. This study shows that a simple, cross-like channel model explains this ratio via a requirement for equal elevation gain between the outlets and drainage-divides of adjacent channels at topographic steady state. This model also explains the dependence of aspect ratio on channel concavity and the location of the widest point on a drainage divide.

Environment Humidity Effect on the Weight of Carbonized Na-Al-Si Glass Fabrics Recovery after Heating

NASA Astrophysics Data System (ADS)

Pentjuss, E.; Lusis, A.; Gabrusenoks, J.; Bajars, G.

2015-03-01

Na-Al-Si glass fabrics fibres contain Na+ ions that diffuse to its surface and along with CO2 and H2O from atmosphere create here the shell of carbonate hydrates. The heating of fabric leads to weight loss by evolving these substances. In this work the results of weight recovery study at room relative humidity (20% - 50%) and elevated humidity (near 70%) of fabrics after its heating at different temperatures (70°C - 150°C) are compared. The experiments shoved the different weight recovery kinetics. The initial exponential stages up to 0.3 h - 0.5 h of the both recoveries are associated with water absorption and differ by its levels. In a case of lower environment humidity the later weight increase are restricted by its value, but at an elevated humidity has a maximum and followed weight increase. The reasons of observed differences are discussed.

Effect of sewage sludge on formation of acidic ground water at a reclaimed coal mine

USGS Publications Warehouse

Cravotta, C.A.

1998-01-01

Data on rock, ground water, vadose water, and vadose gas chemistry were collected for two years after sewage sludge was applied at a reclaimed surface coal mine in Pennsylvania to determine if surface-applied sludge is an effective barrier to oxygen influx, contributes metals and nutrients to ground water, and promotes the acidification of ground water. Acidity, sulfate, and metals concentrations were elevated in the ground water (6- to 21-m depth) from spoil relative to unmined rock because of active oxidation of pyrite and dissolution of aluminosilicate, carbonate, and Mn-Fe-oxide minerals in the spoil. Concentrations of acidity, sulfate, metals (Fe, Mn, Al, Cd, Cu, Cr, Ni, Zn), and nitrate, and abundances of iron-oxidizing bacteria were elevated in the ground water from sludge-treated spoil relative to untreated spoil having a similar mineral composition; however, gaseous and dissolved oxygen concentrations did not differ between the treatments. Abundances of iron-oxidizing bacteria in the ground water samples were positively correlated with concentrations of ammonia, nitrate, acidity, metals, and sulfate. Concentrations of metals in vadose water samples (<5-m depth) from sludge-treated spoil (pH 5.9) were not elevated relative to untreated spoil (pH 4.4). In contrast, concentrations of nitrate were elevated in vadose water samples from sludge-treated spoil, frequently exceeding 10 mg/L. Downgradient decreases in nitrate to less than 3 mg/L and increases in sulfate concentrations in underlying ground water could result from oxidation of pyrite by nitrate. Thus, sewage sludge added to pyritic spoil can increase the growth of iron-oxidizing bacteria, the oxidation of pyrite, and the acidification of ground water. Nevertheless, the overall effects on ground water chemistry from the sludge were small and probably short-lived relative to the effects from mining only.

Evolution of Subaerial Coastal Fluvial Delta Island Topography into Multiple Stable States Under Influence of Vegetation and Stochastic Hydrology

NASA Astrophysics Data System (ADS)

Moffett, K. B.; Smith, B. C.; O'Connor, M.; Mohrig, D. C.

2014-12-01

Coastal fluvial delta morphodynamics are prominently controlled by external fluvial sediment and water supplies; however, internal sediment-water-vegetation feedbacks are now being proposed as potentially equally significant in organizing and maintaining the progradation and aggradation of such systems. The time scales of fluvial and climate influences on these feedbacks, and of their responses, are also open questions. Historical remote sensing study of the Wax Lake Delta model system (Louisiana, USA) revealed trends in the evolution of the subaerial island surfaces from a non-systematic arrangement of elevations to a discrete set of levees and intra-island platforms with distinct vegetation types, designated as high marsh, low marsh, and mudflat habitat. We propose that this elevation zonation is consistent with multiple stable state theory, e.g. as applied to tidal salt marsh systems but not previously to deltas. According to zonally-distributed sediment core analyses, differentiation of island elevations was not due to organic matter accumulation as in salt marshes, but rather by differential mineral sediment accumulation with some organic contributions. Mineral sediment accumulation rates suggested that elevation growth was accelerating or holding steady over time, at least to date in this young delta, in contrast to theory suggesting rates should slow as elevation increases above mean water level. Hydrological analysis of island flooding suggested a prominent role of stochastic local storm events in raising island water levels and supplying mineral sediment to the subaerial island surfaces at short time scales; over longer time scales, the relative influences of local storms and inland/regional floods on the coupled sediment-water-vegetation system of the subaerial delta island surfaces remain the subject of ongoing study. These results help provide an empirical foundation for the next generation of coupled sediment-water-vegetation modeling and theory.

Simulation of hydraulic characteristics in the white sturgeon spawning habitat of the Kootenai River near Bonners Ferry, Idaho

USGS Publications Warehouse

Berenbrock, Charles

2005-01-01

Hydraulic characterization of the Kootenai River, especially in the white sturgeon spawning habitat reach, is needed by the Kootenai River White Sturgeon Recovery Team to promote hydraulic conditions that improve spawning conditions for the white sturgeon (Acipenser transmontanus) in the Kootenai River. The decreasing population and spawning failure of white sturgeon has led to much concern. Few wild juvenile sturgeons are found in the river today. Determining the location of the transition between backwater and free-flowing water in the Kootenai River is a primary focus for biologists who believe that hydraulic changes at the transition affect the location where the sturgeon choose to spawn. The Kootenai River begins in British Columbia, Canada, and flows through Montana, Idaho, and back into British Columbia. The 65.6-mile reach of the Kootenai River in Idaho was studied. The study area encompasses the white sturgeon spawning reach that has been designated as a critical habitat. A one-dimensional hydraulic-flow model of the study reach was developed, calibrated, and used to develop relations between hydraulic characteristics and water-surface elevation, discharge, velocity, and backwater extent. The model used 164 cross sections, most of which came from a previous river survey conducted in 2002-03. The model was calibrated to water-surface elevations at specific discharges at five gaging stations. Calibrated water-surface elevations ranged from about 1,743 to about 1,759 feet, and discharges used in calibration ranged from 5,000 to 47,500 cubic feet per second. Model calibration was considered acceptable when the difference between measured and simulated water-surface elevations was ?0.15 foot or less. Measured and simulated average velocities also were compared. These comparisons indicated agreement between measured and simulated values. The location of the transition between backwater and free-flowing water was determined using the calibrated model. The model was used to simulate hydraulic characteristics for a range of water-surface elevations from 1,741 to 1,762 feet and discharges from 4,000 to 75,000 cubic feet per second. These simulated hydraulic characteristics were used to develop a three-parameter relation-discharge in the study reach, water-surface elevation at Kootenai River at Porthill gaging station (12322000), and the location of the transition between backwater and free-flowing water. Simulated hydraulic characteristics produced backwater locations ranging from river mile (RM) 105.6 (Porthill) to RM 158 (near Crossport), a span of about 52 miles. However, backwater locations from measured data ranged primarily from RM 152 to RM 157, a 5-mile span. The average backwater location from measured data was at about RM 154. Three-parameter relations also were developed for determining the amount of discharge in the Shorty Island side channel and average velocity at selected cross sections in the study reach. Simulated discharge for the side channel relative to measured data ranged from 0 to about 5,500 cubic feet per second, and simulated average velocity relative to measured data ranged from 0 to about 3.5 feet per second. Relations using other hydraulic, sediment/incipient motion, ecological, and biological characteristics also could be developed. The relations also can be used in real time by accessing data from the Web. Discharge and stage data for two gaging stations, Tribal Hatchery (12310100) and Porthill (12322500), are available from the Idaho U.S. Geological Survey web page (URL: http://waterdata.usgs.gov/id/nwis/current/?type=flow). Because the coordinate axes of the three-parameter relations use discharge from the Tribal Hatchery gaging station and water-surface elevation from the Porthill gaging station, the location of the transition between backwater and free-flowing water can be determined for current conditions using the real-time data. Similarly, discharge in the Shorty Island side channel and (or) average velocity at selected cross sections also can be determined for current conditions.

Combining Imagery and Models to Understand River Dynamics

NASA Astrophysics Data System (ADS)

Blain, C. A.; Mied, R. P.; Linzell, R. S.

2014-12-01

Rivers pose one of the most challenging environments to characterize. Their geometric complexity and continually changing position and character are difficult to measure under optimal circumstances. Further compounding the problem is the often inaccessibility of these areas around the globe. Yet details of the river bank position and bed elevation are essential elements in the construction of accurate predictive river models. To meet this challenge, remote sensing imagery is first used to initialize the construction of advanced high resolution river circulation models. In turn, such models are applied to dynamically interpret remotely-sensed surface features. A method has been developed to automatically extract water and shoreline locations from arbitrarily sourced high resolution (~1m gsd) visual spectrum imagery without recourse to the spectral or color information. The approach relies on quantifying the difference in image texture between the relatively smooth water surface and the comparatively rough surface of surrounding land. Processing the segmented land/water interface results in ordered, continuous shoreline coordinates that bound river model construction. In the absence of observed bed elevations, one of several available analytic bathymetry cross-sectional relations are applied to complete the river model configuration. Successful application of this approach to the Snohomish River, WA and the Pearl River, MS are demonstrated. Once constructed, a hydrodynamic model of the river model can also be applied to unravel the dynamics responsible for observed surface features in the imagery. At a creek-river confluence in the Potomac River, MD, an ebb tide front observed in the imagery is analyzed using the model. The result is knowledge that an ebb shoal located just outside of the creek must be present and is essential for front formation. Furthermore, the front is found to be persistent throughout the tidal cycle, although it changes sign between ebb and flood phases. The presence of the creek only minimally modifies the underlying currents.

Questa Baseline and Pre-Mining Ground-Water Quality Investigation. 24. Seismic Refraction Tomography for Volume Analysis of Saturated Alluvium in the Straight Creek Drainage and Its Confluence With Red River, Taos County, New Mexico

USGS Publications Warehouse

Powers, Michael H.; Burton, Bethany L.

2007-01-01

As part of a research effort directed by the New Mexico Environment Department to determine pre-mining water quality of the Red River at a molybdenum mining site in northern New Mexico, we used seismic refraction tomography to create subsurface compressional-wave velocity images along six lines that crossed the Straight Creek drainage and three that crossed the valley of Red River. Field work was performed in June 2002 (lines 1-4) and September 2003 (lines 5-9). We interpreted the images to determine depths to the water table and to the top of bedrock. Depths to water and bedrock in boreholes near the lines correlate well with our interpretations based on seismic data. In general, the images suggest that the alluvium in this area has a trapezoidal cross section. Using a U.S. Geological Survey digital elevation model grid of surface elevations of this region and the interpreted elevations to water table and bedrock obtained from the seismic data, we generated new models of the shape of the buried bedrock surface and the water table through surface interpolation and extrapolation. Then, using elevation differences between the two grids, we calculated volumes of dry and wet alluvium in the two drainages. The Red River alluvium is about 51 percent saturated, whereas the much smaller volume of alluvium in the tributary Straight Creek is only about 18 percent saturated. When combined with average ground-water velocity values, the information we present can be used to determine discharge of Straight Creek into Red River relative to the total discharge of Red River moving past Straight Creek. This information will contribute to more accurate models of ground-water flow, which are needed to determine the pre-mining water quality in the Red River.

River stage influences on uranium transport in a hydrologically dynamic groundwater-surface water transition zone

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zachara, John M.; Chen, Xingyuan; Murray, Chris

In this study, a well-field within a uranium (U) plume in the groundwater-surface water transition zone was monitored for a 3 year period for water table elevation and dissolved solutes. The plume discharges to the Columbia River, which displays a dramatic spring stage surge resulting from snowmelt. Groundwater exhibits a low hydrologic gradient and chemical differences with river water. River water intrudes the site in spring. Specific aims were to assess the impacts of river intrusion on dissolved uranium (U aq), specific conductance (SpC), and other solutes, and to discriminate between transport, geochemical, and source term heterogeneity effects. Time seriesmore » trends for U aq and SpC were complex and displayed large temporal and well-to-well variability as a result of water table elevation fluctuations, river water intrusion, and changes in groundwater flow directions. The wells were clustered into subsets exhibiting common behaviors resulting from the intrusion dynamics of river water and the location of source terms. Hot-spots in U aq varied in location with increasing water table elevation through the combined effects of advection and source term location. Heuristic reactive transport modeling with PFLOTRAN demonstrated that mobilized U aq was transported between wells and source terms in complex trajectories, and was diluted as river water entered and exited the groundwater system. While U aq time-series concentration trends varied significantly from year-to-year as a result of climate-caused differences in the spring hydrograph, common and partly predictable response patterns were observed that were driven by water table elevation, and the extent and duration of river water intrusion.« less

River stage influences on uranium transport in a hydrologically dynamic groundwater-surface water transition zone

DOE PAGES

Zachara, John M.; Chen, Xingyuan; Murray, Chris; ...

2016-03-04

In this study, a well-field within a uranium (U) plume in the groundwater-surface water transition zone was monitored for a 3 year period for water table elevation and dissolved solutes. The plume discharges to the Columbia River, which displays a dramatic spring stage surge resulting from snowmelt. Groundwater exhibits a low hydrologic gradient and chemical differences with river water. River water intrudes the site in spring. Specific aims were to assess the impacts of river intrusion on dissolved uranium (U aq), specific conductance (SpC), and other solutes, and to discriminate between transport, geochemical, and source term heterogeneity effects. Time seriesmore » trends for U aq and SpC were complex and displayed large temporal and well-to-well variability as a result of water table elevation fluctuations, river water intrusion, and changes in groundwater flow directions. The wells were clustered into subsets exhibiting common behaviors resulting from the intrusion dynamics of river water and the location of source terms. Hot-spots in U aq varied in location with increasing water table elevation through the combined effects of advection and source term location. Heuristic reactive transport modeling with PFLOTRAN demonstrated that mobilized U aq was transported between wells and source terms in complex trajectories, and was diluted as river water entered and exited the groundwater system. While U aq time-series concentration trends varied significantly from year-to-year as a result of climate-caused differences in the spring hydrograph, common and partly predictable response patterns were observed that were driven by water table elevation, and the extent and duration of river water intrusion.« less

Real-time estimation of TP load in a Mississippi Delta Stream using a dynamic data driven application system

Treesearch

Ying Ouyang; Theodor D. Leininger; Jeff Hatten

2013-01-01

Elevated phosphorus (P) in surface waters can cause eutrophication of aquatic ecosystems and can impair water for drinking, industry, agriculture, and recreation. Currently, no effort has been devoted to estimating real-time variation and load of total P (TP) in surface waters due to the lack of suitable and/or cost-effective wireless sensors. However, when considering...

Coupled Surface and Groundwater Hydrological Modeling in a Changing Climate.

PubMed

Sridhar, Venkataramana; Billah, Mirza M; Hildreth, John W

2017-11-09

Many current watershed modeling efforts now incorporate surface water and groundwater for managing water resources since the exchanges between groundwater and surface water need a special focus considering the changing climate. The influence of groundwater dynamics on water and energy balance components is investigated in the Snake River Basin (SRB) by coupling the Variable Infiltration Capacity (VIC) and MODFLOW models (VIC-MF) for the period of 1986 through 2042. A 4.4% increase in base flows and a 10.3% decrease in peak flows are estimated by VIC-MF compared to the VIC model in SRB. The VIC-MF model shows significant improvement in the streamflow simulation (Nash-Sutcliffe efficiency [NSE] of 0.84) at King Hill, where the VIC model could not capture the effect of spring discharge in the streamflow simulation (NSE of -0.30); however, the streamflow estimates show an overall decreasing trend. Two climate scenarios representing median and high radiative-forcings such as representative concentration pathways 4.5 and 8.5 show an average increase in the water table elevations between 2.1 and 2.6 m (6.9 and 8.5 feet) through the year 2042. The spatial patterns of these exchanges show a higher groundwater elevation of 15 m (50 feet) in the downstream area and a lower elevation of up to 3 m (10 feet) in the upstream area. Broadly, this study supports results of previous work demonstrating that integrated assessment of groundwater-surface water enables stakeholders to balance pumping, recharge and base flow needs and to manage the watersheds that are subjected to human pressures more sustainably. © 2017, National Ground Water Association.

On the derivation of specific yield and soil water retention characteristics in peatlands from rainfall, microrelief and water level data - Theory and Practice

NASA Astrophysics Data System (ADS)

Dettmann, Ullrich; Bechtold, Michel

2016-04-01

Water level depth is one of the crucial state variables controlling the biogeochemical processes in peatlands. For flat soil surfaces, water level depth dynamics as response to boundary fluxes are primarily controlled by the water retention characteristics of the soil in and above the range of the water level fluctuations. For changing water levels, the difference of the integrals of two soil moisture profiles (ΔAsoil), of a lower and a upper water level, is equal to the amount of water received or released by the soil. Dividing ΔAsoil by the water level change, results into a variable that is known as specific yield (Sy). For water level changes approaching the soil surface, changes in soil water storage are small due to the thin unsaturated zone that remains. Consequentially, Sy values approach zero with an abrupt transition to 1 in case of inundation. However, on contrary, observed water level rises due to precipitation events at various locations showed increasing Sy values for water level changes at shallow depths (Sy = precipitation/water level change; Logsdon et al., 2010). The increase of Sy values can be attributed in large parts to the influence of the microrelief on water level changes in these wet landscapes that are characterized by a mosaic of inundated and non-inundated areas. Consequentially, water level changes are dampened by partial inundation. In this situation, total Sy is composed of a spatially-integrated below ground and above ground contribution. We provide a general one-dimensional expression that correctly represents the effect of a microrelief on the total Sy. The one-dimensional expression can be applied for any soil hydraulic parameterizations and soil surface elevation frequency distributions. We demonstrate that Sy is influenced by the microrelief not only when surface storage directly contributes to Sy by (partial) inundation but also when water levels are lower than the minimum surface elevation. With the derived one-dimensional expression we developed a novel approach for the in situ determination of soil water retention characteristics that is applicable to shallow groundwater systems. Our approach is built on two assumptions: i) for shallow groundwater systems with medium- to high conductive soils the soil moisture profile is always close to hydrostatic equilibrium and ii) over short time periods differences in total water storage due to lateral fluxes are negligible. Given these assumptions, the height of a water level rise due to a precipitation event mainly depends on the soil water retention characteristics, the precipitation amount, the initial water level depth and, if present, the microrelief. We use this dependency to determine water retention characteristics (van Genuchten parameter) by Bayesian inversion. Our results demonstrate that observations of water level rises, caused by precipitation events, contain sufficient information to constrain the water retention characteristics around two dip wells in a Sphagnum bog to plausible ranges. We discuss the possible biases that come along with our approach and point out the research that is needed to quantify their significance.

Development of a channel classification to evaluate potential for cottonwood restoration, lower segments of the Middle Missouri River, South Dakota and Nebraska

USGS Publications Warehouse

Jacobson, Robert B.; Elliott, Caroline M.; Huhmann, Brittany L.

2010-01-01

This report documents development of a spatially explicit river and flood-plain classification to evaluate potential for cottonwood restoration along the Sharpe and Fort Randall segments of the Middle Missouri River. This project involved evaluating existing topographic, water-surface elevation, and soils data to determine if they were sufficient to create a classification similar to the Land Capability Potential Index (LCPI) developed by Jacobson and others (U.S. Geological Survey Scientific Investigations Report 2007–5256) and developing a geomorphically based classification to apply to evaluating restoration potential.Existing topographic, water-surface elevation, and soils data for the Middle Missouri River were not sufficient to replicate the LCPI. The 1/3-arc-second National Elevation Dataset delineated most of the topographic complexity and produced cumulative frequency distributions similar to a high-resolution 5-meter topographic dataset developed for the Lower Missouri River. However, lack of bathymetry in the National Elevation Dataset produces a potentially critical bias in evaluation of frequently flooded surfaces close to the river. High-resolution soils data alone were insufficient to replace the information content of the LCPI. In test reaches in the Lower Missouri River, soil drainage classes from the Soil Survey Geographic Database database correctly classified 0.8–98.9 percent of the flood-plain area at or below the 5-year return interval flood stage depending on state of channel incision; on average for river miles 423–811, soil drainage class correctly classified only 30.2 percent of the flood-plain area at or below the 5-year return interval flood stage. Lack of congruence between soil characteristics and present-day hydrology results from relatively rapid incision and aggradation of segments of the Missouri River resulting from impoundments and engineering. The most sparsely available data in the Middle Missouri River were water-surface elevations. Whereas hydraulically modeled water-surface elevations were available at 1.6-kilometer intervals in the Lower Missouri River, water-surface elevations in the Middle Missouri River had to be interpolated between streamflow-gaging stations spaced 3–116 kilometers. Lack of high-resolution water-surface elevation data precludes development of LCPI-like classification maps.An hierarchical river classification framework is proposed to provide structure for a multiscale river classification. The segment-scale classification presented in this report is deductive and based on presumed effects of dams, significant tributaries, and geological (and engineered) channel constraints. An inductive reach-scale classification, nested within the segment scale, is based on multivariate statistical clustering of geomorphic data collected at 500-meter intervals along the river. Cluster-based classifications delineate reaches of the river with similar channel and flood-plain geomorphology, and presumably, similar geomorphic and hydrologic processes. The dominant variables in the clustering process were channel width (Fort Randall) and valley width (Sharpe), followed by braiding index (both segments).Clusters with multithread and highly sinuous channels are likely to be associated with dynamic channel migration and deposition of fresh, bare sediment conducive to natural cottonwood germination. However, restoration potential within these reaches is likely to be mitigated by interaction of cottonwood life stages with the highly altered flow regime.

30 CFR 77.1200 - Mine map.

Code of Federal Regulations, 2010 CFR

2010-07-01

... SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Maps § 77.1200 Mine... elevation of any body of water dammed or held back in any portion of the mine: Provided, however, Such bodies of water may be shown on overlays or tracings attached to the mine maps; (g) All prospect drill...

Antibiotic resistance and community analysis of surface and subsurface drainage waters in the South Fork Iowa River watershed

USDA-ARS?s Scientific Manuscript database

The Midwest is a center for swine production leading to application of swine manure onto lands that have artificial subsurface drainage. Previous reports have indicated elevated levels of antibiotic resistance genes (ARGs) in surface water and groundwater around confined animal feeding operations w...

Antibiotic resistance and community analysis of surface and subsurface drainage waters in the South Fork Iowa River watershed

USDA-ARS?s Scientific Manuscript database

The Midwest is a center for swine production leading to application of swine manure onto lands that have artificial subsurface drainage. Previous reports have indicated elevated levels of antibiotic resistance genes (ARGs) in surface water and groundwater around confined animal feeding operations wh...

Temperature dependent elasticity and damping in dehydrated sandstone

NASA Astrophysics Data System (ADS)

Darling, T. W.; Struble, W.

2013-12-01

Work reported previously at this conference, outlining our observation of anomalously large elastic softening and damping in dehydrated Berea sandstone at elevated temperatures, has been analysed to study shear and compressional effects separately. Modeling of the sample using COMSOL software was necessary to identify modes, as the vibration spectrum of the sample is poorly approximated by a uniform isotropic solid. The first torsional mode of our evacuated, dry, core softens at nearly twice the rate of Young's modulus modes (bending and compressional) and is also damped nearly twice as strongly as temperature increases. We consider two possible models for explaining this behavior, based on the assumption that the mechanical properties of the sandstone are dominated by the framework of quartz grains and polycrystalline cementation, neglecting initially the effects of clay and feldspar inclusions. The 20cm x 2.54cm diameter core is dry such that the pressure of water vapor in the experiment chamber is below 1e-6 Torr at 70C, suggesting that surface water beyond a small number of monolayers is negligible. Our models consider (1) enhanced sliding of grain boundaries in the cementation at elevated temperature and reduced internal water content, and (2) strain microcracking of the cementatioin at low water content due to anisotropic expansion in the quartz grains. In model (1) interfaces parallel to polyhedral grain surfaces were placed in the cement bonds and assigned frictional properties. Model (2) has not yet been implemented. The overall elasticity of a 3-D several-grain model network was determined by modeling quasistatic loading and measuring displacements. Initial results with a small number of grains/bonds suggests that only the first model provides softening and damping for all the modes, however the details of the effects of defect motioin at individual interfaces as the source for the frictional properties is still being evaluated. Nonlinear effects are experimentally observed at lower temperatures but damping at higher temperatures reduces the strain amplitude so that nonlinearity is not apparent, but may still be present. This work is supported by grant #DE-FG02-11ER16218 from the Geosciences Division of the DOE Office of Basic Energy Sciences.

Using Satellites to Investigate the Sensitivity of Longwave Downward Radiation to Water Vapor at High Elevations

NASA Technical Reports Server (NTRS)

Naud, Catherine M.; Miller, James R.; Landry, Chris

2012-01-01

Many studies suggest that high-elevation regions may be among the most sensitive to future climate change. However, in situ observations in these often remote locations are too sparse to determine the feedbacks responsible for enhanced warming rates. One of these feedbacks is associated with the sensitivity of longwave downward radiation (LDR) to changes in water vapor, with the sensitivity being particularly large in many high-elevation regions where the average water vapor is often low. We show that satellite retrievals from the Moderate Resolution Imaging Spectroradiometer (MODIS) and Clouds and the Earth's Radiant Energy System (CERES) can be used to expand the current ground-based observational database and that the monthly averaged clear-sky satellite estimates of humidity and LDR are in good agreement with the well-instrumented Center for Snow and Avalanche Studies ground-based site in the southwestern Colorado Rocky Mountains. The relationship between MODIS-retrieved precipitable water vapor and surface specific humidity across the contiguous United States was found to be similar to that previously found for the Alps. More important, we show that satellites capture the nonlinear relationship between LDR and water vapor and confirm that LDR is especially sensitive to changes in water vapor at high elevations in several midlatitude mountain ranges. Because the global population depends on adequate fresh water, much of which has its source in high mountains, it is critically important to understand how climate will change there. We demonstrate that satellites can be used to investigate these feedbacks in high-elevation regions where the coverage of surface-based observations is insufficient to do so.

Jøkulhlaup at Blaamannsisen, northern Norway: the 2001 event and future risk

NASA Astrophysics Data System (ADS)

Engeset, R. V.; Jackson, M.

2003-04-01

The first known jøkulhlaup from the glacier BlÅmannsisen in northern Norway occurred on 6th to 7th September 2001. About 40 million cubic meters of water drained from a lake (known as Vatn 1051) that was adjacent to and damned by the glacier. The water drained under the glacier and eventually to the Sisovatn reservoir where the water level rose by 2.5 m. Fortunately, there were no casualties or material damage from the jøkulhlaup; on the contrary, the jøkulhlaup increased the volume of water in the reservoir that is used to supply a hydropower plant operated by Elkem ASA, so was financially beneficial. Comparison of aerial photographs of the glacier taken in 1961 and 1998 (done by comparing digital elevation models calculated from the photographs) indicate that there has been substantial lowering of the surface, especially in the area of the glacier below about 1180 m a.s.l. Here the glacier has lowered by 10 m, and for the glacier tongue and the area immediately adjacent to the lake which drained during the jøkulhlaup, the surface lowering has been up to 55 m. GPS profiling was done on the glacier surface in September 2002 and results were compared with the digital elevation model computed from the 1998 aerial photography. This shows several metres further reduction in surface elevation. Glacier thinning in this ice dam area is thus the probable cause for the 2001 jøkulhlaup. The jøkulhlaup lasted 35 hours, during which the water drained subglacially through a 4.5 km long tunnel under the glacier. Previously the lake had drained in the opposite direction, over the border and into Sweden. Almost the entire lake was drained and caused the lake level to fall by almost 50 m. One year after the event, the lake was one third full. Vatn 1051 has a drainage area of over four square kilometres and a normal annual inflow of nearly 13 million cubic metres. The jøkulhlaup may thus be repeated in 2004-2005, unless the glacier dam develops in such a way that the water cannot find a way under the ice. Glacier mass balance measurements were initiated on the glacier in 2001 as part of an investigation into the possibility of future jøkulhlaups. The measurements for the balance year 2001/2 show a net balance of -1.1 m water equivalent. A study of volume and geometry change between 1961 and 1998 indicate that the glacier then was almost in balance or slightly negative (about -0.1 m water equivalent). Based on climate scenarios for Norway over the next several decades, the net balance will become more negative, by about 0.3 m w.eq., and new jøkulhlaups will occur.

Hydrologic connectivity: Quantitative assessments of hydrologic-enforced drainage structures in an elevation model

USGS Publications Warehouse

Poppenga, Sandra K.; Worstell, Bruce B.

2016-01-01

Elevation data derived from light detection and ranging present challenges for hydrologic modeling as the elevation surface includes bridge decks and elevated road features overlaying culvert drainage structures. In reality, water is carried through these structures; however, in the elevation surface these features impede modeled overland surface flow. Thus, a hydrologically-enforced elevation surface is needed for hydrodynamic modeling. In the Delaware River Basin, hydrologic-enforcement techniques were used to modify elevations to simulate how constructed drainage structures allow overland surface flow. By calculating residuals between unfilled and filled elevation surfaces, artificially pooled depressions that formed upstream of constructed drainage structure features were defined, and elevation values were adjusted by generating transects at the location of the drainage structures. An assessment of each hydrologically-enforced drainage structure was conducted using field-surveyed culvert and bridge coordinates obtained from numerous public agencies, but it was discovered the disparate drainage structure datasets were not comprehensive enough to assess all remotely located depressions in need of hydrologic-enforcement. Alternatively, orthoimagery was interpreted to define drainage structures near each depression, and these locations were used as reference points for a quantitative hydrologic-enforcement assessment. The orthoimagery-interpreted reference points resulted in a larger corresponding sample size than the assessment between hydrologic-enforced transects and field-surveyed data. This assessment demonstrates the viability of rules-based hydrologic-enforcement that is needed to achieve hydrologic connectivity, which is valuable for hydrodynamic models in sensitive coastal regions. Hydrologic-enforced elevation data are also essential for merging with topographic/bathymetric elevation data that extend over vulnerable urbanized areas and dynamic coastal regions.

Persistence and Decontamination of Bacillus atrophaeus subsp. globigii Spores on Corroded Iron in a Model Drinking Water System▿

PubMed Central

Szabo, Jeffrey G.; Rice, Eugene W.; Bishop, Paul L.

2007-01-01

Persistence of Bacillus atrophaeus subsp. globigii spores on corroded iron coupons in drinking water was studied using a biofilm annular reactor. Spores were inoculated at 106 CFU/ml in the dechlorinated reactor bulk water. The dechlorination allowed for observation of the effects of hydraulic shear and biofilm sloughing on persistence. Approximately 50% of the spores initially adhered to the corroded iron surface were not detected after 1 month. Addition of a stable 10 mg/liter free chlorine residual after 1 month led to a 2-log10 reduction of adhered B. atrophaeus subsp. globigii, but levels on the coupons quickly stabilized thereafter. Increasing the free chlorine concentration to 25 or 70 mg/liter had no additional effect on inactivation. B. atrophaeus subsp. globigii spores injected in the presence of a typical distribution system chlorine residual (∼0.75 mg/liter) resulted in a steady reduction of adhered B. atrophaeus subsp. globigii over 1 month, but levels on the coupons eventually stabilized. Adding elevated chlorine levels (10, 25, and 70 mg/liter) after 1 month had no effect on the rate of inactivation. Decontamination with elevated free chlorine levels immediately after spore injection resulted in a 3-log10 reduction within 2 weeks, but the rate of inactivation leveled off afterward. This indicates that free chlorine did not reach portions of the corroded iron surface where B. atrophaeus subsp. globigii spores had adhered. B. atrophaeus subsp. globigii spores are capable of persisting for an extended time in the presence of high levels of free chlorine. PMID:17308186

Currents, drag, and sediment transport induced by a tsunami

USGS Publications Warehouse

Lacy, Jessica R.; Rubin, David M.; Buscombe, Daniel

2012-01-01

We report observations of water surface elevation, currents, and suspended sediment concentration (SSC) from a 10-m deep site on the inner shelf in northern Monterey Bay during the arrival of the 2010 Chile tsunami. Velocity profiles were measured from 3.5 m above the bed (mab) to the surface at 2 min intervals, and from 0.1 to 0.7 mab at 1 Hz. SSC was determined from the acoustic backscatter of the near-bed profiler. The initial tsunami waves were directed cross shore and had a period of approximately 16 min. Maximum wave height was 1.1 m, and maximum current speed was 0.36 m/s. During the strongest onrush, near-bed velocities were clearly influenced by friction and a logarithmic boundary layer developed, extending more than 0.3 mab. We estimated friction velocity and bed shear stress from the logarithmic profiles. The logarithmic structure indicates that the flow can be characterized as quasi-steady at these times. At other phases of the tsunami waves, the magnitude of the acceleration term was significant in the near-bed momentum equation, indicating unsteady flow. The maximum tsunami-induced bed shear stress (0.4 N/m2) exceeded the critical shear stress for the medium-grained sand on the seafloor. Cross-shore sediment flux was enhanced by the tsunami. Oscillations of water surface elevation and currents continued for several days. The oscillations were dominated by resonant frequencies, the most energetic of which was the fundamental longitudinal frequency of Monterey Bay. The maximum current speed (hourly-timescale) in 18 months of observations occurred four hours after the tsunami arrived.

Potential for Small Unmanned Aircraft Systems applications for identifying groundwater-surface water exchange in a meandering river reach

USGS Publications Warehouse

Pai, H.; Malenda, H.; Briggs, Martin A.; Singha, K.; González-Pinzón, R.; Gooseff, M.; Tyler, S.W.; ,

2017-01-01

The exchange of groundwater and surface water (GW-SW), including dissolved constituents and energy, represents a critical yet challenging characterization problem for hydrogeologists and stream ecologists. Here, we describe the use of a suite of high spatial-resolution remote-sensing techniques, collected using a small unmanned aircraft system (sUAS), to provide novel and complementary data to analyze GW-SW exchange. sUAS provided centimeter-scale resolution topography and water surface elevations, which are often drivers of exchange along the river corridor. Additionally, sUAS-based vegetation imagery, vegetation-top elevation, and normalized difference vegetation index (NDVI) mapping indicated GW-SW exchange patterns that are difficult to characterize from the land surface and may not be resolved from coarser satellite-based imagery. We combined these data with estimates of sediment hydraulic conductivity to provide a direct estimate of GW “shortcutting” through meander necks, which was corroborated by temperature data at the riverbed interface.

Potential for Small Unmanned Aircraft Systems Applications for Identifying Groundwater-Surface Water Exchange in a Meandering River Reach

NASA Astrophysics Data System (ADS)

Pai, H.; Malenda, H. F.; Briggs, M. A.; Singha, K.; González-Pinzón, R.; Gooseff, M. N.; Tyler, S. W.

2017-12-01

The exchange of groundwater and surface water (GW-SW), including dissolved constituents and energy, represents a critical yet challenging characterization problem for hydrogeologists and stream ecologists. Here we describe the use of a suite of high spatial resolution remote sensing techniques, collected using a small unmanned aircraft system (sUAS), to provide novel and complementary data to analyze GW-SW exchange. sUAS provided centimeter-scale resolution topography and water surface elevations, which are often drivers of exchange along the river corridor. Additionally, sUAS-based vegetation imagery, vegetation-top elevation, and normalized difference vegetation index mapping indicated GW-SW exchange patterns that are difficult to characterize from the land surface and may not be resolved from coarser satellite-based imagery. We combined these data with estimates of sediment hydraulic conductivity to provide a direct estimate of GW "shortcutting" through meander necks, which was corroborated by temperature data at the riverbed interface.

SWOT: The Surface Water and Ocean Topography Mission. Wide- Swath Altimetric Elevation on Earth

NASA Technical Reports Server (NTRS)

Fu, Lee-Lueng (Editor); Alsdorf, Douglas (Editor); Morrow, Rosemary; Rodriguez, Ernesto; Mognard, Nelly

2012-01-01

The elevation of the surface of the ocean and freshwater bodies on land holds key information on many important processes of the Earth System. The elevation of the ocean surface, called ocean surface topography, has been measured by conventional nadirlooking radar altimeter for the past two decades. The data collected have been used for the study of large-scale circulation and sea level change. However, the spatial resolution of the observations has limited the study to scales larger than about 200 km, leaving the smaller scales containing substantial kinetic energy of ocean circulation that is responsible for the flux of heat, dissolved gas and nutrients between the upper and the deep ocean. This flux is important to the understanding of the ocean's role in regulatingfuture climate change.The elevation of the water bodies on land is a key parameter required for the computation of storage and discharge of freshwater in rivers, lakes, and wetlands. Globally, the spatial and temporal variability of water storage and discharge is poorly known due to the lack of well-sampled observations. In situ networks measuring river flows are declining worldwide due to economic and political reasons. Conventional altimeter observations suffers from the complexity of multiple peaks caused by the reflections from water, vegetation canopy and rough topography, resulting in much less valid data over land than over the ocean. Another major limitation is the large inter track distance preventing good coverage of rivers and other water bodies.This document provides descriptions of a new measurement technique using radar interferometry to obtain wide-swath measurement of water elevation at high resolution over both the ocean and land. Making this type of measurement, which addresses the shortcomings of conventional altimetry in both oceanographic and hydrologic applications, is the objective of a mission concept called Surface Water and Ocean Topography (SWOT), which was recommended by the National Research Council's first decadal survey of NASA's Earth science program. This document provides wide-ranging examples of research opportunities in oceanography and land hydrology that would be enabled by the new type of measurement. Additional applications in many other branches of Earth System science ranging from ocean bathymetry to sea ice dynamics are also discussed. Many of the technical issues in making the measurement are discussed as well. Also presented is a preliminary design of the SWOT Mission concept, which is being jointly developed by NASA and CNES, with contributions from the Canadian Space Agency.

Nanofiltration Membranes for Removal of Color and Pathogens in Small Public Drinking Water Sources

EPA Science Inventory

Small public water supplies that use surface water as a source for drinking water are frequently faced with elevated levels of color and natural organic matter (NOM) that are precursors for chlorinated disinfection byproduct (DBP) formation. Nanofiltration (NF) systems can preve...

44 CFR 64.3 - Flood Insurance Maps.

Code of Federal Regulations, 2010 CFR

2010-10-01

... with water surface elevations determined A0 Area of special flood hazards having shallow water depths... insurance rating purposes AH Areas of special flood hazards having shallow water depths and/or unpredictable... of special flood hazards having shallow water depths and/or unpredictable flow paths between (1) and...

The 3D Elevation Program: summary of program direction

USGS Publications Warehouse

Snyder, Gregory I.

2012-01-01

The 3D Elevation Program (3DEP) initiative responds to a growing need for high-quality topographic data and a wide range of other three-dimensional representations of the Nation's natural and constructed features. The National Enhanced Elevation Assessment (NEEA), which was completed in 2011, clearly documented this need within government and industry sectors. The results of the NEEA indicated that enhanced elevation data have the potential to generate $13 billion in new benefits annually. The benefits apply to food risk management, agriculture, water supply, homeland security, renewable energy, aviation safety, and other areas. The 3DEP initiative was recommended by the National Digital Elevation Program and its 12 Federal member agencies and was endorsed by the National States Geographic Information Council (NSGIC) and the National Geospatial Advisory Committee (NGAC).

Mineral nitrogen transformations in and under seasonal snow in a high-elevation catchment in the Rocky Mountains, United States

USGS Publications Warehouse

Williams, Mark W.; Brooks, Paul D.; Mosier, Arvin; Tonnessen, Kathy A.

1996-01-01

In an effort to understand sources of nitrate (NO3−) in surface waters of high-elevation catchments, nitrogen (N) transformations in and under seasonal snow were investigated from 1993 to 1995 on Niwot Ridge, an alpine ecosystem at 3,500 m located in the Colorado Front Range of the Rocky Mountains. Ammonium (NH4+) and NO3− labeled with 15N applied as nonconservative tracers to the snow showed no evidence of nitrification in the snowpack. Furthermore, NH4+ movement through the amended snowpack was highly correlated with a conservative chloride tracer (r2 = 0.99). In an unamended snowpack NH4+ concentrations in meltwater before contact with the ground were highly correlated with NO3− concentrations (r2 = 0.98), which is consistent with no nitrification in the snowpack. The isotopically labeled 15NH+4applied to the snowpack was found in underlying soils, showing that NH4+ released from snow can be rapidly immobilized. Resin bag (mixed-bed ion-exchange resins) measurements (n = 22) showed that 80% of the mobile inorganic N in unamended subnivial soils was NO3−. Measurements of KCl-extractable inorganic N from surface soils showed that highest values were prior to the initiation of snowmelt and lowest values were during the growing season. The natural δ15N abundance of unamended soils was negative and ranged from −12 to −2, suggesting that atmospheric deposition of δ15N-depleted N is an important component of N cycling in these alpine soils. These results suggest that soil mineralization under seasonal snow, rather than snowmelt release of NO3−, may control NO3− concentrations in surface waters of high-elevation catchments.

NHDPlusHR: A national geospatial framework for surface-water information

USGS Publications Warehouse

Viger, Roland; Rea, Alan H.; Simley, Jeffrey D.; Hanson, Karen M.

2016-01-01

The U.S. Geological Survey is developing a new geospatial hydrographic framework for the United States, called the National Hydrography Dataset Plus High Resolution (NHDPlusHR), that integrates a diversity of the best-available information, robustly supports ongoing dataset improvements, enables hydrographic generalization to derive alternate representations of the network while maintaining feature identity, and supports modern scientific computing and Internet accessibility needs. This framework is based on the High Resolution National Hydrography Dataset, the Watershed Boundaries Dataset, and elevation from the 3-D Elevation Program, and will provide an authoritative, high precision, and attribute-rich geospatial framework for surface-water information for the United States. Using this common geospatial framework will provide a consistent basis for indexing water information in the United States, eliminate redundancy, and harmonize access to, and exchange of water information.

Google Earth Engine derived areal extents to infer elevation variation of lakes and reservoirs

NASA Astrophysics Data System (ADS)

Nguy-Robertson, Anthony; May, Jack; Dartevelle, Sebastien; Griffin, Sean; Miller, Justin; Tetrault, Robert; Birkett, Charon; Lucero, Eileen; Russo, Tess; Zentner, Matthew

2017-04-01

Monitoring water supplies is important for identifying potential national security issues before they begin. As a means to estimate lake and reservoir storage for sites without reliable water stage data, this study defines correlations between water body levels from hypsometry curves based on in situ gauge station and altimeter data (i.e. TOPEX/Poseidon, Jason series) and sensor areal extents observed in historic multispectral (i.e. MODIS and Landsat TM/ETM+/OLI) imagery. Water levels measured using in situ observations and altimeters, when in situ data were unavailable, were used to estimate the relationship between water elevation and surface area for 18 sites globally. Altimeters were generally more accurate (RMSE: 0.40 - 0.49 m) for estimating in situ lake elevations from Iraq and Afghanistan than the modeled elevation data using multispectral sensor areal extents: Landsat (RMSE: 0.25 - 1.5 m) and MODIS (RMSE 0.53 - 3.0 m). Correlations between altimeter data and Landsat imagery processed with Google Earth Engine confirmed similar relationships exists for a broader range of lakes without reported in situ data across the globe (RMSE: 0.24 - 1.6 m). Thus, while altimetry is still preferred to an areal extent model, lake surface area derived with Google Earth Engine can be used as a reasonable proxy for lake storage, expanding the number of observable lakes beyond the current constellation of altimeters and in situ gauges.

High Resolution Photogrammetric Digital Elevation Models Across Calving Fronts and Meltwater Channels in Greenland

NASA Astrophysics Data System (ADS)

Le Bel, D. A.; Brown, S.; Zappa, C. J.; Bell, R. E.; Frearson, N.; Tinto, K. J.

2014-12-01

Photogrammetric digital elevation models (DEMs) are a powerful approach for understanding elevation change and dynamics along the margins of the large ice sheets. The IcePod system, mounted on a New York Air National Guard LC-130, can measure high-resolution surface elevations with a Riegl VQ580 scanning laser altimeter and Imperx Bobcat IGV-B6620 color visible-wavelength camera (6600x4400 resolution); the surface temperature with a Sofradir IRE-640L infrared camera (spectral response 7.7-9.5 μm, 640x512 resolution); and the structure of snow and ice with two radar systems. We show the use of IcePod imagery to develop DEMs across calving fronts and meltwater channels in Greenland. Multiple over-flights of the Kangerlussaq Airport ramp have provided a test of the technique at a location with accurate, independently-determined elevation. Here the photogrammetric DEM of the airport, constrained by ground control measurements, is compared with the Lidar results. In July 2014 the IcePod ice-ocean imaging system surveyed the calving fronts of five outlet glaciers north of Jakobshavn Isbrae. We used Agisoft PhotoScan to develop a DEM of each calving front using imagery captured by the IcePod systems. Adjacent to the ice sheet, meltwater plumes foster mixing in the fjord, moving warm ocean water into contact with the front of the ice sheet where it can undercut the ice front and trigger calving. The five glaciers provide an opportunity to examine the calving front structure in relation to ocean temperature, fjord circulation, and spatial scale of the meltwater plumes. The combination of the accurate DEM of the calving front and the thermal imagery used to constrain the temperature and dynamics of the adjacent plume provides new insights into the ice-ocean interactions. Ice sheet margins provide insights into the connections between the surface meltwater and the fate of the water at the ice sheet base. Surface meltwater channels are visualized here for the first time using the combination of Lidar, photogrammetry DEMs and infrared imagery. These techniques leverage electromagnetic surface properties that allow us to identify the presence of water, measure the slope and elevation of the channel, as well as the two-dimensional temperature variability of the water/ice/snow in multiple melt channels within a drainage system.

18 CFR 8.1 - Publication of license conditions relating to recreation.

Code of Federal Regulations, 2012 CFR

2012-04-01

..., reservoir water surface elevations, minimum water releases or rates of change of water releases and such... 18 Conservation of Power and Water Resources 1 2012-04-01 2012-04-01 false Publication of license conditions relating to recreation. 8.1 Section 8.1 Conservation of Power and Water Resources FEDERAL ENERGY...

SPATIAL AND TEMPORAL DYNAMICS IN ARSENIC SPECIATION ACROSS THE GROUND WATER-SURFACE WATER TRANSITION ZONE AT A CONTAMINATED SITE

EPA Science Inventory

Field investigations have been conducted to understand the fate of arsenic in contaminated ground water during discharge into a small lake. The ground-water plume contains elevated levels of arsenic and hydrocarbon contaminants derived from historical disposal of process wastes ...

75 FR 2129 - Moriah Hydro Corporation; Notice of Preliminary Permit Application Accepted for Filing and...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-14

...-high, containing approximately 100 pump/turbine/ generator units having a total installed capacity of...,400 acre- feet at normal water surface elevation of +1,000 feet Project Datum; (2) a lower reservoir..., with a surface area of about 50 acres and volume of approximately 2,400 acre-feet at normal water...

Elevational Dependence of Catchment-scale Evapotranspiration Partitioning as Revealed by Water Stable Isotopes

NASA Astrophysics Data System (ADS)

Yamanaka, T.; Sato, R.

2017-12-01

Transpiration (T) through plants (i.e., green water) does not induce isotopic fractionation, although evaporation (E) from soils and water surfaces do. Therefore, water stable isotopes offer a powerful tool to partition evapotranspiration (ET) components. We attempted to evaluate catchment-scale T/ET for five mountainous catchments in the central Japan, using river water isotopes and isotope maps of precipitation and soil water as well as climatic and radar precipitation maps. The estimated T/ET ranged from 56% to 79% (ET not including interception loss), and negatively correlated with mean elevation of the catchments (r = -0.88). This is due to decreasing transpiration (-82 mm/yr per 100 m) and slightly increasing evaporation (8 mm/yr per 100 m) with increasing elevation. Another estimation scheme using isotope data only showed a positive correlation between elevation and E/P*, where P* is effective precipitation defined by gross precipitation minus interception. Because the forest coverage within the catchments has positive correlation with catchment-mean-elevation, both decrease in transpiration and increase in soil evaporation seem to reflect structural change in forests (e.g., dense to sparse) along elevation and thus temperature gradients. Applying the space-for-time substitution, our results indicates that global warming will increase transpiration (and thus carbon intake) at mid-latitude mountainous landscapes.

Fatty acid fouling of forward osmosis membrane: Effects of pH, calcium, membrane orientation, initial permeate flux and foulant composition.

PubMed

Zhao, Pin; Gao, Baoyu; Yue, Qinyan; Liu, Pan; Shon, Ho Kyong

2016-08-01

Octanoic acid (OA) was selected to represent fatty acids in effluent organic matter (EOM). The effects of feed solution (FS) properties, membrane orientation and initial permeate flux on OA fouling in forward osmosis (FO) were investigated. The undissociated OA formed a cake layer quickly and caused the water flux to decline significantly in the initial 0.5hr at unadjusted pH3.56; while the fully dissociated OA behaved as an anionic surfactant and promoted the water permeation at an elevated pH of 9.00. Moreover, except at the initial stage, the sudden decline of water flux (meaning the occurrence of severe membrane fouling) occurred in two conditions: 1. 0.5mmol/L Ca(2+), active layer facing draw solution (AL-DS) and 1.5mol/L NaCl (DS); 2. No Ca(2+), active layer-facing FS (AL-FS) and 4mol/L NaCl (DS). This demonstrated that cake layer compaction or pore blocking occurred only when enough foulants were absorbed into the membrane surface, and the water permeation was high enough to compact the deposit inside the porous substrate. Furthermore, bovine serum albumin (BSA) was selected as a co-foulant. The water flux of both co-foulants was between the fluxes obtained separately for the two foulants at pH3.56, and larger than the two values at pH9.00. This manifested that, at pH3.56, BSA alleviated the effect of the cake layer caused by OA, and OA enhanced BSA fouling simultaneously; while at pH9.00, the mutual effects of OA and BSA eased the membrane fouling. Copyright © 2016. Published by Elsevier B.V.

Climate change may affect fish through an interaction of parental and juvenile environments

NASA Astrophysics Data System (ADS)

Donelson, J. M.; Munday, P. L.; McCormick, M. I.

2012-09-01

Changes to tropical sea surface temperature and plankton communities are expected to occur over the next 100 years due to climate change. There is a limited understanding of how these environmental changes are likely to impact coral reef fishes, especially in terms of population replenishment through the quality of progeny produced. The present study investigated the effect that elevated sea water temperature and changes to food availability may have on the production of offspring by the reef fish Acanthochromis polyacanthus (Pomacentridae), as well as the performance of progeny in environments of varying food availability. An orthogonal design of three water temperatures and two food availabilities (high and low ration) was used, with water temperatures being the current-day average for the collection location (28.5 °C), +1.5 °C (30.0 °C) and +3.0 °C (31.5 °C), representing likely temperatures by 2100. Generally, an increase in the water temperature for adults resulted in a reduction in the size, weight and amount of yolk possessed by newly hatched offspring. Offspring whose parents were maintained under elevated temperature (30.0 °C high ration) had lower survival than offspring produced by parents at the current-day temperature (28.5 °C high ration) at 15 days post-hatching, but only when juveniles were reared under conditions of low food availability. In contrast, by 30 days post-hatching, the growth and condition of these offspring produced by parents held under elevated temperature (30.0 °C high ration) were the best of all treatment groups in all levels of juvenile food availability. This result illustrates the potential for initial parental effects to be modified by compensatory growth early in life (within 1 month) and that parental effects are not necessarily long lasting. These findings suggest that the performance of juvenile reef fish in future ocean conditions may not only depend on initial parental effects, but the interaction between their parentally mediated phenotype and their present food availability.

Cardiorespiratory responses of the facultative air-breathing fish jeju, Hoplerythrinus unitaeniatus (Teleostei, Erythrinidae), exposed to graded ambient hypoxia.

PubMed

Oliveira, R D; Lopes, J M; Sanches, J R; Kalinin, A L; Glass, M L; Rantin, F T

2004-12-01

The jeju, Hoplerythrinus unitaeniatus, is equipped with a modified part of the swim bladder that allows aerial respiration. On this background, we have evaluated its respiratory and cardiovascular responses to aquatic hypoxia. Its aquatic O2 uptake (V(O2)) was maintained constant down to a critical P(O2) (P(cO2)) of 40 mm Hg, below which V(O2) declined linearly with further reductions of P(iO2). Just below P(cO2), the ventilatory tidal volume (V(T)) increased significantly along with gill ventilation (V(G)), while respiratory frequency changed little. Consequently, water convection requirement (V(G)/V(O2)) increased steeply. The same threshold applied to cardiovascular responses that included reflex bradycardia and elevated arterial blood pressure (P(a)). Aerial respiration was initiated at water P(O2) of 44 mm Hg and breathing episodes and time at the surface increased linearly with more severe hypoxia. At the lowest water P(O2) (20 mm Hg), the time spent at the surface accounted for 50% of total time. This response has a character of a temporary emergency behavior that may allow the animal to escape hypoxia.

Continuous measurements of water surface height and width along a 6.5km river reach for discharge algorithm development

NASA Astrophysics Data System (ADS)

Tuozzolo, S.; Durand, M. T.; Pavelsky, T.; Pentecost, J.

2015-12-01

The upcoming Surface Water and Ocean Topography (SWOT) satellite will provide measurements of river width and water surface elevation and slope along continuous swaths of world rivers. Understanding water surface slope and width dynamics in river reaches is important for both developing and validating discharge algorithms to be used on future SWOT data. We collected water surface elevation and river width data along a 6.5km stretch of the Olentangy River in Columbus, Ohio from October to December 2014. Continuous measurements of water surface height were supplemented with periodical river width measurements at twenty sites along the study reach. The water surface slope of the entire reach ranged from during 41.58 cm/km at baseflow to 45.31 cm/km after a storm event. The study reach was also broken into sub-reaches roughly 1km in length to study smaller scale slope dynamics. The furthest upstream sub-reaches are characterized by free-flowing riffle-pool sequences, while the furthest downstream sub-reaches were directly affected by two low-head dams. In the sub-reaches immediately upstream of each dam, baseflow slope is as low as 2 cm/km, while the furthest upstream free-flowing sub-reach has a baseflow slope of 100 cm/km. During high flow events the backwater effect of the dams was observed to propagate upstream: sub-reaches impounded by the dams had increased water surface slopes, while free flowing sub-reaches had decreased water surface slopes. During the largest observed flow event, a stage change of 0.40 m affected sub-reach slopes by as much as 30 cm/km. Further analysis will examine height-width relationships within the study reach and relate cross-sectional flow area to river stage. These relationships can be used in conjunction with slope data to estimate discharge using a modified Manning's equation, and are a core component of discharge algorithms being developed for the SWOT mission.

Chlorine stress mediates microbial surface attachment in drinking water systems.

PubMed

Liu, Li; Le, Yang; Jin, Juliang; Zhou, Yuliang; Chen, Guowei

2015-03-01

Microbial attachment to drinking water pipe surfaces facilitates pathogen survival and deteriorates disinfection performance, directly threatening the safety of drinking water. Notwithstanding that the formation of biofilm has been studied for decades, the underlying mechanisms for the origins of microbial surface attachment in biofilm development in drinking water pipelines remain largely elusive. We combined experimental and mathematical methods to investigate the role of environmental stress-mediated cell motility on microbial surface attachment in chlorination-stressed drinking water distribution systems. Results show that at low levels of disinfectant (0.0-1.0 mg/L), the presence of chlorine promotes initiation of microbial surface attachment, while higher amounts of disinfectant (>1.0 mg/L) inhibit microbial attachment. The proposed mathematical model further demonstrates that chlorination stress (0.0-5.0 mg/L)-mediated microbial cell motility regulates the frequency of cell-wall collision and thereby controls initial microbial surface attachment. The results reveal that transport processes and decay patterns of chlorine in drinking water pipelines regulate microbial cell motility and, thus, control initial surface cell attachment. It provides a mechanistic understanding of microbial attachment shaped by environmental disinfection stress and leads to new insights into microbial safety protocols in water distribution systems.

Airborne Imaging in the Yukon River Basin to Characterize SWOT Mission Phenomenology

NASA Astrophysics Data System (ADS)

Moller, D.; Pavelsky, T.; Arvesen, J. C.

2015-12-01

Remote sensing offers intriguing tools to track Arctic hydrology, but current techniques are largely limited to tracking either inundation or water surface elevation only. For the first time, the proposed Surface Water Ocean Topography (SWOT) satellite mission will provide regular, simultaneous observations of inundation extent and water level from space. SWOT is unique and distinct from precursor altimetry missions in some notable regards: 1) 100km+ of swath will provide complete ocean coverage, 2) in addition to the ocean product, land surface water will be mapped for storage measurement and discharge estimation and 3) Ka-band single-pass interferometry will produce the height measurements introducing a new measurement technique. This new approach introduces additional algorithmic, characterization and calibration/validation needs for which the Ka-band SWOT Phenomenology Airborne Radar (KaSPAR) was developed. In May 2015, AirSWOT (comprised of KaSPAR and a color infrared (CIR) high resolution aerial camera) was part of an intensive field campaign including observations of inundation extent and water level and in situ hydrologic measurements in two rivers and 20 lakes within the Yukon River Basin, Alaska. One goal is to explore the fundamental phenomenology of the SWOT measurement. This includes assessment of the effects of vegetation layover and attenuation, wind roughening and classification. Further KaSPAR-derived inundation extent will to be validated using a combination of ground surveys and coregistered CIR imagery. Ultimately, by combining measurements of changing inundation extent and water level between two collection dates, it will be possible to validate lake water storage variations against storage changes computed from in situ water levels and inundation area derived from AirSWOT. Our paper summarizes the campaign, the airborne and in situ measurements and presents some initial KaSPAR and CIR imagery from the Yukon flats region.

Estimation of missing water-level data for the Everglades Depth Estimation Network (EDEN), 2013 update

USGS Publications Warehouse

Petkewich, Matthew D.; Conrads, Paul

2013-01-01

The Everglades Depth Estimation Network is an integrated network of real-time water-level gaging stations, a ground-elevation model, and a water-surface elevation model designed to provide scientists, engineers, and water-resource managers with water-level and water-depth information (1991-2013) for the entire freshwater portion of the Greater Everglades. The U.S. Geological Survey Greater Everglades Priority Ecosystems Science provides support for the Everglades Depth Estimation Network in order for the Network to provide quality-assured monitoring data for the U.S. Army Corps of Engineers Comprehensive Everglades Restoration Plan. In a previous study, water-level estimation equations were developed to fill in missing data to increase the accuracy of the daily water-surface elevation model. During this study, those equations were updated because of the addition and removal of water-level gaging stations, the consistent use of water-level data relative to the North American Vertical Datum of 1988, and availability of recent data (March 1, 2006, to September 30, 2011). Up to three linear regression equations were developed for each station by using three different input stations to minimize the occurrences of missing data for an input station. Of the 667 water-level estimation equations developed to fill missing data at 223 stations, more than 72 percent of the equations have coefficients of determination greater than 0.90, and 97 percent have coefficients of determination greater than 0.70.

The impact of snowpack decline on high elevation surface-water flow in the Willamette River: a stable isotope perspective

NASA Astrophysics Data System (ADS)

Brooks, J. R.; Johnson, H.; Cline, S. P.; Rugh, W.

2015-12-01

Much of the water that people in Western Oregon rely on comes from the snowpack in the Cascade Range, and this snowpack is expected to decrease in coming years with climate change. In fact, the past five years have shown dramatic variation in snowpack from a high of 174% of normal in 2010-11 to a low of 11% for 2014-15, one of the lowest on record. During this timeframe, we have monitored the stable isotopes of water within the Willamette River twice monthly, and mapped the spatial variation of water isotopes across the basin. Within the Willamette Basin, stable isotopes of water in precipitation vary strongly with elevation and provide a marker for determining the mean elevation from which water in the Willamette River is derived. In the winter when snow accumulates in the mountains, low elevation precipitation (primarily rain) contributes the largest proportion of water to the Willamette River. During summer when rainfall is scarce and demand for water is the greatest, water in the Willamette River is mainly derived from high elevation snowmelt. Our data indicate that the proportion of water from high elevation decreased with decreasing snowpack. We combine this information with the river flow data to estimate the volume reduction related to snow pack reduction during the dry summer. Observed reductions in the contribution of high elevation water to the Willamette River after just two years of diminished snowpack indicate that the hydrologic system responds relatively rapidly to changing snowpack volume. Reconciling the demands between human use and biological instream requirements during summer will be challenging under climatic conditions in which winter snowpack is reduced compared to historical amounts.

Warming and Carbon Dioxide Enrichment Alter Plant Production and Ecosystem gas Exchange in a Semi-Arid Grassland Through Direct Responses to Global Change Factors and Indirect Effects on Water Relations

NASA Astrophysics Data System (ADS)

Morgan, J. A.; Pendall, E.; Williams, D. G.; Bachman, S.; Dijkstra, F. A.; Lecain, D. R.; Follett, R.

2007-12-01

The Prairie Heating and CO2 Enrichment (PHACE) experiment was initiated in Spring, 2007 to evaluate the combined effects of warming and elevated CO2 on a northern mixed-grass prairie. Thirty 3-m diameter circular experimental plots were installed in Spring, 2006 at the USDA-ARS High Plains Grasslands Research Station, just west of Cheyenne, WY, USA. Twenty plots were assigned to a two-level factorial combination of two CO2 concentrations (present ambient, 380 ppmV; and elevated, 600 ppmV), and two levels of temperature (present ambient; and elevated temperature, 1.5/3.0 C warmer day/night), with five replications for each treatment. Five of the ten remaining plots were subjected to either frequent, small water additions throughout the growing season, and the other five to a deep watering once or twice during the growing season. The watering treatments were imposed to simulate hypothesized water savings in the CO2-enriched plots, and to contrast the influence of variable water dynamics on ecosystem processes. Carbon dioxide enrichment of the ten CO2- enriched plots is accomplished with Free Air CO2 Enrichment (FACE) technology and occurs during daylight hours of the mid-April - October growing season. Warming is done year-round with circularly-arranged ceramic heater arrays positioned above the ring perimeters, and with temperature feed-backs to control day/night canopy surface temperatures. Carbon dioxide enrichment began in Spring, 2006, and warming was added in Spring, 2007. Results from the first year of CO2 enrichment (2006) confirmed earlier reports that CO2 increases productivity in semi-arid grasslands (21% increase in peak seasonal above ground biomass for plants grown under elevated CO2 compared to non-enriched controls), and that the response was related to CO2- induced water savings. Growth at elevated CO2 reduced leaf carbon isotope discrimination and N concentrations in plants compared to results obtained in control plots, but the magnitude of changes were highly species specific. Ecosystem-level gas exchange measurements indicated that interactions between watering and CO2 enrichment increased C cycling over a range of soil moisture conditions, although watering had a greater relative impact on C fluxes than CO2 enrichment. Results from the combined warming and CO2 enrichment experiment in 2007 indicate soil fluxes of CO2 increased with elevated CO2 and warming, but decreased with warming later in the year compared to un-heated controls. Soil CH4 uptake was enhanced by elevated CO2 but reduced by warming, particularly later in the year. Soil fluxes of N2O were unaffected by treatment. These preliminary results indicate potentially strong feedbacks between carbon cycling and warming are mediated by ecosystem processes in this semiarid rangeland.

Modeling the relationship between water level, wild rice abundance, and waterfowl abundance at a central North American wetland

USGS Publications Warehouse

Aagaard, Kevin; Eash, Josh D.; Ford, Walt; Heglund, Patricia J.; McDowell, Michelle; Thogmartin, Wayne E.

2018-01-01

Recent evidence suggests wild rice (Zizania palustris), an important resource for migrating waterfowl, is declining in parts of central North America, providing motivation to rigorously quantify the relationship between waterfowl and wild rice. A hierarchical mixed-effects model was applied to data on waterfowl abundance for 16 species, wild rice stem density, and two measures of water depth (true water depth at vegetation sampling locations and water surface elevation). Results provide evidence for an effect of true water depth (TWD) on wild rice abundance (posterior mean estimate for TWD coefficient, β TWD = 0.92, 95% confidence interval = 0.11—1.74), but not for an effect of wild rice stem density or water surface elevation on local waterfowl abundance (posterior mean values for relevant parameters overlapped 0). Refined protocols for sampling design and more consistent sampling frequency to increase data quality should be pursued to overcome issues that may have obfuscated relationships evaluated here.

National Enforcement Initiative: Preventing Animal Waste from Contaminating Surface and Ground Water

EPA Pesticide Factsheets

This page describes EPA's goal in preventing animal waste from contaminating surface and ground Water. It is an EPA National Enforcement Initiative. Both enforcement cases, and a map of enforcement actions are provided.

Flooding of Ganymede's bright terrains by low-viscosity water-ice lavas.

PubMed

Schenk, P M; McKinnon, W B; Gwynn, D; Moore, J M

2001-03-01

Large regions of the jovian moon Ganymede have been resurfaced, but the means has been unclear. Suggestions have ranged from volcanic eruptions of liquid water or solid ice to tectonic deformation, but definitive high-resolution morphological evidence has been lacking. Here we report digital elevation models of parts of the surface of Ganymede, derived from stereo pairs combining data from the Voyager and Galileo spacecraft, which reveal bright, smooth terrains that lie at roughly constant elevations 100 to 1,000 metres below the surrounding rougher terrains. These topographic data, together with new images that show fine-scale embayment and burial of older features, indicate that the smooth terrains were formed by flooding of shallow structural troughs by low-viscosity water-ice lavas. The oldest and most deformed areas (the 'reticulate' terrains) in general have the highest relative elevations, whereas units of the most common resurfaced type--the grooved terrain--lie at elevations between those of the smooth and reticulate terrains. Bright terrain, which accounts for some two-thirds of the surface, probably results from a continuum of processes, including crustal rifting, shallow flooding and groove formation. Volcanism plays an integral role in these processes, and is consistent with partial melting of Ganymede's interior.

Ground displacements caused by aquifer-system water-level variations observed using interferometric synthetic aperture radar near Albuquerque, New Mexico

USGS Publications Warehouse

Heywood, Charles E.; Galloway, Devin L.; Stork, Sylvia V.

2002-01-01

Six synthetic aperture radar (SAR) images were processed to form five unwrapped interferometric (InSAR) images of the greater metropolitan area in the Albuquerque Basin. Most interference patterns in the images were caused by range displacements resulting from changes in land-surface elevation. Loci of land- surface elevation changes correlate with changes in aquifer-system water levels and largely result from the elastic response of the aquifer-system skeletal material to changes in pore-fluid pressure. The magnitude of the observed land-surface subsidence and rebound suggests that aquifer-system deformation resulting from ground-water withdrawals in the Albuquerque area has probably remained in the elastic (recoverable) range from July 1993 through September 1999. Evidence of inelastic (permanent) land subsidence in the Rio Rancho area exists, but its relation to compaction of the aquifer system is inconclusive because of insufficient water-level data. Patterns of elastic deformation in both Albuquerque and Rio Rancho suggest that intrabasin faults impede ground- water-pressure diffusion at seasonal time scales and that these faults are probably important in controlling patterns of regional ground-water flow.

Design of an experimental apparatus for measurement of the surface tension of metastable fluids

NASA Astrophysics Data System (ADS)

Vinš, V.; Hrubý, J.; Hykl, J.; Blaha, J.; Šmíd, B.

2013-04-01

A unique experimental apparatus for measurement of the surface tension of aqueous mixtures has been designed, manufactured, and tested in our laboratory. The novelty of the setup is that it allows measurement of surface tension by two different methods: a modified capillary elevation method in a long vertical capillary tube and a method inspired by the approach of Hacker (National Advisory Committee for Aeronautics, Technical Note 2510, 1-20, 1951), i.e. in a short horizontal capillary tube. Functionality of all main components of the apparatus, e.g., glass chamber with the capillary tube, temperature control unit consisting of two thermostatic baths with special valves for rapid temperature jumps, helium distribution setup allowing pressure variation above the liquid meniscus inside the capillary tube, has been successfully tested. Preliminary results for the surface tension of the stable and metastable supercooled water measured by the capillary elevation method at atmospheric pressure are provided. The surface tension of water measured at temperatures between +26 °C and -11 °C is in good agreement with the extrapolated IAPWS correlation (IAPWS Release on Surface Tension of Ordinary Water Substance, September 1994); however it disagrees with data by Hacker.

Temporal and spatial variabilities in the surface moisture content of a fine-grained beach

NASA Astrophysics Data System (ADS)

Namikas, S. L.; Edwards, B. L.; Bitton, M. C. A.; Booth, J. L.; Zhu, Y.

2010-01-01

This study examined spatial and temporal variations in the surface moisture content of a fine-grained beach at Padre Island, Texas, USA. Surface moisture measurements were collected on a 27 × 24 m grid that extended from the dune toe to the upper foreshore. The grid was surveyed at 2 to 4 h intervals for two tidal cycles, generating 17 maps of the spatial distribution of surface moisture. Simultaneous measurements of air temperature and humidity, wind speed and direction, tidal elevation, and water table elevation were used to interpret observed changes in surface moisture. It was found that the spatial distribution of surface moisture was broadly characterized by a cross-shore gradient of high to low content moving landward from the swash zone. The distribution of surface moisture was conceptualized in terms of three zones: saturated (> 25%), intermediate or transitional (5-25%), and dry (< 5%). The position of the saturated zone corresponded to the uppermost swash zone and therefore shifted in accordance with tidal elevation. Moisture contents in the intermediate and dry zones were primarily related to variation in water table depth (which was in turn controlled by tidal elevation) and to a lesser extent by evaporation. Signals associated with atmospheric processes such as evaporation were muted by the minimal degree of variation in atmospheric parameters experienced during most of the study period, but were apparent for the last few hours. The observed spatial and temporal variations in moisture content correspond reasonably well with observations of key controlling processes, but more work is needed to fully characterize this process suite.

Flood of April 2-3, 2005, Esopus Creek Basin, New York

USGS Publications Warehouse

Suro, Thomas P.; Firda, Gary D.

2007-01-01

On April 2-3, 2005, heavy rain moved into southern New York and delivered rainfall amounts that ranged from about 2 in. to almost 6 in. within a 36-hour period. Significant flooding occurred on many small streams and tributaries in the area, and extensive flooding occurred on the Esopus and Roundout Creeks in Ulster and Greene Counties, New York. The flooding damaged many homes, caused millions of dollars worth of damage, and forced hundreds of residents to evacuate their homes. A total of 20 New York counties were declared Federal disaster areas. Disaster recovery assistance for those people affected stands at almost $35 million, according to the Federal Emergency Management Agency, as more than 3,400 New Yorkers registered for Federal aid. U.S. Geological Survey stream-gaging stations on the Esopus Creek above the Ashokan Reservoir at Allaben, N.Y., and below the Ashokan Reservoir at Mount Marion, N.Y., each recorded a new record maximum water-surface elevation and discharge for the respective periods of record as a result of this storm. The peak water-surface elevation and discharge recorded during the April 2-3, 2005, storm at the U.S. Geological Survey stream-gaging station on the Esopus Creek at Cold Brook, N.Y. were the third highest elevation and discharge since the station was put into operation in 1914. Most of the study sites along the Esopus Creek indicated water-surface elevations near the 50-year flood elevations, as documented in flood-insurance studies by the Federal Emergency Management Agency.

Microbiologically Influenced Corrosion

DTIC Science & Technology

2015-11-05

high in water content, are less corrosive owing to their elevated viscosity and resulting low conductivity (᝺-7 S/cm) [30]. Asphaltenes and resins...wet surface to a water-wet surface. Sludge deposits are combinations of hydrocarbons, sand, clay , corTosion prod- ucts, and biomass that can reach 50...fine clay sun·ounded by a film of water. Under low flow conditions, these particles precipitate and form a sludge deposit. 27.4 TESTING 27 .4.1 A

The Influence of Marine Microfouling on the Corrosion Behaviour of Passive Materials and Copper Alloys

DTIC Science & Technology

2008-01-02

to organometallic catalysis, acidification of the electrode surface, the combined effects of elevated H20 2 and decreased pH and the production of...Ennoblement in marine waters has been ascribed to depolarization of the oxygen reduction reaction due to organometallic catalysis, acidification of the...organometallic catalysis, acidification of the electrode surface, the combined effects of elevated hydrogen peroxide (H202) and decreased pH and the production

Estimating shallow subsidence in microtidal salt marshes of the southeastern United States: Kaye and Barghoorn revisited

USGS Publications Warehouse

Cahoon, D.R.; Reed, D.J.; Day, J.W.

1995-01-01

Simultaneous measurements of vertical accretion and change in surface elevation relative to a shallow (3-5 m) subsurface datum were made in selected coastal salt marshes of Louisiana, Florida, and North Carolina to quantitatively test Kaye and Barghoorn's contention that vertical accretion is not a good surrogate for surface elevation change because of autocompaction of the substrate. Rates of subsidence of the upper 3-5 m of marsh substrate were calculated for each marsh as the difference between vertical accretion and elevation change measured with feldspar marker horizons and a sedimentation-erosion table. Surface elevation change was significantly lower than vertical accretion at each site after 2 years, indicating a significant amount of shallow subsidence had occurred, ranging from 0.45 to 4.90 cm. The highest rate of shallow subsidence occurred in the Mississippi delta. Results confirm Kaye and Barghoorn's contention that vertical accretion is not generally a good surrogate for elevation change because of processes occurring in the upper few meters of the substrate, including not only compaction but also apparently shrink-swell from water storage and/or plant production--decomposition at some sites. Indeed, surface elevation change was completely decoupled from vertical accretion at the Florida site. The assumption of a 1:1 relationship between accretionary and substrate processes. Consequently, the potential for coastal marsh submergence should be expressed as an elevation deficit based on direct measures of surface elevation change rather than accretion deficits. These findings also indicate the need for greater understanding of the influence of subsurface and small-scale hydrologic processes on marsh surface elevation.

Mapping Critical Loads of Atmospheric Nitrogen Deposition in the Rocky Mountains, USA

NASA Astrophysics Data System (ADS)

Nanus, L.; Clow, D. W.; Stephens, V. C.; Saros, J. E.

2010-12-01

Atmospheric nitrogen (N) deposition can adversely affect sensitive aquatic ecosystems at high-elevations in the western United States. Critical loads are the amount of deposition of a given pollutant that an ecosystem can receive below which ecological effects are thought not to occur. GIS-based landscape models were used to create maps for high-elevation areas across the Rocky Mountain region showing current atmospheric deposition rates of nitrogen (N), critical loads of N, and exceedances of critical loads of N. Atmospheric N deposition maps for the region were developed at 400 meter resolution using gridded precipitation data and spatially interpolated chemical concentrations in rain and snow. Critical loads maps were developed based on chemical thresholds corresponding to observed ecological effects, and estimated ecosystem sensitivities calculated from basin characteristics. Diatom species assemblages were used as an indicator of ecosystem health to establish critical loads of N. Chemical thresholds (concentrations) were identified for surface waters by using a combination of in-situ growth experiments and observed spatial patterns in surface-water chemistry and diatom species assemblages across an N deposition gradient. Ecosystem sensitivity was estimated using a multiple-linear regression approach in which observed surface water nitrate concentrations at 530 sites were regressed against estimates of inorganic N deposition and basin characteristics (topography, soil type and amount, bedrock geology, vegetation type) to develop predictive models of surface water chemistry. Modeling results indicated that the significant explanatory variables included percent slope, soil permeability, and vegetation type (including barren land, shrub, and grassland) and were used to predict high-elevation surface water nitrate concentrations across the Rocky Mountains. Chemical threshold concentrations were substituted into an inverted form of the model equations and applied to estimate critical loads for each stream reach within a basin, from which critical loads maps were created. Atmospheric N deposition maps were overlaid on the critical loads maps to identify areas in the Rocky Mountain region where critical loads are being exceeded, or where they may do so in the future. This approach may be transferable to other high-elevation areas of the United States and the world.

Spatial-temporal changes in Andean plateau climate and elevation from stable isotopes of mammal teeth

NASA Astrophysics Data System (ADS)

Bershaw, John; Garzione, Carmala N.; Higgins, Pennilyn; MacFadden, Bruce J.; Anaya, Frederico; Alvarenga, Herculano

2010-01-01

Paleoelevation constraints from fossil leaf physiognomy and stable isotopes of sedimentary carbonate suggest that significant surface uplift of the northern Andean plateau, on the order of 2.5 ± 1 km, occurred between ˜ 10.3 and 6.4 Ma. Independent spatial and temporal constraints on paleoelevation and paleoclimate of both the northern and southern plateau are important for understanding the distribution of rapid surface uplift and its relation to climate evolution across the plateau. This study focuses on teeth from modern and extinct mammal taxa (including notoungulates, pyrotheres, and litopterns) spanning ˜ 29 Ma to present, collected from the Altiplano and Eastern Cordillera of Bolivia (16.2°S to 21.4°S), and lowland Brazil. Tooth enamel of large, water-dependent mammals preserves a record of surface water isotopes and the type of plants that animals ingested while their teeth were mineralizing. Previous studies have shown that the δ18O of modern precipitation and surface waters decrease systematically with increasing elevations across the central Andes. Our results from high elevation sites between 3600 and 4100 m show substantially more positive δ18O values for late Oligocene tooth samples compared to < 10 Ma tooth δ18O values. Late Oligocene teeth collected from low elevation sites in southeast Brazil show δ18O values similar (within 2‰) to contemporaneous teeth collected at high elevation in the Eastern Cordillera. This affirms that the Andean plateau was at a very low elevation during the late Oligocene. Late Oligocene teeth from the northern Eastern Cordillera also yield consistent δ13C values of about - 9‰, indicating that the environment was semi-arid at that time. Latitudinal gradients in δ18O values of late Miocene to Pliocene fossil teeth are similar to modern values for large mammals, suggesting that by ˜ 8 Ma in the northern Altiplano and by ˜ 3.6 Ma in the southern Altiplano, both regions had reached high elevation and established a latitudinal rainfall gradient similar to modern.

Assimilation and High Resolution Forecasts of Surface and Near Surface Conditions for the 2010 Vancouver Winter Olympic and Paralympic Games

NASA Astrophysics Data System (ADS)

Bernier, Natacha B.; Bélair, Stéphane; Bilodeau, Bernard; Tong, Linying

2014-01-01

A dynamical model was experimentally implemented to provide high resolution forecasts at points of interests in the 2010 Vancouver Olympics and Paralympics Region. In a first experiment, GEM-Surf, the near surface and land surface modeling system, is driven by operational atmospheric forecasts and used to refine the surface forecasts according to local surface conditions such as elevation and vegetation type. In this simple form, temperature and snow depth forecasts are improved mainly as a result of the better representation of real elevation. In a second experiment, screen level observations and operational atmospheric forecasts are blended to drive a continuous cycle of near surface and land surface hindcasts. Hindcasts of the previous day conditions are then regarded as today's optimized initial conditions. Hence, in this experiment, given observations are available, observation driven hindcasts continuously ensure that daily forecasts are issued from improved initial conditions. GEM-Surf forecasts obtained from improved short-range hindcasts produced using these better conditions result in improved snow depth forecasts. In a third experiment, assimilation of snow depth data is applied to further optimize GEM-Surf's initial conditions, in addition to the use of blended observations and forecasts for forcing. Results show that snow depth and summer temperature forecasts are further improved by the addition of snow depth data assimilation.

Enhanced Climatic Warming in the Tibetan Plateau Due to Double CO2: A Model Study

NASA Technical Reports Server (NTRS)

Chen, Baode; Chao, Winston C.; Liu, Xiao-Dong; Lau, William K. M. (Technical Monitor)

2001-01-01

The NCAR (National Center for Atmospheric Research) regional climate model (RegCM2) with time-dependent lateral meteorological fields provided by a 130-year transient increasing CO2 simulation of the NCAR Climate System Model (CSM) has been used to investigate the mechanism of enhanced ground temperature warming over the TP (Tibetan Plateau). From our model results, a remarkable tendency of warming increasing with elevation is found for the winter season, and elevation dependency of warming is not clearly recognized in the summer season. This simulated feature of elevation dependency of ground temperature is consistent with observations. Based on an analysis of surface energy budget, the short wave solar radiation absorbed at the surface plus downward long wave flux reaching the surface shows a strong elevation dependency, and is mostly responsible for enhanced surface warming over the TP. At lower elevations, the precipitation forced by topography is enhanced due to an increase in water vapor supply resulted from a warming in the atmosphere induced by doubling CO2. This precipitation enhancement must be associated with an increase in clouds, which results in a decline in solar flux reaching surface. At higher elevations, large snow depletion is detected in the 2xCO2run. It leads to a decrease in albedo, therefore more solar flux is absorbed at the surface. On the other hand, much more uniform increase in downward long wave flux reaching the surface is found. The combination of these effects (i.e. decrease in solar flux at lower elevations, increase in solar flux at higher elevation and more uniform increase in downward long wave flux) results in elevation dependency of enhanced ground temperature warming over the TP.

Determination of bromine, chlorine and iodine in environmental aqueous samples by epithermal neutron activation analysis and Compton suppression

USGS Publications Warehouse

Landsberger, S.; O'Kelly, D. J.; Braisted, J.; Panno, S.

2006-01-01

Halides, particularly Br- and Cl-, have been used as indicators of potential sources of Na+ and Cl- in surface water and groundwater with limited success. Contamination of groundwater and surface water by Na+ and Cl- is a common occurrence in growing urban areas and adversely affects municipal and private water supplies in Illinois and other states, as well as vegetation in environmentally sensitive areas. Neutron activation analysis (NAA) can be effectively used to determine these halogens, but often the elevated concentrations of sodium and chlorine in water samples can give rise to very high detection limits for bromine and iodine due to elevated backgrounds from the activation process. We present a detailed analytical scheme to determine Cl, Br and I in aqueous samples with widely varying Na and Cl concentrations using epithermal NAA in conjunction with Compton suppression. ?? 2006 Akade??miai Kiado??.

Elevation trends and shrink-swell response of wetland soils to flooding and drying

USGS Publications Warehouse

Cahoon, Donald R.; Perez, Brian C.; Segura, Bradley D.; Lynch, James C.

2011-01-01

Given the potential for a projected acceleration in sea-level rise to impact wetland sustainability over the next century, a better understanding is needed of climate-related drivers that influence the processes controlling wetland elevation. Changes in local hydrology and groundwater conditions can cause short-term perturbations to marsh elevation trends through shrink—swell of marsh soils. To better understand the magnitude of these perturbations and their impacts on marsh elevation trends, we measured vertical accretion and elevation dynamics in microtidal marshes in Texas and Louisiana during and after the extreme drought conditions that existed there from 1998 to 2000. In a Louisiana marsh, elevation was controlled by subsurface hydrologic fluxes occurring below the root zone but above the 4 m depth (i.e., the base of the surface elevation table benchmark) that were related to regional drought and local meteorological conditions, with marsh elevation tracking water level variations closely. In Texas, a rapid decline in marsh elevation was related to severe drought conditions, which lowered local groundwater levels. Unfragmented marshes experienced smaller water level drawdowns and more rapid marsh elevation recovery than fragmented marshes. It appears that extended drawdowns lead to increased substrate consolidation making it less resilient to respond to future favorable conditions. Overall, changes in water storage lead to rapid and large short-term impacts on marsh elevation that are as much as five times greater than the long-term elevation trend, indicating the importance of long-term, high-resolution elevation data sets to understand the prolonged effects of water deficits on marsh elevation change.

Asymmetric vitreomacular traction and symmetrical full thickness macular hole formation.

PubMed

Woon, Wai H; Greig, Denis; Savage, Mike D; Wilson, Mark C T; Grant, Colin A; Bishop, Fiona; Mokete, Bataung

2015-11-01

A Full Thickness Macular Hole (FTMH) is often associated with vitreomacular traction, and this can be asymmetric with vitreomacular traction on one side of the hole but not the other. In cross-section, the elevated retinal rim around a developed FTMH is seen as a drawbridge elevation, and this drawbridge elevation may be used as a measure of morphological change. Examination of the drawbridge elevation of the retinal rim in FTMH with asymmetric vitreomacular traction may help to clarify the role of vitreomacular traction in the development of FTMH. Cases of FTMH were identified with an initial OCT scan showing vitreomacular traction on one side of the hole only and that had a follow-up OCT scan showing progression of the hole. A tangent to the retinal surface at a distance of 700 microns from the axis of the hole was used as a marker of the drawbridge elevation of the retinal rim around the macular hole. Comparisons of the drawbridge elevation and change in drawbridge elevation between the sides with and without initial vitreomacular traction were made. There was no significant difference between the drawbridge elevation, or change in drawbridge elevation, on the side of the hole with initial vitreomacular traction compared to the side without initial traction. There is some intrinsic mechanism within the retina to link the morphological changes on the two sides of a FTMH. A bistable hypothesis of FTMH formation and closure is postulated to explain this linkage.

The scaling of urban surface water abundance and impairment with city size

NASA Astrophysics Data System (ADS)

Steele, M. K.

2018-03-01

Urbanization alters surface water compared to nonurban landscapes, yet little is known regarding how basic aquatic ecosystem characteristics, such as the abundance and impairment of surface water, differ with population size or regional context. This study examined the abundance, scaling, and impairment of surface water by quantifying the stream length, water body area, and impaired stream length for 3520 cities in the United States with populations from 2500 to 18 million. Stream length, water body area, and impaired stream length were quantified using the National Hydrography Dataset and the EPA's 303(d) list. These metrics were scaled with population and city area using single and piecewise power-law models and related to biophysical factors (precipitation, topography) and land cover. Results show that abundance of stream length and water body area in cities actually increases with city area; however, the per person abundance decreases with population size. Relative to population, impaired stream length did not increase until city populations were > 25,000 people, then scaled linearly with population. Some variation in abundance and impairment was explained by biophysical context and land cover. Development intensity correlated with stream density and impairment; however, those relationships depended on the orientation of the land covers. When high intensity development occupied the local elevation highs (+ 15 m) and undeveloped land the elevation lows, the percentage of impaired streams was less than the opposite land cover orientation (- 15 m) or very flat land. These results show that surface water abundance and impairment across contiguous US cities are influenced by city size and by biophysical setting interacting with land cover intensity.

Lakes and lake-like waters of the Hawaiian Archipelago

USGS Publications Warehouse

Maciolek, J.A.

1982-01-01

This summary of Hawaiian lacustrine limnology is based on 12 years of field and literature surveys of archipelagic inland waters. Lakes here are distinguished from other standing waters by limits on surface oceanic area (> 0.1 ha) and depth (> 2 m), and by the absence of flatural surface oceanic connection. A variety of extinct and existing water bodies, sometimes referred to as lakes, are noted. Six lakes are described. Five of them are in crater basins, 3 are freshwater, and 2 are elevated (highest = 3969 m). The scarcity of elevated lakes results from general permeability of the substrata. Among the 6 lakes, surface areas range from 0.22 to 88 ha and maximum depths from 3 to 248 m. Naturally occurring aquatic biota generally is low in species diversity except for phytoplankton; fishes and submersed vascular plants are absent. Two lowland lakes, freshwater Green (Wai a Pele) and saline Kauhak6, are described for the first time. Profundal Kauhak6, 248 m deep, has a surface area of only 0.35 ha, which results in an extraordinary relative depth of 370%. It is permanently stratified, a condition apparently due primarily to the unique morphometry of its basin. 

Groundwater impacts on surface water quality and nutrient loads in lowland polder catchments: monitoring the greater Amsterdam area

NASA Astrophysics Data System (ADS)

Yu, Liang; Rozemeijer, Joachim; van Breukelen, Boris M.; Ouboter, Maarten; van der Vlugt, Corné; Broers, Hans Peter

2018-01-01

The Amsterdam area, a highly manipulated delta area formed by polders and reclaimed lakes, struggles with high nutrient levels in its surface water system. The polders receive spatially and temporally variable amounts of water and nutrients via surface runoff, groundwater seepage, sewer leakage, and via water inlets from upstream polders. Diffuse anthropogenic sources, such as manure and fertiliser use and atmospheric deposition, add to the water quality problems in the polders. The major nutrient sources and pathways have not yet been clarified due to the complex hydrological system in lowland catchments with both urban and agricultural areas. In this study, the spatial variability of the groundwater seepage impact was identified by exploiting the dense groundwater and surface water monitoring networks in Amsterdam and its surrounding polders. A total of 25 variables (concentrations of total nitrogen (TN), total phosphorus (TP), NH4, NO3, HCO3, SO4, Ca, and Cl in surface water and groundwater, N and P agricultural inputs, seepage rate, elevation, land-use, and soil type) for 144 polders were analysed statistically and interpreted in relation to sources, transport mechanisms, and pathways. The results imply that groundwater is a large source of nutrients in the greater Amsterdam mixed urban-agricultural catchments. The groundwater nutrient concentrations exceeded the surface water environmental quality standards (EQSs) in 93 % of the polders for TP and in 91 % for TN. Groundwater outflow into the polders thus adds to nutrient levels in the surface water. High correlations (R2 up to 0.88) between solutes in groundwater and surface water, together with the close similarities in their spatial patterns, confirmed the large impact of groundwater on surface water chemistry, especially in the polders that have high seepage rates. Our analysis indicates that the elevated nutrient and bicarbonate concentrations in the groundwater seepage originate from the decomposition of organic matter in subsurface sediments coupled to sulfate reduction and possibly methanogenesis. The large loads of nutrient-rich groundwater seepage into the deepest polders indirectly affect surface water quality in the surrounding area, because excess water from the deep polders is pumped out and used to supply water to the surrounding infiltrating polders in dry periods. The study shows the importance of the connection between groundwater and surface water nutrient chemistry in the greater Amsterdam area. We expect that taking account of groundwater-surface water interaction is also important in other subsiding and urbanising deltas around the world, where water is managed intensively in order to enable agricultural productivity and achieve water-sustainable cities.

Modeling hydrodynamics, water quality, and benthic processes to predict ecological effects in Narragansett Bay

EPA Science Inventory

The environmental fluid dynamics code (EFDC) was used to study the three dimensional (3D) circulation, water quality, and ecology in Narragansett Bay, RI. Predictions of the Bay hydrodynamics included the behavior of the water surface elevation, currents, salinity, and temperatur...

AirSWOT Measurements of Water Surface Elevations and Hydraulic Gradients over the Yukon Flats, Alaska

NASA Astrophysics Data System (ADS)

Pitcher, L. H.; Pavelsky, T.; Smith, L. C.; Moller, D.; Altenau, E. H.; Lion, C.; Bertram, M.; Cooley, S. W.

2017-12-01

AirSWOT is an airborne, Ka-band synthetic aperture radar interferometer (InSAR) intended to quantify surface water fluxes by mapping water surface elevations (WSE). AirSWOT will also serve as a calibration/validation tool for the Surface Water and Ocean Topography (SWOT) satellite mission (scheduled for launch in 2021). The hydrology objectives for AirSWOT and SWOT are to measure WSE with accuracies sufficient to estimate hydrologic fluxes in lakes, wetlands and rivers. However, current understanding of the performance of these related though not identical instruments when applied to complex river-lake-wetland fluvial environments remains predominantly theoretical. We present AirSWOT data acquired 15-June-2015 over the Yukon Flats, Alaska, USA, together with in situ field surveys, to assess the accuracy of AirSWOT WSE measurements in lakes and rivers. We use these data to demonstrate that AirSWOT can be used to estimate large-scale hydraulic gradients across wetland complexes. Finally, we present key lessons learned from this AirSWOT analysis for consideration in future campaigns, including: maximizing swath overlap for spatial averaging to minimize uncertainty as well as orienting flight paths parallel to river flow directions to reduce along track aircraft drift for neighboring flight paths. We conclude that spatially dense AirSWOT measurements of river and lake WSEs can improve geospatial understanding of surface water hydrology and fluvial processes.

Quality assurance report - Loch Vale Watershed, 1999-2002

USGS Publications Warehouse

Botte, Jorin A.; Baron, Jill S.

2004-01-01

The National Park Service initiated the Loch Vale Watershed (LVWS) project in 1980 with funding from the Aquatic Effects Research Program of the National Acid Precipitation Assessment Program. Long-term ecological research and monitoring address watershed-scale ecosystem processes, particularly as they respond to atmospheric deposition and climate variability. Monitoring of meteorological, hydrologic, precipitation chemistry, and surface water quality parameters enable us to use long-term trends to distinguish natural from human-caused disturbances. Research into snow distribution, hydrologic flowpaths, vegetation responses to N deposition, isotopic transformations of N by forest and soil processes, trace metals, and aquatic ecological responses to disturbance enable us to understand processes that influence high elevation ecosystems.

Inferring Discharge at River Mouths from Water Surface Height Measurements

NASA Astrophysics Data System (ADS)

Branch, R.; Horner-Devine, A.; Chickadel, C. C.

2016-02-01

Numerical model results suggest that a relationship exists between river discharge and surface height anomalies near the mouth of rivers, which presents an opportunity to use satellite elevation data to measure discharge remotely. Here we investigate whether such a relationship can be observed in the field using airborne lidar data at the mouth of the Columbia River. Airborne Lidar data were used because current NASA altimeter data does not have high enough spatial resolution to image surface elevation along a river. NASA's Surface Water and Ocean Topography, SWOT, sensor is planned to have a spatial resolution of less than 100 m and maximum height precision of 1 cm. The magnitude and temporal duration of the elevation signal found in the lidar data will be used to determine if SWOT will have the resolution and precision capabilities to measure discharge from space. Lidar data were acquired during a range of tidal conditions and discharge rates from May through September of 2013. Our results suggest that there is a measurable surface height anomaly at the river mouth during part of the tidal cycle. A 0.7 m surface depression was found during ebb tide and a uniform surface tilt was found at slack tide. The variation of the anomaly over the tidal period presents a challenge for decoupling the tidal component from that due to the discharge.

Arsenic Concentration in the Surface Water of a Former Mining Area: The La Junta Creek, Baja California Sur, Mexico

PubMed Central

Imaz Lamadrid, Miguel; Acosta Vargas, Baudilio

2018-01-01

The mining activity in the San Antonio-El Triunfo district, located in a mountainous region at 60 km southeast of La Paz, occured for more than 250 years and left behind severe contamination of soils and riverbed sediments which led to elevated concentrations of arsenic and other trace elements in the surface- and groundwater of the region. Although the main mining activity ended around 1911, contamination is still beeing distributed, especially from left behind tailings and mine waste piles. The contamination levels in the groundwater have been reported in several studies, but there is little information available on the surface water quality, and especially the temporal variation. In this study, we analyzed the surface water of the La Junta creek, in the southern part of the San Antonio-El Triunfo mining district. The working hypothesis was that by means of a spatial analysis of surface water and shallow groundwater, in combination with the temporal observation of the concentrations in runoff water, the effects of different sources of arsenic (natural geogene anomalies, due to historic mining activity, and hydrothermal related impact) in the La Junta creek can be recognized. This present study revealed that historic mining activity caused a mojor impact of arsenic but less contamination was observed than in the northern part of the district and elevated arsenic concentrations in stream water generally occurred during times of low streamflow. PMID:29498700

Biofilm Composition and Threshold Concentration for Growth of Legionella pneumophila on Surfaces Exposed to Flowing Warm Tap Water without Disinfectant

PubMed Central

Bakker, Geo L.; Italiaander, Ronald; Veenendaal, Harm R.; Wullings, Bart A.

2017-01-01

ABSTRACT Legionella pneumophila in potable water installations poses a potential health risk, but quantitative information about its replication in biofilms in relation to water quality is scarce. Therefore, biofilm formation on the surfaces of glass and chlorinated polyvinyl chloride (CPVC) in contact with tap water at 34 to 39°C was investigated under controlled hydraulic conditions in a model system inoculated with biofilm-grown L. pneumophila. The biofilm on glass (average steady-state concentration, 23 ± 9 pg ATP cm−2) exposed to treated aerobic groundwater (0.3 mg C liter−1; 1 μg assimilable organic carbon [AOC] liter−1) did not support growth of the organism, which also disappeared from the biofilm on CPVC (49 ± 9 pg ATP cm−2) after initial growth. L. pneumophila attained a level of 4.3 log CFU cm−2 in the biofilms on glass (1,055 ± 225 pg ATP cm−2) and CPVC (2,755 ± 460 pg ATP cm−2) exposed to treated anaerobic groundwater (7.9 mg C liter−1; 10 μg AOC liter−1). An elevated biofilm concentration and growth of L. pneumophila were also observed with tap water from the laboratory. The Betaproteobacteria Piscinibacter and Methyloversatilis and amoeba-resisting Alphaproteobacteria predominated in the clones and isolates retrieved from the biofilms. In the biofilms, the Legionella colony count correlated significantly with the total cell count (TCC), heterotrophic plate count, ATP concentration, and presence of Vermamoeba vermiformis. This amoeba was rarely detected at biofilm concentrations of <100 pg ATP cm−2. A threshold concentration of approximately 50 pg ATP cm−2 (TCC = 1 × 106 to 2 × 106 cells cm−2) was derived for growth of L. pneumophila in biofilms. IMPORTANCE Legionella pneumophila is the etiologic agent in more than 10,000 cases of Legionnaires' disease that are reported annually worldwide and in most of the drinking water-associated disease outbreaks reported in the United States. The organism proliferates in biofilms on surfaces exposed to warm water in engineered freshwater installations. An investigation with a test system supplied with different types of warm drinking water without disinfectant under controlled hydraulic conditions showed that treated aerobic groundwater (0.3 mg liter−1 of organic carbon) induced a low biofilm concentration that supported no or very limited growth of L. pneumophila. Elevated biofilm concentrations and L. pneumophila colony counts were observed on surfaces exposed to two types of extensively treated groundwater, containing 1.8 and 7.9 mg C liter−1 and complying with the microbial water quality criteria during distribution. Control measures in warm tap water installations are therefore essential for preventing growth of L. pneumophila. PMID:28062459

Biofilm Composition and Threshold Concentration for Growth of Legionella pneumophila on Surfaces Exposed to Flowing Warm Tap Water without Disinfectant.

PubMed

van der Kooij, Dick; Bakker, Geo L; Italiaander, Ronald; Veenendaal, Harm R; Wullings, Bart A

2017-03-01

Legionella pneumophila in potable water installations poses a potential health risk, but quantitative information about its replication in biofilms in relation to water quality is scarce. Therefore, biofilm formation on the surfaces of glass and chlorinated polyvinyl chloride (CPVC) in contact with tap water at 34 to 39°C was investigated under controlled hydraulic conditions in a model system inoculated with biofilm-grown L. pneumophila The biofilm on glass (average steady-state concentration, 23 ± 9 pg ATP cm -2 ) exposed to treated aerobic groundwater (0.3 mg C liter -1 ; 1 μg assimilable organic carbon [AOC] liter -1 ) did not support growth of the organism, which also disappeared from the biofilm on CPVC (49 ± 9 pg ATP cm -2 ) after initial growth. L. pneumophila attained a level of 4.3 log CFU cm -2 in the biofilms on glass (1,055 ± 225 pg ATP cm -2 ) and CPVC (2,755 ± 460 pg ATP cm -2 ) exposed to treated anaerobic groundwater (7.9 mg C liter -1 ; 10 μg AOC liter -1 ). An elevated biofilm concentration and growth of L. pneumophila were also observed with tap water from the laboratory. The Betaproteobacteria Piscinibacter and Methyloversatilis and amoeba-resisting Alphaproteobacteria predominated in the clones and isolates retrieved from the biofilms. In the biofilms, the Legionella colony count correlated significantly with the total cell count (TCC), heterotrophic plate count, ATP concentration, and presence of Vermamoeba vermiformis This amoeba was rarely detected at biofilm concentrations of <100 pg ATP cm -2 A threshold concentration of approximately 50 pg ATP cm -2 (TCC = 1 × 10 6 to 2 × 10 6 cells cm -2 ) was derived for growth of L. pneumophila in biofilms. IMPORTANCE Legionella pneumophila is the etiologic agent in more than 10,000 cases of Legionnaires' disease that are reported annually worldwide and in most of the drinking water-associated disease outbreaks reported in the United States. The organism proliferates in biofilms on surfaces exposed to warm water in engineered freshwater installations. An investigation with a test system supplied with different types of warm drinking water without disinfectant under controlled hydraulic conditions showed that treated aerobic groundwater (0.3 mg liter -1 of organic carbon) induced a low biofilm concentration that supported no or very limited growth of L. pneumophila Elevated biofilm concentrations and L. pneumophila colony counts were observed on surfaces exposed to two types of extensively treated groundwater, containing 1.8 and 7.9 mg C liter -1 and complying with the microbial water quality criteria during distribution. Control measures in warm tap water installations are therefore essential for preventing growth of L. pneumophila . Copyright © 2017 American Society for Microbiology.

Groundwater control of mangrove surface elevation: shrink and swell varies with soil depth

USGS Publications Warehouse

Whelan, K.R.T.; Smith, T. J.; Cahoon, D.R.; Lynch, J.C.; Anderson, G.H.

2005-01-01

We measured monthly soil surface elevation change and determined its relationship to groundwater changes at a mangrove forest site along Shark River, Everglades National Park, Florida. We combined the use of an original design, surface elevation table with new rod-surface elevation tables to separately track changes in the mid zone (0?4 m), the shallow root zone (0?0.35 m), and the full sediment profile (0?6 m) in response to site hydrology (daily river stage and groundwater piezometric pressure). We calculated expansion and contraction for each of the four constituent soil zones (surface [accretion and erosion; above 0 m], shallow zone [0?0.35 m], middle zone [0.35?4 m], and bottom zone [4?6 m]) that comprise the entire soil column. Changes in groundwater pressure correlated strongly with changes in soil elevation for the entire profile (Adjusted R2 5 0.90); this relationship was not proportional to the depth of the soil profile sampled. The change in thickness of the bottom soil zone accounted for the majority (R2 5 0.63) of the entire soil profile expansion and contraction. The influence of hydrology on specific soil zones and absolute elevation change must be considered when evaluating the effect of disturbances, sea level rise, and water management decisions on coastal wetland systems.

Fog, plant leaves and deposition of droplets

NASA Astrophysics Data System (ADS)

Konrad, W.; Ebner, M.; Traiser, C.; Roth-Nebelsick, A.

2010-07-01

For various plants and animals, the accumulation of fog or dew droplets constitutes an essential part of their water supply. Understanding how water droplets deposited by fog or dew events interact with plant or animal surfaces is essential for gaining insight into the functionality of these surfaces. Besides being interesting within the realm of biology, this knowledge is indispensable for technical applications. Frequently, it is advantageous to know (i) the growth rate of a droplet attached by surface tension to a surface which grows due to a given influx of fog particles, (ii) the maximum volume and (iii) the "lifespan" of a droplet before it detaches from the surface or starts to slide down along the plant surface, driven by gravity. Starting from principles of physics, we calculate quantitative expressions addressing questions (i) to (iii) for droplets which are attached to surfaces characterised by a high degree of symmetry, such as horizontally oriented or inclined planes, sections of spheres, cones and rotationally symmetric crevices. Furthermore, we treat the behaviour of droplets attached to a surface of non-constant contact angle. Although real surfaces never meet their geometric idealisations, results based on these often represent suitable and useful approximations to reality. Finally, we apply our results to Stipagrostis sabulicola, a dune grass of the Namib desert which satisfies its water demand solely by capturing fog and dew droplets. Pictures taken with a scanning electron microscope show that the stem of S. sabulicola is longitudinally built up by alternating elevated and countersunk strips. Filling gaps in the experimental observation with theoretical speculation, the following picture emerges: Assuming that the elevated strips exhibit a higher contact angle than the countersunk strips, water droplets being deposited on the elevated strips are drawn towards the latter. The lower contact angle which prevails there increases the droplets' contact area with the plant surface at the expense of their thickness, thus expediting coalescence with neighbouring droplets. Once the droplets have grown to the critical size at which surface tension is overcome by gravitational attraction, the countersunk strips act as drainlike channels guiding the sliding droplets towards the basis of the stem and the roots.

A laboratory study of the electromagnetic bias of rough surface scattering by water waves

NASA Technical Reports Server (NTRS)

Parsons, Chester L.; Miller, Lee S.

1990-01-01

The design, development, and use of a focused-beam radar to measure the electromagnetic bias introduced by the scattering of radar waves by a roughened water surface are discussed. The bias measurements were made over wide ranges of environmental conditions in a wavetank laboratory. Wave-elevation data were provided by standard laboratory capacitance probes. Backscattered radar power measurements coincident in time and space with the elevation data were produced by the radar. The two data sets are histogrammed to produce probability density functions for elevation and radar reflectivity, from which the electromagnetic bias is computed. The experimental results demonstrate that the electromagnetic bias is quite variable over the wide range of environmental conditions that can be produced in the laboratory. The data suggest that the bias is dependent upon the local wind field and on the amplitude and frequency of any background wave field that is present.

Design guidelines for horizontal drains used for slope stabilization.

DOT National Transportation Integrated Search

2013-03-01

The presence of water is one of the most critical factors contributing to the instability of hillslopes. A common : solution to stabilize hillslopes is installation of horizontal drains to decrease the elevation of the water table : surface. Lowering...

Calibration of a two-dimensional hydrodynamic model for parts of the Allegheny, Monongahela, and Ohio Rivers, Allegheny County, Pennsylvania

USGS Publications Warehouse

Fulton, John W.; Wagner, Chad R.

2014-01-01

The U.S. Geological Survey (USGS), in cooperation with the Allegheny County Sanitary Authority, developed a validated two-dimensional Resource Management Associates2 (RMA2) hydrodynamic model of parts of the Allegheny, Monongahela, and Ohio Rivers (Three Rivers) to help assess the effects of combined sewer overflows (CSOs) and sanitary sewer overflows (SSOs) on the rivers. The hydrodynamic model was used to drive a water-quality model of the study area that was capable of simulating the transport and fate of fecal-indicator bacteria and chemical constituents under open-water conditions. The study area includes 14 tributary streams and parts of the Three Rivers where they enter and exit Allegheny County, an area of approximately 730 square miles (mi2). The city of Pittsburgh is near the center of the county, where the Allegheny and Monongahela Rivers join to form the headwaters of the Ohio River. The Three Rivers are regulated by a series of fixed-crest dams, gated dams, and radial (tainter) gates and serve as the receiving waters for tributary streams, CSOs, and SSOs. The RMA2 model was separated into four individual segments on the basis of the U.S. Army Corps of Engineers navigational pools in the study area (Dashields; Emsworth; Allegheny River, Pool 2; and Braddock), which were calibrated individually using measured water-surface slope, velocity, and discharge during high- and low-flow conditions. The model calibration process included the comparison of water-surface elevations at five locations and velocity profiles at more than 80 cross sections in the study area. On the basis of the calibration and validation results that included water-surface elevations and velocities, the model is a representative simulation of the Three Rivers flow patterns for discharges ranging from 4,050 to 47,400 cubic feet per second (ft3/s) on the Allegheny River, 2,550 to 40,000 ft3/s on the Monongahela River, and 10,900 to 99,000 ft3/s on the Ohio River. The Monongahela River was characterized by unsteady conditions during low and high flows, which affected the calibration range. The simulated low-flow water-surface elevations typically were within 0.2 feet (ft) of measured values, whereas the simulated high-flow water-surface elevations were typically within 0.3 ft of the measured values. The mean error between simulated and measured velocities was less than 0.07 ft/s for low-flow conditions and less than 0.17 ft/s for high-flow conditions.

A novel algorithm for delineating wetland depressions and mapping surface hydrologic flow pathways using LiDAR data

EPA Science Inventory

In traditional watershed delineation and topographic modeling, surface depressions are generally treated as spurious features and simply removed from a digital elevation model (DEM) to enforce flow continuity of water across the topographic surface to the watershed outlets. In re...

Flood Map for the Winooski River in Waterbury, Vermont, 2014

USGS Publications Warehouse

Olson, Scott A.

2015-01-01

High-water marks from Tropical Storm Irene were available for seven locations along the study reach. The highwater marks were used to estimate water-surface profiles and discharges resulting from Tropical Storm Irene throughout the study reach. From a comparison of the estimated water-surface profile for Tropical Storm Irene with the water-surface profiles for the 1- and 0.2-percent annual exceedance probability (AEP) floods, it was determined that the high-water elevations resulting from Tropical Storm Irene exceeded the estimated 1-percent AEP flood throughout the Winooski River study reach but did not exceed the estimated 0.2-percent AEP flood at any location within the study reach.

A WRF simulation of the impact of 3-D radiative transfer on surface hydrology over the Rocky Mountains and Sierra Nevada

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liou, K. N.; Gu, Y.; Leung, L. R.

2013-01-01

We investigate 3-D mountains/snow effects on solar flux distributions and their impact on surface hydrology over the western United States, specifically the Rocky Mountains and Sierra Nevada. The Weather Research and Forecasting (WRF) model, applied at a 30 km grid resolution, is used in conjunction with a 3-D radiative transfer parameterization covering a time period from 1 November 2007 to 31 May 2008, during which abundant snowfall occurred. A comparison of the 3-D WRF simulation with the observed snow water equivalent (SWE) and precipitation from Snowpack Telemetry (SNOTEL) sites shows reasonable agreement in terms of spatial patterns and daily andmore » seasonal variability, although the simulation generally has a positive precipitation bias. We show that 3-D mountain features have a profound impact on the diurnal and monthly variation of surface radiative and heat fluxes, and on the consequent elevation-dependence of snowmelt and precipitation distributions. In particular, during the winter months, large deviations (3-D-PP, in which PP denotes the plane-parallel approach) of the monthly mean surface solar flux are found in the morning and afternoon hours due to shading effects for elevations below 2.5 km. During spring, positive deviations shift to the earlier morning. Over mountaintops higher than 3 km, positive deviations are found throughout the day, with the largest values of 40–60 W m -2 occurring at noon during the snowmelt season of April to May. The monthly SWE deviations averaged over the entire domain show an increase in lower elevations due to reduced snowmelt, which leads to a reduction in cumulative runoff. Over higher elevation areas, positive SWE deviations are found because of increased solar radiation available at the surface. Overall, this study shows that deviations of SWE due to 3-D radiation effects range from an increase of 18% at the lowest elevation range (1.5–2 km) to a decrease of 8% at the highest elevation range (above 3 km). Since lower elevation areas occupy larger fractions of the land surface, the net effect of 3-D radiative transfer is to extend snowmelt and snowmelt-driven runoff into the warm season.Finally, because 60–90% of water resources originate from mountains worldwide, the aforementioned differences in simulated hydrology due solely to 3-D interactions between solar radiation and mountains/snow merit further investigation in order to understand the implications of modeling mountain water resources, and these resources' vulnerability to climate change and air pollution.« less

Subarctic physicochemical weathering of serpentinized peridotite

NASA Astrophysics Data System (ADS)

Ulven, O. I.; Beinlich, A.; Hövelmann, J.; Austrheim, H.; Jamtveit, B.

2017-06-01

Frost weathering is effective in arctic and subarctic climate zones where chemical reactions are limited by the reduced availability of liquid water and the prevailing low temperature. However, small scale mineral dissolution reactions are nevertheless important for the generation of porosity by allowing infiltration of surface water with subsequent fracturing due to growth of ice and carbonate minerals. Here we combine textural and mineralogical observations in natural samples of partly serpentinized ultramafic rocks with a discrete element model describing the fracture mechanics of a solid when subject to pressure from the growth of ice and carbonate minerals in surface-near fractures. The mechanical model is coupled with a reaction-diffusion model that describes an initial stage of brucite dissolution as observed during weathering of serpentinized harzburgites and dunites from the Feragen Ultramafic Body (FUB), SE-Norway. Olivine and serpentine are effectively inert at relevant conditions and time scales, whereas brucite dissolution produces well-defined cm to dm thick weathering rinds with elevated porosity that allows influx of water. Brucite dissolution also increases the water saturation state with respect to hydrous Mg carbonate minerals, which are commonly found as infill in fractures in the fresh rock. This suggests that fracture propagation is at least partly driven by carbonate precipitation. Dissolution of secondary carbonate minerals during favorable climatic conditions provides open space available for ice crystallization that drives fracturing during winter. Our model reproduces the observed cm-scale meandering fractures that propagate into the fresh part of the rock, as well as dm-scale fractures that initiate the breakup of larger domains. Rock disintegration increases the reactive surface area and hence the rate of chemical weathering, enhances transport of dissolved and particulate matter in the weathering fluid, and facilitates CO2 uptake by carbonate precipitation. Our observations have implications for element cycling and CO2 sequestration in natural gravel and mine tailings.

Case Studies of Water Vapor and Surface Liquid Water from AVIRIS Data Measured Over Denver, CO and Death Valley, CA

NASA Technical Reports Server (NTRS)

Gao, B.-C.; Kierein-Young, K. S.; Goetz, A. F. H.; Westwater, E. R.; Stankov, B. B.; Birkenheuer, D.

1991-01-01

High spatial resolution column atmospheric water vapor amounts and equivalent liquid water thicknesses of surface targets are retrieved from spectral data collected by the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS). The retrievals are made using a nonlinear least squares curve fitting technique. Two case studies from AVIRIS data acquired over Denver-Platteville area, Colorado and over Death Valley, California are presented. The column water vapor values derived from AVIRIS data over the Denver-Platteville area are compared with those obtained from radiosondes, ground level upward-looking microwave radiometers, and geostationary satellite measurements. The column water vapor image shows spatial variation patterns related to the passage of a weather front system. The column water vapor amounts derived from AVIRIS data over Death Valley decrease with increasing surface elevation. The derived liquid water image clearly shows surface drainage patterns.

In-Situ Wave Observations in the High Resolution Air-Sea Interaction DRI

DTIC Science & Technology

2008-09-30

Program ( CDIP ) Harvest buoy located in 204 m depth off Point Conception. The initial sea surface is assumed Gaussian and homogeneous, with spectral...of simulated sea surface elevation. Right panels: corresponding observed frequency-directional wave spectra (source: CDIP ). Upper panels: Typical

Two Preliminary SRTM DEMs Within the Amazon Basin

NASA Astrophysics Data System (ADS)

Alsdorf, D.; Hess, L.; Melack, J.; Dunne, T.; Mertes, L.; Ballantine, A.; Biggs, T.; Holmes, K.; Sheng, Y.; Hendricks, G.

2002-12-01

Digital topography provides important measures, such as hillslope lengths and flow path networks, for understanding hydrologic and geomorphic processes (e.g., runoff response to land use change and floodplain inundation volume). Two preliminary Shuttle Radar Topography Mission digital elevation models of Manaus (1S to 5S and 59W to 63W) and Rondonia (9S to 12S and 61W to 64W) were received from NASA JPL in August 2002. The "PI Processor" produced these initial DEM segments and we are using them to assess the initial accuracy of the interferometrically derived heights and for hydrologic research. The preliminary SRTM derived absolute elevations across the Amazon floodplain in the Cabaliana region generally range from 5 to 15 m with reported errors of 1 to 3 m. This region also includes some preliminary elevations that are erroneously negative. However, topographic contours on 1:100,000 scale quadrangles of 1978 to 1980 vintage indicate elevations of 20 to 30 m. Because double-bounce travel paths are possible over the sparsely vegetated and very-flat 2400 sq-km water surface of the Balbina reservoir near Manaus, it serves to identify the relative accuracy of the SRTM heights. Here, cell-to-cell height changes are generally 0 to 1 m and changes across a ~100 km transect rarely exceed 3 m. Reported errors throughout the transect range from 1 to 2 m with some errors up to 5 m. Deforestation in Rondonia is remarkably clear in the C-band DEM where elevations are recorded from the canopy rather than bare earth. Here, elevation changes are ~30 m (with reported 1 to 2 m errors) across clear-cut areas. Field derived canopy heights are in agreement with this change. Presently, we are deriving stream networks in the Amazon floodplain for comparison with our previous network extraction from JERS-1 SAR mosaics and for hydrologic modeling.

High-precision measurements of wetland sediment elevation. II The rod surface elevation table

USGS Publications Warehouse

Cahoon, D.R.; Lynch, J.C.; Perez, B.C.; Segura, B.; Holland, R.D.; Stelly, C.; Stephenson, G.; Hensel, P.

2002-01-01

A new high-precision device for measuring sediment elevation in emergent and shallow water wetland systems is described. The rod surface-elevation table (RSET) is a balanced, lightweight mechanical leveling device that attaches to both shallow ( 1 m in order to be stable. The pipe is driven to refusal but typically to a depth shallower than the rod bench mark because of greater surface resistance of the pipe. Thus, the RSET makes it possible to partition change in sediment elevation over shallower (e.g., the root zone) and deeper depths of the sediment profile than is possible with the SET. The confidence intervals for the height of an individual pin measured by two different operators with the RSET under laboratory conditions were A? 1.0 and A? 1.5 mm. Under field conditions, confidence intervals for the measured height of an individual pin ranged from A? 1.3 mm in a mangrove forest up to A? 4.3 mm in a salt marsh.

A climatology and preliminary investigation of predictability of pristine nocturnal convective initiation in the central United States

NASA Astrophysics Data System (ADS)

Stelten, Sean; Gallus, William

2017-04-01

The prediction of convective initiation remains a challenge to forecasters in the central United States, especially for elevated events at night. This study examines a subset of 287 nocturnal elevated convective initiation events that occurred without direct influence from surface boundaries or pre-existing convection over a four-month period during the summer of 2015 (May, June, July, and August). Events were first classified into one of four types based on apparent formation mechanisms and location relative to any low-level jet. A climatology of each of the four types was performed focusing on general spatial tendencies over the central United States and initiation timing trends. Additionally, analysis of initiation elevation was performed. Simulations from five convection-allowing models available during the Plains Elevated Convection At Night (PECAN) field campaign, along with four versions of a 4km horizontal grid spacing Weather Research and Forecasting (WRF) model using different planetary boundary layer (PBL) parameterizations, were used to examine predictability of these types of convective initiation. The climatology revealed a dual-peak pattern for initiation timing with one peak near 0400 UTC and another 0700 UTC, and it was found that the dual peak structure was present for all four types of events, suggesting that the evolution of the low-level jet was not directly responsible for the twin peaks. Subtle differences in location and elevation of the initiation for the different types were identified. The convection-allowing models run during the PECAN project were found to be more deficient with location than timing. Threat scores typically averaged around 0.3 for the models, with false alarm ratios and hit rates both averaging around 0.5 to 0.6 for the various models. Initiation occurring within the low-level jet but far from a surface front was the one type that was occasionally missed by all five models examined. Once case for each of the four types was then simulated with four different configurations of a 4 km horizontal grid spacing WRF model. These WRF runs showed similar location errors and problems with initiating convection at a lower altitude than observed as was found from the simulations performed during PECAN. Three of the four PBL schemes behaved similarly, but one, the ACM2, was often an outlier, failing to indicate the convective initiation.

Environmental Flow for Sungai Johor Estuary

NASA Astrophysics Data System (ADS)

Adilah, A. Kadir; Zulkifli, Yusop; Zainura, Z. Noor; Bakhiah, Baharim N.

2018-03-01

Sungai Johor estuary is a vital water body in the south of Johor and greatly affects the water quality in the Johor Straits. In the development of the hydrodynamic and water quality models for Sungai Johor estuary, the Environmental Fluid Dynamics Code (EFDC) model was selected. In this application, the EFDC hydrodynamic model was configured to simulate time varying surface elevation, velocity, salinity, and water temperature. The EFDC water quality model was configured to simulate dissolved oxygen (DO), dissolved organic carbon (DOC), chemical oxygen demand (COD), ammoniacal nitrogen (NH3-N), nitrate nitrogen (NO3-N), phosphate (PO4), and Chlorophyll a. The hydrodynamic and water quality model calibration was performed utilizing a set of site specific data acquired in January 2008. The simulated water temperature, salinity and DO showed good and fairly good agreement with observations. The calculated correlation coefficients between computed and observed temperature and salinity were lower compared with the water level. Sensitivity analysis was performed on hydrodynamic and water quality models input parameters to quantify their impact on modeling results such as water surface elevation, salinity and dissolved oxygen concentration. It is anticipated and recommended that the development of this model be continued to synthesize additional field data into the modeling process.

Large-scale hydrological model river storage and discharge correction using a satellite altimetry-based discharge product

NASA Astrophysics Data System (ADS)

Emery, Charlotte Marie; Paris, Adrien; Biancamaria, Sylvain; Boone, Aaron; Calmant, Stéphane; Garambois, Pierre-André; Santos da Silva, Joecila

2018-04-01

Land surface models (LSMs) are widely used to study the continental part of the water cycle. However, even though their accuracy is increasing, inherent model uncertainties can not be avoided. In the meantime, remotely sensed observations of the continental water cycle variables such as soil moisture, lakes and river elevations are more frequent and accurate. Therefore, those two different types of information can be combined, using data assimilation techniques to reduce a model's uncertainties in its state variables or/and in its input parameters. The objective of this study is to present a data assimilation platform that assimilates into the large-scale ISBA-CTRIP LSM a punctual river discharge product, derived from ENVISAT nadir altimeter water elevation measurements and rating curves, over the whole Amazon basin. To deal with the scale difference between the model and the observation, the study also presents an initial development for a localization treatment that allows one to limit the impact of observations to areas close to the observation and in the same hydrological network. This assimilation platform is based on the ensemble Kalman filter and can correct either the CTRIP river water storage or the discharge. Root mean square error (RMSE) compared to gauge discharges is globally reduced until 21 % and at Óbidos, near the outlet, RMSE is reduced by up to 52 % compared to ENVISAT-based discharge. Finally, it is shown that localization improves results along the main tributaries.

Seasonal and Interannual Variations of Ice Sheet Surface Elevation at the Summit of Greenland: Observed and Modeled

NASA Technical Reports Server (NTRS)

Zwally, H. Jay; Jun, Li; Koblinsky, Chester J. (Technical Monitor)

2001-01-01

Observed seasonal and interannual variations in the surface elevation over the summit of the Greenland ice sheet are modeled using a new temperature-dependent formulation of firn-densification and observed accumulation variations. The observed elevation variations are derived from ERS (European Remote Sensing)-1 and ERS-2 radar altimeter data for the period between April 1992 and April 1999. A multivariate linear/sine function is fitted to an elevation time series constructed from elevation differences measured by radar altimetry at orbital crossovers. The amplitude of the seasonal elevation cycle is 0.25 m peak-to-peak, with a maximum in winter and a minimum in summer. Inter-annually, the elevation decreases to a minimum in 1995, followed by an increase to 1999, with an overall average increase of 4.2 cm a(exp -1) for 1992 to 1999. Our densification formulation uses an initial field-density profile, the AWS (automatic weather station) surface temperature record, and a temperature-dependent constitutive relation for the densification that is based on laboratory measurements of crystal growth rates. The rate constant and the activation energy commonly used in the Arrhenius-type constitutive relation for firn densification are also temperature dependent, giving a stronger temperature and seasonal amplitudes about 10 times greater than previous densification formulations. Summer temperatures are most important, because of the strong non-linear dependence on temperature. Much of firn densification and consequent surface lowering occurs within about three months of the summer season, followed by a surface build-up from snow accumulation until spring. Modeled interannual changes of the surface elevation, using the AWS measurements of surface temperature and accumulation and results of atmospheric modeling of precipitation variations, are in good agreement with the altimeter observations. In the model, the surface elevation decreases about 20 cm over the seven years due to more compaction driven by increasing summer temperatures. The minimum elevation in 1995 is driven mainly by a temporary accumulation decrease and secondarily by warmer temperatures. However, the overall elevation increase over the seven years is dominated by the accumulation increase in the later years.

Creating a monthly time series of the potentiometric surface in the Upper Floridan aquifer, Northern Tampa Bay area, Florida, January 2000-December 2009

USGS Publications Warehouse

Lee, Terrie M.; Fouad, Geoffrey G.

2014-01-01

In Florida’s karst terrain, where groundwater and surface waters interact, a mapping time series of the potentiometric surface in the Upper Floridan aquifer offers a versatile metric for assessing the hydrologic condition of both the aquifer and overlying streams and wetlands. Long-term groundwater monitoring data were used to generate a monthly time series of potentiometric surfaces in the Upper Floridan aquifer over a 573-square-mile area of west-central Florida between January 2000 and December 2009. Recorded groundwater elevations were collated for 260 groundwater monitoring wells in the Northern Tampa Bay area, and a continuous time series of daily observations was created for 197 of the wells by estimating missing daily values through regression relations with other monitoring wells. Kriging was used to interpolate the monthly average potentiometric-surface elevation in the Upper Floridan aquifer over a decade. The mapping time series gives spatial and temporal coherence to groundwater monitoring data collected continuously over the decade by three different organizations, but at various frequencies. Further, the mapping time series describes the potentiometric surface beneath parts of six regionally important stream watersheds and 11 municipal well fields that collectively withdraw about 90 million gallons per day from the Upper Floridan aquifer. Monthly semivariogram models were developed using monthly average groundwater levels at wells. Kriging was used to interpolate the monthly average potentiometric-surface elevations and to quantify the uncertainty in the interpolated elevations. Drawdown of the potentiometric surface within well fields was likely the cause of a characteristic decrease and then increase in the observed semivariance with increasing lag distance. This characteristic made use of the hole effect model appropriate for describing the monthly semivariograms and the interpolated surfaces. Spatial variance reflected in the monthly semivariograms decreased markedly between 2002 and 2003, timing that coincided with decreases in well-field pumping. Cross-validation results suggest that the kriging interpolation may smooth over the drawdown of the potentiometric surface near production wells. The groundwater monitoring network of 197 wells yielded an average kriging error in the potentiometric-surface elevations of 2 feet or less over approximately 70 percent of the map area. Additional data collection within the existing monitoring network of 260 wells and near selected well fields could reduce the error in individual months. Reducing the kriging error in other areas would require adding new monitoring wells. Potentiometric-surface elevations fluctuated by as much as 30 feet over the study period, and the spatially averaged elevation for the entire surface rose by about 2 feet over the decade. Monthly potentiometric-surface elevations describe the lateral groundwater flow patterns in the aquifer and are usable at a variety of spatial scales to describe vertical groundwater recharge and discharge conditions for overlying surface-water features.

Stabilizing Nanocrystalline Oxide Nanofibers at Elevated Temperatures by Coating Nanoscale Surface Amorphous Films.

PubMed

Yao, Lei; Pan, Wei; Luo, Jian; Zhao, Xiaohui; Cheng, Jing; Nishijima, Hiroki

2018-01-10

Nanocrystalline materials often exhibit extraordinary mechanical and physical properties but their applications at elevated temperatures are impaired by the rapid grain growth. Moreover, the grain growth in nanocrystalline oxide nanofibers at high temperatures can occur at hundreds of degrees lower than that would occur in corresponding bulk nanocrystalline materials, which would eventually break the fibers. Herein, by characterizing a model system of scandia-stabilized zirconia using hot-stage in situ scanning transmission electron microscopy, we discover that the enhanced grain growth in nanofibers is initiated at the surface. Subsequently, we demonstrate that coating the fibers with nanometer-thick amorphous alumina layer can enhance their temperature stability by nearly 400 °C via suppressing the surface-initiated grain growth. Such a strategy can be effectively applied to other oxide nanofibers, such as samarium-doped ceria, yttrium-stabilized zirconia, and lanthanum molybdate. The nanocoatings also increase the flexibility of the oxide nanofibers and stabilize the high-temperature phases that have 10 times higher ionic conductivity. This study provides new insights into the surface-initiated grain growth in nanocrystalline oxide nanofibers and develops a facile yet innovative strategy to improve the high-temperature stability of nanofibers for a broad range of applications.

Integration of coastal inundation modeling from storm tides to individual waves

NASA Astrophysics Data System (ADS)

Li, Ning; Roeber, Volker; Yamazaki, Yoshiki; Heitmann, Troy W.; Bai, Yefei; Cheung, Kwok Fai

2014-11-01

Modeling of storm-induced coastal inundation has primarily focused on the surge generated by atmospheric pressure and surface winds with phase-averaged effects of the waves as setup. Through an interoperable model package, we investigate the role of phase-resolving wave processes in simulation of coastal flood hazards. A spectral ocean wave model describes generation and propagation of storm waves from deep to intermediate water, while a non-hydrostatic storm-tide model has the option to couple with a spectral coastal wave model for computation of phase-averaged processes in a near-shore region. The ocean wave and storm-tide models can alternatively provide the wave spectrum and the surface elevation as the boundary and initial conditions for a nested Boussinesq model. Additional surface-gradient terms in the Boussinesq equations maintain the quasi-steady, non-uniform storm tide for modeling of phase-resolving surf and swash-zone processes as well as combined tide, surge, and wave inundation. The two nesting schemes are demonstrated through a case study of Hurricane Iniki, which made landfall on the Hawaiian Island of Kauai in 1992. With input from a parametric hurricane model and global reanalysis and tidal datasets, the two approaches produce comparable significant wave heights and phase-averaged surface elevations in the surf zone. The nesting of the Boussinesq model provides a seamless approach to augment the inundation due to the individual waves in matching the recorded debris line along the coast.

Topography of the Flattest Surface on Earth: using ICESAT, GPS, and MISR to Measure Salt Surface Topography on Salar de Uyuni, Bolivia

NASA Technical Reports Server (NTRS)

Comstock, Robert L.; Bills, Bruce G.

2004-01-01

Salt flats are aptly named: they are composed largely of salt, and are maintained as nearly equipotential surfaces via frequent flooding. The salar de Uyuni, on the Altiplano in southwestern Bolivia, is the largest salt flat on Earth, with an area of 9,800 sq km. Except for a few bedrock islands, it has less than 40 cm of relief. The upper-most salt unit averages 5 m thick and contains 50 cu km of nearly pure halite. It includes most of the salt that was in solution in paleolake Minchin, which attained a maximum area of 60,000 sq km and a maximum depth of 150 m, roughly 15 kyr ago. Despite approx. 10 m of differential isostatic rebound since deposition, the salar surface has been actively maintained as an extraordinarily flat and smooth surface by annual flooding during the rainy season. We have used the strong optical absorption properties of water in the visible band to map spatial variations in water depth during a time when the salar was flooded. As water depth increases, the initially pure white surface appears both darker and bluer. We utilized MISR images taken during the interval from April to November 2001. The red and infra-red bands (672 and 867 nm wavelength) were most useful since the water depth is small and the absorption at those wavelengths is quite strong. Nadir pointed MISR images have 275 m spatial resolution. To aid in our evaluation of water depth variations over the saiar surface, we utilized two sources of direct topographic measurements: several ICESAT altimetry tracks cross the area, and a 40x50 km GPS grid was surveyed to calibrate ICESAT. A difficulty in using these data types is that both give salt surface elevations relative to the ellipsoid, whereas the water surface will, in the absence of wind or tidal disturbances, follow an equipotential surface. Geoid height is not known to the required accuracy of a few cm in the central Andes. As a result, before comparing optical absorption from MISR to salt surface topography from GPS or ICESAT, we removed the longest wavelengths from both.

Determining the Hydrological Importance of Coastal Fog in Northern California Using Stable Isotopes of Water

NASA Astrophysics Data System (ADS)

Scholl, M. A.; Torregrosa, A.; Coplen, T. B.

2014-12-01

Fog and cloud water can be an important part of the water cycle in mountainous coastal areas. In coastal California's Mediterranean climate, fog is the predominant precipitation source during the summer months. Here we report initial results of a study utilizing stable hydrogen and oxygen isotopes of water to investigate the role of fog in the hydrology of two ecosystems in Sonoma County, CA. The two study sites were the Bodega Marine Laboratory (BML) at 13 m elevation at the coast, and the Pepperwood Preserve at 375 m elevation in the North Coast Range, 44 km inland to the northeast. During a 1-week period in July 2014, fog samples were collected at 30-minute intervals using small active-strand cloudwater collectors (mini-CASCCs) and automated precipitation samplers. Four overnight fog events were collected at the Pepperwood site, while at the BML site, the liquid water content of the fog was very low, and only one cumulative sample was obtained. Groundwater samples from five wells and seven springs, and surface water samples from two streams were collected in and around the Pepperwood Preserve and on Bodega Head near BML. Droplet size distribution of the fog at BML was monitored, and at both sites, air temperature was measured at 10-minute intervals to assess variation in the δ 18O and δ 2H values of fog related to temperature. Relative humidity, wind speed, and wind direction were obtained from weather stations at each site. Previous work in this area (Coplen et al., in prep) documented the isotopic signatures of winter precipitation from frontal systems and landfalling Pacific storms. These results will be combined with the isotopic signature of summer fog water to determine whether fog contributes to shallow groundwater recharge or streamflow at the two sites.

The Proposed Surface Water and Ocean Topography (SWOT) Mission

NASA Astrophysics Data System (ADS)

Fu, Lee-Lueng; Alsdorf, Douglas; Rodriguez, Ernesto; Morrow, Rosemary; Mognard, Nelly; Vaze, Parag; Lafon, Thierry

2013-09-01

A new space mission concept called Surface Water and Ocean Topography (SWOT) is being developed jointly by a collaborative effort of the international oceanographic and hydrological communities for making high-resolution measurement of the water elevation of both the ocean and land surface water to answer the questions about the oceanic submesoscale processes and the storage and discharge of land surface water. The key instrument payload would be a Ka-band radar interferometer capable of making high-resolution wide-swath altimetry measurement. This paper describes the proposed science objectives and requirements as well as the measurement approach of SWOT, which is baselined to be launched in 2019. SWOT would demonstrate this new approach to advancing both oceanography and land hydrology and set a standard for future altimetry missions.

The Proposed Surface Water and Ocean Topography (SWOT) Mission

NASA Technical Reports Server (NTRS)

Fu, Lee-Lueng; Alsdorf, Douglas; Rodriguez, Ernesto; Morrow, Rosemary; Mognard, Nelly; Vaze, Parag; Lafon, Thierry

2012-01-01

A new space mission concept called Surface Water and Ocean Topography (SWOT) is being developed jointly by a collaborative effort of the international oceanographic and hydrological communities for making high-resolution measurement of the water elevation of both the ocean and land surface water to answer the questions about the oceanic submesoscale processes and the storage and discharge of land surface water. The key instrument payload would be a Ka-band radar interferometer capable of making high-resolution wide-swath altimetry measurement. This paper describes the proposed science objectives and requirements as well as the measurement approach of SWOT, which is baselined to be launched in 2019. SWOT would demonstrate this new approach to advancing both oceanography and land hydrology and set a standard for future altimetry missions.

Presence of organoarsenicals used in cotton production in agricultural water and soil of the Southern United States

USGS Publications Warehouse

Bednar, A.J.; Garbarino, J.R.; Ranville, J.F.; Wildeman, T.R.

2002-01-01

Arsenicals have been used extensively in agriculture in the United States as insecticides and herbicides. Mono- and disodium methylarsonate and dimethylarsinic acid are organoarsenicals used to control weeds in cotton fields and as defoliation agents applied prior to cotton harvesting. Because the toxicity of most organoarsenicals is less than that of inorganic arsenic species, the introduction of these compounds into the environment might seem benign. However, biotic and abiotic degradation reactions can produce more problematic inorganic forms of arsenic, such as arsenite [As(III)] and arsenate [As(V)]. This study investigates the occurrences of these compounds in samples of soil and associated surface and groundwaters. Preliminary results show that surface water samples from cotton-producing areas have elevated concentrations of methylarsenic species (>10 ??g of As/L) compared to background areas (<1 ??g of As/L). Species transformations also occur between surface waters and adjacent soils and groundwaters, which also contain elevated arsenic. The data indicate that point sources of arsenic related to agriculture might be responsible for increased arsenic concentrations in local irrigation wells, although the elevated concentrations did not exceed the new (2002) arsenic maximum contaminant level of 10 ??g/L in any of the wells sampled thus far.

Evaluation of streambed scour at bridges over tidal waterways in Alaska

USGS Publications Warehouse

Conaway, Jeffrey S.; Schauer, Paul V.

2012-01-01

The potential for streambed scour was evaluated at 41 bridges that cross tidal waterways in Alaska. These bridges are subject to several coastal and riverine processes that have the potential, individually or in combination, to induce streambed scour or to damage the structure or adjacent channel. The proximity of a bridge to the ocean and water-surface elevation and velocity data collected over a tidal cycle were criteria used to identify the flow regime at each bridge, whether tidal, riverine, or mixed, that had the greatest potential to induce streambed scour. Water-surface elevations measured through at least one tide cycle at 32 bridges were correlated to water levels at the nearest tide station. Asymmetry of the tidal portion of the hydrograph during the outgoing tide at 12 bridges indicated that riverine flows were stored upstream of the bridge during the tidal exchange. This scenario results in greater discharges and velocities during the outgoing tide compared to those on the incoming tide. Velocity data were collected during outgoing tides at 10 bridges that experienced complete flow reversals, and measured velocities during the outgoing tide exceeded the critical velocity required to initiate sediment transport at three sites. The primary risk for streambed scour at most of the sites considered in this study is from riverine flows rather than tidal fluctuations. A scour evaluation for riverine flow was completed at 35 bridges. Scour from riverine flow was not the primary risk for six tidally-controlled bridges and therefore not evaluated at those sites. Field data including channel cross sections, a discharge measurement, and a water-surface slope were collected at the 35 bridges. Channel instability was identified at 14 bridges where measurable scour and or fill were noted in repeated surveys of channel cross sections at the bridge. Water-surface profiles for the 1-percent annual exceedance probability discharge were calculated by using the Hydrologic Engineering Center’s River Analysis System model, and scour depths were calculated using methods recommended by the Federal Highway Administration. Computed contraction-scour depths were greater than 2.0 feet at five bridges and computed pier-scour depths were 4.0 feet or greater at 15 bridges. The potential for streambed scour by both coastal and riverine processes at the bridges considered in this study were evaluated, ranked, and summed to determine a cumulative risk factor for each bridge. Possible factors that could mitigate the scour risks were investigated at 22 bridges that had high individual or cumulative rankings. Mitigating factors such as piers founded in bedrock, deep pier foundations relative to scour depths, and lack of observed scour during field measurements were documented for 13 sites, but additional study and monitoring is needed to better quantify the streambed scour potential for nine sites. Three bridges prone to being affected by storm surges will require more data collection and possibly complex hydrodynamic modeling to accurately quantify the streambed scour potential. Continuous monitoring of water-surface and streambed elevation at one or more piers is needed for two bridges to better understand the tidal and riverine influences on streambed scour.

Forecasted Flood Depth Grids Providing Early Situational Awareness to FEMA during the 2017 Atlantic Hurricane Season

NASA Astrophysics Data System (ADS)

Jones, M.; Longenecker, H. E., III

2017-12-01

The 2017 hurricane season brought the unprecedented landfall of three Category 4 hurricanes (Harvey, Irma and Maria). FEMA is responsible for coordinating the federal response and recovery efforts for large disasters such as these. FEMA depends on timely and accurate depth grids to estimate hazard exposure, model damage assessments, plan flight paths for imagery acquisition, and prioritize response efforts. In order to produce riverine or coastal depth grids based on observed flooding, the methodology requires peak crest water levels at stream gauges, tide gauges, high water marks, and best-available elevation data. Because peak crest data isn't available until the apex of a flooding event and high water marks may take up to several weeks for field teams to collect for a large-scale flooding event, final observed depth grids are not available to FEMA until several days after a flood has begun to subside. Within the last decade NOAA's National Weather Service (NWS) has implemented the Advanced Hydrologic Prediction Service (AHPS), a web-based suite of accurate forecast products that provide hydrograph forecasts at over 3,500 stream gauge locations across the United States. These forecasts have been newly implemented into an automated depth grid script tool, using predicted instead of observed water levels, allowing FEMA access to flood hazard information up to 3 days prior to a flooding event. Water depths are calculated from the AHPS predicted flood stages and are interpolated at 100m spacing along NHD hydrolines within the basin of interest. A water surface elevation raster is generated from these water depths using an Inverse Distance Weighted interpolation. Then, elevation (USGS NED 30m) is subtracted from the water surface elevation raster so that the remaining values represent the depth of predicted flooding above the ground surface. This automated process requires minimal user input and produced forecasted depth grids that were comparable to post-event observed depth grids and remote sensing-derived flood extents for the 2017 hurricane season. These newly available forecasted models were used for pre-event response planning and early estimated hazard exposure counts, allowing FEMA to plan for and stand up operations several days sooner than previously possible.

Fifty-year flood-inundation maps for La Lima, Honduras

USGS Publications Warehouse

Mastin, Mark C.; Olsen, T.D.

2002-01-01

After the devastating floods caused by Hurricane Mitch in 1998, maps of the areas and depths of the 50-year-flood inundation at 15 municipalities in Honduras were prepared as a tool for agencies involved in reconstruction and planning. This report, which is one in a series of 15, presents maps of areas in the municipality of La Lima that would be inundated by Rio Chamelecon with a discharge of 500 cubic meters per second, the approximate capacity of the river channel through the city of La Lima. The 50-year flood (2,400 cubic meters per second), the original design flow to be mapped, would inundate the entire area surveyed for this municipality. Because water-surface elevations of the 50-year flood could not be mapped properly without substantially expanding the area of the survey, the available data were used instead to estimate the channel capacity of Rio Chamelecon in La Lima by trial-and-error runs of different flows in a numerical model and to estimate the increase in height of levees needed to contain flows of 1,000 and 2,400 cubic meters per second. Geographic Information System (GIS) coverages of the flood inundation are available on a computer in the municipality of La Lima as part of the Municipal GIS project and on the Internet at the Flood Hazard Mapping Web page (http://mitchnts1.cr.usgs.gov/projects/floodhazard.html). These coverages allow users to view the flood inundation in much more detail than is possible using the maps in this report. Water-surface elevations for various discharges on Rio Chamelecon at La Lima were determined using HEC-RAS, a one-dimensional, steady-flow, step-backwater computer program. The channel and floodplain cross sections used in HEC-RAS were developed from an airborne light-detection-and-ranging (LIDAR) topographic survey of the area and ground surveys at three bridges. Top-of-levee or top-of-channel-bank elevations and locations at the cross sections were critical to estimating the channel capacity of Rio Chamelecon. These elevations and locations are provided along with the water-surface elevations for the 500-cubic-meter-per-second flow of Rio Chamelecon. Also, water-surface elevations of the 1,000 and 2,400 cubic-meter-per-second flows are provided, assuming that the existing levees are raised to contained the flows.

Structural Change of Aerosol Particle Aggregates with Exposure to Elevated Relative Humidity.

PubMed

Montgomery, James F; Rogak, Steven N; Green, Sheldon I; You, Yuan; Bertram, Allan K

2015-10-20

Structural changes of aggregates composed of inorganic salts exposed to relative humidity (RH) between 0 and 80% after formation at selected RH between 0 and 60% were investigated using a tandem differential mobility analyzer (TDMA) and fluorescence microscopy. The TDMA was used to measure a shift in peak mobility diameter for 100-700 nm aggregates of hygroscopic aerosol particles composed of NaCl, Na2SO4, (NH4)2SO4, and nonhygroscopic Al2O3 as the RH was increased. Aggregates of hygroscopic particles were found to shrink when exposed to RH greater than that during the aggregation process. The degree of aggregate restructuring is greater for larger aggregates and greater increases in RH. Growth factors (GF) calculated from mobility diameter measurements as low as 0.77 were seen for NaCl before deliquescence. The GF subsequently increased to 1.23 at 80% RH, indicating growth after deliquescence. Exposure to RH lower than that experienced during aggregation did not result in structural changes. Fluorescent microscopy confirmed that aggregates formed on wire surfaces undergo an irreversible change in structure when exposed to elevated RH. Analysis of 2D movement of aggregates shows a displacement of 5-13% compared to projected length of initial aggregate from a wire surface. Surface tension due to water adsorption within the aggregate structure is a potential cause of the structural changes.

Hydrology, secondary growth, and elevation accuracy in two preliminary Amazon Basin SRTM DEMs

NASA Astrophysics Data System (ADS)

Alsdorf, D.; Hess, L.; Sheng, Y.; Souza, C.; Pavelsky, T.; Melack, J.; Dunne, T.; Hendricks, G.; Ballantine, A.; Holmes, K.

2003-04-01

Two preliminary Shuttle Radar Topography Mission digital elevation models (SRTM DEMs) of Manaus (1S to 5S and 59W to 63W) and Rondonia (9S to 12S and 61W to 64W) were received from the "PI Processor" at NASA JPL. We compared the Manaus DEM (C-band) with a previously constructed Cabaliana floodplain classification based on Global RainForest Mapping (GRFM) JERS-1 SAR data (L-band) and determined that habitats of open water, bare ground, and flooded shrub contained the lowest elevations; macrophyte and non-flooded shrub habitats are marked by intermediate elevations; and the highest elevations are found within flooded and non-flooded forest. Although the water surface typically produces specular reflections, double-bounce travel paths result from dead, leafless trees found across the Balbina reservoir near Manaus. There (i.e., in Balbina) the water surface is marked by pixel-to-pixel height changes of generally 0 to 1 m and changes across a ˜100 km transect rarely exceed 3 m. Reported SRTM errors throughout the transect range from 1 to 2 m with some errors up to 5 m. The smooth Balbina surface contrasts with the wind-roughened Amazon River surface where SRTM height variations easily range from 1 to 10 m (reported errors often exceed 5 m). Deforestation and subsequent regrowth in the Rondonia DEM is remarkably clear. Our colleagues used a 20 year sequence of Landsat TM/MSS classified imagery to delineate areas in various stages of secondary growth and we find a general trend of increasing vegetation height with increasing age. Flow path networks derived from the Cabaliana floodplain DEM are in general agreement with networks previously extracted from the GRFM mosaics; however, watershed boundaries differ. We have also developed an algorithm for extracting channel widths, which is presently being applied to the DEM and classified imagery to determine morphological variations between reaches.

America's Urban Forests: Keeping Our Cities Cool

NASA Technical Reports Server (NTRS)

Luvall, Jeffrey C.; Quattrochi, Dale A.

1997-01-01

The additional heating of the air over the city is the result of the replacement of naturally vegetated surfaces with those composed of asphalt, concrete, rooftops and other man-made materials. The temperatures of these artificial surfaces can be 20 to 40 C higher than vegetated surfaces. Materials such as asphalt store much of the sun's energy and remains hot long after sunset. This produces a dome of elevated air temperatures 5 to 8 C greater over the city, compared to the air temperatures over adjacent rural areas. This effect is called the "urban heat island". Tree canopies can reduce the urban heat island effect by dissipating the solar energy received by transpiring water from leaf surfaces which cools the air by taking "heat" from the air to evaporate the water and by shading surfaces like asphalt, roofs, and concrete parking lots which prevents initial heating and storage of heat. It is difficult to take enough temperature measurements over a large city area to characterize the surface temperature variability and quantify the temperature reduction effects of tree canopies. However, the use of remotely sensed thermal data from airborne scanners are ideal for the task. In a study funded by NASA, a series of flights over Huntsville AL were performed in September 1994 and over Atlanta in May 1997. In this article we will examine the techniques of analyzing remotely sensed data for measuring the effect of tree canopies in reducing the urban heat island effect.

Distribution and photoreactivity of chromophoric dissolved organic matter in northern Gulf of Mexico shelf waters

NASA Astrophysics Data System (ADS)

Shank, G. Christopher; Evans, Anne

2011-07-01

The distribution and photoreactivity of chromophoric dissolved organic matter (CDOM) in the northern Gulf of Mexico along the Louisiana coastal shelf were examined during three cruises in summer 2007, fall 2007, and summer 2008. The influence of the Mississippi River plume was clearly evident as CDOM levels (defined as a305) and dissolved organic carbon (DOC) concentrations were well-correlated with salinity during all cruises. Elevated CDOM and CDOM:DOC ratios of surface samples collected offshore of Atchafalaya Bay and the Breton-Chandeleur Sound complex indicated emanations of organic-rich waters from coastal wetlands are also an important source to nearshore shelf waters. Generally, CDOM and DOC levels were highest in surface waters and decreased with depth, but during summer 2007 and summer 2008, CDOM levels in near-bottom samples were occasionally higher than at mid-depths without concomitant increases in DOC. CDOM photobleaching was measured during 24 irradiations using a SunTest XLS+ solar simulator with photobleaching rate coefficients ( k305) ranging from 0.011 to 0.32 h -1. For fall 2007 and summer 2008, higher k305 values were generally observed in samples with higher initial CDOM levels. However, samples collected during summer 2007 did not exhibit a similar pattern nor were there differences in photobleaching rates between surface and bottom samples. Spectral slope coefficients ( S275-295 or S350-400) and DOC levels were largely unchanged after 24 h irradiations. Modeled CDOM photobleaching for northern Gulf of Mexico mid-shelf waters predicts that during the summer when solar irradiance is high and the water column becomes stratified, nearly 90% of the CDOM in the upper 1 m may be lost to photobleaching, with losses up to 20% possible even at 10 m depth.

Water Mapping Using Multispectral Airborne LIDAR Data

NASA Astrophysics Data System (ADS)

Yan, W. Y.; Shaker, A.; LaRocque, P. E.

2018-04-01

This study investigates the use of the world's first multispectral airborne LiDAR sensor, Optech Titan, manufactured by Teledyne Optech to serve the purpose of automatic land-water classification with a particular focus on near shore region and river environment. Although there exist recent studies utilizing airborne LiDAR data for shoreline detection and water surface mapping, the majority of them only perform experimental testing on clipped data subset or rely on data fusion with aerial/satellite image. In addition, most of the existing approaches require manual intervention or existing tidal/datum data for sample collection of training data. To tackle the drawbacks of previous approaches, we propose and develop an automatic data processing workflow for land-water classification using multispectral airborne LiDAR data. Depending on the nature of the study scene, two methods are proposed for automatic training data selection. The first method utilizes the elevation/intensity histogram fitted with Gaussian mixture model (GMM) to preliminarily split the land and water bodies. The second method mainly relies on the use of a newly developed scan line elevation intensity ratio (SLIER) to estimate the water surface data points. Regardless of the training methods being used, feature spaces can be constructed using the multispectral LiDAR intensity, elevation and other features derived from these parameters. The comprehensive workflow was tested with two datasets collected for different near shore region and river environment, where the overall accuracy yielded better than 96 %.

Modeling Water-Surface Elevations and Virtual Shorelines for the Colorado River in Grand Canyon, Arizona

USGS Publications Warehouse

Magirl, Christopher S.; Breedlove, Michael J.; Webb, Robert H.; Griffiths, Peter G.

2008-01-01

Using widely-available software intended for modeling rivers, a new one-dimensional hydraulic model was developed for the Colorado River through Grand Canyon from Lees Ferry to Diamond Creek. Solving one-dimensional equations of energy and continuity, the model predicts stage for a known steady-state discharge at specific locations, or cross sections, along the river corridor. This model uses 2,680 cross sections built with high-resolution digital topography of ground locations away from the river flowing at a discharge of 227 m3/s; synthetic bathymetry was created for topography submerged below the 227 m3/s water surface. The synthetic bathymetry was created by adjusting the water depth at each cross section up or down until the model?s predicted water-surface elevation closely matched a known water surface. This approach is unorthodox and offers a technique to construct one-dimensional hydraulic models of bedrock-controlled rivers where bathymetric data have not been collected. An analysis of this modeling approach shows that while effective in enabling a useful model, the synthetic bathymetry can differ from the actual bathymetry. The known water-surface profile was measured using elevation data collected in 2000 and 2002, and the model can simulate discharges up to 5,900 m3/s. In addition to the hydraulic model, GIS-based techniques were used to estimate virtual shorelines and construct inundation maps. The error of the hydraulic model in predicting stage is within 0.4 m for discharges less than 1,300 m3/s. Between 1,300-2,500 m3/s, the model accuracy is about 1.0 m, and for discharges between 2,500-5,900 m3/s, the model accuracy is on the order of 1.5 m. In the absence of large floods on the flow-regulated Colorado River in Grand Canyon, the new hydraulic model and the accompanying inundation maps are a useful resource for researchers interested in water depths, shorelines, and stage-discharge curves for flows within the river corridor with 2002 topographic conditions.

Dynamic factor modeling of ground and surface water levels in an agricultural area adjacent to Everglades National Park

NASA Astrophysics Data System (ADS)

Ritter, A.; Muñoz-Carpena, R.

2006-02-01

The extensive eastern boundary of Everglades National Park (ENP) in south Florida (USA) is subject to one the most expensive and ambitious environmental restoration projects in history. Understanding and predicting the interaction between the shallow aquifer and surface water is a key component for fine-tuning the process. The Frog Pond is an intensively instrumented agricultural 2023 ha area adjacent to ENP. The interactions among 21 multivariate daily time series (ground and surface water elevations, rainfall and evapotranspiration) available from this area were studied by means of dynamic factor analysis, a novel technique in the field of hydrology. This method is designed to determine latent or background effects governing variability or fluctuations in non-stationary time series. Water levels in 16 wells and two drainage ditch locations inside the area were selected as response variables, and canal levels and net recharge as explanatory variables. Elevations in the two canals delimiting the Frog Pond area were found to be the main factors explaining the response variables. This influence of canal elevations on water levels inside the area was complementary and inversely related to the distance between the observation point and each canal. Rainfall events do not affect daily water levels significantly but are responsible for instantaneous or localized groundwater responses that in some cases can be directly associated with the risk of flooding. This close coupling between surface and groundwater levels, that corroborates that found by other authors using different methods, could hinder on-going environmental restoration efforts in the area by bypassing the function of wetlands and other surface features. An empirical model with a reduced set of parameters was successfully developed and validated in the area by interpolating the results from the dynamic factor analysis across the spatial domain (coefficient of efficiency across the domain: 0.66-0.99). Although specific to the area, the resulting model is deemed useful for water management within the wide range of conditions similar to those present during the experimental period.

New Theory for Tsunami Propagation and Estimation of Tsunami Source Parameters

NASA Astrophysics Data System (ADS)

Mindlin, I. M.

2007-12-01

In numerical studies based on the shallow water equations for tsunami propagation, vertical accelerations and velocities within the sea water are neglected, so a tsunami is usually supposed to be produced by an initial free surface displacement in the initially still sea. In the present work, new theory for tsunami propagation across the deep sea is discussed, that accounts for the vertical accelerations and velocities. The theory is based on the solutions for the water surface displacement obtained in [Mindlin I.M. Integrodifferential equations in dynamics of a heavy layered liquid. Moscow: Nauka*Fizmatlit, 1996 (Russian)]. The solutions are valid when horizontal dimensions of the initially disturbed area in the sea surface are much larger than the vertical displacement of the surface, which applies to the earthquake tsunamis. It is shown that any tsunami is a combination of specific basic waves found analytically (not superposition: the waves are nonlinear), and consequently, the tsunami source (i.e., the initially disturbed body of water) can be described by the numerable set of the parameters involved in the combination. Thus the problem of theoretical reconstruction of a tsunami source is reduced to the problem of estimation of the parameters. The tsunami source can be modelled approximately with the use of a finite number of the parameters. Two-parametric model is discussed thoroughly. A method is developed for estimation of the model's parameters using the arrival times of the tsunami at certain locations, the maximum wave-heights obtained from tide gauge records at the locations, and the distances between the earthquake's epicentre and each of the locations. In order to evaluate the practical use of the theory, four tsunamis of different magnitude occurred in Japan are considered. For each of the tsunamis, the tsunami energy (E below), the duration of the tsunami source formation T, the maximum water elevation in the wave originating area H, mean radius of the area R, and the average magnitude of the sea surface displacement at the margin of the wave originating area h are estimated using tide gauges records. The results are compared (and, in the author's opinion, are in line) with the estimates known in the literature. Compared to the methods employed in the literature, there is no need to use bathymetry (and, consequently, refraction diagrams) for the estimations. The present paper follows closely earlier works [Mindlin I.M., 1996; Mindlin I.M. J. Appl. Math. Phys. (ZAMP), 2004, vol.55, pp. 781-799] and adds to their theoretical results. Example. The Hiuganada earthquake of 1968, April, 1, 9h 42m JST. A tsunami of moderate size arrived at the coast of the south-western part of Shikoku and the eastern part of Kyushu, Japan. Tsunami parameters listed above are estimated with the theory being discussed for two models of tsunami generation: (a) by initial free surface displacement (the case for numerical studies): E=1.91· 1012J, R=22km, h=17.2cm; and (b) by a sudden change in the velocity field of initially still water: E=8.78· 1012J, R=20.4km, h=9.2cm. These values are in line with known estimates [Soloviev S.L., Go Ch.N. Catalogue of tsunami in the West of Pacific Ocean. Moscow, 1974]: E=1.3· 1013J (attributed to Hatori), E=(1.4 - 2.2)· 1012J (attributed to Aida), R=21.2km, h=20cm [Hatory T., Bull. Earthq. Res. Inst., Tokyo Univ., 1969, vol. 47, pp. 55-63]. Also, estimates are obtained for the values that could not be found based on shallow water wave theory: (a) H=3.43m and (b) H=1.38m, T=16.4sec.

Using Imaging Spectrometry measurements of Ecosystem Composition to constrain Regional Predictions of Carbon, Water and Energy Fluxes

NASA Astrophysics Data System (ADS)

Anderson, C.; Bond-Lamberty, B. P.; Huang, M.; Xu, Y.; Stegen, J.

2016-12-01

Ecosystem composition is a key attribute of terrestrial ecosystems, influencing the fluxes of carbon, water, and energy between the land surface and the atmosphere. The description of current ecosystem composition has traditionally come from relatively few ground-based inventories of the plant canopy, but are spatially limited and do not provide a comprehensive picture of ecosystem composition at regional or global scales. In this analysis, imaging spectrometry measurements, collected as part of the HyspIRI Preparatory Mission, are used to provide spatially-resolved estimates of plant functional type composition providing an important constraint on terrestrial biosphere model predictions of carbon, water and energy fluxes across the heterogeneous landscapes of the Californian Sierras. These landscapes include oak savannas, mid-elevation mixed pines, fir-cedar forests, and high elevation pines. Our results show that imaging spectrometry measurements can be successfully used to estimate regional-scale variation in ecosystem composition and resulting spatial heterogeneity in patterns of carbon, water and energy fluxes and ecosystem dynamics. Simulations at four flux tower sites within the study region yield patterns of seasonal and inter-annual variation in carbon and water fluxes that have comparable accuracy to simulations initialized from ground-based inventory measurements. Finally, results indicate that during the 2012-2015 Californian drought, regional net carbon fluxes fell by 84%, evaporation and transpiration fluxes fell by 53% and 33% respectively, and sensible heat increase by 51%. This study provides a framework for assimilating near-future global satellite imagery estimates of ecosystem composition with terrestrial biosphere models, constraining and improving their predictions of large-scale ecosystem dynamics and functioning.

Using Imaging Spectrometry measurements of Ecosystem Composition to constrain Regional Predictions of Carbon, Water and Energy Fluxes

NASA Astrophysics Data System (ADS)

Antonarakis, A. S.; Bogan, S.; Moorcroft, P. R.

2017-12-01

Ecosystem composition is a key attribute of terrestrial ecosystems, influencing the fluxes of carbon, water, and energy between the land surface and the atmosphere. The description of current ecosystem composition has traditionally come from relatively few ground-based inventories of the plant canopy, but are spatially limited and do not provide a comprehensive picture of ecosystem composition at regional or global scales. In this analysis, imaging spectrometry measurements, collected as part of the HyspIRI Preparatory Mission, are used to provide spatially-resolved estimates of plant functional type composition providing an important constraint on terrestrial biosphere model predictions of carbon, water and energy fluxes across the heterogeneous landscapes of the Californian Sierras. These landscapes include oak savannas, mid-elevation mixed pines, fir-cedar forests, and high elevation pines. Our results show that imaging spectrometry measurements can be successfully used to estimate regional-scale variation in ecosystem composition and resulting spatial heterogeneity in patterns of carbon, water and energy fluxes and ecosystem dynamics. Simulations at four flux tower sites within the study region yield patterns of seasonal and inter-annual variation in carbon and water fluxes that have comparable accuracy to simulations initialized from ground-based inventory measurements. Finally, results indicate that during the 2012-2015 Californian drought, regional net carbon fluxes fell by 84%, evaporation and transpiration fluxes fell by 53% and 33% respectively, and sensible heat increase by 51%. This study provides a framework for assimilating near-future global satellite imagery estimates of ecosystem composition with terrestrial biosphere models, constraining and improving their predictions of large-scale ecosystem dynamics and functioning.

A Paleoclimate Modeling Perspective on the Challenges to Quantifying Paleoelevation

NASA Astrophysics Data System (ADS)

Poulsen, C. J.; Aron, P.; Feng, R.; Fiorella, R.; Shen, H.; Skinner, C. B.

2016-12-01

Surface elevation is a fundamental characteristic of the land surface. Gradients in elevation associated with mountain ranges are a first order control on local and regional climate; weathering, erosion and nutrient transport; and the evolution and biodiversity of organisms. In addition, surface elevations are a proxy for the geodynamic processes that created them. Efforts to quantify paleoelevation have relied on reconstructions of mineralogical and fossil proxies that preserve environmental signals such as surface temperature, moist enthalpy, or surface water isotopic composition that have been observed to systematically vary with elevation. The challenge to estimating paleoelevation from proxies arises because the modern-day elevation dependence of these environmental parameters is not constant and has differed in the past in response to changes in both surface elevation and other climatic forcings, including greenhouse gas and orbital variations. For example, downward mixing of vapor that is isotopically enriched through troposphere warming under greenhouse forcing reduces the isotopic lapse rate. Without considering these factors, paleoelevation estimates for orogenic systems can be in error by hundreds of meters or more. Isotope-enabled climate models provide a tool for separating the climate response to these forcings into elevation and non-elevation components and for identifying the processes that alter the elevation dependence of environmental parameters. Our past and ongoing work has focused on the simulated climate response to surface uplift of the South American Andes, the North American Cordillera, and the Tibetan-Himalyan system during the Cenozoic, and its implication for interpreting proxy records from these regions. This work demonstrates that the climate response to uplift, and the implications for interpreting proxy records, varies tremendously by region. In this presentation, we synthesize climate responses to uplift across orogens, present new results examining the affect of orbital variations on elevation-dependent environmental parameters, and discuss the implications of our work for quantifying paleoelevations.

Inorganic Geochemistry of Flowback Water from the Montney Formation: Potential Sources of Elevated Ion Concentrations

NASA Astrophysics Data System (ADS)

Owen, J.; Bustin, R.

2016-12-01

An inorganic geochemical analysis was conducted on flowback water from hydraulically fractured oil and gas wells of the Montney Formation of varying thermal maturity and stratigraphy in the Western Canadian Sedimentary Basin. The results of this study provide insight into potential sources of the elevated ion concentrations and can be used to assist with wastewater management and blending of water for reuse. Samples were obtained from 31 wells across the Montney and include wells completed in the lower, middle, and upper units. Selected fluid samples from each well were analyzed using ICP-OES, ICP-MS, and IC. Oxygen and hydrogen isotope analysis was performed using a liquid-water isotope analyzer. The flowback waters are classified as sodium-chloride type. In addition to Na and Cl, calcium, potassium, magnesium, and strontium are elevated and increase during the flowback period. Barium, iron, and lithium are also elevated at some locations. The early flowback water chemistry varies within the formation: higher initial TDS values of approximately 50,000mg/L in Upper Montney flowback water relative to the initial TDS from both Middle and Lower Montney wells (<25,000mg/L and <15,000mg/L, respectively). However, overall, the maximum TDS attained later in the flowback period does not show a consistent stratigraphic trend (range: 55,000 - 130,000mg/L) except for one region in the Middle Montney where the maximum TDS remains consistently lower than other areas (<50,000mg/L). Barium is notable in Montney flowback due to its high variability, with the lowest concentrations occurring in Middle Montney flowback and the highest in Lower Montney flowback. Comparing closely spaced wells completed on the same pad and in the same zone, the flowback waters generally have similar ion concentrations and consistent ion ratios. The increasing ion concentrations as well as the stable water isotopes support mixing between the hydraulic fracturing fluid, which has relatively low ion concentrations, and more saline connate formation water. Geochemical modeling indicates the ion concentrations in the flowback water are a complex product of mineral precipitation/dissolution, ion exchange with the reservoir, geochemistry of the connate water and water saturation of the reservoir.

Pore Pressure Distribution and Flank Instability in Hydrothermally Altered Stratovolcanoes

NASA Astrophysics Data System (ADS)

Ball, J. L.; Taron, J.; Hurwitz, S.; Reid, M. E.

2015-12-01

Field and geophysical investigations of stratovolcanoes with long-lived hydrothermal systems commonly reveal that initially permeable regions (such as brecciated layers of pyroclastic material) can become both altered and water-bearing. Hydrothermal alteration in these regions, including clay formation, can turn them into low-permeability barriers to fluid flow, which could increase pore fluid pressures resulting in flank slope instability. We examined elevated pore pressure conditions using numerical models of hydrothermal flow in stratovolcanoes, informed by geophysical data about internal structures and deposits. Idealized radially symmetric meshes were developed based on cross-sectional profiles and alteration/permeability structures of Cascade Range stratovolcanoes. We used the OpenGeoSys model to simulate variably saturated conditions in volcanoes heated only by regional heat fluxes, as well as 650°C intrusions at two km depth below the surface. Meteoric recharge was estimated from precipitation rates in the Cascade Range. Preliminary results indicate zones of elevated pore pressures form: 1) where slopes are underlain by continuous low-permeability altered layers, or 2) when the edifice has an altered core with saturated, less permeable limbs. The first scenario might control shallow collapses on the slopes above the altered layers. The second could promote deeper flank collapses that are initially limited to the summit and upper slopes, but could progress to the core of an edifice. In both scenarios, pore pressures can be further elevated by shallow intrusions, or evolve over longer time scales under forcing from regional heat flux. Geometries without confining low-permeability layers do not show these pressure effects. Our initial scenarios use radially symmetric models, but we are also simulating hydrothermal flow under real 3D geometries with asymmetric subsurface structures (Mount Adams). Simulation results will be used to inform 3D slope-stability models.

Development of a hydraulic model and flood-inundation maps for the Wabash River near the Interstate 64 Bridge near Grayville, Illinois

USGS Publications Warehouse

Boldt, Justin A.

2018-01-16

A two-dimensional hydraulic model and digital flood‑inundation maps were developed for a 30-mile reach of the Wabash River near the Interstate 64 Bridge near Grayville, Illinois. The flood-inundation maps, which can be accessed through the U.S. Geological Survey (USGS) Flood Inundation Mapping Science web site at http://water.usgs.gov/osw/flood_inundation/, depict estimates of the areal extent and depth of flooding corresponding to selected water levels (stages) at the USGS streamgage on the Wabash River at Mount Carmel, Ill (USGS station number 03377500). Near-real-time stages at this streamgage may be obtained on the internet from the USGS National Water Information System at http://waterdata.usgs.gov/ or the National Weather Service (NWS) Advanced Hydrologic Prediction Service (AHPS) at http://water.weather.gov/ahps/, which also forecasts flood hydrographs at this site (NWS AHPS site MCRI2). The NWS AHPS forecasts peak stage information that may be used with the maps developed in this study to show predicted areas of flood inundation.Flood elevations were computed for the Wabash River reach by means of a two-dimensional, finite-volume numerical modeling application for river hydraulics. The hydraulic model was calibrated by using global positioning system measurements of water-surface elevation and the current stage-discharge relation at both USGS streamgage 03377500, Wabash River at Mount Carmel, Ill., and USGS streamgage 03378500, Wabash River at New Harmony, Indiana. The calibrated hydraulic model was then used to compute 27 water-surface elevations for flood stages at 1-foot (ft) intervals referenced to the streamgage datum and ranging from less than the action stage (9 ft) to the highest stage (35 ft) of the current stage-discharge rating curve. The simulated water‑surface elevations were then combined with a geographic information system digital elevation model, derived from light detection and ranging data, to delineate the area flooded at each water level.The availability of these maps, along with information on the internet regarding current stage from the USGS streamgage at Mount Carmel, Ill., and forecasted stream stages from the NWS AHPS, provides emergency management personnel and residents with information that is critical for flood-response activities such as evacuations and road closures, as well as for postflood recovery efforts.

1997 flood tracking chart for the Red River of the North basin

USGS Publications Warehouse

Wiche, G.J.; Martin, C.R.; Albright, L.L.; Wald, Geraldine B.

1997-01-01

The flood tracking chart for the Red River of the North Basin can be used by local citizens and emergency response personnel to determine the latest river stage. By comparing the current stage (water-surface elevation above some datum) and predicted flood crest to the recorded peak stages of previous floods, emergency response personnel and residents can make informed decisions concerning the threat to life and property. The flood tracking chart shows a map of the basin with the location of major real-time streamflow-gaging stations in the basin. Click on a station in the map or in the list below the map. Streamflow and stage information for the last 7 days, current stage relative to recorded peak stages, and streamflow for the previous 18 months are provided in graphic form, along with information such as station location and length of record. The National Weather Service has direct access to all information collected by the USGS for use in their forecasting models and routinely broadcasts the forecast information to the news media and on shortwave radio. The radio frequencies are 162.400 MHz (megahertz) in Petersburg, N. Dak., and Detroit Lakes, Minn.; 162.425 MHz in Webster, N. Dak., and Bemidji, Minn.; 162.450 MHz in Roosevelt, Minn.; 162.475 MHz in Grand Forks and Amenia, N. Dak.; and 162.550 MHz in Thief River Falls, Minn. To use the flood tracking chart for a particular property, determine the approximate elevation of the threatened property and the elevation of the gaging station that is closest to the threatened property. For example, most people in Grand Forks, N. Dak., probably will use the Red River of the North at Grand Forks station. Record the flood elevation for the gaging station. Compare the flood elevation to the elevation of the property to immediately know if the property has an impending threat of flooding. One must be cautioned by the fact that the surface of flowing water is not flat but has a slope. Therefore, the water-surface elevation near a threatened property might not be the same as the river stages at the gaging stations. The network of river-gaging stations in the Red River of the North Basin is operated by the USGS in cooperation with the U.S. Army Corps of Engineers, the North Dakota State Water Commission, the Minnesota Department of Natural Resources, the Southeast Cass Water Resources District, the Cass County Joint Water Resource District, the Red River Joint Water Resource Board, and the Red River Watershed Management Board. For more information about USGS programs in North Dakota, contact the District Chief, U.S. Geological Survey, North Dakota District, at (701) 250-7400.

Elevated CO2 facilitates C and N accumulation in a rice paddy ecosystem.

PubMed

Guo, Jia; Zhang, Mingqian; Wang, Xiaowen; Zhang, Weijian

2015-03-01

Elevated CO2 can stimulate wetland carbon (C) and nitrogen (N) exports through gaseous and dissolved pathways, however, the consequent influences on the C and N pools are still not fully known. Therefore, we set up a free-air CO2 enrichment experiment in a paddy field in Eastern China. After five year fumigation, we studied C and N in the plant-water-soil system. The results showed: (1) elevated CO2 stimulated rice aboveground biomass and N accumulations by 19.1% and 12.5%, respectively. (2) Elevated CO2 significantly increased paddy soil TOC and TN contents by 12.5% and 15.5%, respectively in the 0-15 cm layer, and 22.7% and 26.0% in the 15-30 cm soil layer. (3) Averaged across the rice growing period, elevated CO2 greatly increased TOC and TN contents in the surface water by 7.6% and 11.4%, respectively. (4) The TOC/TN ratio and natural δ15N value in the surface soil showed a decreasing trend under elevated CO2. The above results indicate that elevated CO2 can benefit C and N accumulation in paddy fields. Given the similarity between the paddies and natural wetlands, our results also suggest a great potential for long-term C and N accumulation in natural wetlands under future climate patterns. Copyright © 2015. Published by Elsevier B.V.

Experimental study on soluble chemical transfer to surface runoff from soil.

PubMed

Tong, Juxiu; Yang, Jinzhong; Hu, Bill X; Sun, Huaiwei

2016-10-01

Prevention of chemical transfer from soil to surface runoff, under condition of irrigation and subsurface drainage, would improve surface water quality. In this paper, a series of laboratory experiments were conducted to assess the effects of various soil and hydraulic factors on chemical transfer from soil to surface runoff. The factors include maximum depth of ponding water on soil surface, initial volumetric water content of soil, depth of soil with low porosity, type or texture of soil and condition of drainage. In the experiments, two soils, sand and loam, mixed with different quantities of soluble KCl were filled in the sandboxes and prepared under different initial saturated conditions. Simulated rainfall induced surface runoff are operated in the soils, and various ponding water depths on soil surface are simulated. Flow rates and KCl concentration of surface runoff are measured during the experiments. The following conclusions are made from the study results: (1) KCl concentration in surface runoff water would decrease with the increase of the maximum depth of ponding water on soil surface; (2) KCl concentration in surface runoff water would increase with the increase of initial volumetric water content in the soil; (3) smaller depth of soil with less porosity or deeper depth of soil with larger porosity leads to less KCl transfer to surface runoff; (4) the soil with finer texture, such as loam, could keep more fertilizer in soil, which will result in more KCl concentration in surface runoff; and (5) good subsurface drainage condition will increase the infiltration and drainage rates during rainfall event and will decrease KCl concentration in surface runoff. Therefore, it is necessary to reuse drained fertile water effectively during rainfall, without polluting groundwater. These study results should be considered in agriculture management to reduce soluble chemical transfer from soil to surface runoff for reducing non-point sources pollution.

Physiological acclimation dampens initial effects of elevated temperature and atmospheric CO2 concentration in mature boreal Norway spruce.

PubMed

Lamba, Shubhangi; Hall, Marianne; Räntfors, Mats; Chaudhary, Nitin; Linder, Sune; Way, Danielle; Uddling, Johan; Wallin, Göran

2018-02-01

Physiological processes of terrestrial plants regulate the land-atmosphere exchange of carbon, water, and energy, yet few studies have explored the acclimation responses of mature boreal conifer trees to climate change. Here we explored the acclimation responses of photosynthesis, respiration, and stomatal conductance to elevated temperature and/or CO 2 concentration ([CO 2 ]) in a 3-year field experiment with mature boreal Norway spruce. We found that elevated [CO 2 ] decreased photosynthetic carboxylation capacity (-23% at 25 °C) and increased shoot respiration (+64% at 15 °C), while warming had no significant effects. Shoot respiration, but not photosynthetic capacity, exhibited seasonal acclimation. Stomatal conductance at light saturation and a vapour pressure deficit of 1 kPa was unaffected by elevated [CO 2 ] but significantly decreased (-27%) by warming, and the ratio of intercellular to ambient [CO 2 ] was enhanced (+17%) by elevated [CO 2 ] and decreased (-12%) by warming. Many of these responses differ from those typically observed in temperate tree species. Our results show that long-term physiological acclimation dampens the initial stimulation of plant net carbon assimilation to elevated [CO 2 ], and of plant water use to warming. Models that do not account for these responses may thus overestimate the impacts of climate change on future boreal vegetation-atmosphere interactions. © 2017 John Wiley & Sons Ltd.

Frost Tables, Barrow, Alaska, NGEE Areas B, C and D for 2012, 2013, 2014, Final Version, 20150312

DOE Data Explorer

Liljedahl, Anna

2014-03-24

This dataset represent spatially intensive thaw depth surveys with individual point measurements spaced approximately 0.5 m apart. The three approximate10x10m grids cover an ice wedge and a portion of its two neighboring polygons. The file contains thaw depth, frost table elevation, ground surface elevation, active layer depth and surface water inundation across three seasons (2012, 2013 and 2014) at Barrow NGEE Areas B, C and D.

Ocean acidification causes structural deformities in juvenile coral skeletons.

PubMed

Foster, Taryn; Falter, James L; McCulloch, Malcolm T; Clode, Peta L

2016-02-01

Rising atmospheric CO2 is causing the oceans to both warm and acidify, which could reduce the calcification rates of corals globally. Successful coral recruitment and high rates of juvenile calcification are critical to the replenishment and ultimate viability of coral reef ecosystems. Although elevated Pco2 (partial pressure of CO2) has been shown to reduce the skeletal weight of coral recruits, the structural changes caused by acidification during initial skeletal deposition are unknown. We show, using high-resolution three-dimensional x-ray microscopy, that ocean acidification (Pco2 ~900 μatm, pH ~7.7) not only causes reduced overall mineral deposition but also a deformed and porous skeletal structure in newly settled coral recruits. In contrast, elevated temperature (+3°C) had little effect on skeletal formation except to partially mitigate the effects of elevated Pco2. The striking structural deformities we observed show that new recruits are at significant risk, being unable to effectively build their skeletons in the Pco2 conditions predicted to occur for open ocean surface waters under a "business-as-usual" emissions scenario [RCP (representative concentration pathway) 8.5] by the year 2100.

Ocean acidification causes structural deformities in juvenile coral skeletons

PubMed Central

Foster, Taryn; Falter, James L.; McCulloch, Malcolm T.; Clode, Peta L.

2016-01-01

Rising atmospheric CO2 is causing the oceans to both warm and acidify, which could reduce the calcification rates of corals globally. Successful coral recruitment and high rates of juvenile calcification are critical to the replenishment and ultimate viability of coral reef ecosystems. Although elevated Pco2 (partial pressure of CO2) has been shown to reduce the skeletal weight of coral recruits, the structural changes caused by acidification during initial skeletal deposition are unknown. We show, using high-resolution three-dimensional x-ray microscopy, that ocean acidification (Pco2 ~900 μatm, pH ~7.7) not only causes reduced overall mineral deposition but also a deformed and porous skeletal structure in newly settled coral recruits. In contrast, elevated temperature (+3°C) had little effect on skeletal formation except to partially mitigate the effects of elevated Pco2. The striking structural deformities we observed show that new recruits are at significant risk, being unable to effectively build their skeletons in the Pco2 conditions predicted to occur for open ocean surface waters under a “business-as-usual” emissions scenario [RCP (representative concentration pathway) 8.5] by the year 2100. PMID:26989776

Hurricane Rita surge data, southwestern Louisiana and southeastern Texas, September to November 2005

USGS Publications Warehouse

McGee, Benton D.; Goree, Burl B.; Tollett, Roland W.; Woodward, Brenda K.; Kress, Wade H.

2006-01-01

Pressure transducers and high-water marks were used to document the inland water levels related to storm surge generated by Hurricane Rita in southwestern Louisiana and southeastern Texas. On September 22-23, 2005, an experimental monitoring network consisting of 47 pressure transducers (sensors) was deployed at 33 sites over an area of about 4,000 square miles to record the timing, extent, and magnitude of inland hurricane storm surge and coastal flooding. Sensors were programmed to record date and time, temperature, and barometric or water pressure. Water pressure was corrected for changes in barometric pressure and salinity. Elevation surveys using global-positioning systems and differential levels were used to relate all storm-surge water-level data, reference marks, benchmarks, sensor measuring points, and high-water marks to the North American Vertical Datum of 1988 (NAVD 88). The resulting data indicated that storm-surge water levels over 14 feet above NAVD 88 occurred at three locations and rates of water-level rise greater than 5 feet per hour occurred at three locations near the Louisiana coast. Quality-assurance measures were used to assess the variability and accuracy of the water-level data recorded by the sensors. Water-level data from sensors were similar to data from co-located sensors, permanent U.S. Geological Survey streamgages, and water-surface elevations performed by field staff. Water-level data from sensors at selected locations were compared to corresponding high-water mark elevations. In general, the water-level data from sensors were similar to elevations of high quality high-water marks, while reporting consistently higher than elevations of lesser quality high-water marks.

Development of a Hydrodynamic and Transport model of Bellingham Bay in Support of Nearshore Habitat Restoration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Taiping; Yang, Zhaoqing; Khangaonkar, Tarang

2010-04-22

In this study, a hydrodynamic model based on the unstructured-grid finite volume coastal ocean model (FVCOM) was developed for Bellingham Bay, Washington. The model simulates water surface elevation, velocity, temperature, and salinity in a three-dimensional domain that covers the entire Bellingham Bay and adjacent water bodies, including Lummi Bay, Samish Bay, Padilla Bay, and Rosario Strait. The model was developed using Pacific Northwest National Laboratory’s high-resolution Puget Sound and Northwest Straits circulation and transport model. A sub-model grid for Bellingham Bay and adjacent coastal waters was extracted from the Puget Sound model and refined in Bellingham Bay using bathymetric lightmore » detection and ranging (LIDAR) and river channel cross-section data. The model uses tides, river inflows, and meteorological inputs to predict water surface elevations, currents, salinity, and temperature. A tidal open boundary condition was specified using standard National Oceanic and Atmospheric Administration (NOAA) predictions. Temperature and salinity open boundary conditions were specified based on observed data. Meteorological forcing (wind, solar radiation, and net surface heat flux) was obtained from NOAA real observations and National Center for Environmental Prediction North American Regional Analysis outputs. The model was run in parallel with 48 cores using a time step of 2.5 seconds. It took 18 hours of cpu time to complete 26 days of simulation. The model was calibrated with oceanographic field data for the period of 6/1/2009 to 6/26/2009. These data were collected specifically for the purpose of model development and calibration. They include time series of water-surface elevation, currents, temperature, and salinity as well as temperature and salinity profiles during instrument deployment and retrieval. Comparisons between model predictions and field observations show an overall reasonable agreement in both temporal and spatial scales. Comparisons of root mean square error values for surface elevation, velocity, temperature, and salinity time series are 0.11 m, 0.10 m/s, 1.28oC, and 1.91 ppt, respectively. The model was able to reproduce the salinity and temperature stratifications inside Bellingham Bay. Wetting and drying processes in tidal flats in Bellingham Bay, Samish Bay, and Padilla Bay were also successfully simulated. Both model results and observed data indicated that water surface elevations inside Bellingham Bay are highly correlated to tides. Circulation inside the bay is weak and complex and is affected by various forcing mechanisms, including tides, winds, freshwater inflows, and other local forcing factors. The Bellingham Bay model solution was successfully linked to the NOAA oil spill trajectory simulation model “General NOAA Operational Modeling Environment (GNOME).” Overall, the Bellingham Bay model has been calibrated reasonably well and can be used to provide detailed hydrodynamic information in the bay and adjacent water bodies. While there is room for further improvement with more available data, the calibrated hydrodynamic model provides useful hydrodynamic information in Bellingham Bay and can be used to support sediment transport and water quality modeling as well as assist in the design of nearshore restoration scenarios.« less

ISOTOPIC EVIDENCE FOR NATURALLY OCCURRING SULFATE PONDS IN THE KANKAKEE RIVER BASIN, ILLINOIS-INDIANA

EPA Science Inventory

Design of constructed wetlands in the Kankakee watershed, Indiana, include pumping and distribution ditches leaving former channelized river levees intact. Resultant changes in shallow ground water - surface water interactions may be contributing elevated sulfate to wetland ponds...

Resistance of rainbow trout to Flavobacterium psychrophilum infection: integrating selective breeding and microbial genomics

USDA-ARS?s Scientific Manuscript database

Bacterial cold water disease (BCWD) is a frequent cause of elevated loss in juvenile salmonid fish and development of effective control strategies is a priority. At the National Center for Cool and Cold Water Aquaculture (NCCCWA), we initiated a multidisciplinary program designed to better understan...

Nutrients in ground water and surface water of the United States; an analysis of data through 1992

USGS Publications Warehouse

Mueller, D.K.; Hamilton, P.A.; Helsel, D.R.; Hitt, K.J.; Ruddy, B.C.

1995-01-01

Historical data on nutrient (nitrogen and phosphorus species) concentrations in ground-and surface-water samples were compiled from 20 study units of the National Water-Quality Assessment (NAWQA) Program and 5 supplemental study areas. The resultant national retrospective data sets contained analyses of about 12,000 Found-water and more than 22,000 surface-water samples. These data were interpreted on regional and national scales by relating the distributions of nutrient concentrations to ancillary data, such as land use, soil characteristics, and hydrogeology, provided by local study-unit personnel. The information provided in this report on environmental factors that affect nutrient concentrations in ground and surface water can be used to identify areas of the Nation where the vulnerability to nutrient contamination is greatest. Nitrate was the nutrient of greatest concern in the historical ground-water data. It is the only nutrient that is regulated by a national drinking-water standard. Nitrate concentrations were significantly different in ground water affected by various land uses. Concentrations in about 16 percent of the samples collected in agricultural areas exceeded the drinking-water standard. However, the standard was exceeded in only about 1 percent of samples collected from public-supply wells. A variety of ancillary factors had significant relations to nitrate concentrations in ground water beneath agricultural areas. Concentrations generally were highest within 100 feet of the land surface. They were also higher in areas where soil and geologic characteristics promoted rapid movement of water to the aquifer. Elevated concentrations commonly occurred in areas underlain by permeable materials, such as carbonate bedrock or unconsolidated sand and gravel, and where soils are generally well drained. In areas where water movement is impeded, denitrification might lead to low concentrations of nitrate in the ground water. Low concentrations were also related to interspersion of pasture and woodland with cropland in agricultural areas. Elevated nitrate concentrations in areas of more homogeneous cropland probably were a result of intensive nitrogen fertilizer application on large tracts of land. Certain regions of the United States seemed more vulnerable to nitrate contamination of ground water in agricultural areas. Regions of greater vulnerability included parts of the Northeast, Midwest, and West Coast. The well-drained soils, typical in these regions, have little capacity to hold water and nutrients; therefore, these soils receive some of the largest applications of fertilizer and irrigation in the Nation. The agricultural land is intensively cultivated for row crops, with little interspersion of pasture and woodland. Nutrient concentrations in surface water also were generally related to land use. Nitrate concentrations were highest in samples from sites downstream from agricultural or urban areas. However, concentrations were not as high as in ground water and rarely exceeded the drinking-water standard. Elevated concentrations of nitrate in surface water of the Northeastern United States might be related to large amounts of atmospheric deposition (acid rain). High concentrations in parts of the Midwest might be related to tile drainage of agricultural fields. Ammonia and phosphorus concentrations were highest downstream from urban areas. These concentrations generally were high enough to warrant concerns about toxicity to fish and accelerated eutrophication. Recent improvements in wastewater treatment have decreased ammonia concentrations downstream from some urban areas, but the result has been an increase in nitrate concentrations. Information on environmental factors that affect water quality is useful to identify drainage basins throughout the Nation with the greatest vulnerability for nutrient contamination and to delineate areas where ground-water or surface-water contamination is most likely to oc

Distribution of volatile organic compounds (VOCs) in surface water, soil, and groundwater within a chemical industry park in Eastern China.

PubMed

Liu, Benhua; Chen, Liang; Huang, Linxian; Wang, Yongseng; Li, Yuehua

2015-01-01

This paper focuses on the distribution of volatile organic compounds (VOCs) in the surface water, soil, and groundwater within a chemical industry park in Eastern China. At least one VOC was detected in each of the 20 sampling sites, and the maximum number of VOCs detected in the surface water, groundwater, and soil were 13, 16, and 14, respectively. Two of the 10 VOCs with elevated concentrations detected in surface water, groundwater, and soil were chloroform and 1,2-dichloroethane. The characteristics of VOCs, which include volatility, boiling point, and solubility, could significantly affect their distribution in surface water, soil, and groundwater. However, due to the direct discharging of chemical industry wastewater into surface water, higher concentrations of VOCs (except chloroform) were detected in surface water than in soil and groundwater. Fortunately, the higher volatility of VOCs prevents the VOCs from impacting groundwater, which helps to maintain a lower concentration of VOCs in the groundwater than in both surface water and soil. This is because pollutants with relatively higher boiling points and lower solubilities have higher detection frequencies in soil, and contaminants with relatively lower boiling points and higher solubilities have higher detection frequencies in water, notably in surface water.

Re-examining data-intensive surface water models with high-resolution topography derived from unmanned aerial system photogrammetry

NASA Astrophysics Data System (ADS)

Pai, H.; Tyler, S.

2017-12-01

Small, unmanned aerial systems (sUAS) are quickly becoming a cost-effective and easily deployable tool for high spatial resolution environmental sensing. Land surface studies from sUAS imagery have largely focused on accurate topographic mapping, quantifying geomorphologic changes, and classification/identification of vegetation, sediment, and water quality tracers. In this work, we explore a further application of sUAS-derived topographic mapping to a two-dimensional (2-d), depth-averaged river hydraulic model (Flow and Sediment Transport with Morphological Evolution of Channels, FaSTMECH) along a short, meandering reach of East River, Colorado. On August 8, 2016, we flew a sUAS as part of the Center for Transformative Environmental Monitoring Programs with a consumer-grade visible camera and created a digital elevation map ( 1.5 cm resolution; 5 cm accuracy; 500 m long river corridor) with Agisoft Photoscan software. With the elevation map, we created a longitudinal water surface elevation (WSE) profile by manually delineating the bank-water interface and river bathymetry by applying refraction corrections for more accurate water depth estimates, an area of ongoing research for shallow and clear river systems. We tested both uncorrected and refraction-corrected bathymetries with the steady-state, 2-d model, applying sensitivities for dissipation parameters (bed roughness and eddy characteristics). Model performance was judged from the WSE data and measured stream velocities. While the models converged, performance and insights from model output could be improved with better bed roughness characterization and additional water depth cross-validation for refraction corrections. Overall, this work shows the applicability of sUAS-derived products to a multidimensional river model, where bathymetric data of high resolution and accuracy are key model input requirements.

Detailed scour measurements around a debris accumulation

USGS Publications Warehouse

Mueller, David S.; Parola, Arthur C.

1998-01-01

Detailed scour measurements were made at Farm-Market 2004 over the Brazos River near Lake Jackson, Tex. during flooding in October 1994. Woody debris accumulations on bents 6, 7, and 8 obstructed flow through the bridge, causing scour of the streambed. Measurements at the site included three-dimensional velocities, channel bathymetry, water-surface elevations, water-surface slope, and discharge. Channel geometry upstream from the bridge caused approach conditions to be nonuniform.

Influence of the Hyporheic Zone on Supersaturated Gas Exposure to Incubating Chum Salmon

DOE Office of Scientific and Technical Information (OSTI.GOV)

Arntzen, Evan V.; Geist, David R.; Murray, Katherine J.

2009-12-01

Supersaturated total dissolved gas (TDG) is elevated seasonally in the lower Columbia River, with surface water concentrations approaching 120% saturation of TDG. Chum salmon (Oncorhynchus keta) embryos incubating in nearby spawning areas could be affected if depth-compensated TDG concentrations within the hyporheic zone exceed 103% TDG. The objective of this study was to determine if TDG of the hyporheic zone in two chum salmon spawning areas -- one in a side channel near Ives Island, Washington, and another on the mainstem Columbia River near Multnomah Falls, Oregon -- was affected by the elevated TDG of the surface water. Depth-compensated hyporheicmore » TDG did not exceed 103% at the Multnomah Falls site. However, in the Ives Island area, chum salmon redds were exposed to TDG greater than 103% for more than 600 hours. In response to river depth fluctuations, TDG varied significantly in the Ives Island area, suggesting increased interaction between the hyporheic zone and surface water at that site. We conclude from this study that the interaction between surface water and the hyporheic zone affects the concentration of TDG within the hyporheic zone directly via physical mixing as well as indirectly by altering water chemistry and thus dissolved gas solubility. These interactions are important considerations when estimating TDG exposure within egg pocket environments, facilitating improved exposure estimates, and enabling managers to optimize recovery strategies.« less

Nature of water and hydrogen reactions on transition metal surfaces studied by scanning tunneling microscopy

NASA Astrophysics Data System (ADS)

Tatarkhanov, Mouslim Magomedovich

Scanning Tunneling Microscopy (STM) has already been established as a tool for the investigation of simple reaction mechanisms. In this work I present results of two parallel studies using STM: first, hydrogen on Ru(0001) surface and second, water on Ru(0001) and Pd(111). In both studies initial stages of adsorption up to saturation monolayer coverage were investigated by variable temperature scanning tunneling microscopy (VT STM). The first step of the hydrogen adsorption study was the identification and characterization of the various coverage structures on clean Ru(0001). Hydrogen was found to adsorb dissociatively forming ( 3x3 )R30°, 3 domains of (2x1), (2x2)-3H and (1x1) for increasing coverages of theta=0.3 ML, 0.5 ML, 0.75 ML and 0.1 ML respectively. Some of these structures were observed to coexist at intermediate coverage values. In addition effects of impurities such as oxygen and carbon on hydrogen adsorption has been discussed. Next, near saturation coverage the interesting mechanism of how H 2 dissociates and binds to the surface of Ru(0001) has been observed. We found that the H2 dissociation takes place only on Ru sites where the metal atom is not bound to any H atom. Such active sites are formed when at least 3 H-vacancies aggregate by thermal diffusion. Sites formed by single H-vacancies (i.e. unoccupied Ru sites) or pairs of adjoining vacancies were found to be unreactive toward H2. H-vacancies were observed as single entities diffusing on the surface at 50 K and able to form transient triangular shaped aggregations where H2 molecules dissociated. It was found that the diffusion and aggregation of the H-vacancies is essential in creation of active sites where dissociative adsorption of hydrogen occurs. The first step of water studies was the initial stages of growth of water on the hexagonal surfaces of Pd(111) and Ru(0001) in the temperature range between 40 K and 130 K. In addition, DFT calculations and STM image simulations were used to validate the models. Below 130 K water dissociation does not occur at any appreciable rate and only molecular films are formed. At these temperatures the kinetics of water growth leads to structures where the molecules bind to the metal substrate through the O-lone pair while making 3 H-bonds with neighboring molecules and form clusters of hexagonal units with a honeycomb structure. This bonding geometry imposes limitations to the size of the clusters, with unsaturated H-bonds confined to the cluster periphery. It is found that growth proceeds by attachement of water molecules to the edge of the clusters by H-bonds. These molecules bind only weakly to the metal substrate and can hop around the edges. Comparison of DFT and STM image calculations with experiments shows that on Pd the edge-attached molecules form two different structures, a metastable one where the molecule is elevated by 2.7 A with respect to the cluster molecules, and another where they are elevated by only 0.4 A. On Ru only the less elevated (0.4 A higher) edge-attached molecules are observed. In next final step, water structures on Ru(0001) were studied at temperatures above 140K. STM findings were backed by x-ray absorption spectroscopy. Additional DFT calculations and STM simulations provided validation of proposed models. It was found that while undissociated water layers are metastable below 140 K, heating above this temperature produces drastic transformations whereby a fraction of the water molecules partially dissociate and form mixed H 2O-OH structures. XPS and XAS revealed the presence of hydroxyl groups with their O-H bond essentiallymostly parallel to the surface. STM images show that the mixed H2O-OH structures consist of long narrow stripes aligned with the three crystallographic directions perpendicular to the close-packed atomic rows of the Ru(0001) substrate. The internal structure of the stripes is a honeycomb network of H-bonded water and hydroxyl species. We found that the metastable low temperature molecular phase can also be converted to a mixed H2O-OH phase through excitation by the tunneling electrons when their energy is 0.5 eV or higher above the Fermi level. Structural models based on the STM images were used for Density Functional Theory optimizations of the stripes geometry. The optimized geometry was then utilized to calculate STM images for comparison with the experiment.

Spring sapping origin of the enigmatic relict valleys of Cape Cod and Martha's Vineyard and Nantucket Islands, Massachusetts

USGS Publications Warehouse

Uchupi, E.; Oldale, R.N.

1994-01-01

Steep-sided, flat-floored linear valleys that lack well developed tributaries and end in amphitheater-like heads are eroded on the outwash plains of Cape Cod, Martha's Vineyard and Nantucket Island. The valleys are restricted from the mid to the distal ends of the outwash plains and show no connection to possible water sources at the updip end of the plains. Their distribution and morphology lead us to propose that they were eroded by groundwater seeps fed by proglacial lakes (the high hydrostatic heads of the lakes led to the elevation of the water table) dammed by the outwash plains and associated moraines. The valleys on Cape Cod were initiated by seeps along the foreset surfaces of sandy deltas emplaced in lakes in Nantucket Sound and Cape Cod Bay after these lakes drained. Those on Martha's Vineyard and Nantucket islands were either eroded by seeps at the distal ends of outwash plain wedges emplaced atop the subareal continental shelf south of the islands or along the foreset surfaces of sandy deltas emplaced on a lake behind a peripheral crustal bulge south of the glacial front. Valley erosion terminated after the lakes were drained and the water table dropped. ?? 1994.

Sources, behaviors and degradation of dissolved organic matter in the East China Sea

NASA Astrophysics Data System (ADS)

Chen, Yan; Yang, Gui-Peng; Liu, Li; Zhang, Peng-Yan; Leng, Wei-Song

2016-03-01

Concentrations of dissolved organic carbon (DOC), dissolved inorganic nitrogen (DIN), dissolved organic nitrogen (DON) and its major compound classes-total hydrolysable amino acids (THAA) were measured at 4 cross-shelf transects of the East China Sea in July 2011. Surface concentrations of DOC, DIN, DON and THAA at the nearshore stations were mostly in excess of those found at the offshore sites, indicating either substantial autochthonous production or allochthonous inputs from the Changjiang River. The vertical distributions of DOC, DON and THAA showed similar trends with higher values in the surface layer, whereas the elevated concentrations of DIN were observed in the bottom layer. Major constituents of THAA presented in the study area were glycine, serine, alanine, glutamic acid, aspartic acid and valine. The mole percentages of neutral amino acids increased from surface water to bottom water, whereas acidic and hydroxy amino acids decreased with the water depth. Concentrations of DOC and THAA were negatively correlated to the ΔDIN values (the difference between the real concentration and theoretical concentration), respectively, indicating the coupling relation between dissolved organic matter (DOM) remineralization and nutrient regeneration in the water column. The C/N ratios in the water column exhibited different characteristics with elevated values appearing in the surface and bottom layers. Box and whisker plots showed that both degradation index (DI) values and THAA yields displayed a decreasing trend from the surface layer to the bottom layer, implying increasing degradation with the water depth. Our data revealed that glycine and alanine increased in relative abundance with decreasing DI, while tyrosine, valine, phenylalanine and isoleucine increased with increasing DI.

Dynamic perennial firn aquifer on an Arctic glacier

NASA Astrophysics Data System (ADS)

Christianson, Knut; Kohler, Jack; Alley, Richard B.; Nuth, Christopher; Pelt, Ward J. J.

2015-03-01

Ice-penetrating radar and GPS observations reveal a perennial firn aquifer (PFA) on a Svalbard ice field, similar to those recently discovered in southeastern Greenland. A bright, widespread radar reflector separates relatively dry and water-saturated firn. This surface, the phreatic firn water table, is deeper beneath local surface elevation maxima, shallower in surface lows, and steeper where the surface is steep. The reflector crosscuts snow stratigraphy; we use the apparent deflection of accumulation layers due to the higher dielectric permittivity below the water table to infer that the firn pore space becomes progressively more saturated as depth increases. Our observations indicate that PFAs respond rapidly (subannually) to surface forcing, and are capable of providing significant input to the englacial hydrology system.

Forecasting landscape effects of Mississippi River diversions on elevation and accretion in Louisiana deltaic wetlands under future environmental uncertainty scenarios

USGS Publications Warehouse

Wang, Hongqing; Steyer, Gregory D.; Couvillion, Brady R.; John M. Rybczyk,; Beck, Holly J.; William J. Sleavin,; Ehab A. Meselhe,; Mead A. Allison,; Ronald G. Boustany,; Craig J. Fischenich,; Victor H. Rivera-Monroy,

2014-01-01

Large sediment diversions are proposed and expected to build new wetlands to alleviate the extensive wetland loss (5,000 km2) affecting coastal Louisiana during the last 78 years. Current assessment and prediction of the impacts of sediment diversions have focused on the capture and dispersal of both water and sediment on the adjacent river side and the immediate outfall marsh area. However, little is known about the effects of sediment diversions on existing wetland surface elevation and vertical accretion dynamics in the receiving basin at the landscape scale. In this study, we used a spatial wetland surface elevation model developed in support of Louisiana's 2012 Coastal Master Plan to examine such landscape-scale effects of sediment diversions. Multiple sediment diversion projects were incorporated in the model to simulate surface elevation and vertical accretion for the next 50 years (2010-2060) under two environmental (moderate and less optimistic) scenarios. Specifically, we examined landscape-scale surface elevation and vertical accretion trends under diversions with different geographical locations, diverted discharge rates, and geomorphic characteristics of the receiving basin. Model results indicate that small diversions (< 283 m3 s-1) tend to have limited effects of reducing landscape-scale elevation loss (< 3%) compared to a future without action (FWOA) condition. Large sediment diversions (> 1,500 m3 s-1) are required to achieve landscape-level benefits to promote surface elevation via vertical accretion to keep pace with rising sea level.

Evaluation of airborne lidar elevation surfaces for propagation of coastal inundation: the importance of hydrologic connectivity

USGS Publications Warehouse

Poppenga, Sandra K.; Worstell, Bruce B.

2015-01-01

Detailed information about coastal inundation is vital to understanding dynamic and populated areas that are impacted by storm surge and flooding. To understand these natural hazard risks, lidar elevation surfaces are frequently used to model inundation in coastal areas. A single-value surface method is sometimes used to inundate areas in lidar elevation surfaces that are below a specified elevation value. However, such an approach does not take into consideration hydrologic connectivity between elevation grids cells resulting in inland areas that should be hydrologically connected to the ocean, but are not. Because inland areas that should drain to the ocean are hydrologically disconnected by raised features in a lidar elevation surface, simply raising the water level to propagate coastal inundation will lead to inundation uncertainties. We took advantage of this problem to identify hydrologically disconnected inland areas to point out that they should be considered for coastal inundation, and that a lidar-based hydrologic surface should be developed with hydrologic connectivity prior to inundation analysis. The process of achieving hydrologic connectivity with hydrologic-enforcement is not new, however, the application of hydrologically-enforced lidar elevation surfaces for improved coastal inundation mapping as approached in this research is innovative. In this article, we propagated a high-resolution lidar elevation surface in coastal Staten Island, New York to demonstrate that inland areas lacking hydrologic connectivity to the ocean could potentially be included in inundation delineations. For inland areas that were hydrologically disconnected, we evaluated if drainage to the ocean was evident, and calculated an area exceeding 11 ha (~0.11 km2) that could be considered in inundation delineations. We also assessed land cover for each inland area to determine the type of physical surfaces that would be potentially impacted if the inland areas were considered as part of a coastal inundation. A visual analysis indicated that developed, medium intensity and palustrine forested wetland land cover types would be impacted for those locations. This article demonstrates that hydrologic connectivity is an important factor to consider when inundating a lidar elevation surface. This information is needed for inundation monitoring and management in sensitive coastal regions.

Modeling river discharge and sediment transport in the Wax Lake-Atchafalaya basin with remote sensing parametrization.

NASA Astrophysics Data System (ADS)

Simard, M.; Liu, K.; Denbina, M. W.; Jensen, D.; Rodriguez, E.; Liao, T. H.; Christensen, A.; Jones, C. E.; Twilley, R.; Lamb, M. P.; Thomas, N. A.

2017-12-01

Our goal is to estimate the fluxes of water and sediments throughout the Wax Lake-Atchafalaya basin. This was achieved by parametrization of a set of 1D (HEC-RAS) and 2D (DELFT3D) hydrology models with state of the art remote sensing measurements of water surface elevation, water surface slope and total suspended sediment (TSS) concentrations. The model implementations are spatially explicit, simulating river currents, lateral flows to distributaries and marshes, and spatial variations of sediment concentrations. Three remote sensing instruments were flown simultaneously to collect data over the Wax Lake-Atchafalaya basin, and along with in situ field data. A Riegl Lidar was used to measure water surface elevation and slope, while the UAVSAR L-band radar collected data in repeat-pass interferometric mode to measure water level change within adjacent marshes and islands. These data were collected several times as the tide rose and fell. AVRIS-NG instruments measured water surface reflectance spectra, used to estimate TSS. Bathymetry was obtained from sonar transects and water level changes were recorded by 19 water level pressure transducers. We used several Acoustic Doppler Current Profiler (ADCP) transects to estimate river discharge. The remotely sensed measurements of water surface slope were small ( 1cm/km) and varied slightly along the channel, especially at the confluence with bayous and the intra-coastal waterway. The slope also underwent significant changes during the tidal cycle. Lateral fluxes to island marshes were mainly observed by UAVSAR close to the distributaries. The extensive remote sensing measurements showed significant disparity with the hydrology model outputs. Observed variations in water surface slopes were unmatched by the model and tidal wave propagation was much faster than gauge measurements. The slope variations were compensated for in the models by tuning local lateral fluxes, bathymetry and riverbed friction. Overall, the simpler 1D model could best simulate observed tidal wave propagation and water surface slope. The complexity of the 2D model requires further quantification of parameter sensitivity and improvement of the parametrization routine.

Factors that influence the hydrologic recovery of wetlands in the Northern Tampa Bay area, Florida

USGS Publications Warehouse

Metz, P.A.

2011-01-01

Although of less importance than the other three factors, a low-lying topographical position benefited the hydrologic condition of several of the study wetlands (S-68 Cypress and W-12 Cypress) both before and after the reductions in groundwater withdrawals. Compared to wetlands in a higher topographical position, those in a lower position had longer hydroperiods because of their greater ability to receive more runoff from higher elevation wetlands and to establish surface-water connections to other isolated wetlands and surface-water bodies through low-lying surface-water channels during wet conditions. In addition, wetlands in low-lying areas benefited from groundwater inflow when groundwater levels were higher than wetland water levels.

The use of fluoride as a natural tracer in water and the relationship to geological features: Examples from the Animas River Watershed, San Juan Mountains, Silverton, Colorado

USGS Publications Warehouse

Bove, D.J.; Walton-Day, K.; Kimball, B.A.

2009-01-01

Investigations within the Silverton caldera, in southwestern Colorado, used a combination of traditional geological mapping, alteration-assemblage mapping, and aqueous geochemical sampling that showed a relationship between geological and hydrologic features that may be used to better understand the provenance and evolution of the water. Veins containing fluorite, huebnerite, and elevated molybdenum concentrations are temporally and perhaps genetically associated with the emplacement of high-silica rhyolite intrusions. Both the rhyolites and the fluorite-bearing veins produce waters containing elevated concentrations of F-, K and Be. The identification of water samples with elevated F/Cl molar ratios (> 10) has also aided in the location of water draining F-rich sources, even after these waters have been diluted substantially. These unique aqueous geochemical signatures can be used to relate water chemistry to key geological features and mineralized source areas. Two examples that illustrate this relationship are: (1) surface-water samples containing elevated F-concentrations (> 1.8 mg/l) that closely bracket the extent of several small high-silica rhyolite intrusions; and (2) water samples containing elevated concentrations of F-(> 1.8 mg/ l) that spatially relate to mines or areas that contain late-stage fluorite/huebnerite veins. In two additional cases, the existence of high F-concentrations in water can be used to: (1) infer interaction of the water with mine waste derived from systems known to contain the fluorite/huebnerite association; and (2) relate changes in water quality over time at a high elevation mine tunnel to plugging of a lower elevation mine tunnel and the subsequent rise of the water table into mineralized areas containing fluorite/huebnerite veining. Thus, the unique geochemical signature of the water produced from fluorite veins indicates the location of high-silica rhyolites, mines, and mine waste containing the veins. Existence of high F-concentrations along with K and Be in water in combination with other geological evidence may be used to better understand the provenance of the water. ?? 2009 AAG/Geological Society of London.

Simulations of the effects of U.S. Highway 231 and the proposed Montgomery outer loop on flooding in the Catoma Creek and Little Catoma Creek Basins near Montgomery, Alabama

USGS Publications Warehouse

Hedgecock, T. Scott

1999-01-01

A two-dimensional finite-element surface-water model was used to study the effects of U.S. Highway 231 and the proposed Montgomery Outer Loop on the water-surface elevations and flow distributions during flooding in the Catoma Creek and Little Catoma Creek Basins southeast of Montgomery, Montgomery County, Alabama. The effects of flooding were simulated for two scenarios--existing and proposed conditions--for the 100- and 500-year recurrence intervals. The first scenario was to model the existing bridge and highway configuration for U.S. Highway 231 and the existing ponds that lie just upstream from this crossing. The second scenario was to model the proposed bridge and highway configuration for the Montgomery Outer Loop and the Montgomery Loop Interchange at U.S. Highway 231 as well as the proposed modifications to the ponds upstream. Simulation of floodflow for Little Catoma Creek for the existing conditions at U.S. Highway 231 indicates that, for the 100-year flood, 54 percent of the flow (8,140 cubic feet per second) was conveyed by the northernmost bridge, 21 percent (3,130 cubic feet per second) by the middle bridge, and 25 percent (3,780 cubic feet per second) by the southernmost bridge. No overtopping of U.S. Highway 231 occurred. However, the levees of the catfish ponds immediately upstream from the crossing were completely overtopped. The average water- surface elevations for the 100-year flood at the upstream limits of the study reach for Catoma Creek and Little Catoma Creek were 216.9 and 218.3 feet, respectively. For the 500-year flood, the simulatin indicates that 51 percent of the flow (11,200 cubic feet per second) was conveyed by the northernmost bridge, 25 percent (5,480 cubic feet per second) by the middle bridge, and 24 percent (5,120 cubic feet per second) by the southernmost bridge. The average water0surface elevations for the 500-year flood at the upstream limits of the study reach for Catoma Creek and Little Catoma Creek were 218.2 and 219.5 feet, respectively. For the 500-year flood, no overtopping of U.S. Highway 231 occurred. Simulation of the 100-year floodflow for Little Catoma Creek for the proposed conditions indicates that, for the existing bridges on U.S. Highway 231, 54 percent of the flow (8,190 cubic feet per second) was conveyed by the northernmost bridge, 22 percent (3,350 cubic feet per second) by the middle bridge, and 24 percent (3,490 cubic feet per second) by the southernmost bridge. The two proposed relief bridges on the Montgomery Outer Loop upstream from the proposed remaining catfish ponds conveyed about 7,750 cubic feet per second (3,400 cubic feet per second for the west relief bridge and 4,350 cubic feet per second for the east relief bridge) with an average depth of flow of about 7 feet. The average water-surface elevation at the upstream limit of the study reach for Little Catoma Creek was 218.8 feet, which is about 0.5 foot higher than the average water-surface elevation for the existing conditions. For the 100-year flood, there was no overtopping of either U.S. Highway 231 or the Montgomery Outer Loop. However, the levees of the proposed remaining catfish ponds were completely overtopped. For the Montgomery Outer Loop crossing of Catoma Creek, simulation of the 100-year floodflow indicates that about 58 percent of the flow (14,100 cubic feet per second) was conveyed by the proposed main channel bridge and 42 percent (10,200 cubic feet per second) by the proposed relief bridge. The average water-surface elevation at the upstream limit of the study reach for Catoma Creek was 216.9 feet, which is the same as the water-surface elevation for the existing conditions. Results of model simulations for the 500-year flood for the proposed conditions indicate that there was no overtopping on either U.S. Highway 231 or the Montgomery Outer Loop. For the existing bridges on U.S. Highway 231, 42 percent of the flow (11,300 cubic feet per second) was conveyed by the northernmost bridge

An Assessment of Hydrology, Fluvial Geomorphology, and Stream Ecology in the Cardwell Branch Watershed, Nebraska, 2003-04

USGS Publications Warehouse

Rus, David L.; Dietsch, Benjamin J.; Woodward, Brenda K.; Fry, Beth E.; Wilson, Richard C.

2007-01-01

An assessment of the 16.3-square-mile Cardwell Branch watershed characterized the hydrology, fluvial geomorphology, and stream ecology in 2003-04. The study - performed by the U.S. Geological Survey in cooperation with the City of Lincoln, Nebraska, and the Lower Platte South Natural Resources District - focused on the 7.7-square-mile drainage downstream from Yankee Hill Reservoir. Hydrologic and hydraulic models were developed using the Hydrologic Modeling System (HEC-HMS) and River Analysis System (HEC-RAS) of the U.S. Army Corps of Engineers Hydraulic Engineering Center. Estimates of streamflow and water-surface elevation were simulated for 24-hour-duration design rainstorms ranging from a 50-percent frequency to a 0.2-percent frequency. An initial HEC-HMS model was developed using the standardized parameter estimation techniques associated with the Soil Conservation Service curve number technique. An adjusted HEC-HMS model also was developed in which parameters were adjusted in order for the model output to better correspond to peak streamflows estimated from regional regression equations. Comparisons of peak streamflow from the two HEC-HMS models indicate that the initial HEC-HMS model may better agree with the regional regression equations for higher frequency storms, and the adjusted HEC-HMS model may perform more closely to regional regression equations for larger, rarer events. However, a lack of observed streamflow data, coupled with conflicting results from regional regression equations and local high-water marks, introduced considerable uncertainty into the model simulations. Using the HEC-RAS model to estimate water-surface elevations associated with the peak streamflow, the adjusted HEC-HMS model produced average increases in water-surface elevation of 0.2, 1.1, and 1.4 feet for the 50-, 1-, and 0.2-percent-frequency rainstorms, respectively, when compared to the initial HEC-HMS model. Cross-sectional surveys and field assessments conducted between November 2003 and March 2004 indicated that Cardwell Branch and its unnamed tributary appear to be undergoing incision (the process of downcutting) (with three locations showing 2 or more feet of streambed incision since 1978) that is somewhat moderated by the presence of grade controls and vegetation along the channel profile. Although streambank failures were commonly observed, 96 percent of the surveyed cross sections were classified as stable by planar and rotational failure analysis-a disconnect that may have been the result of assumed soil properties. Two process-based classification systems each indicated that the reaches within the study area were incising and widening, and the Rosgen classification system characterized the streams as either type E6 or B6c. E6 channels are hydraulically efficient with low width-depth ratios, low to moderate sinuosity, and gentle to moderately steep slopes. B6c channels typically are incised with low width-depth ratios maintained by riparian vegetation, low bedload transport, and high washload transport. No obvious nickpoints (interruption or break in slope) were observed in the thalweg profile (line of maximum streambed descent), and the most acute incision occurred immediately downstream from bridges and culverts. Nine water-quality samples were collected between August 2003 and November 2004 near the mouth of the watershed. Sediment-laden rainfall-runoff substantially affected the water quality in Cardwell Branch, leading to greater biochemical and chemical oxygen demands as well as increased concentrations of several nutrient, bacteriological, sediment, and pesticide constituents. The storage of rainfall runoff in Yankee Hill Reservoir may prolong the presence of runoff-related constituents downstream. Across the study area, there was a lack of habitat availability for aquatic biota because of low dissolved oxygen levels and low streamflows or dry channels. In August 2003, the aquatic community near the mouth of

Modeling Lake Storage Dynamics to support Arctic Boreal Vulnerability Experiment (ABoVE)

NASA Astrophysics Data System (ADS)

Vimal, S.; Lettenmaier, D. P.; Smith, L. C.; Smith, S.; Bowling, L. C.; Pavelsky, T.

2017-12-01

The Arctic and Boreal Zone (ABZ) of Canada and Alaska includes vast areas of permafrost, lakes, and wetlands. Permafrost thawing in this area is expected to increase due to the projected rise of temperature caused by climate change. Over the long term, this may reduce overall surface water area, but in the near-term, the opposite is being observed, with rising paludification (lake/wetland expansion). One element of NASA's ABoVE field experiment is observations of lake and wetland extent and surface elevations using NASA's AirSWOT airborne interferometric radar, accompanied by a high-resolution camera. One use of the WSE retrievals will be to constrain model estimates of lake storage dynamics. Here, we compare predictions using the lake dynamics algorithm within the Variable Infiltration Capacity (VIC) land surface scheme. The VIC lake algorithm includes representation of sub-grid topography, where the depth and area of seasonally-flooded areas are modeled as a function of topographic wetness index, basin area, and slope. The topography data used is from a new global digital elevation model, MERIT-DEM. We initially set up VIC at sites with varying permafrost conditions (i.e., no permafrost, discontinuous, continuous) in Saskatoon and Yellowknife, Canada, and Toolik Lake, Alaska. We constrained the uncalibrated model with the WSE at the time of the first ABoVE flight, and quantified the model's ability to predict WSE and ΔWSE during the time of the second flight. Finally, we evaluated the sensitivity of the VIC-lakes model and compared the three permafrost conditions. Our results quantify the sensitivity of surface water to permafrost state across the target sites. Furthermore, our evaluation of the lake modeling framework contributes to the modeling and mapping framework for lake and reservoir storage change evaluation globally as part of the SWOT mission, planned for launch in 2021.

Use of reconstituted waters to evaluate effects of elevated major ions associated with mountaintop coal mining on freshwater invertebrates

USGS Publications Warehouse

Kunz, James L.; Conley, Justin M.; Buchwalter, David B.; ,; Teresa, J.; Kemble, Nile E.; Wang, Ning; Ingersoll, Christopher G.

2013-01-01

In previous laboratory chronic 7-d toxicity tests conducted with the cladoceran Ceriodaphnia dubia, surface waters collected from Appalachian sites impacted by coal mining have shown toxic effects associated with elevated total dissolved solids (TDS). The objective of the present study was to evaluate the effects of elevated major ions in chronic laboratory tests with C. dubia (7-d exposure), a unionid mussel (Lampsilis siliquoidea; 28-d exposure), an amphipod (Hyalella azteca; 28-d exposure), and a mayfly (Centroptilum triangulifer; 35-d exposure) in 3 reconstituted waters designed to be representative of 3 Appalachian sites impacted by coal mining. Two of the reconstituted waters had ionic compositions representative of alkaline mine drainage associated with mountaintop removal and valley fill-impacted streams (Winding Shoals and Boardtree, with elevated Mg, Ca, K, SO4, HCO3), and a third reconstituted water had an ionic composition representative of neutralized mine drainage (Upper Dempsey, with elevated Na, K, SO4, and HCO3). The waters with similar conductivities but, with different ionic compositions had different effects on the test organisms. The Winding Shoals and Boardtree reconstituted waters were consistently toxic to the mussel, the amphipod, and the mayfly. In contrast, the Upper Dempsey reconstituted water was toxic to the mussel, the amphipod, and the cladoceran but was not toxic to the mayfly. These results indicate that, although elevated TDS can be correlated with toxicity, the specific major ion composition of the water is important. Moreover, the choice of test organism is critical, particularly if a test species is to be used as a surrogate for a range of faunal groups.

USGS reservoir and lake gage network: Elevation and volumetric contents data, and their uses

USGS Publications Warehouse

Kroska, Anita C.

2014-01-01

In December of 2013, the U.S. Geological Survey (USGS) marked the 125th anniversary of the installation of its first official water level and streamflow gage, on the Rio Grande at Embudo, New Mexico. The gage was installed because it was recognized that water data were important to expanding irrigation needs. The USGS is a federal agency that provides nationally consistent and unbiased surface-water elevation and streamflow data at more than 10,000 gaging locations in the United States, about 330 of which are lakes and reservoirs (referred to hereafter as lakes) (Figure 1). The job of quantifying water resources, whether lakes, streams, or aquifers, is fundamental to proper water management and conservation of resources.

Simulated and measured water levels and estimated water-level changes in the Albuquerque area, central New Mexico, 1950-2012

USGS Publications Warehouse

Rice, Steven E.; Oelsner, Gretchen P.; Heywood, Charles E.

2014-01-01

and again for 2008. Both the water-table elevations and production-zone hydraulic heads declined over time with the largest change occurring between 1970 and 1980, which was a period of rapid population growth and groundwater use. Declines in the water-table elevations and production-zone hydraulic heads are focused around major pumping centers and are largest in the production zone. Hydrographs from nine production-zone piezometers in the modeled area indicated varying responses to the increased use of surface-water diversions during 2009–12, with responses related to the locations of the wells within the study area and their proximity to pumping centers and the Rio Grande.

Comparison of Bacteria and Color Removal in Two Surface Waters using Nanofiltration

EPA Science Inventory

Small communities typically have small budgets, but big issues to deal with in providing safe drinking water and protecting public health. Communities in remote locations are frequently faced with elevated levels of naturally-occurring organic matter (NOM) that combine with chlo...

Comparison of Bacteria and Color Removal in Two Surface Waters using Nanofiltration

EPA Science Inventory

Small communities typically have small budgets, but big issues to deal with in providing safe drinking water and protecting public health. Communities in remote locations are frequently faced with elevated levels of naturally-occurring organic matter (NOM) that combine with chlor...

Delineating wetland catchments and modeling hydrologic connectivity using lidar data and aerial imagery

EPA Science Inventory

In traditional watershed delineation and topographic modeling, surface depressions are generally treated as spurious features and simply removed from a digital elevation model (DEM) to enforce flow continuity of water across the topographic surface to the watershed outlets. In re...

A simple hypothesis of how leaf and canopy-level transpiration and assimilation respond to elevated CO2 reveals distinct response patterns between disturbed and undisturbed vegetation

NASA Astrophysics Data System (ADS)

Donohue, Randall J.; Roderick, Michael L.; McVicar, Tim R.; Yang, Yuting

2017-01-01

Elevated CO2 increases leaf-level water-use efficiency (ω) almost universally. How canopy-level transpiration and assimilation fluxes respond to increased ω is currently unclear. We present a simple, resource-availability-based hypothesis of how equilibrium (or mature) leaf and canopy transpiration and assimilation rates, along with leaf area index (L), respond to elevated CO2. We quantify this hypothesis in the form of a model and test it against observations from eight Free Air CO2 Enrichment sites that span a wide range of resource availabilities. Sites were grouped according to vegetation disturbance status. We find the model adequately accounts for the responses of undisturbed vegetation (R2 = 0.73, 11% error) but cannot account for the responses of disturbed vegetation (R2 = 0.47, 17% error). At undisturbed sites, the responses of L and of leaf and canopy transpiration vary predictably (7% error) with resource availability, whereas the leaf assimilation response is less predictable. In contrast, the L and transpiration flux responses at the disturbed (mostly forested) sites are highly variable and are not strongly related to resource availability. Initial analyses suggest that they are more strongly related to regrowth age than to resource availability. We conclude that (i) our CO2 response hypothesis is valid for capturing the responses of undisturbed vegetation only, (ii) that the responses of disturbed vegetation are distinctly different from undisturbed vegetation, and (iii) that these differences need to be accounted for when predicting the effects of elevated CO2 on land surface processes generally, and on leaf area and water fluxes in particular.

Seasonal changes in peatland surface elevation recorded at GPS stations in the Red Lake Peatlands, northern Minnesota, USA

USGS Publications Warehouse

Reeve, A.S.; Glaser, P.H.; Rosenberry, Donald O.

2013-01-01

Northern peatlands appear to hold large volumes of free-phase gas (e.g., CH4 and CO2), which has been detected by surface deformations, pore pressure profiles, and electromagnetic surveys. Determining the gas content and its impact in peat is challenging because gas storage depends on both the elastic properties of the peat matrix and the buoyant forces exerted by pore fluids. We therefore used a viscoelastic deformation model to estimate these variables by adjusting model runs to reproduce observed changes in peat surface elevation within a 1300 km2 peatland. A local GPS network documented significant changes in surface elevations throughout the year with the greatest vertical displacements associated with rapid changes in peat water content and unloadings due to melting of the winter snowpack. These changes were coherent with changes in water table elevation and also abnormal pore pressure changes measured by nests of instrumented piezometers. The deformation model reproduced these changes when the gas content was adjusted to 10% of peat volume, and Young's modulus was varied between 5 and 100 kPa as the peat profile shifted from tension to compression. In contrast, the model predicted little peat deformation when the gas content was 3% or lower. These model simulations are consistent with previous estimates of gas volume in northern peatlands and suggest an upper limit of gas storage controlled by the elastic moduli of the peat fabric.

Miocene Surface Temperature Estimates of the Southern Altiplano and Their Implications for Surface Uplift

NASA Astrophysics Data System (ADS)

Smith, J. J.; Garzione, C.; Higgins, P.; MacFadden, B.; Auerbach, D.; Croft, D.

2008-12-01

Surface temperature estimates derived from stable isotopes can be used to infer tectonic history and subsequent climate change of the Bolivian Altiplano. This study compares surface temperatures calculated from two fossil localities (Cerdas and Quehua) that span middle to late Miocene age in the southern Altiplano. Temperatures were calculated using the approach of Zanazzi et al. (2007) by comparing the stable isotopes of fossil tooth enamel and concurrent fossilized bones. The δ18O of the surface water is derived from fossil tooth enamel that mineralized at a known mammal body temperature. Surface water compositions are then used to calculate the temperature at which fossil bones were diagenetically altered, using the assumption that most alteration of fossil bones occurs within 20 to 50 thousand years of deposition. These surface temperature estimates can be used as a proxy for the amount of surface uplift based on modern temperature lapse rates. The vertical surface temperature gradient observed in the present-day Andes is about 4.66°C/km. Changes in surface elevations may explain large temperature changes reflected throughout the middle to late Miocene. Cerdas and Quehua, at modern elevations of ~3800m, have fossil records that include teeth and diagenetically altered bones that were deposited before and during a period of inferred rapid surface uplift of the northern Altiplano of 2.5 ± 1 km between ~10 to 6 Ma. Both sites have been dated by magnetostratigraphy and by 40Ar/39Ar dating of tuffs: Cerdas dates from 16.358 ± 0.071 to 15.105 ± 0.073 Ma, and Quehua ranges from 12.611 ± 0.034 to 6.844 ± 0.386 Ma. The close proximity and current elevation of Cerdas (21.9°S, 3800m) and Quehua (20.0°S, 3800m) allows for the assumption that their elevations were closely correlated through time. Thus the temperatures and elevation estimates derived from each location are assumed to reflect the larger extent of the southern Altiplano. If analysis of fossil enamel and bone from these locations shows a significant temperature decrease from middle to late Miocene, this would support the hypothesis of rapid regional surface uplift of the Altiplano during the late Miocene due to loss of the dense lower crust and/or lithospheric mantle.

Spatial extent and temporal variability of Greenland firn aquifers detected by ground and airborne radars

NASA Astrophysics Data System (ADS)

Miège, Clément; Forster, Richard R.; Brucker, Ludovic; Koenig, Lora S.; Solomon, D. Kip; Paden, John D.; Box, Jason E.; Burgess, Evan W.; Miller, Julie Z.; McNerney, Laura; Brautigam, Noah; Fausto, Robert S.; Gogineni, Sivaprasad

2016-12-01

We document the existence of widespread firn aquifers in an elevation range of 1200-2000 m, in the high snow-accumulation regions of the Greenland ice sheet. We use NASA Operation IceBridge accumulation radar data from five campaigns (2010-2014) to estimate a firn-aquifer total extent of 21,900 km2. We investigate two locations in Southeast Greenland, where repeated radar profiles allow mapping of aquifer-extent and water table variations. In the upper part of Helheim Glacier the water table rises in spring following above-average summer melt, showing the direct firn-aquifer response to surface meltwater production changes. After spring 2012, a drainage of the firn-aquifer lower margin (5 km) is inferred from both 750 MHz accumulation radar and 195 MHz multicoherent radar depth sounder data. For 2011-2014, we use a ground-penetrating radar profile located at our Ridgeline field site and find a spatially stable aquifer with a water table fluctuating less than 2.5 m vertically. When combining radar data with surface topography, we find that the upper elevation edge of firn aquifers is located directly downstream of locally high surface slopes. Using a steady state 2-D groundwater flow model, water is simulated to flow laterally in an unconfined aquifer, topographically driven by ice sheet surface undulations until the water encounters crevasses. Simulations suggest that local flow cells form within the Helheim aquifer, allowing water to discharge in the firn at the steep-to-flat transitions of surface topography. Supported by visible imagery, we infer that water drains into crevasses, but its volume and rate remain unconstrained.

Surface Water Connectivity, Flow Pathways and Water Level Fluctuation in a Cold Region Deltaic Ecosystem

NASA Astrophysics Data System (ADS)

Peters, D. L.; Niemann, O.; Skelly, R.; Monk, W. A.; Baird, D. J.

2017-12-01

The Peace-Athabasca Delta (PAD) is a 6000 km2 deltaic floodplain ecosystem of international importance (Wood Buffalo National Park, Ramsar Convention, UNESCO World Heritage, and SWOT satellite water level calibration/validation site). The low-relief floodplain formed at the confluence of the Peace, Athabasca and Birch rivers with Lake Athabasca. More than 1000 wetland and lake basins have varying degrees of connectivity to the main flow system. Hydroperiod and water storage is influenced by ice-jam and open-water inundations and prevailing semi-arid climate that control water drawdown. Prior studies have identified pathways of river-to-wetland floodwater connection and historical water level fluctuation/trends as a key knowledge gaps, limiting our knowledge of deltaic ecosystem status and potential hydroecological responses to climate change and upstream water alterations to flow contributions. To address this knowledge gap, surface elevation mapping of the PAD has been conducted since 2012 using aerial remote sensing Light Detection and Ranging (LiDAR), plus thousands of ground based surface and bathymetric survey points tied to Global Positioning System (GPS) were obtained. The elevation information was used to develop a high resolution digital terrain model to simulate and investigate surface water connectivity. Importantly, the surveyed areas contain a set of wetland monitoring sites where ground-based surface water connectivity, water level/depth, water quality, and aquatic ecology (eg, vegetation, macroinvertebrate and muskrat) have been examined. The goal of this presentation is to present an assessment of: i) surface water fluctuation and connectivity for PAD wetland sites; ii) 40+ year inter-annual hydroperiod reconstruction for a perched basin using a combination of field measurements, remote sensing estimates, and historical documents; and iii) outline an approach to integrate newly available hydro-bio-geophysical information into a novel, multi-platform aquatic ecosystem observation system (eg, upcoming SWOT satellite and newly developed DNA metabarcoding) for cold regions deltaic wetlands, that will enable the assessment of floodplain ecosystem change resulting from multiple stressors, such as climate change and upstream development (hydroelectric and mining).

Predicting Fish Growth Potential and Identifying Water Quality Constraints: A Spatially-Explicit Bioenergetics Approach

NASA Astrophysics Data System (ADS)

Budy, Phaedra; Baker, Matthew; Dahle, Samuel K.

2011-10-01

Anthropogenic impairment of water bodies represents a global environmental concern, yet few attempts have successfully linked fish performance to thermal habitat suitability and fewer have distinguished co-varying water quality constraints. We interfaced fish bioenergetics, field measurements, and Thermal Remote Imaging to generate a spatially-explicit, high-resolution surface of fish growth potential, and next employed a structured hypothesis to detect relationships among measures of fish performance and co-varying water quality constraints. Our thermal surface of fish performance captured the amount and spatial-temporal arrangement of thermally-suitable habitat for three focal species in an extremely heterogeneous reservoir, but interpretation of this pattern was initially confounded by seasonal covariation of water residence time and water quality. Subsequent path analysis revealed that in terms of seasonal patterns in growth potential, catfish and walleye responded to temperature, positively and negatively, respectively; crappie and walleye responded to eutrophy (negatively). At the high eutrophy levels observed in this system, some desired fishes appear to suffer from excessive cultural eutrophication within the context of elevated temperatures whereas others appear to be largely unaffected or even enhanced. Our overall findings do not lead to the conclusion that this system is degraded by pollution; however, they do highlight the need to use a sensitive focal species in the process of determining allowable nutrient loading and as integrators of habitat suitability across multiple spatial and temporal scales. We provide an integrated approach useful for quantifying fish growth potential and identifying water quality constraints on fish performance at spatial scales appropriate for whole-system management.

Flood of April 2-3, 2005, Neversink River Basin, New York

USGS Publications Warehouse

Suro, Thomas P.; Firda, Gary D.

2006-01-01

Heavy rain on April 2-3, 2005 produced rainfall amounts of 3 inches to almost 6 inches within a 36-hour period throughout the Delaware River basin. Major flooding occurred in the East and West Branches of the Delaware River and their tributaries, the main stem of the Delaware River and the Neversink River, a major tributary to the Delaware River. The resultant flooding damaged hundreds of homes, caused millions of dollars in damage to infrastructure in Orange and Sullivan Counties, and forced more than 1,000 residents to evacuate their homes. A total of 20 New York counties were declared Federal disaster areas. Some of the most extensive flooding occurred along the Neversink and Delaware Rivers in Orange and Sullivan Counties, New York. Disaster recovery assistance from the April 2005 flooding in New York stood at almost $35 million in 2005, at which time more than 3,400 New Yorkers had registered for Federal aid. All U.S. Geological Survey stream-gaging stations on the Neversink River below the Neversink Reservoir recorded peak water-surface elevations higher than those recorded during the September 2004 flooding. Peak water-surface elevations at some study sites on the Neversink River exceeded the 500-year flood elevation as documented in flood-insurance studies by the Federal Emergency Management Agency. Flood peaks at some long-term U.S. Geological Survey stream-gaging stations were the highest ever recorded. Several U.S. Geological Survey stream-gaging stations on the Delaware River also recorded peak water-surface elevations that exceeded those recorded during the September 2004 flooding.

Bathymetric survey and estimation of storage capacity of lower Sixmile Creek reservoir, Ithaca, New York

USGS Publications Warehouse

Wernly, John F.; Zajd, Jr., Henry J.; Coon, William F.

2016-10-05

During 2015, the U.S. Geological Survey, in cooperation with the City of Ithaca, New York, and the New York State Department of State, conducted a bathymetric survey of the lower Sixmile Creek reservoir in Tompkins County, New York. A former water-supply reservoir for the City of Ithaca, the reservoir is no longer a functional component of Ithaca’s water-supply system, having been replaced by a larger reservoir less than a mile upstream in 1911. Excessive sedimentation has substantially reduced the reservoir’s water-storage capacity and made the discharge gate at the base of the 30-foot dam, which creates the reservoir, inoperable. U.S. Geological Survey personnel collected bathymetric data by using an acoustic Doppler current profiler. Across more than half of the approximately 14-acre reservoir, depths were manually measured because of interference from aquatic vegetation with the acoustic Doppler current profiler. City of Ithaca personnel created a bottom-elevation surface from these depth data. A second surface was created from depths that were manually measured by City of Ithaca personnel during 1938. Surface areas and storage capacities were computed at 1-foot increments of elevation for both bathymetric surveys. The results indicate that the current storage capacity of the reservoir at its normal water-surface elevation is about 84 acre-feet and that sediment accumulated between 1938 and 2015 has decreased the reservoir’s capacity by about 68 acre-feet. This sediment load is attributed to annual inputs from the watershed above the reservoir, as well as from an episodic landslide that filled a large part of the reservoir along its northern edge in 1949.

Perspectives on Proterozoic surface ocean redox from iodine contents in ancient and recent carbonate

NASA Astrophysics Data System (ADS)

Hardisty, Dalton S.; Lu, Zunli; Bekker, Andrey; Diamond, Charles W.; Gill, Benjamin C.; Jiang, Ganqing; Kah, Linda C.; Knoll, Andrew H.; Loyd, Sean J.; Osburn, Magdalena R.; Planavsky, Noah J.; Wang, Chunjiang; Zhou, Xiaoli; Lyons, Timothy W.

2017-04-01

The Proterozoic Eon hosted the emergence and initial recorded diversification of eukaryotes. Oxygen levels in the shallow marine settings critical to these events were lower than today's, although how much lower is debated. Here, we use concentrations of iodate (the oxidized iodine species) in shallow-marine limestones and dolostones to generate the first comprehensive record of Proterozoic near-surface marine redox conditions. The iodine proxy is sensitive to both local oxygen availability and the relative proximity to anoxic waters. To assess the validity of our approach, Neogene-Quaternary carbonates are used to demonstrate that diagenesis most often decreases and is unlikely to increase carbonate-iodine contents. Despite the potential for diagenetic loss, maximum Proterozoic carbonate iodine levels are elevated relative to those of the Archean, particularly during the Lomagundi and Shuram carbon isotope excursions of the Paleo- and Neoproterozoic, respectively. For the Shuram anomaly, comparisons to Neogene-Quaternary carbonates suggest that diagenesis is not responsible for the observed iodine trends. The baseline low iodine levels in Proterozoic carbonates, relative to the Phanerozoic, are linked to a shallow oxic-anoxic interface. Oxygen concentrations in surface waters would have at least intermittently been above the threshold required to support eukaryotes. However, the diagnostically low iodine data from mid-Proterozoic shallow-water carbonates, relative to those of the bracketing time intervals, are consistent with a dynamic chemocline and anoxic waters that would have episodically mixed upward and laterally into the shallow oceans. This redox instability may have challenged early eukaryotic diversification and expansion, creating an evolutionary landscape unfavorable for the emergence of animals.

Agrichemicals in surface water and birth defects in the United States

PubMed Central

Winchester, Paul D; Huskins, Jordan; Ying, Jun

2009-01-01

Objectives: To investigate if live births conceived in months when surface water agrichemicals are highest are at greater risk for birth defects. Methods: Monthly concentrations during 1996–2002 of nitrates, atrazine and other pesticides were calculated using United States Geological Survey's National Water Quality Assessment data. Monthly United States birth defect rates were calculated for live births from 1996 to 2002 using United States Centers for Disease Control and Prevention natality data sets. Birth defect rates by month of last menstrual period (LMP) were then compared to pesticide/nitrate means using logistical regression models. Results: Mean concentrations of agrichemicals were highest in April–July. Total birth defects, and eleven of 22 birth defect subcategories, were more likely to occur in live births with LMPs between April and July. A significant association was found between the season of elevated agrichemicals and birth defects. Conclusion: Elevated concentrations of agrichemicals in surface water in April–July coincided with higher risk of birth defects in live births with LMPs April–July. While a causal link between agrichemicals and birth defects cannot be proven from this study an association might provide clues to common factors shared by both variables. PMID:19183116

Trends and causes of historical wetland loss, Sabine National Wildlife Refuge, southwest Louisiana

USGS Publications Warehouse

Bernier, Julie C.; Morton, Robert A.; Kelso, Kyle W.

2011-01-01

The thickness of the uppermost Holocene sediments (peat and organic-rich mud) and the elevation of stratigraphic contacts were compared at marsh and open-water sites across areas of formerly continuous marsh to estimate magnitudes of recent elevation loss caused by vertical erosion and subsidence. Results of these analyses indicate that erosion greatly exceeded subsidence at most of the core sites, although both processes have contributed to historical wetland loss. Comparison of these results with results of our prior studies indicates that magnitudes of subsidence and total accommodation space that formed in the western chenier plain were less than those in the delta plain. Compared with the delta plain, where subsidence generally exceeded erosion and peat thicknesses were so great that peat was preserved even where erosion was greater than subsidence, the SNWR peats are thin and were absent (eroded) at most open-water sites. Although historical subsidence rates in the chenier plain are substantially lower than most of the same rates in the delta plain, the temporal and spatial trends of rapid wetland loss, highest rates of land-surface subsidence, and high rates of oil-and-gas production are similar, indicating that historical wetland loss was likely initiated by similar processes (deep-subsurface subsidence) in both regions.

Modeling surface-water flow and sediment mobility with the Multi-Dimensional Surface-Water Modeling System (MD_SWMS)

USGS Publications Warehouse

McDonald, Richard; Nelson, Jonathan; Kinzel, Paul; Conaway, Jeffrey S.

2006-01-01

The Multi-Dimensional Surface-Water Modeling System (MD_SWMS) is a Graphical User Interface for surface-water flow and sediment-transport models. The capabilities of MD_SWMS for developing models include: importing raw topography and other ancillary data; building the numerical grid and defining initial and boundary conditions; running simulations; visualizing results; and comparing results with measured data.

Tidally driven water column hydro-geochemistry in a remediating acidic wetland

NASA Astrophysics Data System (ADS)

Johnston, Scott G.; Keene, Annabelle F.; Bush, Richard T.; Sullivan, Leigh A.; Wong, Vanessa N. L.

2011-10-01

SummaryManaged tidal inundation is a newly evolved technique for remediating coastal acid sulphate soil (CASS) wetlands. However, there remains considerable uncertainty regarding the hydro-geochemical pathways and spatiotemporal dynamics of residual H + and metal(loid) mobilisation into the tidal fringe surface waters of these uniquely iron-rich landscapes. Here, we examine the hydrology and water column chemistry across the intertidal slope of a remediating CASS wetland during several tide cycles. There was extreme spatial and temporal dynamism in water column chemistry, with pH fluctuating by ˜3 units (˜3.5-6.5) during a single tide cycle. Acute acidity was spatially confined to the upper intertidal slope, reflecting surface sediment properties, and tidal overtopping is an important pathway for mobilisation of residual H + and Al 3+ to the water column. Marine derived HCO3- was depleted from surface waters migrating across the intertidal slope and a strong gradient in HCO3- was observed from the tidal fringe to the adjacent tributary channel and nearby estuary. Tidal forcing generated oscillating hydraulic gradients in the shallow fringing aquifer, favouring ebb-tide seepage and driving rapid, heterogeneous advection of groundwater on the lower intertidal slope via surface connected macropores. A combination of diffusive and advective flux across the sediment-water interface led to persistent, elevated surface water Fe 2+ (˜10-1000 μM). The geochemical processes associated with Fe 2+ mobilisation displayed distinct spatial zonation, with low pH, proton-promoted desorption occurring on the upper intertidal slope, whilst circum-neutral pH, Fe(III)-reducing processes dominated the lower intertidal slope. Arsenic was also mobilised into surface waters on the lower intertidal slope under moderate pH (˜6.0) conditions and was strongly positively correlated with Fe 2+. Saturation index values for aragonite were substantially depressed (-1 to -5) and significantly negatively correlated with elevation, thereby presenting a barrier to re-colonisation of the upper intertidal slope by calcifying benthic organisms. These findings highlight the spatially complex hydrological and geochemical controls on surface water quality that can occur in tidally inundated acid sulphate soil environments.

75 FR 28596 - Bryant Mountain LLC; Notice of Preliminary Permit Application Accepted for Filing and Soliciting...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-21

... acre-feet and normal water surface elevation of 5500 feet mean sea level; (2) an earthen dam... facility to release water into the stream below the dam; and (4) intake facilities for the power tunnel with facilities to store additional water to provide black start capability. Lower Reservoir (1) Will...

Controlling Heterogeneous Catalysis of Water Dissociation Using Cu-Ni Bimetallic Alloy Surfaces: A Quantum Dynamics Study.

PubMed

Ray, Dhiman; Ghosh, Smita; Tiwari, Ashwani Kumar

2018-06-07

Copper-Nickel bimetallic alloys are emerging heterogeneous catalysts for water dissociation which is the rate determining step of industrially important Water Gas Shift (WGS) reaction. Yet, the detailed quantum dynamics studies of water-surface scattering in literature are limited to pure metal surfaces. We present here, a three dimensional wave-packet dynamics study of water dissociation on Cu-Ni alloy surfaces, using a pseudo diatomic model of water on a London-Eyring-Polanyi-Sato (LEPS) potential energy surface in order to study the effect of initial vibration, rotation and orientation of water molecule on reactivity. For all the chosen surfaces reactivity increases significantly with vibrational excitation. In general, for lower vibrational states the reactivity increases with increasing rotational excitation but it decreases in higher vibrational states. Molecular orientation strongly affects reactivity by helping the molecule to align along the reaction path at higher vibrational states. For different alloys, the reaction probability follows the trend of barrier heights and the surfaces having all Ni atoms in the uppermost layer are much more reactive than the ones with Cu atoms. Hence the nature of the alloy surface and initial quantum state of the incoming molecule significantly influence the reactivity in surface catalyzed water dissociation.

Effects of experimental warming and elevated CO2 on surface methane and CO­2 fluxes from a boreal black spruce peatland

NASA Astrophysics Data System (ADS)

Gill, A. L.; Finzi, A.; Giasson, M. A.

2015-12-01

High latitude peatlands represent a major terrestrial carbon store sensitive to climate change, as well as a globally significant methane source. While elevated atmospheric carbon dioxide concentrations and warming temperatures may increase peat respiration and C losses to the atmosphere, reductions in peatland water tables associated with increased growing season evapotranspiration may alter the nature of trace gas emission and increase peat C losses as CO2 relative to methane (CH4). As CH4 is a greenhouse gas with twenty times the warming potential of CO2, it is critical to understand how surface fluxes of CO2 and CH4 will be influenced by factors associated with global climate change. We used automated soil respiration chambers to assess the influence of elevated atmospheric CO2 and whole ecosystem warming on peatland CH4 and CO2 fluxes at the SPRUCE (Spruce and Peatland Responses Under Climatic and Environmental Change) Experiment in northern Minnesota. Belowground warming treatments were initiated in July 2014 and whole ecosystem warming and elevated CO2 treatments began in August 2015. Here we report soil iCO2 and iCH4 flux responses to the first year of belowground warming and the first two months of whole ecosystem manipulation. We also leverage the spatial and temporal density of measurements across the twenty autochambers to assess how physical (i.e., plant species composition, microtopography) and environmental (i.e., peat temperature, water table position, oxygen availability) factors influence observed rates of CH4 and CO2 loss. We find that methane fluxes increased significantly across warming treatments following the first year of belowground warming, while belowground warming alone had little influence on soil CO2 fluxes. Peat microtopography strongly influenced trace gas emission rates, with higher CH4 fluxes in hollow locations and higher CO2 fluxes in hummock locations. While there was no difference in the isotopic composition of the methane fluxes between hollow and hummock locations, δ13CH4 was more depleted in the early and late growing season, indicating a transition from hydrogenotrophic to acetoclastic methanogenesis during periods of high photosynthetic input.

Hydrographic Surveys for Six Water Bodies in Eastern Nebraska, 2005-07

USGS Publications Warehouse

Johnson, Michaela R.; Andersen, Michael J.; Sebree, Sonja K.

2008-01-01

The U.S. Geological Survey, in cooperation with the Nebraska Department of Environmental Quality, completed hydrographic surveys for six water bodies in eastern Nebraska: Maskenthine Wetland, Olive Creek Lake, Standing Bear Lake, Wagon Train Lake and Wetland, Wildwood Lake, and Yankee Hill Lake and sediment basin. The bathymetric data were collected using a boat-mounted survey-grade fathometer that operated at 200 kHz, and a differentially corrected Global Positioning System with antenna mounted directly above the echo-sounder transducer. Shallow-water and terrestrial areas were surveyed using a Real-Time Kinematic Global Positioning System. The bathymetric, shallow-water, and terrestrial data were processed in a geographic information system to generate a triangulated irregular network representation of the bottom of the water body. Bathymetric contours were interpolated from the triangulated irregular network data using a 2-foot contour interval. Bathymetric contours at the conservation pool elevation for Maskenthine Wetland, Yankee Hill Lake, and Yankee Hill sediment pond also were interpolated in addition to the 2-foot contours. The surface area and storage capacity of each lake or wetland were calculated for 1-foot intervals of water surface elevation and are tabulated in the Appendix for all water bodies.

Determination of cloud liquid water content using the SSM/I

NASA Technical Reports Server (NTRS)

Alishouse, John C.; Snider, Jack B.; Westwater, Ed R.; Swift, Calvin T.; Ruf, Christopher S.

1990-01-01

As part of a calibration/validation effort for the special sensor microwave/imager (SSM/I), coincident observations of SSM/I brightness temperatures and surface-based observations of cloud liquid water were obtained. These observations were used to validate initial algorithms and to derive an improved algorithm. The initial algorithms were divided into latitudinal-, seasonal-, and surface-type zones. It was found that these initial algorithms, which were of the D-matrix type, did not yield sufficiently accurate results. The surface-based measurements of channels were investigated; however, the 85V channel was excluded because of excessive noise. It was found that there is no significant correlation between the SSM/I brightness temperatures and the surface-based cloud liquid water determination when the background surface is land or snow. A high correlation was found between brightness temperatures and ground-based measurements over the ocean.

Aluminium concentrations in Swedish forest streams and co-variations with catchment characteristics.

PubMed

Löfgren, Stefan; Cory, Neil; Zetterberg, Therese

2010-07-01

The negative effects of elevated concentrations of inorganic aluminium on aquatic organisms are well documented. Acid deposition is often cited as a main driver behind the mobilisation and speciation of aluminium in soils and surface waters. In the study, we tested the hypothesis that sulphur deposition is the main driver for elevated concentrations of inorganic aluminium in 114 base poor, boreal Swedish streams. However, the deposition of anthropogenic sulphate has decreased substantially since it peaked in the 1970s, and at the current deposition levels, we hypothesise that local site parameters play an important role in determining vulnerability to elevated concentrations of inorganic aluminium in boreal stream waters. Presented here are the results of a principal components analysis of stream water chemistry, acid deposition data and local site variables, including forest composition and stem volume. It is shown that the concentrations of both organic and inorganic aluminium are not explained by either historical or current acid deposition, but are instead explained by a combination of local site characteristics. Sites with elevated concentrations of inorganic aluminium were characterised by small catchments (<500 ha) dominated by mature stands of Norway spruce with high stem volume. Using data from the Swedish National Forest Inventory the area of productive forest land in Sweden with a higher vulnerability for elevated inorganic aluminium concentrations in forests streams is approximately 1.5 million hectares or 7% of the total productive forest area; this is higher in the south of Sweden (10%) and lower in the north (2%). A better understanding of the effects of natural processes and forest management in controlling aquatic inorganic aluminium concentrations is therefore important in future discussions about measures against surface water acidification.

Monitoring Reservoir Storage in South Asia from Satellite Remote Sensing

NASA Astrophysics Data System (ADS)

Zhang, S.; Gao, H.; Naz, B.

2013-12-01

Realtime reservoir storage information is essential for accurate flood monitoring and prediction in South Asia, where the fatality rate (by area) due to floods is among the highest in the world. However, South Asia is dominated by international river basins where communications among neighboring countries about reservoir storage and management are extremely limited. In this study, we use a suite of NASA satellite observations to achieve high quality estimation of reservoir storage and storage variations at near realtime in South Asia. The monitoring approach employs vegetation indices from the Moderate Resolution Imaging Spectroradiometer (MODIS) 16-day 250 m MOD13Q1 product and the surface elevation data from the Geoscience Laser Altimeter System (GLAS) on board the Ice, Cloud and land Elevation Satellite (ICESat). This approach contains four steps: 1) identifying the reservoirs with ICESat GLAS overpasses and extracting the elevation data for these locations; 2) using the K-means method for water classification from MODIS andapplying a novel post-classification algorithm to enhance water area estimation accuracy; 3) deriving the relationship between the MODIS water surface area and the ICESat elevation; and 4) estimating the storage of reservoirs over time based on the elevation-area relationship and the MODIS water area time series. For evaluation purposes, we compared the satellite-based reservoir storage with gauge observations for 16 reservoirs in South Asia. The storage estimates were highly correlated with observations (R = 0.92 to 0.98), with values for the normalized root mean square error (NRMSE) ranging from 8.7% to 25.2%. Using this approach, storage and storage variations were estimated for 16 South Asia reservoirs from 2000 to 2012.

Assessment of ground-water contamination near Lantana landfill, Southeast Florida

USGS Publications Warehouse

Russell, G.M.; Higer, A.L.

1988-01-01

The Lantana landfill located in Palm Beach County rises 40 to 50 feet above normal ground level and consists of about 250 acres of compacted garbage and trash, some below the water table. Surface-resistivity measurements and water-quality analyses indicate a contaminant plume along the eastern perimeter of the landfill that has migrated about 300 feet eastward toward an adjacent lake. Concentrations of chloride, ammonia, and nitrate were elevated within the plume. The surficial aquifer consists primarily of sand from 0 to about 68 feet, and sand interbedded with sandstone and limestone from 68 to 220 feet. A slight hydraulic gradient exists, indicating ground-water movement from the landfill toward a lake to the east. Analyses of geoelectric, lithologic, and water-quality data indicate that surface geophysical techniques were successful in determining the areal and vertical extent of leachate migration at this location.The Lantana landfill located in Palm Beach County rises 40 to 50 feet above normal ground level and consists of about 250 acres of compacted garbage and trash, some below the water table. Surface-resistivity measurements and water-quality analyses indicate a contaminant plume along the eastern perimeter of the landfill that has migrated about 300 feet eastward toward an adjacent lake. Concentrations of chloride, ammonia, and nitrate were elevated within the plume. The surficial aquifer consists primarily of sand from 0 to about 68 feet, and sand interbedded with sandstone and limestone from 68 to 220 feet. A slight hydraulic gradient exists, indicating ground-water movement from the landfill toward a lake to the east. Analyses of geoelectric, lithologic, and water-quality data indicate that surface geophysical techniques were successful in determining the areal and vertical extent of leachate migration at this location.

Water quality following extensive beetle-induced tree mortality: Interplay of aromatic carbon loading, disinfection byproducts, and hydrologic drivers.

PubMed

Brouillard, Brent M; Dickenson, Eric R V; Mikkelson, Kristin M; Sharp, Jonathan O

2016-12-01

The recent bark beetle epidemic across western North America may impact water quality as a result of elevated organic carbon release and hydrologic shifts associated with extensive tree dieback. Analysis of quarterly municipal monitoring data from 2004 to 2014 with discretization of six water treatment facilities in the Rocky Mountains by extent of beetle impact revealed a significant increasing trend in total organic carbon (TOC) and total trihalomethane (TTHM) production within high (≳50% areal infestation) beetle-impacted watersheds while no or insignificant trends were found in watersheds with lower impact levels. Alarmingly, the TTHM concentration trend in the high impact sites exceeded regulatory maximum contaminant levels during the most recent two years of analysis (2013-14). To evaluate seasonal differences, explore the interplay of water quality and hydrologic processes, and eliminate variability associated with municipal reporting, these treatment facilities were targeted for more detailed surface water sampling and characterization. Surface water samples collected from high impact watersheds exhibited significantly higher TOC, aromatic signatures, and disinfection byproduct (DBP) formation potential than watersheds with lower infestation levels. Spectroscopic analyses of surface water samples indicated that these heightened DBP precursor levels are a function of both elevated TOC loading and increased aromatic character. This association was heightened during precipitation and runoff events in high impact sites, supporting the hypothesis that altered hydrologic flow paths resulting from tree mortality mobilize organic carbon and elevate DBP formation potential for several months after runoff ceases. The historical trends found here likely underestimate the full extent of TTHM shifts due to monitoring biases with the extended seasonal release of DBP precursors increasing the potential for human exposure. Collectively, our analysis suggests that while water quality impacts continue to rise nearly one decade after infestation, significant increases in TOC mobilization and DBP precursors are limited to watersheds that experience extensive tree mortality. Copyright © 2016 Elsevier B.V. All rights reserved.

Selenium mobilization during a flood experiment in a contaminated wetland: Stewart Lake Waterfowl Management Area, Utah

USGS Publications Warehouse

Naftz, D.L.; Yahnke, J.; Miller, J.; Noyes, S.

2005-01-01

Constructed and natural wetlands can accumulate elevated levels of Se; however, few data are available on cost-effective methods for remobilization and removal of Se from these areas. A field experiment was conducted to assess the effectiveness of flooding on the removal of Se from dry surface sediments. The 83-m2 flood-experiment plot contained 10 monitoring wells, a water-quality minimonitor (continuous measurement of pH, specific conductance, water temperature, and dissolved O2), a down-hole Br electrode, and 2 pressure transducers. Flooding was initiated on August 27, 2002, and a Br tracer was added to water delivered through a pipeline to the flood plot during the first 1.2 h. Standing water depth in the flood plot was maintained at 0.3 m through September 1, 2002. The Br tracer data indicate a dual porosity system that includes fracture (mud cracks) and matrix flow components. Mean vertical water velocities for the matrix flow component were estimated to range from 0.002 to 0.012 m/h. Dissolved (less than 0.45 ??m) Se increased from pre-flood concentrations of less than 10 ??g/L to greater than 800 ??g/L during flooding in samples from deep (2.0 m below land surface) ground water. Selenium concentrations exceeded 5500 ??g/L in samples from shallow (0.8 m below land surface) ground water. Ratios of Se to Br in water samples indicate that Se moved conservatively during the experiment and was derived from leaching of near-surface sediments. Cumulative Se flux to the deep ground water during the experiment ranged from 9.0 to 170 mg/m2. Pre- and post-flood surface soil sampling indicated a mean Se flux of 720 mg/m2 through the top 15 cm of soil. Ground-water samples collected 8 months after termination of the flood experiment contained Se concentrations of less than 20 ??g/L. The minimonitor data indicate a rapid return to chemically reducing conditions in the deep ground water, limiting the mobility of the Se dissolved in the water pulse introduced during the flood experiment. Ratios of Se to Br in deep ground-water samples collected 8 months after the experiment confirmed the removal of Se from the aqueous phase. Based on the median Se flux rate estimated during the experiment of 0.65 mg/h/m2 (n = 52), 7 flooding cycles would be required to meet the 4 ??g/g remediation goal in surface soils from the SLWMA wetland.

Hydrogeology and simulation of ground-water flow at the Gettysburg Elevator Plant Superfund Site, Adams County, Pennsylvania

USGS Publications Warehouse

Low, Dennis J.; Goode, Daniel J.; Risser, Dennis W.

2000-01-01

Ground water in Triassic-age sedimentary fractured-rock aquifers in the area of Gettysburg, Pa., is used as drinking water and for industrial and commercial supply. In 1983, ground water at the Gettysburg Elevator Plant was found by the Pennsylvania Department of Environmental Resources to be contaminated with trichloroethene, 1,1,1-trichloroethane, and other synthetic organic compounds. As part of the U.S. Environmental Protection Agency?s Comprehensive Environmental Response, Compensation, and Liability Act, 1980 process, a Remedial Investigation was completed in July 1991, a method of site remediation was issued in the Record of Decision dated June 1992, and a Final Design Report was completed in May 1997. In cooperation with the U.S. Environmental Protection Agency in the hydrogeologic assessment of the site remediation, the U.S. Geological Survey began a study in 1997 to determine the effects of the onsite and offsite extraction wells on ground-water flow and contaminant migration from the Gettysburg Elevator Plant. This determination is based on hydrologic and geophysical data collected from 1991 to 1998 and on results of numerical model simulations of the local ground-water flow-system. The Gettysburg Elevator Site is underlain by red, green, gray, and black shales of the Heidlersburg Member of the Gettysburg Formation. Correlation of natural-gamma logs indicates the sedimentary rock strike about N. 23 degrees E. and dip about 23 degrees NW. Depth to bedrock onsite commonly is about 6 feet but offsite may be as deep as 40 feet. The ground-water system consists of two zones?a thin, shallow zone composed of soil, clay, and highly weathered bedrock and a thicker, nonweathered or fractured bedrock zone. The shallow zone overlies the bedrock zone and truncates the dipping beds parallel to land surface. Diabase dikes are barriers to ground-water flow in the bedrock zone. The ground-water system is generally confined or semi-confined, even at shallow depths. Depth to water can range from flowing at land surface to more than 71 feet below land surface. Potentiometric maps based on measured water levels at the Gettysburg Elevator Plant indicate ground water flows from west to east, towards Rock Creek. Multiple-well aquifer tests indicate the system is heterogeneous and flow is primarily in dipping beds that contain discrete secondary openings separated by less permeable beds. Water levels in wells open to the pumped bed, as projected along the dipping stratigraphy, are drawn down more than water levels in wells not open to the pumped bed. Ground-water flow was simulated for steady-state conditions prior to pumping and long-term average pumping conditions. The three-dimensional numerical flow model (MODFLOW) was calibrated by use of a parameter estimation program (MODFLOWP). Steady-state conditions were assumed for the calibration period of 1996. An effective areal recharge rate of 7 inches was used in model calibration. The calibrated flow model was used to evaluate the effectiveness of the current onsite and offsite extraction well system. The simulation results generally indicate that the extraction system effectively captures much of the ground-water recharge at the Gettysburg Elevator Plant and, hence, contaminated ground-water migrating from the site. Some of the extraction wells pump at low rates and have very small contributing areas. Results indicate some areal recharge onsite will move to offsite extraction wells.

Method and apparatus for measuring surface contour on parts with elevated temperatures

DOEpatents

Horvath, Mark S.; Nance, Roy A.; Cohen, George H.; Fodor, George

1991-01-01

The invention is directed to a method and apparatus for measuring the surface contour of a test piece, such as the bow of a radioactive fuel rod, which is completely immersed in water. The invention utilizes ultrasonic technology and is capable of measuring surface contours of test pieces which are at a higher temperature than the surrounding water. The presence of a test piece at a higher temperature adversely affects the distance measurements by causing thermal variations in the water near the surface of the test piece. The contour measurements depend upon a constant temperature of the water in the path of the ultrasonic wave to provide a constant acoustical velocity (the measurement is made by the time of flight measurement for an ultrasonic wave). Therefore, any variations of water temperature near the surface will introduce errors degrading the measurement. The present invention overcomes these problems by assuring that the supply of water through which the ultrasonic waves travel is at a predetermined and constant temperature.

Brine Spills Associated with Unconventional Oil Development in North Dakota.

PubMed

Lauer, Nancy E; Harkness, Jennifer S; Vengosh, Avner

2016-05-17

The rapid rise of unconventional oil production during the past decade in the Bakken region of North Dakota raises concerns related to water contamination associated with the accidental release of oil and gas wastewater to the environment. Here, we characterize the major and trace element chemistry and isotopic ratios ((87)Sr/(86)Sr, δ(18)O, δ(2)H) of surface waters (n = 29) in areas impacted by oil and gas wastewater spills in the Bakken region of North Dakota. We establish geochemical and isotopic tracers that can identify Bakken brine spills in the environment. In addition to elevated concentrations of dissolved salts (Na, Cl, Br), spill waters also consisted of elevated concentrations of other contaminants (Se, V, Pb, NH4) compared to background waters, and soil and sediment in spill sites had elevated total radium activities ((228)Ra + (226)Ra) relative to background, indicating accumulation of Ra in impacted soil and sediment. We observed that inorganic contamination associated with brine spills in North Dakota is remarkably persistent, with elevated levels of contaminants observed in spills sites up to 4 years following the spill events.

Application of Geographical Information System Arc/info Grid-Based Surface Hyrologic Modeling to the Eastern Hellas Region, Mars

NASA Astrophysics Data System (ADS)

Mest, S. C.; Harbert, W.; Crown, D. A.

2001-05-01

Geographical Information System GRID-based raster modeling of surface water runoff in the eastern Hellas region of Mars has been completed. We utilized the 0.0625 by 0.0625 degree topographic map of Mars collected by the Mars Global Surveyor Mars Orbiter Laser Altimeter (MOLA) instrument to model watershed and surface runoff drainage systems. Scientific interpretation of these models with respect to ongoing geological mapping is presented in Mest et al., (2001). After importing a region of approximately 77,000,000 square kilometers into Arc/Info 8.0.2 we reprojected this digital elevation model (DEM) from a Mars sphere into a Mars ellipsoid. Using a simple cylindrical geographic projection and horizontal spatial units of decimal degrees and then an Albers projection with horizontal spatial units of meters, we completed basic hydrological modeling. Analysis of the raw DEM to determine slope, aspect, flow direction, watershed and flow accumulation grids demonstrated the need for correction of single pixel sink anomalies. After analysis of zonal elevation statistics associated with single pixel sinks, which identified 0.8 percent of the DEM points as having undefined surface water flow directions, we filled single pixel sink values of 89 meters or less. This correction is comparable with terrestrial DEMs that contain 0.9 percent to 4.7 percent of cells, which are sinks (Tarboton et al., 1991). The fill-corrected DEM was then used to determine slope, aspect, surface water flow direction and surface water flow accumulation. Within the region of interest 8,776 watersheds were identified. Using Arc/Info GRID flow direction and flow accumulation tools, regions of potential surface water flow accumulation were identified. These networks were then converted to a Strahler ordered stream network. Surface modeling produced Strahler orders one through six. As presented in Mest et al., (2001) comparisons of mapped features may prove compatible with drainage networks and watersheds derived using this methodology. Mest, Scott C., Crown, David A., and Harbert, William, 2001, Highland drainage basins and valley networks in the eastern Hellas Region of Mars, Abstract 1419, Lunar and Planetary Science XXXII Meeting Houston (CDROM). Tarboton D. G., Bras, R. L., and Rodriguez-Iturbe, 1991, On the Extraction of Channel Networks from Digital Elevation Data, Hydrological Processes, v. 5, 81-100. http://viking.eps.pitt.edu

Constraints on Late Tertiary Elevation of the Colorado Plateau From Carbonate Clumped- Isotope Thermometry

NASA Astrophysics Data System (ADS)

Huntington, K. W.; Wernicke, B. P.; Eiler, J. M.

2009-05-01

Topography is a first-order expression of the buoyancy of the lithosphere, and the timing and pattern of elevation change can place fundamental constraints on mantle flow and continental dynamics. We investigate the timing of Colorado Plateau uplift using clumped-isotope thermometry to independently constrain both the temperature and isotopic composition of ancient surface waters based on the 13C-18O bond enrichment in carbonates. Analyses of ancient lake sediments from the plateau interior and adjacent lowlands are compared to signals recorded by modern sediments collected over 3 km of elevation in the region. Comparison of modern and ancient samples deposited near sea level provides an opportunity to quantify the influence of climate on changes in temperature, and therefore more accurately assess the contribution from changes in elevation. Both modern and ancient (Miocene-Pliocene) carbonates record near-surface spring/summer lake water temperatures that vary strongly with elevation. Modern and ancient lake carbonate temperature lapse rates of -4.2±0.7°C/km and -4.1±0.6°C/km, respectively, suggest that little if any post-16 Ma change in elevation of the southern plateau is required to explain the data. Agreement of δ18O data for modern and ancient surface waters supports this interpretation. The zero-elevation intercept of the ancient trend is 7.7±2.0°C warmer than the modern trend, indicating significant cooling due to climate change since Late Miocene time. The temperature data are permissive of up to 450 m of uplift or 250 m of subsidence of the plateau interior since 6 Ma, but do not support km-scale changes. Combined with previous constraints, the data suggest that most uplift of the south-central plateau occurred during Late Cretaceous/earliest Tertiary time, favoring uplift mechanisms such as crustal thickening by channel flow, hydration of the mantle lithosphere due to volatile flux from the Laramide flat slab, or dynamic topography associated with slab foundering. The data do not support explanations that ascribe most uplift to ca. 40-0 Ma disposal of the Farallon or North American mantle lithosphere.

Water-surface elevations and channel characteristics for a selected reach of the Applegate River, Jackson County, Oregon

USGS Publications Warehouse

Harris, David Dell; Alexander, Clyde W.

1970-01-01

In land-use planning for the Applegate River and its flood plain, consideration should be given to (1) preservation of the recreational attributes of the area, (2) allowance for optimum development of the flood plain's natural resources, and (3) protection of the rights of private landowners. Major factors that influence evaluation of the above considerations are the elevations and characteristics of floods. Heretofore, such flood data for the Applegate River have been inadequate to evaluate the flood potential or to use as a basis for delineating reasonable land-use zones. Therefore, at the request of Jackson County, this study was made to provide flood elevations, water-surface profiles, and channel characteristics (geometry and slope) for a reach of the Applegate River from the Jackson-Josephine County line upstream to the Applegate damsite (fig. 1). A similar study was previously made for reaches of adjacent Rogue River and Elk Creek (Harris, 1970).

Investigation of water seepage through porous media using X-ray imaging technique

NASA Astrophysics Data System (ADS)

Jung, Sung Yong; Lim, Seungmin; Lee, Sang Joon

2012-07-01

SummaryDynamic movement of wetting front and variation of water contents through three different porous media were investigated using X-ray radiography. Water and natural sand particles were used as liquid and porous media in this study. To minimize the effects of minor X-ray attenuation and uneven illumination, the flat field correction (FFC) was applied before determining the position of wetting front. In addition, the thickness-averaged (in the direction of the X-ray penetration) water content was obtained by employing the Beer-Lambert law. The initial inertia of water droplet influences more strongly on the vertical migration, compared to the horizontal migration. The effect of initial inertia on the horizontal migration is enhanced as sand size decreases. The pattern of water transport is observed to be significantly affected by the initial water contents. As the initial water contents increases, the bulb-type transport pattern is shifted to a trapezoidal shape. With increasing surface temperature, water droplets are easily broken on the sand surface. This consequently decreases the length of the initial inertia region. Different from the wetting front migration, the water contents at the initial stage clearly exhibit a preferential flow along the vertical direction. The water transport becomes nearly uniform in all directions beyond the saturation state.

GPS-derived estimates of surface mass balance and ocean-induced basal melt for Pine Island Glacier ice shelf, Antarctica

NASA Astrophysics Data System (ADS)

Shean, David E.; Christianson, Knut; Larson, Kristine M.; Ligtenberg, Stefan R. M.; Joughin, Ian R.; Smith, Ben E.; Stevens, C. Max; Bushuk, Mitchell; Holland, David M.

2017-11-01

In the last 2 decades, Pine Island Glacier (PIG) experienced marked speedup, thinning, and grounding-line retreat, likely due to marine ice-sheet instability and ice-shelf basal melt. To better understand these processes, we combined 2008-2010 and 2012-2014 GPS records with dynamic firn model output to constrain local surface and basal mass balance for PIG. We used GPS interferometric reflectometry to precisely measure absolute surface elevation (zsurf) and Lagrangian surface elevation change (Dzsurf/ Dt). Observed surface elevation relative to a firn layer tracer for the initial surface (zsurf - zsurf0') is consistent with model estimates of surface mass balance (SMB, primarily snow accumulation). A relatively abrupt ˜ 0.2-0.3 m surface elevation decrease, likely due to surface melt and increased compaction rates, is observed during a period of warm atmospheric temperatures from December 2012 to January 2013. Observed Dzsurf/ Dt trends (-1 to -4 m yr-1) for the PIG shelf sites are all highly linear. Corresponding basal melt rate estimates range from ˜ 10 to 40 m yr-1, in good agreement with those derived from ice-bottom acoustic ranging, phase-sensitive ice-penetrating radar, and high-resolution stereo digital elevation model (DEM) records. The GPS and DEM records document higher melt rates within and near features associated with longitudinal extension (i.e., transverse surface depressions, rifts). Basal melt rates for the 2012-2014 period show limited temporal variability despite large changes in ocean temperature recorded by moorings in Pine Island Bay. Our results demonstrate the value of long-term GPS records for ice-shelf mass balance studies, with implications for the sensitivity of ice-ocean interaction at PIG.

Sediment infilling and wetland formation dynamics in an active crevasse splay of the Mississippi River delta

USGS Publications Warehouse

Cahoon, Donald R.; White, David A.; Lynch, James C.

2011-01-01

Crevasse splay environments provide a mesocosm for evaluating wetland formation and maintenance processes on a decadal time scale. Site elevation, water levels, vertical accretion, elevation change, shallow subsidence, and plant biomass were measured at five habitats along an elevation gradient to evaluate wetland formation and development in Brant Pass Splay; an active crevasse splay of the Balize delta of the Mississippi River. The processes of vertical development (vertical accretion, elevation change, and shallow subsidence) were measured with the surface elevation table–marker horizon method. There were three distinct stages to the accrual of elevation capital and wetland formation in the splay: sediment infilling, vegetative colonization, and development of a mature wetland community. Accretion, elevation gain, and shallow subsidence all decreased by an order of magnitude from the open water (lowest elevation) to the forest (highest elevation) habitats. Vegetative colonization occurred within the first growing season following emergence of the mud surface. An explosively high rate of below-ground production quickly stabilized the loosely consolidated sub-aerial sediments. After emergent vegetation colonization, vertical development slowed and maintenance of marsh elevation was driven both by sediment trapping by the vegetation and accumulation of plant organic matter in the soil. Continued vertical development and survival of the marsh then depended on the health and productivity of the plant community. The process of delta wetland formation is both complex and nonlinear. Determining the dynamics of wetland formation will help in understanding the processes driving the past building of the delta and in developing models for restoring degraded wetlands in the Mississippi River delta and other deltas around the world.

Overview and technical and practical aspects for use of geostatistics in hazardous-, toxic-, and radioactive-waste-site investigations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bossong, C.R.; Karlinger, M.R.; Troutman, B.M.

1999-10-01

Technical and practical aspects of applying geostatistics are developed for individuals involved in investigation at hazardous-, toxic-, and radioactive-waste sites. Important geostatistical concepts, such as variograms and ordinary, universal, and indicator kriging, are described in general terms for introductory purposes and in more detail for practical applications. Variogram modeling using measured ground-water elevation data is described in detail to illustrate principles of stationarity, anisotropy, transformations, and cross validation. Several examples of kriging applications are described using ground-water-level elevations, bedrock elevations, and ground-water-quality data. A review of contemporary literature and selected public domain software associated with geostatistics also is provided, asmore » is a discussion of alternative methods for spatial modeling, including inverse distance weighting, triangulation, splines, trend-surface analysis, and simulation.« less

Impacts of initial convective structure on subsequent squall line evolution

NASA Astrophysics Data System (ADS)

Varble, A.; Morrison, H.; Zipser, E. J.

2017-12-01

A Weather Research and Forecasting simulation of the 20 May 2011 MC3E squall line using 750-m horizontal grid spacing produces wide convective regions with strongly upshear tilted convective updrafts and mesoscale bowing segments that are not produced in radar observations. Similar features occur across several different bulk microphysics schemes, despite surface observations exhibiting cold pool equivalent potential temperature drops that are similar to and pressure rises that are greater than those in the simulation. Observed rear inflow remains more elevated than simulated, partly counteracting the cold pool circulation, whereas the simulated rear inflow descends to low levels, maintaining its strength and reinforcing the cold pool circulation that overpowers the pre-squall line low level vertical wind shear. The descent and strength of the simulated rear inflow is fueled by strong latent cooling caused by large ice water contents detrained from upshear tilted convective cores that accumulate at the rear of the stratiform region. This simulated squall evolution is sensitive to model resolution, which is too coarse to resolve individual convective drafts. Nesting a 250-m horizontal grid spacing domain into the 750-m domain substantially alters the initial convective cells with reduced latent cooling, weaker convective downdrafts, and a weaker initial cold pool. As the initial convective cells develop into a squall line, the rear inflow remains more elevated in the 250-m domain with a cold pool that eventually develops to be just as strong and deeper than the one in the 750-m run. Despite this, the convective cores remain more upright in the 250-m run with the rear inflow partly counteracting the cold pool circulation, whereas the 750-m rear inflow near the surface reinforces the shallower cold pool and causes bowing in the squall line. The different structure in the 750-m run produces excessive mid-level front-to-rear detrainment that widens the convective region relative to the 250-m run and observations while continuing the cycle of excessive latent cooling and rear inflow descent at the rear of the stratiform region in a positive feedback. The causes of initial convective structure differences that produce the divergence in simulated squall line evolutions are explored.

Estimated Depth to Ground Water and Configuration of the Water Table in the Portland, Oregon Area

USGS Publications Warehouse

Snyder, Daniel T.

2008-01-01

Reliable information on the configuration of the water table in the Portland metropolitan area is needed to address concerns about various water-resource issues, especially with regard to potential effects from stormwater injection systems such as UIC (underground injection control) systems that are either existing or planned. To help address these concerns, this report presents the estimated depth-to-water and water-table elevation maps for the Portland area, along with estimates of the relative uncertainty of the maps and seasonal water-table fluctuations. The method of analysis used to determine the water-table configuration in the Portland area relied on water-level data from shallow wells and surface-water features that are representative of the water table. However, the largest source of available well data is water-level measurements in reports filed by well constructors at the time of new well installation, but these data frequently were not representative of static water-level conditions. Depth-to-water measurements reported in well-construction records generally were shallower than measurements by the U.S. Geological Survey (USGS) in the same or nearby wells, although many depth-to-water measurements were substantially deeper than USGS measurements. Magnitudes of differences in depth-to-water measurements reported in well records and those measured by the USGS in the same or nearby wells ranged from -119 to 156 feet with a mean of the absolute value of the differences of 36 feet. One possible cause for the differences is that water levels in many wells reported in well records were not at equilibrium at the time of measurement. As a result, the analysis of the water-table configuration relied on water levels measured during the current study or used in previous USGS investigations in the Portland area. Because of the scarcity of well data in some areas, the locations of select surface-water features including major rivers, streams, lakes, wetlands, and springs representative of where the water table is at land surface were used to augment the analysis. Ground-water and surface-water data were combined for use in interpolation of the water-table configuration. Interpolation of the two representations typically used to define water-table position - depth to the water table below land surface and elevation of the water table above a datum - can produce substantially different results and may represent the end members of a spectrum of possible interpolations largely determined by the quantity of recharge and the hydraulic properties of the aquifer. Datasets of depth-to-water and water-table elevation for the current study were interpolated independently based on kriging as the method of interpolation with parameters determined through the use of semivariograms developed individually for each dataset. Resulting interpolations were then combined to create a single, averaged representation of the water-table configuration. Kriging analysis also was used to develop a map of relative uncertainty associated with the values of the water-table position. Accuracy of the depth-to-water and water-table elevation maps is dependent on various factors and assumptions pertaining to the data, the method of interpolation, and the hydrogeologic conditions of the surficial aquifers in the study area. Although the water-table configuration maps generally are representative of the conditions in the study area, the actual position of the water-table may differ from the estimated position at site-specific locations, and short-term, seasonal, and long-term variations in the differences also can be expected. The relative uncertainty map addresses some but not all possible errors associated with the analysis of the water-table configuration and does not depict all sources of uncertainty. Depth to water greater than 300 feet in the Portland area is limited to parts of the Tualatin Mountains, the foothills of the Cascade Range, and muc

Mixture and method for simulating soiling and weathering of surfaces

DOEpatents

Sleiman, Mohamad; Kirchstetter, Thomas; Destaillats, Hugo; Levinson, Ronnen; Berdahl, Paul; Akbari, Hashem

2018-01-02

This disclosure provides systems, methods, and apparatus related to simulated soiling and weathering of materials. In one aspect, a soiling mixture may include an aqueous suspension of various amounts of salt, soot, dust, and humic acid. In another aspect, a method may include weathering a sample of material in a first exposure of the sample to ultraviolet light, water vapor, and elevated temperatures, depositing a soiling mixture on the sample, and weathering the sample in a second exposure of the sample to ultraviolet light, water vapor, and elevated temperatures.

From Outlet Glacier Changes to Ice Sheet Mass Balance - Evolution of Greenland Ice Sheet from Laser Altimetry Data

NASA Astrophysics Data System (ADS)

Csatho, B. M.; Schenk, A.; Nagarajan, S.; Babonis, G. S.

2010-12-01

Investigations of ice sheet mass balance and the changing dynamics of outlet glaciers have been hampered by the lack of comprehensive data. In recent years, this situation has been remedied. Satellite laser altimetry data from the Ice Cloud and land Elevation Satellite mission (ICESat), combined with airborne laser altimetry, provide accurate measurements of surface elevation changes, and surface velocities derived from various satellite platforms yield crucial information on changing glacier dynamics. Taken together, a rich and diverse data set is emerging that allows for characterizing the spatial and temporal evolution of ice sheets and outlet glaciers. In particular, it enables quantitative studies of outlet glaciers undergoing rapid and complex changes. Although airborne and laser altimetry have been providing precise measurements of ice sheet topography since the early 1990s, determining detailed and accurate spatial and temporal distribution of surface changes remains a challenging problem. We have developed a new, comprehensive method, called Surface Elevation Reconstruction And Change detection (SERAC), which estimates surface changes by a simultaneous reconstruction of surface topography from fused multisensor data. The mathematical model is based on the assumption that for a small surface area, only the absolute elevation changes over time but not the shape of the surface patch. Therefore, laser points of all time epochs contribute to the shape parameters; points of each time period determine the absolute elevation of the surface patch at that period. This method provides high-resolution surface topography, precise changes and a rigorous error estimate of the quantities. By using SERAC we combined ICESat and ATM laser altimetry data to determine the evolution of surface change rates of the whole Greenland Ice Sheet between 2003 and 2009 on a high-resolution grid. Our reconstruction, consistent with GRACE results, shows ice sheet thinning propagating along the NW coast, and thinning expanding to higher elevations in SW and N Greenland. Several outlet glaciers, for example Humboldt and Petermann glaciers in NW Greenland and Kangilerngata Sermia in W Greenland exhibit a complex spatial and temporal pattern of thickening-thinning with regions of thickening observed at lower elevations. We will examine the thickening and thinning history and the record of surface velocity of these glaciers to investigate the processes responsible for initiating and sustaining these changes. Moreover, by analyzing the detailed surface elevation change history along flowlines or across drainage basins, the propagation of thinning following perturbations at the glacier terminus can be investigated. Results, depicting the evolution of surface elevation changes of three major outlet glaciers, Jakobshavn, Helheim and Kangerlussuaq glaciers, will be shown.

A combined surface/volume scattering retracking algorithm for ice sheet satellite altimetry

NASA Technical Reports Server (NTRS)

Davis, Curt H.

1992-01-01

An algorithm that is based upon a combined surface-volume scattering model is developed. It can be used to retrack individual altimeter waveforms over ice sheets. An iterative least-squares procedure is used to fit the combined model to the return waveforms. The retracking algorithm comprises two distinct sections. The first generates initial model parameter estimates from a filtered altimeter waveform. The second uses the initial estimates, the theoretical model, and the waveform data to generate corrected parameter estimates. This retracking algorithm can be used to assess the accuracy of elevations produced from current retracking algorithms when subsurface volume scattering is present. This is extremely important so that repeated altimeter elevation measurements can be used to accurately detect changes in the mass balance of the ice sheets. By analyzing the distribution of the model parameters over large portions of the ice sheet, regional and seasonal variations in the near-surface properties of the snowpack can be quantified.

Deep water tsunami simulation at global scale using an elastoacoustic approach

NASA Astrophysics Data System (ADS)

Salazar Monroy, E. F.; Ramirez-Guzman, L.; Bielak, J.; Sanchez-Sesma, F. J.

2017-12-01

In this work, we present the results for the first stage of a tsunami global simulation project using an elastoacoustic approach. The solid-fluid interaction, which is only valid on a global scale and far distances from the coast, is modelled using a finite element scheme for a 2D geometry. Comparing analytic and numerical solutions, we observe a good fit for a homogeneous domain - with an extension of 20 km - using 15 points per wavelength. Subsequently, we performed 2D realizations taking a section from a global 3D model and projecting the Tohoku-Oki source obtained by the USGS. The 3D Global model uses the ETOPO1 and the Preliminary Reference Earth Model (Dziewonski and Anderson, 1981). We analysed 3 cross sections, defined using DART buoys as a reference for each section (i.e., initial and final profile point). Surface water elevation obtained with this coupling strategy is constrained at low frequencies (0.2 Hz). We expect that this coupling strategy could approximate the model to high frequencies and realistic scenarios considering other geometries (i.e., 3D) and a complete domain (i.e., surface and deep).

WatER: The proposed Water Elevation Recovery satellite mission

NASA Astrophysics Data System (ADS)

Alsdorf, D.; Mognard, N.; Rodriguez, E.; Participants, W.

2005-12-01

Surface fresh water is essential for life, yet we have surprisingly poor knowledge of the spatial and temporal dynamics of surface water storage and discharge globally. The core mission objective is to describe and understand the continental water cycle and the hydrological processes (e.g., floodplain hydraulics) at work in a river basin. The key question that will be answered by WatER is: "Where is water stored on Earth's land surfaces, and how does this storage vary in space and time?" WatER will facilitate societal needs by (1) improving our understanding of flood hazards; (2) freely providing water volume information to countries who critically rely on rivers that cross political borders; and (3) mapping the variations in water bodies that contribute to disease vectors (e.g., malaria). Conventional altimeter profiles are, without question, incapable of supplying the measurements needed to address scientific and societal questions. WatER will repeatedly measure the spatially distributed water surface elevations (h) of wetlands, rivers, lakes, reservoirs, etc. Successive h measurements yield dh/dt, (t is time), hence a volumetric change in water stored or lost. Individual images of h yield dh/dx (x is distance), hence surface water slope, which is necessary for estimating streamflow. WatER's main instrument is a Ka-band radar interferometer (KaRIN) which is the only technology capable of supplying the required imaging capability of h. KaRIN has a rich heritage based on (1) the many highly successful ocean observing radar altimeters, (2) the Shuttle Radar Topography Mission (SRTM), and (3) the development effort of the Wide Swath Ocean Altimeter (WSOA). The interferometric altimeter is a near-nadir viewing, 120 km wideswath based instrument that uses interferometric SAR processing of the returned pulses to yield single-look 5m azimuth and 10m to 70m range resolution, with an elevation accuracy of approximately 50 cm. Polynomial based averaging of heights along the water body increases the height accuracy to about 3 cm. The entire globe is covered twice every 16 days and orbit subcycles allow the average visit to be about half this time at low to mid-latitudes, and almost daily at high latitudes. The WatER mission is an international effort with a large, supporting scientific community. It is already proposed as an ESA Earth Explorer Core mission and will also be jointly submitted to NASA's Earth System Science Pathfinder program. WatER is designed to meet high priority targets for all nations and will provide essential data for the EU Water Framework Directive and the European Flood Alert System. WatER will meet the United Nations call for a "greater focus on water related issues", responds to the hydroclimatological needs of the International Working Group on Earth Observations, and answers the U.S. federal government call to focus on our "ability to measure, monitor, and forecast U.S. and global supplies of fresh water".

Application of High-resolution Aerial LiDAR Data in Calibration of a Two-dimensional Urban Flood Simulation

NASA Astrophysics Data System (ADS)

Piotrowski, J.; Goska, R.; Chen, B.; Krajewski, W. F.; Young, N.; Weber, L.

2009-12-01

In June 2008, the state of Iowa experienced an unprecedented flood event which resulted in an economic loss of approximately $2.88 billion. Flooding in the Iowa River corridor, which exceeded the previous flood of record by 3 feet, devastated several communities, including Coralville and Iowa City, home to the University of Iowa. Recognizing an opportunity to capture a unique dataset detailing the impacts of the historic flood, the investigators contacted the National Center for Airborne Laser Mapping (NCALM), which performed an aerial Light Detection and Ranging (LiDAR) survey along the Iowa River. The survey, conducted immediately following the flood peak, provided coverage of a 60-mile reach. The goal of the present research is to develop a process by which flood extents and water surface elevations can be accurately extracted from the LiDAR data set and to evaluate the benefit of such data in calibrating one- and two-dimensional hydraulic models. Whereas data typically available for model calibration include sparsely distributed point observations and high water marks, the LiDAR data used in the present study provide broad-scale, detailed, and continuous information describing the spatial extent and depth of flooding. Initial efforts were focused on a 10-mile, primarily urban reach of the Iowa River extending from Coralville Reservoir, a United States Army Corps of Engineers flood control project, downstream through the Coralville and Iowa City. Spatial extent and depth of flooding were estimated from the LiDAR data. At a given cross-sectional location, river channel and floodplain measurements were compared. When differences between floodplain and river channel measurements were less than a standard deviation of the vertical uncertainty in the LiDAR survey, floodplain measurements were classified as flooded. A flood water surface DEM was created using measurements classified as flooded. A two-dimensional, depth-averaged numerical model of a 10-mile reach of the Iowa River corridor was developed using the United States Bureau of Reclamation SRH-2D hydraulic modeling software. The numerical model uses an unstructured numerical mesh and variable surface roughness, assigned according to observed land use and cover. The numerical model was calibrated using inundation extents and water surface elevations derived from the LiDAR data. It was also calibrated using high water marks and land survey data collected daily during the 2008 flood. The investigators compared the two calibrations to evaluate the benefit of high-resolution LiDAR data in improving the accuracy of a two-dimensional urban flood simulation.

Polonium-210 accumulates in a lake receiving coal mine discharges-anthropogenic or natural?

PubMed

Nelson, A W; Eitrheim, E S; Knight, A W; May, D; Wichman, M D; Forbes, T Z; Schultz, M K

2017-02-01

Coal is an integral part of global energy production; however, coal mining is associated with numerous environmental health impacts. It is well documented that coal-mine waste can contaminate the environment with naturally-occurring radionuclides from the uranium-238 ( 238 U) decay series. However, the behavior of the final radionuclide in the 238 U-series, i.e., polonium-210 ( 210 Po) arising from coal-mine waste-water discharge is largely unexplored. Here, results of a year-long (2014-2015) field study, in which the concentrations of 210 Po in sediments and surface water of a lake that receives coal-mine waste-water discharge in West Virginia are presented. Initial measurements identified levels of 210 Po in the lake sediments that were in excess of that which could be attributed to ambient U-series parent radionuclides; and were indicative of discharge site contamination of the lake ecosystem. However, control sediment obtained from a similar lake system in Iowa (an area with no coal mining or unconventional drilling) suggests that the levels of 210 Po in the lake are a natural phenomenon; and are likely unrelated to waste-water treatment discharges. Elevated levels of 210 Po have been reported in lake bottom sediments previously, yet very little information is available on the radioecological implications of 210 Po accumulation in lake bottom sediments. The findings of this study suggest that (Monthly Energy Review, 2016) the natural accumulation and retention of 210 Po in lake sediments may be a greater than previously considered (Chadwick et al., 2013) careful selection of control sites is important to prevent the inappropriate attribution of elevated levels of NORM in lake bottom ecosystems to industrial sources; and (Van Hook, 1979) further investigation of the source-terms and potential impacts on elevated 210 Po in lake-sediment ecosystems is warranted. Copyright © 2016 Elsevier Ltd. All rights reserved.

Detection and measurement of land subsidence using interferometric synthetic aperture radar and Global Positioning System, San Bernardino County, Mojave Desert, California

USGS Publications Warehouse

Sneed, Michelle; Ikehara, Marti E.; Stork, Sylvia V.; Amelung, Falk; Galloway, Devin L.

2003-01-01

Land subsidence associated with ground-water-level declines has been recognized as a potential problem in parts of the Mojave Desert, California. Ground water has been the primary source of domestic, agricultural, and municipal water supplies in the desert since the early 1900s. Pumping of ground water from the Mojave River and Morongo ground-water basins in the southwestern Mojave Desert resulted in water-level declines of more than 30 meters (100 feet) between the 1950s and the 1990s. A Global Positioning System (GPS) survey of a geodetic network was used to determine the location, extent, and magnitude of vertical land-surface changes in Lucerne Valley in the Morongo ground-water basin. The GPS survey was conducted in 1998 to estimate historical elevation changes by comparing GPS-derived elevations with historical elevations (which were available for some of the monuments in the network as early as 1944) and to establish baseline values that can be used for comparisons with future GPS surveys. The GPS measurements indicated that about 600 millimeters (2 feet) [plus or minus 1,500 millimeters (5 feet)] of subsidence occurred at three of the monuments between 1969 and 1998 but that very little to no vertical change in position occurred at seven other monuments in the network. Water levels in the area of subsidence in Lucerne Valley declined about 15 meters (50 feet) during 1970-98. Interferometric synthetic aperture radar (InSAR) methods were used to characterize vertical land-surface changes in the Mojave River and Morongo ground-water basins during various intervals of time between 1992 and 1999. Interferograms, InSAR-generated displacement maps, show that subsidence ranging from 45 to 90 mm (0.15 to 0.3 ft) occurred in four areas of these two ground-water basins--the El Mirage, Lockhart-Harper Lake (dry), Newberry Springs, and Lucerne Valley areas. Some of the InSAR measurements were affected by the earthquakes at Landers and Hector Mine, California, and by atmospheric artifacts. Water-level data were examined for areas undergoing vertical land-surface changes to determine whether the vertical land-surface changes may be related to aquifer-system compaction caused by ground-water-level changes. Temporally relevant water-level data were sparse for some areas, particularly the El Mirage and Lockhart-Harper Lake (dry) areas. Water levels in wells proximate to the subsiding areas generally declined between 1992 and 1999; water levels in some wells proximate to the subsiding areas experienced seasonal periods of declines and recoveries.

Mercury Release from the Rathburn Mine, Petray Mine, and Bear Valley Saline Springs, Colusa County, California 2004-2006

USGS Publications Warehouse

Slowey, Aaron J.; Rytuba, James J.

2008-01-01

This report summarizes data obtained from field sampling of mine tailings and waste rock at the Rathburn and Petray Mines that was initiated in July 17, 2001 and water and sediment in regional springs and tributaries that drain from the mine area into Bear Creek on December 14, 2004 and February 16 and May 27, 2005. Although it was initially assumed that the mines were the cause of elevated levels of monomethyl Hg measured by the Central Regional Water Quality Control Board in tributaries near their confluence with Bear Creek (Foe and others, unpublished results), it became apparent during this study that ground water springs were also potential sources of Hg. In addition to sampling of springs in May 2005, saline ground water seepage along an unnamed fault on the west side of Bear Valley was sampled on December 13-14, 2006. We did not sample water or sediment in Bear Creek itself during this study. Our results permit a preliminary assessment of mining and natural sources of Hg and associated chemical constituents that could elevate levels of monomethyl Hg in Bear Creek.

30 CFR 783.25 - Cross sections, maps, and plans.

Code of Federal Regulations, 2014 CFR

2014-07-01

...) Elevations and locations of monitoring stations used to gather data on water quality and quantity, fish and... aquifers on cross-sections and contour maps; (7) Location of surface water bodies such as streams, lakes... permit area; (9) Location and dimensions of existing areas of spoil, waste, coal development waste, and...

30 CFR 783.25 - Cross sections, maps, and plans.

Code of Federal Regulations, 2011 CFR

2011-07-01

...) Elevations and locations of monitoring stations used to gather data on water quality and quantity, fish and... aquifers on cross-sections and contour maps; (7) Location of surface water bodies such as streams, lakes... permit area; (9) Location and dimensions of existing areas of spoil, waste, coal development waste, and...

30 CFR 783.25 - Cross sections, maps, and plans.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) Elevations and locations of monitoring stations used to gather data on water quality and quantity, fish and... aquifers on cross-sections and contour maps; (7) Location of surface water bodies such as streams, lakes... permit area; (9) Location and dimensions of existing areas of spoil, waste, coal development waste, and...

30 CFR 783.25 - Cross sections, maps, and plans.

Code of Federal Regulations, 2012 CFR

2012-07-01

...) Elevations and locations of monitoring stations used to gather data on water quality and quantity, fish and... aquifers on cross-sections and contour maps; (7) Location of surface water bodies such as streams, lakes... permit area; (9) Location and dimensions of existing areas of spoil, waste, coal development waste, and...

30 CFR 783.25 - Cross sections, maps, and plans.

Code of Federal Regulations, 2013 CFR

2013-07-01

...) Elevations and locations of monitoring stations used to gather data on water quality and quantity, fish and... aquifers on cross-sections and contour maps; (7) Location of surface water bodies such as streams, lakes... permit area; (9) Location and dimensions of existing areas of spoil, waste, coal development waste, and...

WATERSHED CHARACTERISTICS AND PRE-RESTORATION SURFACE-WATER HYDROLOGY OF MINEBANK RUN, BALTIMORE COUNTY, MARYLAND, WATER YEARS 2002-04

EPA Science Inventory

Stream restoration efforts have been ongoing in Maryland since the early 1990s. Physical stream restoration often involves replacement of lost sediments to elevate degraded streambeds, re-establishment of riffle-pool sequences along the channel profile, planting vegetation in rip...

Genomic and Transcriptomic Analyses to Identify Pathways Involved in Nanoparticle Generation in the Ubiquitous Marine Bacterium Alteromonas macleodii Under Elevated Copper Conditions

NASA Astrophysics Data System (ADS)

Cusick, K. D.; Dale, J.; Little, B.; Cockrell, A.; Biffinger, J.

2016-02-01

Alteromonas macleodii is a ubiquitous marine bacterium that clusters by molecular analyses into two ecotypes: surface and deep-water. Our group isolated a marine bacterium from copper coupons that generates nanoparticles (NPs) at elevated copper concentrations. Sequencing of the 16S rRNA gene identified it as an A. macleodii strain. In phylogenetic analyses based on the gyrB gene, it clustered with other surface isolates; however, it formed a unique cluster separate from that of other surface isolates based on rpoB gene sequences. Copper is commonly employed as an antifouling agent on the hulls of ships, and so copper tolerance and NP generation is under investigation in this strain. The overall goals of this study were: (1) to determine if copper tolerance is the result of changes at the genetic or transcriptional level and (2) to identify the genes involved in NP formation. Sub-cultures were established from the initial isolate in which copper concentrations were increased in .25 mM increments through multiple generations. These sub-cultures were assayed for NP formation in seawater medium supplemented with 3-4 mM copper. Scanning electron microscopy revealed large aggregates of NPs on the exterior surface of all sub-cultures. Additionally, a portion of the cells in all sub-cultures displayed an elongated morphology in comparison to the wild-type. No NPs were observed in wild-type controls grown without the addition of increased copper. Metagenomic sequencing of natural populations of A. macleodii revealed extreme divergence in several large genomic regions whose content includes genes coding for exopolysaccharide production and metal resistance. High-throughput sequencing is being used to determine whether copper tolerance and NP generation is the result of genetic or transcriptional changes. These results will be extended to natural communities to gain insights into the role of bacterial NPs during conditions of elevated metal concentrations in coastal systems.

Mathematical Modelling of Arctic Polygonal Tundra with Ecosys: 1. Microtopography Determines How Active Layer Depths Respond to Changes in Temperature and Precipitation

NASA Astrophysics Data System (ADS)

Grant, R. F.; Mekonnen, Z. A.; Riley, W. J.; Wainwright, H. M.; Graham, D.; Torn, M. S.

2017-12-01

Microtopographic variation that develops among features (troughs, rims, and centers) within polygonal landforms of coastal arctic tundra strongly affects movement of surface water and snow and thereby affects soil water contents (θ) and active layer depth (ALD). Spatial variation in ALD among these features may exceed interannual variation in ALD caused by changes in climate and so needs to be represented in projections of changes in arctic ALD. In this study, increases in near-surface θ with decreasing surface elevation among polygon features at the Barrow Experimental Observatory (BEO) were modeled from topographic effects on redistribution of surface water and snow and from lateral water exchange with a subsurface water table during a model run from 1981 to 2015. These increases in θ caused increases in thermal conductivity that in turn caused increases in soil heat fluxes and hence in ALD of up to 15 cm with lower versus higher surface elevation which were consistent with increases measured at BEO. The modeled effects of θ caused interannual variation in maximum ALD that compared well with measurements from 1985 to 2015 at the Barrow Circumpolar Active Layer Monitoring (CALM) site (R2 = 0.61, RMSE = 0.03 m). For higher polygon features, interannual variation in ALD was more closely associated with annual precipitation than mean annual temperature, indicating that soil wetting from increases in precipitation may hasten permafrost degradation beyond that caused by soil warming from increases in air temperature. This degradation may be more rapid if increases in precipitation cause sustained wetting in higher features.

Delineation of Nested Wetland Catchments and Modeling of Hydrologic Connectivity Using LiDAR Data and Aerial Imagery

EPA Science Inventory

In traditional watershed delineation and topographic modelling, surface depressions are generally treated as spurious features and simply removed from a digital elevation model (DEM) to enforce flow continuity of water across the topographic surface to the watershed outlets. In r...

Nitrogen species in drinking water indicate potential exposure pathway for Balkan Endemic Nephropathy.

PubMed

Niagolova, Nedialka; McElmurry, Shawn P; Voice, Thomas C; Long, David T; Petropoulos, Evangelos A; Havezov, Ivan; Chou, Karen; Ganev, Varban

2005-03-01

This study explored two hypotheses relating elevated concentrations of nitrogen species in drinking water and the disease Balkan Endemic Nephropathy (BEN). Drinking water samples were collected from a variety of water supplies in both endemic and non-endemic villages in the Vratza and Montana districts of Bulgaria. The majority of well water samples exceeded US drinking water standards for nitrate + nitrite. No statistically significant difference was observed for any of the nitrogen species between villages classified as endemic and non-endemic. Other constituents (sodium, potassium and chloride) known to be indicators of anthropogenic pollution were also found at elevated concentrations and all followed the order wells > springs > taps. This ordering coincides with the proximity of human influences to the water sources. Our results clearly establish an exposure pathway between anthropogenic activity and drinking water supplies, suggesting that the causative agent for BEN could result from surface contamination.

Controls on the distributions of organic carbon and nitrogen in the eastern Pacific Ocean

NASA Astrophysics Data System (ADS)

Hansell, Dennis A.; Waterhouse, Tye Y.

1997-05-01

Measurements of total organic carbon (TOC) and nitrogen (TON) were made on the WOCE P18 line (from 67°S to 23°N along 103°/110°W). There was an accumulation of TOC on the equator and in the oligotrophic waters north and south of the equator. The concentrations of TOC were well correlated with temperature, indicating an important physical control on its distribution. The boundary separating shallow, TOC-rich water from deep, TOC-poor water overlaid the main thermocline. This observation suggests that water column stability or residence time imparted by the main thermocline is a primary determinant of TOC accumulation. Elevated TON concentrations were found in all surface waters, with the lowest values found in the region of 20-35°S. Net TON drawdown in the South Pacific subtropical gyre, likely due to biological utilization and vertical export of the nitrogen, was initiated with depletion of equatorially upwelled nitrate. The degree to which inorganic nitrogen was limiting in the surface layer south of the equator served to control the concentrations of TON. Such controls were not exerted on organic carbon, as reflected by increasing C:N ratios of organic matter as TON was removed. Unlike the findings in the South Pacific, TON concentrations in oligotrophic waters north of the equator were frequently higher than on the equator. Such accumulations are hypothesized to be maintained from nitrogen fixation, nitrogen input due to vertical migration of autotrophs or diffusive flux of inorganic nitrogen into the euphotic zone across the relatively shallow nitracline.

Base of the upper layer of the phase-three Elkhorn-Loup groundwater-flow model, north-central Nebraska

USGS Publications Warehouse

Stanton, Jennifer S.

2013-01-01

The Elkhorn and Loup Rivers in Nebraska provide water for irrigation, recreation, hydropower produc­tion, aquatic life, and municipal water systems for the Omaha and Lincoln metropolitan areas. Groundwater is another important resource in the region and is extracted primarily for agricultural irrigation. Water managers of the area are interested in balancing and sustaining the long-term uses of these essential surface-water and groundwater resources. Thus, a cooperative study was established in 2006 to compile reliable data describing hydrogeologic properties and water-budget components and to improve the understanding of stream-aquifer interactions in the Elkhorn and Loup River Basins. A groundwater-flow model was constructed as part of the first two phases of that study as a tool for under­standing the effect of groundwater pumpage on stream base flow and the effects of management strategies on hydrologically connected groundwater and surface-water supplies. The third phase of the study was implemented to gain additional geologic knowledge and update the ELM with enhanced water-budget information and refined discretization of the model grid and stress periods. As part of that effort, the ELM is being reconstructed to include two vertical model layers, whereas phase-one and phase-two simulations represented the aquifer system using one vertical model layer. This report presents a map of and methods for developing the elevation of the base of the upper model layer for the phase-three ELM. Digital geospatial data of elevation contours and geologic log sites used to esti­mate elevation contours are available as part of this report.

Uplift and submarine formation of some Melanesian porphyry copper deposits: Stable isotope evidence

USGS Publications Warehouse

Chivas, A.R.; O'Neil, J.R.; Katchan, G.

1984-01-01

Hydrogen and oxygen isotope analyses of sericites and kaolinites from four young porphyry copper deposits (Ok Tedi (1.2 Ma) and Yandera (6.5 Ma), Papua New Guinea; Koloula (1.5 Ma), Solomon Islands; and Waisoi (<5 Ma), Fiji) indicate that the fluids from which these minerals precipitated were of mixed magmatic and non-magmatic sources. The non-magmatic component of the fluid from the island arc deposits (Koloula, Waisoi) was ocean water. For Ok Tedi, the non-magmatic component was a meteoric water with an isotopic composition different from that of the present meteoric water in the region. The isotopic signature of the former meteoric water is consistent with a surface elevation of 200 m a.s.l. or less at the time of mineralization. The deposit was later exposed and supergene kaolinitization commenced at approximately 1200 m a.s.l. Uplift and erosion has continued to the present at which time the elevation of the exposed deposit is 1800 m a.s.l. This rate of uplift is consistent with that known from other geological evidence. If the rate of uplift were approximately constant during the last 1.2 Ma, the age of supergene enrichment can be dated at approximately 0.4 Ma B.P. Similarly, influx of meteoric water at Yandera occurred when the ground surface above the deposit was at an elevation of approximately 600 m a.s.l. The deposit's present elevation is 1600 m a.s.l. In this case a total uplift of approximately 2.2 km is indicated, with removal of 1.2 km of overburden by erosion. ?? 1984.

Estimated Flood Discharges and Map of Flood-Inundated Areas for Omaha Creek, near Homer, Nebraska, 2005

USGS Publications Warehouse

Dietsch, Benjamin J.; Wilson, Richard C.; Strauch, Kellan R.

2008-01-01

Repeated flooding of Omaha Creek has caused damage in the Village of Homer. Long-term degradation and bridge scouring have changed substantially the channel characteristics of Omaha Creek. Flood-plain managers, planners, homeowners, and others rely on maps to identify areas at risk of being inundated. To identify areas at risk for inundation by a flood having a 1-percent annual probability, maps were created using topographic data and water-surface elevations resulting from hydrologic and hydraulic analyses. The hydrologic analysis for the Omaha Creek study area was performed using historical peak flows obtained from the U.S. Geological Survey streamflow gage (station number 06601000). Flood frequency and magnitude were estimated using the PEAKFQ Log-Pearson Type III analysis software. The U.S. Army Corps of Engineers' Hydrologic Engineering Center River Analysis System, version 3.1.3, software was used to simulate the water-surface elevation for flood events. The calibrated model was used to compute streamflow-gage stages and inundation elevations for the discharges corresponding to floods of selected probabilities. Results of the hydrologic and hydraulic analyses indicated that flood inundation elevations are substantially lower than from a previous study.

A global model simulation for 3-D radiative transfer impact on surface hydrology over the Sierra Nevada and Rocky Mountains

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, W. -L.; Gu, Y.; Liou, K. N.

2015-05-19

We investigate 3-D mountain effects on solar flux distributions and their impact on surface hydrology over the western United States, specifically the Rocky Mountains and the Sierra Nevada, using the global CCSM4 (Community Climate System Model version 4; Community Atmosphere Model/Community Land Model – CAM4/CLM4) with a 0.23° × 0.31° resolution for simulations over 6 years. In a 3-D radiative transfer parameterization, we have updated surface topography data from a resolution of 1 km to 90 m to improve parameterization accuracy. In addition, we have also modified the upward-flux deviation (3-D–PP (plane-parallel)) adjustment to ensure that the energy balance atmore » the surface is conserved in global climate simulations based on 3-D radiation parameterization. We show that deviations in the net surface fluxes are not only affected by 3-D mountains but also influenced by feedbacks of cloud and snow in association with the long-term simulations. Deviations in sensible heat and surface temperature generally follow the patterns of net surface solar flux. The monthly snow water equivalent (SWE) deviations show an increase in lower elevations due to reduced snowmelt, leading to a reduction in cumulative runoff. Over higher-elevation areas, negative SWE deviations are found because of increased solar radiation available at the surface. Simulated precipitation increases for lower elevations, while it decreases for higher elevations, with a minimum in April. Liquid runoff significantly decreases at higher elevations after April due to reduced SWE and precipitation.« less

Hydrologic considerations in defining isolated wetlands

USGS Publications Warehouse

Winter, T.C.; LaBaugh, J.W.

2003-01-01

Wetlands that are not connected by streams to other surface-water bodies are considered to be isolated. Although the definition is based on surface-water connections to other water bodies, isolated wetlands commonly are integral parts of extensive ground-water flow systems, and isolated wetlands can spill over their surface divides into adjacent surface-water bodies during periods of abundant precipitation and high water levels. Thus, characteristics of ground-water flow and atmospheric-water flow affect the isolation of wetlands. In general, the degree that isolated wetlands are connected through the ground-water system to other surface-water bodies depends to a large extent on the rate that ground water moves and the rate that hydrologic stresses can be transmitted through the ground-water system. Water that seeps from an isolated wetland into a gravel aquifer can travel many kilometers through the ground-water system in one year. In contrast, water that seeps from an isolated wetland into a clayey or silty substrate may travel less than one meter in one year. For wetlands that can spill over their surface watersheds during periods of wet climate conditions, their isolation is related to the height to a spill elevation above normal wetland water level and the recurrence interval of various magnitudes of precipitation. The concepts presented in this paper indicate that the entire hydrologic system needs to be considered in establishing a definition of hydrologic isolation.

Hurricane effects on a shallow lake ecosystem and its response to a controlled manipulation of water level.

PubMed

Havens, K E; Jin, K R; Rodusky, A J; Sharfstein, B; Brady, M A; East, T L; Iricanin, N; James, R T; Harwell, M C; Steinman, A D

2001-04-04

In order to reverse the damage to aquatic plant communities caused by multiple years of high water levels in Lake Okeechobee, Florida (U.S.), the Governing Board of the South Florida Water Management District (SFWMD) authorized a "managed recession" to substantially lower the surface elevation of the lake in spring 2000. The operation was intended to achieve lower water levels for at least 8 weeks during the summer growing season, and was predicted to result in a large-scale recovery of submerged vascular plants. We treated this operation as a whole ecosystem experiment, and assessed ecological responses using data from an existing network of water quality and submerged plant monitoring sites. As a result of large-scale discharges of water from the lake, coupled with losses to evaporation and to water supply deliveries to agriculture and other regional users, the lake surface elevation receded by approximately 1 m between April and June. Water depths in shoreline areas that historically supported submerged plant communities declined from near 1.5 m to below 0.5 m. Low water levels persisted for the entire summer. Despite shallow depths, the initial response (in June 2000) of submerged plants was very limited and water remained highly turbid (due at first to abiotic seston and later to phytoplankton blooms). Turbidity decreased in July and the biomass of plants increased. However, submerged plant biomass did not exceed levels observed during summer 1999 (when water depths were greater) until August. Furthermore, a vascular plant-dominated assemblage (Vallisneria, Potamogeton, and Hydrilla) that occurred in 1999 was replaced with a community of nearly 98% Chara spp. (a macro-alga) in 2000. Hence, the lake"s submerged plant community appeared to revert to an earlier successional stage despite what appeared to be better conditions for growth. To explain this unexpected response, we evaluated the impacts that Hurricane Irene may have had on the lake in the previous autumn. In mid-October 1999, this category 1 hurricane passed just to the south of the lake, with wind velocities over the lake surface reaching 90 km h(-1) at their peak. Output from a three-dimensional hydrodynamic/sediment transport model indicates that during the storm, current velocities in surface waters of the lake increased from near 5 cm s(-1) to as high as 100 cm s(-1). These strong velocities were associated with large-scale uplifting and horizontal transport of fine- grained sediments from the lake bottom. Water quality data collected after the storm confirmed that the hurricane resulted in lake-wide nutrient and suspended solids concentrations far in excess of those previously documented for a 10-year data set. These conditions persisted through the winter months and may have negatively impacted plants that remained in the lake at the end of the 1999 growing season. The results demonstrate that in shallow lakes, unpredictable external forces, such as hurricanes, can play a major role in ecosystem dynamics. In regions where these events are common (e.g., the tropics and subtropics), consideration should be given to how they might affect long-term lake management programs.

Landscape unit based digital elevation model development for the freshwater wetlands within the Arthur C. Marshall Loxahatchee National Wildlife Refuge, Southeastern Florida

USGS Publications Warehouse

Xie, Zhixiao; Liu, Zhongwei; Jones, John W.; Higer, Aaron L.; Telis, Pamela A.

2011-01-01

The hydrologic regime is a critical limiting factor in the delicate ecosystem of the greater Everglades freshwater wetlands in south Florida that has been severely altered by management activities in the past several decades. "Getting the water right" is regarded as the key to successful restoration of this unique wetland ecosystem. An essential component to represent and model its hydrologic regime, specifically water depth, is an accurate ground Digital Elevation Model (DEM). The Everglades Depth Estimation Network (EDEN) supplies important hydrologic data, and its products (including a ground DEM) have been well received by scientists and resource managers involved in Everglades restoration. This study improves the EDEN DEMs of the Loxahatchee National Wildlife Refuge, also known as Water Conservation Area 1 (WCA1), by adopting a landscape unit (LU) based interpolation approach. The study first filtered the input elevation data based on newly available vegetation data, and then created a separate geostatistical model (universal kriging) for each LU. The resultant DEMs have encouraging cross-validation and validation results, especially since the validation is based on an independent elevation dataset (derived by subtracting water depth measurements from EDEN water surface elevations). The DEM product of this study will directly benefit hydrologic and ecological studies as well as restoration efforts. The study will also be valuable for a broad range of wetland studies.

Kinetics of scheelite dissolution in groundwater: defining the release rate of tungsten contamination from a natural source

NASA Astrophysics Data System (ADS)

Montgomery, S. D.; Mckibben, M. A.

2011-12-01

Tungsten, an emerging contaminant, has no EPA standard for its permissible levels in drinking water. At sites in California, Nevada, and Arizona there may be a correlation between elevated levels of tungsten in drinking water and clusters of childhood acute lymphocytic leukemia (ALL). Developing a better understanding of how tungsten is released from rocks into surface and groundwaters is therefore of growing environmental interest. Knowledge of tungstate ore mineral weathering processes, particularly the rates of dissolution of scheelite (CaWO4) in groundwater, could improve models of how tungsten is released and transported in natural waters. Our research is focusing on experimental determination of the rates and products of tungstate mineral dissolution in synthetic groundwater, as a function of temperature, pH and mineral surface area. The initial rate method is being used to develop rate laws. Batch reactor experiments are conducted within constant temperature circulation baths over a pH range of 2-9. Cleaned scheelite powder with grain diameters of 106-150um is placed between two screens in a sample platform and then placed inside a two liter Teflon vessel filled with synthetic groundwater. Ports on the vessel allow sample extraction, temperature and pH measurement, gas inflow, and water circulation. Aliquots of solution are taken periodically for product analysis by ICP -MS. Changes in mineral surface characteristics are monitored using SEM and EDS methods. Results so far reveal that the dissolution of scheelite is incongruent at both neutral and low pH. Solid tungstic acid forms on scheelite mineral surfaces under acidic conditions, implying that this phase controls the dissolution rate in acidic environments. The influence of dissolved CO2 and resultant calcium carbonate precipitation on the dissolution of scheelite at higher pH is also being investigated. The rate law being developed for scheelite dissolution will be useful in reactive-transport computer codes designed to model tungsten contamination in a variety of surface and groundwater settings.

Coastal Inlets Research Program. Barrier Island Migration Over a Consolidating Substrate

DTIC Science & Technology

2009-09-01

the toe of the dune to the high water line) for full development of eolian transport. However, the original Shore Protection Manual (1984...tested. Barrier islands overlying a compressible substrate are more likely to have reduced dune elevations due to consolidation, incur overall...migra- tion when the dune reaches a critical elevation with respect to the prev- alent storm conditions. Initial large-scale infusion of sand from an

Do initial conditions matter? A comparison of model climatologies generated from different initial states

NASA Technical Reports Server (NTRS)

Spar, J.; Cohen, C.; Wu, P.

1981-01-01

A coarse mesh (8 by 10) 7 layer global climate model was used to compute 15 months of meteorological history in two perpetual January experiments on a water planet (without continents) with a zonally symmetric climatological January sea surface temperature field. In the first of the two water planet experiments the initial atmospheric state was a set of zonal mean values of specific humidity, temperature, and wind at each latitude. In the second experiment the model was initialized with globally uniform mean values of specific humidity and temperature on each sigma level surface, constant surface pressure (1010 mb), and zero wind everywhere. A comparison was made of the mean January climatic states generated by the two water planet experiments. The first two months of each 15 January run were discarded, and 13 month averages were computed from months 3 through 15.

Application of current and future satellite missions to hydrologic prediction in transboundary rivers

NASA Astrophysics Data System (ADS)

Biancamaria, S.; Clark, E.; Lettenmaier, D. P.

2010-12-01

More than 256 major global river basins, which cover about 45% of the continental land surface, are shared among two or more countries. The flow of such a large part of the global runoff across international boundaries has led to tension in many cases between upstream and downstream riparian countries. Among many examples, this is the case of the Ganges and the Brahmaputra Rivers, which cross the boundary between India and Bangladesh. Hydrological data (river discharge, reservoir storage) are viewed as sensitive by India (the upstream country) and are therefore not shared with Bangladesh, which can only monitor river discharge and water depth at the international border crossing. These measurements only allow forecasting of floods in the interior and southern portions of the country two to three days in advance. These forecasts are not long enough either for agricultural water management purposes (for which knowledge of upstream reservoir storage is essential) or for disaster preparedness purposes. Satellite observations of river spatial extent, surface slope, reservoir area and surface elevation have the potential to make tremendous changes in management of water within the basins. In this study, we examine the use of currently available satellite measurements (in India) and in-situ measurements in Bangladesh to increase forecast lead time in the Ganges and Brahmaputra Rivers. Using nadir altimeters, we find that it is possible to forecast the discharge of the Ganges River at the Bangladesh border with lead time 3 days and mean absolute error of around 25%. On the Ganges River, 2-day forecasts are possible with a mean absolute error of around 20%. When combined with optical/infra-red MODIS images, it is possible to map water elevations along the river and its floodplain upstream of the boundary, and to compute water storage. However, the high frequency of clouds in this region results in relatively large errors in the water mask. Due to the nadir altimeter temporal repeat (10 days for current satellites) and to gaps in the water mask, water volume estimates are meaningful only at the monthly scale. Furthermore, this information is limited to channels with wider than 250-500 m. The future Surface Water and Ocean Topography (SWOT) mission, which is intended to be launched in 2020, will provide global maps of water elevations, with a spatial resolution of 100 m and errors on the water elevation equal to or below 10 cm. The SWOT Ka band interferometric Synthetic Aperture Radar (SAR), will not be affected by cloud cover (aside from infrequent heavy rain); therefore, estimation of the water volume change on the Ganges and on the Brahmaputra upstream to the Bangladesh provided by SWOT should be much more accurate in space and time than can currently be achieved. We discuss the implications of future SWOT observations in the context of our preliminary work on the Ganges-Brahmaputra Rivers using current generation satellite data.

Dependence of flow and transport through the Williamson River Delta, Upper Klamath Lake, Oregon, on wind, river inflow, and lake elevation

USGS Publications Warehouse

Wood, Tamara M.

2012-01-01

The hydrodynamic model of Upper Klamath and Agency Lakes, Oregon, was used to run 384 realizations of a numerical tracer experiment in order to understand the relative effects of wind, lake elevation, and Williamson River inflow on flow and transport (the movement of water and passively transported constituents) through the Williamson River Delta. Significant findings from this study include: * The replacement rate of water increased in Tulana and Goose Bay with increasing lake elevation, Williamson River inflow, and wind speed. * The fraction of Williamson River inflow passing through either side of the Delta increased with lake elevation and Williamson River inflow. * The partial replacement rate of water in Goose Bay with water from the Williamson River increased with wind speed. * The partial replacement rate of water in Tulana with water from the Williamson River decreased with wind speed. * Strong wind forcing at the water surface caused more of the Williamson River inflow to pass through Goose Bay than through Tulana. * Westerly to northwesterly winds result in more of the Williamson River inflow passing through the Goose Bay side of the Delta than through the Tulana side. * Regression models developed from the tracer experiments can be used to quantify the dependencies between transport and the independent variables to obtain rough estimates of useful quantities such as residence time and steady-state solute concentrations.

Simulation of water-surface elevations for a hypothetical 100-year peak flow in Birch Creek at the Idaho National Engineering and Environmental Laboratory, Idaho

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berenbrock, C.; Kjelstrom, L.C.

1997-10-01

Delineation of areas at the Idaho National Engineering and Environmental Laboratory that would be inundated by a 100-year peak flow in Birch Creek is needed by the US Department of Energy to fulfill flood-plain regulatory requirements. Birch Creek flows southward about 40 miles through an alluvium-filled valley onto the northern part of the Idaho National Engineering and Environmental laboratory site on the eastern Snake River Plain. The lower 10-mile reach of Birch Creek that ends in Birch Creek Playa near several Idaho National Engineering and Environmental Laboratory facilities is of particular concern. Twenty-six channel cross sections were surveyed to developmore » and apply a hydraulic model to simulate water-surface elevations for a hypothetical 100-year peak flow in Birch Creek. Model simulation of the 100-year peak flow (700 cubic feet per second) in reaches upstream from State Highway 22 indicated that flow was confined within channels even when all flow was routed to one channel. Where the highway crosses Birch Creek, about 315 cubic feet per second of water was estimated to move downstream--115 cubic feet per second through a culvert and 200 cubic feet per second over the highway. Simulated water-surface elevation at this crossing was 0.8 foot higher than the elevation of the highway. The remaining 385 cubic feet per second flowed southwestward in a trench along the north side of the highway. Flow also was simulated with the culvert removed. The exact location of flood boundaries on Birch Creek could not be determined because of the highly braided channel and the many anthropogenic features (such as the trench, highway, and diversion channels) in the study area that affect flood hydraulics and flow. Because flood boundaries could not be located exactly, only a generalized flood-prone map was developed.« less

Potential Environmental Factors Affecting Oil-Degrading Bacterial Populations in Deep and Surface Waters of the Northern Gulf of Mexico

PubMed Central

Liu, Jiqing; Bacosa, Hernando P.; Liu, Zhanfei

2017-01-01

Understanding bacterial community dynamics as a result of an oil spill is important for predicting the fate of oil released to the environment and developing bioremediation strategies in the Gulf of Mexico. In this study, we aimed to elucidate the roles of temperature, water chemistry (nutrients), and initial bacterial community in selecting oil degraders through a series of incubation experiments. Surface (2 m) and bottom (1537 m) waters, collected near the Deepwater Horizon site, were amended with 200 ppm light Louisiana sweet crude oil and bacterial inoculums from surface or bottom water, and incubated at 4 or 24°C for 50 days. Bacterial community and residual oil were analyzed by pyrosequencing and gas chromatography-mass spectrometry (GC-MS), respectively. The results showed that temperature played a key role in selecting oil-degrading bacteria. Incubation at 4°C favored the development of Cycloclasticus, Pseudoalteromonas, Sulfitobacter, and Reinekea, while 24°C incubations enhanced Oleibacter, Thalassobius, Phaeobacter, and Roseobacter. Water chemistry and the initial community also had potential roles in the development of hydrocarbon-degrading bacterial communities. Pseudoalteromonas, Oleibacter, and Winogradskyella developed well in the nutrient-enriched bottom water, while Reinekea and Thalassobius were favored by low-nutrient surface water. We revealed that the combination of 4°C, crude oil and bottom inoculum was a key factor for the growth of Cycloclasticus, while the combination of surface inoculum and bottom water chemistry was important for the growth of Pseudoalteromonas. Moreover, regardless of the source of inoculum, bottom water at 24°C was a favorable condition for Oleibacter. Redundancy analysis further showed that temperature and initial community explained 57 and 19% of the variation observed, while oil and water chemistry contributed 14 and 10%, respectively. Overall, this study revealed the relative roles of temperature, water chemistry, and initial bacterial community in selecting oil degraders and regulating their evolution in the northern Gulf of Mexico. PMID:28119669

Potential Environmental Factors Affecting Oil-Degrading Bacterial Populations in Deep and Surface Waters of the Northern Gulf of Mexico.

PubMed

Liu, Jiqing; Bacosa, Hernando P; Liu, Zhanfei

2016-01-01

Understanding bacterial community dynamics as a result of an oil spill is important for predicting the fate of oil released to the environment and developing bioremediation strategies in the Gulf of Mexico. In this study, we aimed to elucidate the roles of temperature, water chemistry (nutrients), and initial bacterial community in selecting oil degraders through a series of incubation experiments. Surface (2 m) and bottom (1537 m) waters, collected near the Deepwater Horizon site, were amended with 200 ppm light Louisiana sweet crude oil and bacterial inoculums from surface or bottom water, and incubated at 4 or 24°C for 50 days. Bacterial community and residual oil were analyzed by pyrosequencing and gas chromatography-mass spectrometry (GC-MS), respectively. The results showed that temperature played a key role in selecting oil-degrading bacteria. Incubation at 4°C favored the development of Cycloclasticus, Pseudoalteromonas , Sulfitobacter , and Reinekea , while 24°C incubations enhanced Oleibacter, Thalassobius, Phaeobacter, and Roseobacter. Water chemistry and the initial community also had potential roles in the development of hydrocarbon-degrading bacterial communities. Pseudoalteromonas , Oleibacter , and Winogradskyella developed well in the nutrient-enriched bottom water, while Reinekea and Thalassobius were favored by low-nutrient surface water. We revealed that the combination of 4°C, crude oil and bottom inoculum was a key factor for the growth of Cycloclasticus , while the combination of surface inoculum and bottom water chemistry was important for the growth of Pseudoalteromonas . Moreover, regardless of the source of inoculum, bottom water at 24°C was a favorable condition for Oleibacter. Redundancy analysis further showed that temperature and initial community explained 57 and 19% of the variation observed, while oil and water chemistry contributed 14 and 10%, respectively. Overall, this study revealed the relative roles of temperature, water chemistry, and initial bacterial community in selecting oil degraders and regulating their evolution in the northern Gulf of Mexico.

Hydrologic assessment of the Edwin B. Forsythe National Wildlife Refuge

USGS Publications Warehouse

Wieben, Christine M.; Chepiga, Mary M.

2018-03-19

The Edwin B. Forsythe National Wildlife Refuge (hereafter Forsythe refuge or the refuge) is situated along the central New Jersey coast and provides a mixture of freshwater and saltwater habitats for numerous bird, wildlife, and plant species. Little data and information were previously available regarding the freshwater dynamics that support the refuge’s ecosystems. In cooperation with the U.S. Fish and Wildlife Service, the U.S. Geological Survey conducted an assessment of the hydrologic resources and processes in the refuge and surrounding areas to provide baseline information for evaluating restoration projects and future changes in the hydrologic system associated with climate change and other anthropogenic stressors.During spring 2015, water levels were measured at groundwater and surface-water sites in and near the Forsythe refuge. These water-level measurements, along with surface-water elevations obtained from digital elevation models, were used to construct water-table-elevation and depth-to-water maps of the refuge and surrounding areas. Water-table elevations in the refuge ranged from sea level to approximately 65 feet above sea level; in most of the refuge, the water-table elevation was within 3 feet of sea level. The water-table-elevation map indicates that the direction of shallow groundwater flow at the regional scale is generally from west to east (much of it from the northwest to the southeast), and groundwater moves downgradient from the uplands toward major groundwater discharge areas consisting of coastal streams and wetlands. The depth to water is estimated to be less than 2 feet for approximately 86 percent of the refuge, which coincides closely with the percentage of wetland area in the refuge. Depth to water in excess of 20 feet below land surface is limited to higher elevation areas of the refuge.Streamflow data collected at continuous-record streamgages and partial-record stations within the Mullica-Toms Basin were summarized. Hydrograph separation of streamflow data for eight streamgages (2004–13) reveals that base flow accounts for 68–94 percent of streamflow in basins upstream from the refuge. The high base-flow inputs underscore the importance of groundwater as a source of freshwater that supports both the streams that flow into the refuge and the hydroecology of the contributing basins. Mean annual flow typically ranged from 1.7 to 2.1 cubic feet per second per square mile at the streamgages (2004–13) and between 1.2 and 2.3 cubic feet per second per square mile at the partial-record stations (1965–2015) but was notably greater or lower than these ranges at several stations.Mean annual water budgets were estimated for multiple regions of the refuge for 2004–13 using data compiled from nearby meteorological stations and groundwater flows derived from previously calibrated groundwater-flow models. Precipitation, groundwater recharge, and evapotranspiration were estimated from available data; direct runoff was calculated as the residual component of the water balance. Groundwater recharge rates were greatest in the upland-dominated areas of the refuge with estimates of 14.4 to 18.9 inches per year, which are equivalent to 30 to 40 percent of precipitation. Groundwater recharge rates were nearly zero in the central coastal areas because these areas are major groundwater discharge zones, the water table is near land surface, the subsurface is close to saturation and cannot accept much recharge, and much of the area is underlain by thick marsh deposits likely with low permeability. Estimates of evapotranspiration varied from about 26 inches per year in the upland-dominated areas to more than 35 inches per year in the coastal wetlands, equivalent to 55–79 percent of mean annual precipitation, indicating that it is a major component of the hydrodynamics of the Forsythe refuge.On the basis of output from previously calibrated groundwater-flow models, nearly all of the groundwater exiting the surficial aquifer system in the central coastal areas of the refuge is discharged to wetlands, which highlights the importance of groundwater discharge in supporting the ecosystems of the Forsythe refuge. In the central coastal areas, horizontal flow contributes more than 90 percent of the groundwater flow to the surficial system, indicating that the upbasin areas are a substantial source of water that ultimately discharges to streams and wetlands in the refuge.

Occurrence and Distribution of Mercury in the SurficialAquifer, Long Neck Peninsula, Sussex County, Delaware, 2003-04

USGS Publications Warehouse

Koterba, Michael T.; Andres, A. Scott; Vrabel, Joseph; Crilley, Dianna M.; Szabo, Zoltan; DeWild, John F.; Aiken, George R.; Reyes-Padro, Betzaida

2006-01-01

In January 2001, mercury (Hg) was detected (500 nanograms per liter, ng/L, or greater) in the distribution system of the Long Neck Water Company (LNWC), Pot Nets, Delaware. By April 2001, two LNWC production wells had been taken off-line because discharge concentrations of total mercury (HgT) either had exceeded or approached the Federal limit of 2,000 ng/L. From October 2003 through January 2005, the U.S. Geological Survey, Delaware Geological Survey, and Delaware Department of Natural Resources and Environmental Control conducted a cooperative study to (a) determine if the Hg contamination was widespread, (b) identify possible forms of Hg in ground water, and (c) examine Hg occurrence in relation to (geo)chemical conditions and characteristics of ground water and sediment in the surficial aquifer on the Long Neck Peninsula, Sussex County, Delaware. An initial water-quality survey conducted with samples from 22 production wells revealed that concentrations of HgT in ground water in the surficial aquifer ranged from 0.11 to 1,820 ng/L. Shallow ground water (less than 120 feet below land surface) throughout most of the peninsula, including that which contained elevated concentrations of HgT (exceeding 100 ng/L), appeared to be affected by human activities. All samples contained volatile organic compounds (VOCs) and elevated nitrate-nitrogen (NO3-N, exceeding 0.4 milligrams per liter, mg/L). Most (16 of 22) samples had elevated specific conductance (SC, in excess of 100 microsiemens per centimeter at 25 degrees Celsius). Elevated concentrations of HgT, however, only occurred in five production wells in the Pot Nets Bayside and Lakeside communities. The vertical distribution of HgT in shallow ground water (less than 80 feet below land surface) was determined with samples collected at 5 to 6 vertical-nest short-screened (2 - 5-foot length) monitoring wells installed near Bayside and Lakeside production wells with the highest HgT concentrations (exceeding 1,000 ng/L). Elevated concentrations ofHgT (100-6,380 ng/L) occurred in the shallow aquifer near each well at different depths. Chemical analyses of selected soil, fill, and aquifer sediment samples, obtained during the installation of nested wells, indicated that little HgT occurred in soil or fill at either site (40 micrograms per kilogram, ?g/kg, or less). No HgT was detected (less than 20 ?g/kg) in aquifer sediment samples. These low HgT concentrations imply that neither the soil, fill, nor aquifer sediment was a likely source of the elevated Hg in ground water. Given Hg occurrence appeared to be a ground-water transport phenomenon, the forms of Hg in transport were investigated. Differences in HgT concentrations between raw and filtered (0.1- and (or) 0.4-absolute micrometer pore size) samples from nested wells were random in sign and similar in magnitude to the variability in measuring HgT attributed to field and laboratory methods (? 5-10 percent, for HgT concentrations exceeding 100 ng/L). Thus, Hg transport likely occurred in a dissolved or fine-colloidal nonparticulate phase. Methyl mercury (HgMe) only was detected at low concentrations (0.06 ng/L or less) in nested-well samples with low to moderate concentrations of HgT (less than 366 ng/L). Whether HgMe occurred at similar concentrations in samples with high HgT concentrations was unresolved due to a sample-matrix interference problem. Potential complex forms of Hg were investigated in relation to the occurrence of selected ligands (organic carbon, sulfide, and chloride concentrations) and geochemical conditions (for example, pH and dissolved oxygen concentrations). Only dissolved organic carbon (DOC) appeared directly related to Hg occurrence. Elevated concentrations of HgT and DOC co-occurred in ground water at both Pot Nets sites. The average concentration of DOC was about four times greater in samples from the Pot Nets wells with the highest HgT concentrations (exceeding 1,000 ng/L) than in most Pot Nets o

Halogens in oil and gas production-associated wastewater.

NASA Astrophysics Data System (ADS)

Harkness, J.; Warner, N. R.; Dwyer, G. S.; Mitch, W.; Vengosh, A.

2014-12-01

Elevated chloride and bromide in oil and gas wastewaters that are released to the environment are one of the major environmental risks in areas impacted by shale gas development [Olmstead et al.,2013]. In addition to direct contamination of streams, the potential for formation of highly toxic disinfection by-products (DBPs) in drinking water in utilities located downstream from disposal sites poses a serious risk to human health. Here we report on the occurrence of iodide in oil and gas wastewater. We conducted systematic measurements of chloride, bromide, and iodide in (1) produced waters from conventional oil and gas wells from the Appalachian Basin; (2) hydraulic fracturing flowback fluids from unconventional Marcellus and Fayetteville shale gas, (3) effluents from a shale gas spill site in West Virginia; (4) effluents of oil and gas wastewater disposed to surface water from three brine treatment facilities in western Pennsylvania; and (5) surface waters downstream from the brine treatment facilities. Iodide concentration was measured by isotope dilution-inductively coupled plasma-mass spectrometry, which allowed for a more accurate measurement of iodide in a salt-rich matrix. Iodide in both conventional and unconventional oil and gas produced and flowback waters varied from 1 mg/L to 55 mg/L, with no systematic enrichment in hydraulic fracturing fluids. The similarity in iodide content between the unconventional Marcellus flowback waters and the conventional Appalachian produced waters clearly indicate that the hydraulic fracturing process does not induce additional iodide and the iodide content is related to natural variations in the host formations. Our data show that effluents from the brine treatment facilities have elevated iodide (mean = 20.9±1 mg/L) compared to local surface waters (0.03± 0.1 mg/L). These results indicate that iodide, in addition to chloride and bromide in wastewater from oil and gas production, poses an additional risk to downstream surface water quality and drinking water utilities given the potential of formation of iodate-DBPs in drinking water. Olmstead, S.M. et al. (2013). Shale gas development impacts on surface water quality in Pennsylvania, PNAS, 110, 4962-4967.

A global database of lake surface temperatures collected by in situ and satellite methods from 1985–2009

PubMed Central

Sharma, Sapna; Gray, Derek K; Read, Jordan S; O’Reilly, Catherine M; Schneider, Philipp; Qudrat, Anam; Gries, Corinna; Stefanoff, Samantha; Hampton, Stephanie E; Hook, Simon; Lenters, John D; Livingstone, David M; McIntyre, Peter B; Adrian, Rita; Allan, Mathew G; Anneville, Orlane; Arvola, Lauri; Austin, Jay; Bailey, John; Baron, Jill S; Brookes, Justin; Chen, Yuwei; Daly, Robert; Dokulil, Martin; Dong, Bo; Ewing, Kye; de Eyto, Elvira; Hamilton, David; Havens, Karl; Haydon, Shane; Hetzenauer, Harald; Heneberry, Jocelyne; Hetherington, Amy L; Higgins, Scott N; Hixson, Eric; Izmest’eva, Lyubov R; Jones, Benjamin M; Kangur, Külli; Kasprzak, Peter; Köster, Olivier; Kraemer, Benjamin M; Kumagai, Michio; Kuusisto, Esko; Leshkevich, George; May, Linda; MacIntyre, Sally; Müller-Navarra, Dörthe; Naumenko, Mikhail; Noges, Peeter; Noges, Tiina; Niederhauser, Pius; North, Ryan P; Paterson, Andrew M; Plisnier, Pierre-Denis; Rigosi, Anna; Rimmer, Alon; Rogora, Michela; Rudstam, Lars; Rusak, James A; Salmaso, Nico; Samal, Nihar R; Schindler, Daniel E; Schladow, Geoffrey; Schmidt, Silke R; Schultz, Tracey; Silow, Eugene A; Straile, Dietmar; Teubner, Katrin; Verburg, Piet; Voutilainen, Ari; Watkinson, Andrew; Weyhenmeyer, Gesa A; Williamson, Craig E; Woo, Kara H

2015-01-01

Global environmental change has influenced lake surface temperatures, a key driver of ecosystem structure and function. Recent studies have suggested significant warming of water temperatures in individual lakes across many different regions around the world. However, the spatial and temporal coherence associated with the magnitude of these trends remains unclear. Thus, a global data set of water temperature is required to understand and synthesize global, long-term trends in surface water temperatures of inland bodies of water. We assembled a database of summer lake surface temperatures for 291 lakes collected in situ and/or by satellites for the period 1985–2009. In addition, corresponding climatic drivers (air temperatures, solar radiation, and cloud cover) and geomorphometric characteristics (latitude, longitude, elevation, lake surface area, maximum depth, mean depth, and volume) that influence lake surface temperatures were compiled for each lake. This unique dataset offers an invaluable baseline perspective on global-scale lake thermal conditions as environmental change continues. PMID:25977814

Effects of ocean acidification, warming and melting of sea ice on aragonite saturation of the Canada Basin surface water

NASA Astrophysics Data System (ADS)

Yamamoto-Kawai, M.; McLaughlin, F. A.; Carmack, E. C.

2011-02-01

In 2008, surface waters in the Canada Basin of the Arctic Ocean were found to be undersaturated with respect to aragonite. This is associated with recent extensive melting of sea ice in this region, as well as elevated sea surface temperature and atmospheric CO2 concentrations. We have estimated the relative contribution of each of these controlling factors to the calcium carbonate saturation state (Ω) from observations of dissolved inorganic carbon, total alkalinity and oxygen isotope ratio. Results indicate that the increase in atmospheric CO2 has lowered surface Ω by ˜0.3 in the Canada Basin since the preindustrial period. Recent melting of sea ice has further lowered mean Ω by 0.4, and of this, half was due to dilution of surface water and half was due to the change in air-sea disequilibrium state. Surface water warming has generally counteracted the mean decrease in Ω by 0.1.

A global database of lake surface temperatures collected by in situ and satellite methods from 1985-2009.

PubMed

Sharma, Sapna; Gray, Derek K; Read, Jordan S; O'Reilly, Catherine M; Schneider, Philipp; Qudrat, Anam; Gries, Corinna; Stefanoff, Samantha; Hampton, Stephanie E; Hook, Simon; Lenters, John D; Livingstone, David M; McIntyre, Peter B; Adrian, Rita; Allan, Mathew G; Anneville, Orlane; Arvola, Lauri; Austin, Jay; Bailey, John; Baron, Jill S; Brookes, Justin; Chen, Yuwei; Daly, Robert; Dokulil, Martin; Dong, Bo; Ewing, Kye; de Eyto, Elvira; Hamilton, David; Havens, Karl; Haydon, Shane; Hetzenauer, Harald; Heneberry, Jocelyne; Hetherington, Amy L; Higgins, Scott N; Hixson, Eric; Izmest'eva, Lyubov R; Jones, Benjamin M; Kangur, Külli; Kasprzak, Peter; Köster, Olivier; Kraemer, Benjamin M; Kumagai, Michio; Kuusisto, Esko; Leshkevich, George; May, Linda; MacIntyre, Sally; Müller-Navarra, Dörthe; Naumenko, Mikhail; Noges, Peeter; Noges, Tiina; Niederhauser, Pius; North, Ryan P; Paterson, Andrew M; Plisnier, Pierre-Denis; Rigosi, Anna; Rimmer, Alon; Rogora, Michela; Rudstam, Lars; Rusak, James A; Salmaso, Nico; Samal, Nihar R; Schindler, Daniel E; Schladow, Geoffrey; Schmidt, Silke R; Schultz, Tracey; Silow, Eugene A; Straile, Dietmar; Teubner, Katrin; Verburg, Piet; Voutilainen, Ari; Watkinson, Andrew; Weyhenmeyer, Gesa A; Williamson, Craig E; Woo, Kara H

2015-01-01

Global environmental change has influenced lake surface temperatures, a key driver of ecosystem structure and function. Recent studies have suggested significant warming of water temperatures in individual lakes across many different regions around the world. However, the spatial and temporal coherence associated with the magnitude of these trends remains unclear. Thus, a global data set of water temperature is required to understand and synthesize global, long-term trends in surface water temperatures of inland bodies of water. We assembled a database of summer lake surface temperatures for 291 lakes collected in situ and/or by satellites for the period 1985-2009. In addition, corresponding climatic drivers (air temperatures, solar radiation, and cloud cover) and geomorphometric characteristics (latitude, longitude, elevation, lake surface area, maximum depth, mean depth, and volume) that influence lake surface temperatures were compiled for each lake. This unique dataset offers an invaluable baseline perspective on global-scale lake thermal conditions as environmental change continues.

A global database of lake surface temperatures collected by in situ and satellite methods from 1985–2009

USGS Publications Warehouse

Sharma, Sapna; Gray, Derek; Read, Jordan S.; O'Reilly, Catherine; Schneider, Philipp; Qudrat, Anam; Gries, Corinna; Stefanoff, Samantha; Hampton, Stephanie; Hook, Simon; Lenters, John; Livingstone, David M.; McIntyre, Peter B.; Adrian, Rita; Allan, Mathew; Anneville, Orlane; Arvola, Lauri; Austin, Jay; Bailey, John E.; Baron, Jill S.; Brookes, Justin D; Chen, Yuwei; Daly, Robert; Ewing, Kye; de Eyto, Elvira; Dokulil, Martin; Hamilton, David B.; Havens, Karl; Haydon, Shane; Hetzenaeur, Harald; Heneberry, Jocelyn; Hetherington, Amy; Higgins, Scott; Hixson, Eric; Izmest'eva, Lyubov; Jones, Benjamin M.; Kangur, Kulli; Kasprzak, Peter; Kraemer, Benjamin; Kumagai, Michio; Kuusisto, Esko; Leshkevich, George; May, Linda; MacIntyre, Sally; Dörthe Müller-Navarra,; Naumenko, Mikhail; Noges, Peeter; Noges, Tiina; Pius Niederhauser,; North, Ryan P.; Andrew Paterson,; Plisnier, Pierre-Denis; Rigosi, Anna; Rimmer, Alon; Rogora, Michela; Rudstam, Lars G.; Rusak, James A.; Salmaso, Nico; Samal, Nihar R.; Daniel E. Schindler,; Geoffrey Schladow,; Schmidt, Silke R.; Tracey Schultz,; Silow, Eugene A.; Straile, Dietmar; Teubner, Katrin; Verburg, Piet; Voutilainen, Ari; Watkinson, Andrew; Weyhenmeyer, Gesa A.; Craig E. Williamson,; Kara H. Woo,

2015-01-01

Global environmental change has influenced lake surface temperatures, a key driver of ecosystem structure and function. Recent studies have suggested significant warming of water temperatures in individual lakes across many different regions around the world. However, the spatial and temporal coherence associated with the magnitude of these trends remains unclear. Thus, a global data set of water temperature is required to understand and synthesize global, long-term trends in surface water temperatures of inland bodies of water. We assembled a database of summer lake surface temperatures for 291 lakes collected in situ and/or by satellites for the period 1985–2009. In addition, corresponding climatic drivers (air temperatures, solar radiation, and cloud cover) and geomorphometric characteristics (latitude, longitude, elevation, lake surface area, maximum depth, mean depth, and volume) that influence lake surface temperatures were compiled for each lake. This unique dataset offers an invaluable baseline perspective on global-scale lake thermal conditions as environmental change continues.

Undecompressed microbial populations from the deep sea.

PubMed Central

Jannasch, H J; Wirsen, C O; Taylor, C D

1976-01-01

Metabolic transformations of glutamate and Casamino Acids by natural microbial populations collected from deep waters (1,600 to 3,100 m) were studied in decompressed and undecompressed samples. Pressure-retaining sampling/incubation vessels and appropriate subsampling/incubation vessels and appropriate subsampling techniques permitted time course experiments. In all cases the metabolic activity in undecompressed samples was lower than it was when incubated at 1 atm. Surface water controls showed a reduced activity upon compression. The processes involving substrate incorporation into cell material were more pressure sensitive than was respiration. The low utilization of substrates, previously found by in situ incubations for up to 12 months, was confirmed and demonstrated to consist of an initial phase of activity, in the range of 5 to 60 times lower than the controls, followed by a stationary phase of virtually no substrate utilization. No barophilic growth response (higher rates at elevated pressure than at 1 atm) was recorded; all populations observed exhibition various degrees of barotolerance. Images PMID:791117

RIPGIS-NET: a GIS tool for riparian groundwater evapotranspiration in MODFLOW.

PubMed

Ajami, Hoori; Maddock, Thomas; Meixner, Thomas; Hogan, James F; Guertin, D Phillip

2012-01-01

RIPGIS-NET, an Environmental System Research Institute (ESRI's) ArcGIS 9.2/9.3 custom application, was developed to derive parameters and visualize results of spatially explicit riparian groundwater evapotranspiration (ETg), evapotranspiration from saturated zone, in groundwater flow models for ecohydrology, riparian ecosystem management, and stream restoration. Specifically RIPGIS-NET works with riparian evapotranspiration (RIP-ET), a modeling package that works with the MODFLOW groundwater flow model. RIP-ET improves ETg simulations by using a set of eco-physiologically based ETg curves for plant functional subgroups (PFSGs), and separates ground evaporation and plant transpiration processes from the water table. The RIPGIS-NET program was developed in Visual Basic 2005, .NET framework 2.0, and runs in ArcMap 9.2 and 9.3 applications. RIPGIS-NET, a pre- and post-processor for RIP-ET, incorporates spatial variability of riparian vegetation and land surface elevation into ETg estimation in MODFLOW groundwater models. RIPGIS-NET derives RIP-ET input parameters including PFSG evapotranspiration curve parameters, fractional coverage areas of each PFSG in a MODFLOW cell, and average surface elevation per riparian vegetation polygon using a digital elevation model. RIPGIS-NET also provides visualization tools for modelers to create head maps, depth to water table (DTWT) maps, and plot DTWT for a PFSG in a polygon in the Geographic Information System based on MODFLOW simulation results. © 2011, The Author(s). Ground Water © 2011, National Ground Water Association.

Kinematics and depth-integrated terms in surf zone waves from laboratory measurement

NASA Astrophysics Data System (ADS)

Stansby, Peter K.; Feng, Tong

2005-04-01

Kinematics of nominally periodic surf zone waves have been measured in the laboratory using LDA (laser Doppler anemometry), above trough level as well as below, for weakly plunging breakers transforming into bores in shallower water. The aim was to determine, through phase- or ensemble-averaging, periodic flow structures in a two-dimensional vertical plane, from large-scale down to small-scale vortical structures. Coherent multiple vortical structures were evident at the initiation of breaking, becoming elongated along the surface during bore propagation. The initial region is likely to become more extensive as waves become more strongly plunging and could explain the difference in turbulence characteristics between plunging and spilling breakers observed elsewhere. Comparison of vorticity magnitudes with hydraulic-jump measurements showed some similarities during the initial stages of breaking, but these quickly grew less as breaking progressed into shallower water. Period-averaged kinematics and vorticity were also obtained showing shoreward mass transport above trough level and undertow below, with a thick layer of vorticity at trough level and a thin layer of vorticity of opposite rotation at the bed. There were also concentrated regions of mean vorticity near the end of the plunging region. Residual turbulence of relatively high frequency was presented as Reynolds stresses, showing marked anisotrophy. Dynamic pressure (pressure minus its hydrostatic component) was determined from the kinematics. The magnitudes of different effects were evaluated through the depth-integrated Reynolds-averaged Navier-Stokes (RANS) equations, which may be reduced to nine terms (the standard inviscid terms of the shallow-water equations conserving mass and momentum with hydrostatic pressure, and six additional terms), assuming that the complex, often aerated, free surface is treated as a simple interface. All terms were evaluated, assuming that a space/time transformation was justified with a slowly varying phase speed, and the net balance was always small in relation to the maxima of the larger terms. Terms due to dynamic pressure and vertical dispersion (due to the vertical variation of velocity) were as significant as the three terms in the inviscid shallow-water equations; terms involving residual turbulence were insignificant. The r.m.s. (root mean square) variation of each along the slope is highly irregular, with the inertia term due to (Eulerian) acceleration always greatest. This is consistent with complex, though repetitive, coherent structures. Modelling the flow with the shallow-water equations, using the surface elevation variation at the break point as input, nevertheless gave a good prediction of the wave height variation up the slope.

Transforming Surface Water Hydrology Through SWOT Altimetry

NASA Astrophysics Data System (ADS)

Alsdorf, Douglas; Mognard, Nelly; Rodriguez, Ernesto

2013-09-01

SWOT will measure water surface elevations across rivers, lakes, wetlands, and reservoirs with a 120km wide swath using decimeter-scale pixels having centimetric-scale height accuracies. Nothing like this "water surface topography" has been collected on a consistent basis from any method. Thus, SWOT will provide a transformative measurement for global hydrology. Storage change measurements from SWOT are expected to have an error of 10% or better for 250m2 and larger water bodies. Discharge estimation is complicated by the lack of channel bathymetric knowledge. Nevertheless, two model-based studies of the Ohio River suggest SWOT discharge errors will be 10%. Important questions will be addressed via SWOT measurements, e.g., (1) What is the water balance of the Congo Basin and indeed of any basin? (2) Where does a wetland receive its water: from upland runoff or from an adjacent river? (3) What are the implications for transboundary rivers?

EverVIEW: a visualization platform for hydrologic and Earth science gridded data

USGS Publications Warehouse

Romañach, Stephanie S.; McKelvy, James M.; Suir, Kevin J.; Conzelmann, Craig

2015-01-01

The EverVIEW Data Viewer is a cross-platform desktop application that combines and builds upon multiple open source libraries to help users to explore spatially-explicit gridded data stored in Network Common Data Form (NetCDF). Datasets are displayed across multiple side-by-side geographic or tabular displays, showing colorized overlays on an Earth globe or grid cell values, respectively. Time-series datasets can be animated to see how water surface elevation changes through time or how habitat suitability for a particular species might change over time under a given scenario. Initially targeted toward Florida's Everglades restoration planning, EverVIEW has been flexible enough to address the varied needs of large-scale planning beyond Florida, and is currently being used in biological planning efforts nationally and internationally.

Impact of meander geometry and stream flow events on residence times and solute transport in the intra-meander flow

NASA Astrophysics Data System (ADS)

Nasir Mahmood, Muhammad; Schmidt, Christian; Trauth, Nico

2017-04-01

Stream morphological features, in combination with hydrological variability play a key role in water and solute exchange across surface and subsurface waters. Meanders are prominent morphological features within stream systems which exhibit unique hydrodynamics. The water surface elevation difference across the inner bank of a meander induces lateral hyporheic exchange within the intra-meander region. This hyporheic flow is characterized by considerably prolonged flow paths and residence times (RT) compared to smaller scales of hyporheic exchange. In this study we examine the impact of different meander geometries on the intra-meander hyporheic flow field and solute mobilization under both steady state and transient flow conditions. We developed a number of artificial meander shape scenarios, representing various meander evolution stages, ranging from a typical initial to advanced stage (near cut off ) meander. Three dimensional steady state numerical groundwater flow simulations including the unsaturated zone were performed for the intra-meander region. The meandering stream was implemented in the model by adjusting the top layers of the modelling domain to the streambed elevation and assigning linearly decreasing head boundary conditions to the streambed cells. Residence times for the intra-meander region were computed by advective particle tracking across the inner bank of meander. Selected steady state cases were extended to transient flow simulations to evaluate the impact of stream discharge events on the temporal behavior of the water exchange and solute transport in the intra-meander region. The transient stream discharge was simulated for a number of discharge events of variable duration and peak height using the surface water model HEC-RAS. Transient hydraulic heads obtained from the surface water model were applied as transient head boundary conditions to the streambed cells of the groundwater model. A solute concentration source was added in the unsaturated zone to evaluate the effect of transient flow conditions on solute mobilization. Our preliminary results indicate that residence times ranging from 0.5 to 250 hours are influenced by meander geometry, as well as the size of the intra-meander area. In general, we found that larger intra-meander areas lead to longer flow paths and higher mean intra-meander residence times (MRTs). The shortest RTs were observed near the meander neck in all scenarios, a feature most predominant in more developed meander resulting shorter MRTs. Transient modelling results show that fluctuations in stream hydraulic head influence the transport and zonation of the solute concentration in the intra-meander area with higher and longer stream discharge events leading to stronger mobilization and removal of solutes dominated mainly around meander neck area.

Interactive Mapping of Inundation Metrics Using Cloud Computing for Improved Floodplain Conservation and Management

NASA Astrophysics Data System (ADS)

Bulliner, E. A., IV; Lindner, G. A.; Bouska, K.; Paukert, C.; Jacobson, R. B.

2017-12-01

Within large-river ecosystems, floodplains serve a variety of important ecological functions. A recent survey of 80 managers of floodplain conservation lands along the Upper and Middle Mississippi and Lower Missouri Rivers in the central United States found that the most critical information needed to improve floodplain management centered on metrics for characterizing depth, extent, frequency, duration, and timing of inundation. These metrics can be delivered to managers efficiently through cloud-based interactive maps. To calculate these metrics, we interpolated an existing one-dimensional hydraulic model for the Lower Missouri River, which simulated water surface elevations at cross sections spaced (<1 km) to sufficiently characterize water surface profiles along an approximately 800 km stretch upstream from the confluence with the Mississippi River over an 80-year record at a daily time step. To translate these water surface elevations to inundation depths, we subtracted a merged terrain model consisting of floodplain LIDAR and bathymetric surveys of the river channel. This approach resulted in a 29000+ day time series of inundation depths across the floodplain using grid cells with 30 m spatial resolution. Initially, we used these data on a local workstation to calculate a suite of nine spatially distributed inundation metrics for the entire model domain. These metrics are calculated on a per pixel basis and encompass a variety of temporal criteria generally relevant to flora and fauna of interest to floodplain managers, including, for example, the average number of days inundated per year within a growing season. Using a local workstation, calculating these metrics for the entire model domain requires several hours. However, for the needs of individual floodplain managers working at site scales, these metrics may be too general and inflexible. Instead of creating a priori a suite of inundation metrics able to satisfy all user needs, we present the usage of Google's cloud-based Earth Engine API to allow users to define and query their own inundation metrics from our dataset and produce maps nearly instantaneously. This approach allows users to select the time periods and inundation depths germane to managing local species, potentially facilitating conservation of floodplain ecosystems.

Antimicrobial Effect of An Essential Oil Blend on Surface-attached Salmonella on Polyvinyl Chloride

USDA-ARS?s Scientific Manuscript database

The majority of drinking water lines for broilers are made of polyvinyl chloride (PVC) and surface attachment of Salmonella on the inner surface of water lines can be the initial stage of biofilm development. These biofilms can be the source of Salmonella infection in water lines and are known to re...

Mountain Meadows and their contribution to Sierra Nevada Water Resources

NASA Astrophysics Data System (ADS)

Cornwell, K.; Brown, K.; Monohan, C.

2007-12-01

Human alterations of California's waterscape have exploited rivers, wetlands and meadows of the Sierra Nevada. A century of intensive logging, mining, railroad building, development, fire suppression, and grazing by sheep and cattle has left only 25 percent "intact" natural habitat in the Sierra Nevada (SNEP 1995). Much of this intact habitat occurs at higher elevations, often in non-forested alpine or in less productive forests and woodlands where mountain meadows exist. Mountain meadows serve many ecological functions including habitat for threatened and endangered terrestrial and aquatic species, and are considered to be essential physical components to watershed function and hydrology with significant water storage, filtration and flood attenuation properties. This study evaluates the physical characteristics and hydrologic function of Clarks Meadow located in northern Sierra Nevada, Plumas County, California. In 2001, Clarks Meadow received significant restoration work in the upstream half of the meadow which diverted the stream from an incised channel to a shallow remnant channel, creating a stable channel and reconnecting the groundwater table to the stream. No restoration work was done in the lower half of Clarks Meadow where the stream still flows through an incised channel. Clarks Meadow offers a unique opportunity to study both a restored, hydrologically functional meadow and an incised, hydrologically disconnected stretch of the same stream and meadow. The physical characteristics of Clarks Meadows that were measured include surface area, subsurface thickness, porosity and permeability of subsurface materials, potential water storage volume, and surface infiltration rates. The goal of this study is to refine hydrologic characterization methods, quantify water storage potential of a healthy, non-incised meadow and assess its role in attenuating flood flows during high discharge times. Initial results suggest that significant subsurface storage volume is available in the meadow. Incising conditions in the unstable lower channel tends to dewater the lower portion of the meadow which encourages bank erosion through piping and corrasion. This study addresses questions that have broad implications for water management throughout the state because much of California gets water from Sierra high elevation watersheds in which meadows are thought to play a critical role in sustained long-term hydrologic function. The results of this study will be used to inform Integrated Regional Water Management Plans throughout Northern California.

Treatment of Chlorinated Aliphatic Contamination of Groundwater by Horizontal Recirculation Wells and by Constructed Vertical Flow Wetlands

DTIC Science & Technology

2002-03-01

groundwater laden with contaminants. Once the contaminated water is at the surface, it must be treated for contaminant destruction, generally by...treatment walls only work under very specific hydrogeologic conditions (relatively shallow water table, no seasonal fluctuations in groundwater flow...GCWs Elevation Schematic Water Table Contaminated Groundwater Contaminated Groundwater Treated Groundwater Treated Groundwater Reactive Porous Medium

Instrumental record of debris flow initiation during natural rainfall: Implications for modeling slope stability

USGS Publications Warehouse

Montgomery, D.R.; Schmidt, K.M.; Dietrich, W.E.; McKean, J.

2009-01-01

The middle of a hillslope hollow in the Oregon Coast Range failed and mobilized as a debris flow during heavy rainfall in November 1996. Automated pressure transducers recorded high spatial variability of pore water pressure within the area that mobilized as a debris flow, which initiated where local upward flow from bedrock developed into overlying colluvium. Postfailure observations of the bedrock surface exposed in the debris flow scar reveal a strong spatial correspondence between elevated piezometric response and water discharging from bedrock fractures. Measurements of apparent root cohesion on the basal (Cb) and lateral (Cl) scarp demonstrate substantial local variability, with areally weighted values of Cb = 0.1 and Cl = 4.6 kPa. Using measured soil properties and basal root strength, the widely used infinite slope model, employed assuming slope parallel groundwater flow, provides a poor prediction of hydrologie conditions at failure. In contrast, a model including lateral root strength (but neglecting lateral frictional strength) gave a predicted critical value of relative soil saturation that fell within the range defined by the arithmetic and geometric mean values at the time of failure. The 3-D slope stability model CLARA-W, used with locally observed pore water pressure, predicted small areas with lower factors of safety within the overall slide mass at sites consistent with field observations of where the failure initiated. This highly variable and localized nature of small areas of high pore pressure that can trigger slope failure means, however, that substantial uncertainty appears inevitable for estimating hydrologie conditions within incipient debris flows under natural conditions. Copyright 2009 by the American Geophysical Union.

Assessment of the hydrologic interaction between Imikpuk Lake and the adjacent airstrip site near Barrow, Alaska, 1993

USGS Publications Warehouse

McCarthy, Kathleen A.; Solin, Gary L.; Trabant, Dennis

1994-01-01

Imikpuk Lake serves as the drinking water source for the Ukpeagvik Inupiat Corporation-National Arctic Research Laboratory (UIC-NARL), formerly known as the Naval Arctic Research Laboratory, near Barrow, Alaska. During the 1970's and 1980's, accidental releases of more than 1,300 cubic meters of various types of fuel occurred at the airstrip site adjacent to the lake. To aid an assessment of the potential risk 10 the quality of water in the lake posed by fuel remaining in the subsurface, the hydrologic interaction between the lake and ground water at the airstrip site was examined. The study area lies within the region of continuous permafrost where hydrologic processes are largely controlled by the short annual thaw season and the presence of near-surface permafrost. Runoff occurs for only a short period each year, typically from early or mid-June to late September, and a shallow ground- water system develops during approximately the same period as a result of shallow thawing of the subsurface. During the spring and summer of 1993, snowpack and surface-water data were collected throughout the Imikpuk Lake basin, and subsurface- flow-system data were collected at the airstrip site. The total annual inflow to the lake was estimated 10 be approximately 300,000 cubic meters per year, based on four methods of estimation. The ground-water flow system at the airstrip site is complex, primarily because of variations in local land-surface topography. Subsurface frost-elevation data indicate that a permafrost ridge exists beneath one of the elevated building pads at the site. Similar ridges beneath elevated roadways at the site may act as impediments to ground-water flow, reducing the flux of subsurface water to Imikpuk Lake. However, on the basis of the assumption that such impediments do not reduce flux substantially, the ground-water flux from the airstrip site was estimated to be approximately 173 cubic meters per year--less than 0.1 percent of the estimated annual inflow to Imikpuk Lake.

Spatial distribution and controlling factors of stable isotopes in meteoric waters on the Tibetan Plateau: Implications for paleoelevation reconstruction

NASA Astrophysics Data System (ADS)

Li, Lin; Garzione, Carmala N.

2017-02-01

Debates persist about the interpretations of stable isotope based proxies for the surface uplift of the central-northern Tibetan Plateau. These disputes arise from the uncertain relationship between elevation and the δ18 O values of meteoric waters, based on modern patterns of isotopes in precipitation and surface waters. We present a large river water data set (1,340 samples) covering most parts of the Tibetan Plateau to characterize the spatial variability and controlling factors of their isotopic compositions. Compared with the amount-weighted mean annual oxygen isotopic values of precipitation, we conclude that river water is a good substitute for isotopic studies of precipitation in the high flat (e.g., elevation >3,300 m) interior of the Tibetan Plateau in the mean annual timescale. We construct, for the first time based on field data, contour maps of isotopic variations of meteoric waters (δ18 O, δD and d-excess) on the Tibetan Plateau. In the marginal mountainous regions of the Plateau, especially the southern through eastern margins, the δ18 O and δD values of river waters decrease with increasing mean catchment elevation, which can be modeled as a Rayleigh distillation process. However, in the interior of the Plateau, northward increasing trends in δ18 O and δD values are pronounced and present robust linear relations; d-excess values are lower than the marginal regions and exhibit distinct contrasts between the eastern (8 ‰- 12 ‰) and western (<8‰) Plateau. We suggest that these isotopic features of river waters in the interior of the Tibetan Plateau result from the combined effects of: 1) mixing of different moisture sources transported by the South Asian monsoon and Westerly winds; 2) contribution of moisture from recycled surface water; and 3) sub-cloud evaporation. We further provide a sub-cloud evaporation modified Rayleigh distillation and mixing model to simulate the isotopic variations in the western Plateau. Results of this work suggest that stable isotope-based paleoaltimetry studies are reliable in the southern through eastern Plateau margins; towards the central-northern Plateau, this method cannot be applied without additional constraints and/or large uncertainties.

Methods for developing time-series climate surfaces to drive topographically distributed energy- and water-balance models

USGS Publications Warehouse

Susong, D.; Marks, D.; Garen, D.

1999-01-01

Topographically distributed energy- and water-balance models can accurately simulate both the development and melting of a seasonal snowcover in the mountain basins. To do this they require time-series climate surfaces of air temperature, humidity, wind speed, precipitation, and solar and thermal radiation. If data are available, these parameters can be adequately estimated at time steps of one to three hours. Unfortunately, climate monitoring in mountain basins is very limited, and the full range of elevations and exposures that affect climate conditions, snow deposition, and melt is seldom sampled. Detailed time-series climate surfaces have been successfully developed using limited data and relatively simple methods. We present a synopsis of the tools and methods used to combine limited data with simple corrections for the topographic controls to generate high temporal resolution time-series images of these climate parameters. Methods used include simulations, elevational gradients, and detrended kriging. The generated climate surfaces are evaluated at points and spatially to determine if they are reasonable approximations of actual conditions. Recommendations are made for the addition of critical parameters and measurement sites into routine monitoring systems in mountain basins.Topographically distributed energy- and water-balance models can accurately simulate both the development and melting of a seasonal snowcover in the mountain basins. To do this they require time-series climate surfaces of air temperature, humidity, wind speed, precipitation, and solar and thermal radiation. If data are available, these parameters can be adequately estimated at time steps of one to three hours. Unfortunately, climate monitoring in mountain basins is very limited, and the full range of elevations and exposures that affect climate conditions, snow deposition, and melt is seldom sampled. Detailed time-series climate surfaces have been successfully developed using limited data and relatively simple methods. We present a synopsis of the tools and methods used to combine limited data with simple corrections for the topographic controls to generate high temporal resolution time-series images of these climate parameters. Methods used include simulations, elevational gradients, and detrended kriging. The generated climate surfaces are evaluated at points and spatially to determine if they are reasonable approximations of actual conditions. Recommendations are made for the addition of critical parameters and measurement sites into routine monitoring systems in mountain basins.

Cycling of oxyanion-forming trace elements in groundwaters from a freshwater deltaic marsh

NASA Astrophysics Data System (ADS)

Telfeyan, Katherine; Breaux, Alexander; Kim, Jihyuk; Kolker, Alexander S.; Cable, Jaye E.; Johannesson, Karen H.

2018-05-01

Pore waters and surface waters were collected from a freshwater system in southeastern Louisiana to investigate the geochemical cycling of oxyanion-forming trace elements (i.e., Mo, W, As, V). A small bayou (Bayou Fortier) receives input from a connecting lake (Lac des Allemands) and groundwater input at the head approximately 5 km directly south of the Mississippi River. Marsh groundwaters exchange with bayou surface water but are otherwise relatively isolated from outside hydrologic forcings, such as tides, storms, and effects from local navigation canals. Rather, redox processes in the marsh groundwaters appear to drive changes in trace element concentrations. Elevated dissolved S(-II) concentrations in marsh groundwaters suggest greater reducing conditions in the late fall and winter as compared to the spring and late summer. The data suggest that reducing conditions in marsh groundwaters initiate the dissolution of Fe(III)/Mn(IV) oxide/hydroxide minerals, which releases adsorbed and/or co-precipitated trace elements into solution. Once in solution, the fate of these elements is determined by complexation with aqueous species and precipitation with iron sulfide minerals. The trace elements remain soluble in the presence of Fe(III)- and SO42-- reducing conditions, suggesting that either kinetic limitations or complexation with aqueous ligands obfuscates the correlation between V and Mo sequestration in sediments with reducing or euxinic conditions.

Freshwater molluscs as indicators of bioavailability and toxicity of metals in surface-water systems

USGS Publications Warehouse

Elder, John F.; Collins, Jerilyn J.; Ware, George W.

1991-01-01

During the past several decades, studies from a variety of locations have demonstrated widespread occurrence of metals in surface waters at concentrations significantly higher than background levels. Elevated concentrations are not limited to certain water types or polluted areas; they appear in all types of systems and in all geographic areas. It is clear that metals enter the aquatic systems from diverse sources, both point and nonpoint, and they can be readily transported from one system to another. Transport routes include atmospheric, terrestrial, subterranean, aquatic, and biological pathways (Elder 1988; Salomons and Forstner 1984).

Steady flow past a vertical surface-piercing circular cylinder

NASA Astrophysics Data System (ADS)

Chaplin, J. R.; Teigen, P.

2003-09-01

This paper describes experiments in which a vertical surface-piercing circular cylinder with a large draught was towed at steady speeds through water initially at rest. The cylinder diameter d was 210mm, and measurements were made of pressures around its circumference at elevations between 2.4d below still water level to 0.7d above, at Froude numbers (based on d) up to 1.67. The tests were carried out at a constant ratio of Reynolds number to Froude number of 2.79×105. The total resistance coefficient reached a maximum at a Froude number of about 1, when that part of the loading that can be attributed to the presence of the free surface was equivalent to the submerged form drag on a length of cylinder of about 0.9d. Measurements are also presented of the run-up on the front of the cylinder and of the depth of the depression at the back. Previous measurements by Hay (Flow about Semi-submerged Cylinders of Finite Length. Princeton University Report, Princeton, NJ, 1947) for the case of a cylinder with a submerged free end, and by Hsieh (Proc. Am. Soc. Civil Eng. 90 (1964) 161) of forces on cylinders standing on the floor of an open channel, are reanalysed. In most respects these results are found to be compatible with the present data for a cylinder of large draught.

Assessment of Shallow-Water Habitat Availability in Modified Dike Structures, Lower Missouri River, 2004

USGS Publications Warehouse

Jacobson, Robert B.; Elliott, Caroline M.; Johnson, Harold E.

2004-01-01

This study documented the effects of wing-dike notching on the availabilit of shallow water habitat in the Lower Missouri River. Five wing dikes were surveyed in late May 2004 after they were notched in early May as part of shallow-water habitat (SWH) rehabilitation activities undertaken by the U.S. Army Corps of Engineers. Surveys included high-resolution hydroacoustic depth, velocity, and substrate mapping. Relations of bottom elevations within the wing dike fields to index discharges and water-surface elevations indicate that little habitat meeting the SWH definition was created immediately following notching. This result is not unexpected, as significant geomorphic adjustment may require large flow events. Depth, velocity, and substrate measurements in the post-rehabilitation time period provide baseline data for monitoring ongoing changes. Differences in elevation and substrate were noted at all sites. Most dike fields showed substantial aggradation and replacement of mud substrate with sandier sediment, although the changes did not result in increased availability of SWH at the index discharge. It is not known how much of the elevation and substrate changes can be attributed directly to notching and how much would result from normal sediment transport variation.

Use of fathometers and electrical-conductivity probes to monitor riverbed scour at bridge piers

USGS Publications Warehouse

Hayes, Donald C.; Drummond, F.E.

1995-01-01

Two methods, a fathometer system and an electrical- conductivity probe system, were developed to monitor scour at bridge piers. The scour-monitoring systems consisted of a sensor (fathometer or electrical- conductivity probe), power supply, data logger, relay, and system program. The fathometer system was installed and tested at a bridge over the Leipsic River at Leipsic, Delaware, and at a bridge over Sinepuxent Bay near Ocean City. Maryland. Field data collected indicate that fathometers can be used to identify and monitor the riverbed elevation if post processing of the data and trends in the data are used to determine the riverbed location in relation to the transducer. The accuracy of the system is approximately the same as the resolution of the fathometer. Signal scatter can be a major source of error in the data. The electrical- conductivity probe system was installed and tested at a bridge over the Pamunkey River near Hanover, Virginia. The approximate elevation of the riverbed is determined by comparing conductivities of the surface-water flow with conductivities of submerged bed material from sensors located in each. Field data collected indicate that an electrical- conductivity probe, as tested, has limited usefulness in identifying and monitoring the riverbed elevation during high flows. As the discharge increases, the concentration of sediment in the surface-water flow increases, especially near the riverbed. Conductivities, measured at the sensors in the surface-water flow could not be distinguished from conductivities measured at the shallowest sensor in the submerged bed material.

Ground Water Levels for NGEE Areas A, B, C and D, Barrow, Alaska, 2012-2014

DOE Data Explorer

Anna Liljedahl; Cathy Wilson

2015-06-08

Ice wedge polygonal tundra water levels were measured at a total of 45 locations representing polygon centers and troughs during three summers. Early season water levels, which were still affected by ice and snow, are represented by manual measurements only. Continuous (less than hourly) measurements followed through early fall (around mid-Sep). The data set contains inundation depth (cm), absolute water level and local ground surface elevation (masl).

Ground and surface water developmental toxicity at a municipal landfill--Description and weather-related variation

USGS Publications Warehouse

Bruner, M.A.; Rao, M.; Dumont, J.N.; Hull, M.; Jones, T.; Bantle, J.A.

1998-01-01

Contaminated groundwater poses a significant health hazard and may also impact wildlife such as amphibians when it surfaces. Using FETAX (Frog Embryo Teratogenesis Assay-Xenopus), the developmental toxicity of ground and surface water samples near a closed municipal landfill at Norman, OK, were evaluated. The groundwater samples were taken from a network of wells in a shallow, unconfined aquifer downgradient from the landfill. Surface water samples were obtained from a pond and small stream adjacent to the landfill. Surface water samples from a reference site in similar habitat were also analyzed. Groundwater samples were highly toxic in the area near the landfill, indicating a plume of toxicants. Surface water samples from the landfill site demonstrated elevated developmental toxicity. This toxicity was temporally variable and was significantly correlated with weather conditions during the 3 days prior to sampling. Mortality was negatively correlated with cumulative rain and relative humidity. Mortality was positively correlated with solar radiation and net radiation. No significant correlations were observed between mortality and weather parameters for days 4–7 preceding sampling.

Enhancement of Biomass and Lipid Productivities of Water Surface-Floating Microalgae by Chemical Mutagenesis

PubMed Central

Nojima, Daisuke; Ishizuka, Yuki; Muto, Masaki; Ujiro, Asuka; Kodama, Fumito; Yoshino, Tomoko; Maeda, Yoshiaki; Matsunaga, Tadashi; Tanaka, Tsuyoshi

2017-01-01

Water surface-floating microalgae have great potential for biofuel applications due to the ease of the harvesting process, which is one of the most problematic steps in conventional microalgal biofuel production. We have collected promising water surface-floating microalgae and characterized their capacity for biomass and lipid production. In this study, we performed chemical mutagenesis of two water surface-floating microalgae to elevate productivity. Floating microalgal strains AVFF007 and FFG039 (tentatively identified as Botryosphaerella sp. and Chlorococcum sp., respectively) were exposed to ethyl methane sulfonate (EMS) or 1-methyl-3-nitro-1-nitrosoguanidine (MNNG), and pale green mutants (PMs) were obtained. The most promising FFG039 PM formed robust biofilms on the surface of the culture medium, similar to those formed by wild type strains, and it exhibited 1.7-fold and 1.9-fold higher biomass and lipid productivities than those of the wild type. This study indicates that the chemical mutation strategy improves the lipid productivity of water surface-floating microalgae without inhibiting biofilm formation and floating ability. PMID:28555001

Enhancement of Biomass and Lipid Productivities of Water Surface-Floating Microalgae by Chemical Mutagenesis.

PubMed

Nojima, Daisuke; Ishizuka, Yuki; Muto, Masaki; Ujiro, Asuka; Kodama, Fumito; Yoshino, Tomoko; Maeda, Yoshiaki; Matsunaga, Tadashi; Tanaka, Tsuyoshi

2017-05-27

Water surface-floating microalgae have great potential for biofuel applications due to the ease of the harvesting process, which is one of the most problematic steps in conventional microalgal biofuel production. We have collected promising water surface-floating microalgae and characterized their capacity for biomass and lipid production. In this study, we performed chemical mutagenesis of two water surface-floating microalgae to elevate productivity. Floating microalgal strains AVFF007 and FFG039 (tentatively identified as Botryosphaerella sp. and Chlorococcum sp., respectively) were exposed to ethyl methane sulfonate (EMS) or 1-methyl-3-nitro-1-nitrosoguanidine (MNNG), and pale green mutants (PMs) were obtained. The most promising FFG039 PM formed robust biofilms on the surface of the culture medium, similar to those formed by wild type strains, and it exhibited 1.7-fold and 1.9-fold higher biomass and lipid productivities than those of the wild type. This study indicates that the chemical mutation strategy improves the lipid productivity of water surface-floating microalgae without inhibiting biofilm formation and floating ability.

Structures and processes of biological soil crusts during initial ecosystem genesis of an artificial watershed in Lusatia, NE Germany

NASA Astrophysics Data System (ADS)

Spröte, Roland; Fischer, Thomas; Veste, Maik; Yair, Aaron; Wiehe, Wolfgang; Lange, Philipp; Bens, Oliver; Raab, Thomas; Hüttl, Reinhard F.

2010-05-01

The influence of biological soil crusts (BSC) in natural ecosystems on structures and processes is well investigated. In southern Brandenburg (NE Germany) it was possible to study the development of BSCs during initial ecosystem genesis on the artificial water catchment 'Hühnerwasser'. The experimental site is located in the recultivation area of the lignite open-cast mining district of southern Brandenburg (Germany). The geomorphological differentiation at the site was related to crust development, where substrate-dependent water availability defined the crust types. The mosaic-like pattern of the BSCs was associated with the distribution of fine-grained material. We defined three types if BSC: (a) initial cyanobacterial crusts (BSC-I), (b) cyanobacterial and green algae crusts on the soil surface (BSC-CG) and (c) crusts with mosses (BSC-M) between dense vegetation. The chlorophyll A content as an index for the biomass of the cryptogams increased significantly with crust type from 0.97 mg m-2 (BSC-I), 6.34 mg m-2 (BSC-CG) to 13.32 mg m-2(BSC-M). The sandy substrates with high contents of silt and clay were poorly sorted and spatially re-distributed by fluvial and aeolian processes. The contents of silt and clay were 15.9%-23.8% in the cyanobacterial crusts (BSC-I, BSC-CG) and 30.5% in the moss-crust (BSC-M). The pH values were about 7 (neutral) in all BSCs. The heighest Corg contents were found in BSC-CG (0.51%), but were not significantly lower in BSC-I (0.47%) and BSC-M (0.44%), where Corg concentrations of the original substrate ranged from 0.16 to 0.22% at construction of the catchment. The BSC types were very heterogeneously distributed and developed. Different crust types occurred in small-scale patches. Cyanobacteria which exude mucilaginous material and the rhizoids and protonemata of mosses contributed to aggregating sand grains and enhanced the topsoil stability. Furthermore, filamentous cyanobacteria and algae partially filled in the matrix pores and enmeshed sand grains, and in a wet condition extracellular polymeric substances (EPS) clogged the available pore space. Once settled, the crusts influenced the water regime of the soils. They were not pronounced hydrophobic, yet surface polarity differed between the crust types. Water infiltration was influenced by two factors: (i) the crust type, where infiltration rates were highest on almost bare substrate (BSC-I) and least when cyanobacteria and green algae formed a dense cover on the surface (BSC-CG), and (ii) the texture. Compared to BSC-CG, infiltration rates were elevated in BSC-M, pointing to decline of surface sealing when mosses penetrated the dense microphytic crust. However, the relationships among crust types, water repellency, particle size composition and infiltration are complex and need further investigation on different scales. This project is part of the Transregional Collaborative Research Centre 38 'Structures and processes of the initial ecosystem development phase in an artificial water catchment' and funded by the Deutsche Forschungsgemeinschaft.

Sea level and turbidity controls on mangrove soil surface elevation change

USGS Publications Warehouse

Lovelock, Catherine E.; Fernanda Adame, Maria; Bennion, Vicki; Hayes, Matthew; Reef, Ruth; Santini, Nadia; Cahoon, Donald R.

2015-01-01

Increases in sea level are a threat to seaward fringing mangrove forests if levels of inundation exceed the physiological tolerance of the trees; however, tidal wetlands can keep pace with sea level rise if soil surface elevations can increase at the same pace as sea level rise. Sediment accretion on the soil surface and belowground production of roots are proposed to increase with increasing sea level, enabling intertidal habitats to maintain their position relative to mean sea level, but there are few tests of these predictions in mangrove forests. Here we used variation in sea level and the availability of sediments caused by seasonal and inter-annual variation in the intensity of La Nina-El Nino to assess the effects of increasing sea level on surface elevation gains and contributing processes (accretion on the surface, subsidence and root growth) in mangrove forests. We found that soil surface elevation increased with mean sea level (which varied over 250 mm during the study) and with turbidity at sites where fine sediment in the water column is abundant. In contrast, where sediments were sandy, rates of surface elevation gain were high, but not significantly related to variation in turbidity, and were likely to be influenced by other factors that deliver sand to the mangrove forest. Root growth was not linked to soil surface elevation gains, although it was associated with reduced shallow subsidence, and therefore may contribute to the capacity of mangroves to keep pace with sea level rise. Our results indicate both surface (sedimentation) and subsurface (root growth) processes can influence mangrove capacity to keep pace with sea level rise within the same geographic location, and that current models of tidal marsh responses to sea level rise capture the major feature of the response of mangroves where fine, but not coarse, sediments are abundant.

Mapping benefits from updated ifsar data in Alaska: improved source data enables better maps

USGS Publications Warehouse

Craun, Kari J.

2015-08-06

The U.S. Geological Survey (USGS) and partners in other Federal and State agencies are working collaboratively toward Statewide coverage of interferometric synthetic aperture radar (ifsar) elevation data in Alaska. These data will provide many benefits to a wide range of stakeholders and users. Some applications include development of more accurate and highly detailed topographic maps; improvement of surface water information included in the National Hydrography (NHD) and Watershed Boundary Datasets (WBDs); and use in scientific modeling applications such as calculating glacier surface elevation differences over time and estimating tsunami inundation areas.

Groundwater–surface water mixing shifts ecological assembly processes and stimulates organic carbon turnover

PubMed Central

Stegen, James C.; Fredrickson, James K.; Wilkins, Michael J.; Konopka, Allan E.; Nelson, William C.; Arntzen, Evan V.; Chrisler, William B.; Chu, Rosalie K.; Danczak, Robert E.; Fansler, Sarah J.; Kennedy, David W.; Resch, Charles T.; Tfaily, Malak

2016-01-01

Environmental transitions often result in resource mixtures that overcome limitations to microbial metabolism, resulting in biogeochemical hotspots and moments. Riverine systems, where groundwater mixes with surface water (the hyporheic zone), are spatially complex and temporally dynamic, making development of predictive models challenging. Spatial and temporal variations in hyporheic zone microbial communities are a key, but understudied, component of riverine biogeochemical function. Here, to investigate the coupling among groundwater–surface water mixing, microbial communities and biogeochemistry, we apply ecological theory, aqueous biogeochemistry, DNA sequencing and ultra-high-resolution organic carbon profiling to field samples collected across times and locations representing a broad range of mixing conditions. Our results indicate that groundwater–surface water mixing in the hyporheic zone stimulates heterotrophic respiration, alters organic carbon composition, causes ecological processes to shift from stochastic to deterministic and is associated with elevated abundances of microbial taxa that may degrade a broad suite of organic compounds. PMID:27052662

Groundwater-surface water mixing shifts ecological assembly processes and stimulates organic carbon turnover.

PubMed

Stegen, James C; Fredrickson, James K; Wilkins, Michael J; Konopka, Allan E; Nelson, William C; Arntzen, Evan V; Chrisler, William B; Chu, Rosalie K; Danczak, Robert E; Fansler, Sarah J; Kennedy, David W; Resch, Charles T; Tfaily, Malak

2016-04-07

Environmental transitions often result in resource mixtures that overcome limitations to microbial metabolism, resulting in biogeochemical hotspots and moments. Riverine systems, where groundwater mixes with surface water (the hyporheic zone), are spatially complex and temporally dynamic, making development of predictive models challenging. Spatial and temporal variations in hyporheic zone microbial communities are a key, but understudied, component of riverine biogeochemical function. Here, to investigate the coupling among groundwater-surface water mixing, microbial communities and biogeochemistry, we apply ecological theory, aqueous biogeochemistry, DNA sequencing and ultra-high-resolution organic carbon profiling to field samples collected across times and locations representing a broad range of mixing conditions. Our results indicate that groundwater-surface water mixing in the hyporheic zone stimulates heterotrophic respiration, alters organic carbon composition, causes ecological processes to shift from stochastic to deterministic and is associated with elevated abundances of microbial taxa that may degrade a broad suite of organic compounds.

Subalpine Conifer Seedling Demographics: Species Responses to Climate Manipulations Across an Elevational Gradient at Niwot Ridge, Colorado

NASA Astrophysics Data System (ADS)

Castanha, C.; Germino, M. J.; Torn, M. S.; Ferrenberg, S.; Harte, J.; Kueppers, L. M.

2010-12-01

The effect of climate change on future ranges of treeline species is poorly understood. For example, it is not known whether trees will recruit into the alpine, above the current treeline, and whether population-level differences in trees will mediate range shifts. At Niwot Ridge, Colorado, we used common gardens and climate manipulations to test predictions that warming will lead to greater recruitment at and beyond the cold edge of these species ranges, and will reduce recruitment at the warm edge. Seed from local populations of limber pine and Englemann spruce was harvested and reciprocally planted in 3 experimental sites spanning an elevation gradient from lower subalpine forest (10,000’), to the upper subalpine treeline ecotone (11,000’), to the alpine tundra (11,300’). In Fall 2009 seeds were sown into 20 plots at each site. Overhead infrared heaters targeted increases in growing season surface soil temperature of 4-5°C. The heating treatment, which began in October 2009, was crossed with manual watering, which was initiated following snowmelt in 2010. Over the 2010 growing season, we surveyed seedling germination and mortality weekly. Germination began in early May at the forest site, in early June at the krummholz site, and in early July at the alpine site. Depending on the site and plot, heating accelerated germination by 1 to 4 weeks. Seed source elevation, species, and site all affected germination, with effects for the two species also depending on site. At all sites, lower elevation, warm-edge populations had higher germination rates than high-elevation, cool-edge populations, indicating a potential bottleneck for germination of the high elevation seed sources in the adjacent alpine tundra. At all sites, survival was generally higher for pine than for spruce. Watering tended to enhance pine germinant survival while heating tended to depress spruce germinant survival. Our results indicate that the alpine tundra, generally considered an inhospitable environment, was not favorable for Englemann spruce, even with warming. In contrast, once seeds were introduced, the alpine tundra proved favorable to limber pine germination, irrespective of the climate manipulation.

Plasma nanotexturing of silicon surfaces for photovoltaics applications: influence of initial surface finish on the evolution of topographical and optical properties

PubMed Central

FISCHER, GUILLAUME; DRAHI, ETIENNE; FOLDYNA, MARTIN; GERMER, THOMAS A.; JOHNSON, ERIK V.

2018-01-01

Using a plasma to generate a surface texture with feature sizes on the order of tens to hundreds of nanometers (“nanotexturing”) is a promising technique being considered to improve efficiency in thin, high-efficiency crystalline silicon solar cells. This study investigates the evolution of the optical properties of silicon samples with various initial surface finishes (from mirror polish to various states of micron-scale roughness) during a plasma nanotexturing process. It is shown that during said process, the appearance and growth of nanocone-like structures are essentially independent of the initial surface finish, as quantified by the auto-correlation function of the surface morphology. During the first stage of the process (2 min to 15 min etching), the reflectance and light-trapping abilities of the nanotextured surfaces are strongly influenced by the initial surface roughness; however, the differences tend to diminish as the nanostructures become larger. For the longest etching times (15 min or more), the effective reflectance is less than 5 % and a strong anisotropic scattering behavior is also observed for all samples, leading to very elevated levels of light-trapping. PMID:29220984

Investigation of Water Dissociation and Surface Hydroxyl Stability on Pure and Ni-Modified CoOOH by Ambient Pressure Photoelectron Spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Zhu; Kronawitter, Coleman X.; Waluyo, Iradwikanari

Water adsorption and reaction on pure and Ni-modified CoOOH nanowires were investigated using ambient pressure photoemission spectroscopy (APPES). The unique capabilities of APPES enable us to observe water dissociation and monitor formation of surface species on pure and Ni-modified CoOOH under elevated pressures and temperatures for the first time. Over a large range of pressures (UHV to 1 Torr), water dissociates readily on the pure and Ni-modified CoOOH surfaces at 27 °C. With an increase in H 2O pressure, a greater degree of surface hydroxylation was observed for all samples. At 1 Torr H 2O, ratios of different oxygen speciesmore » indicate a transformation of CoOOH to CoO xH y in pure and Ni-modified CoOOH. In temperature dependent studies, desorption of weakly bound water and surface dehydroxylation were observed with increasing temperature. In conclusion, larger percentages of surface hydroxyl groups at higher temperatures were observed on Ni-modified CoOOH compared to pure CoOOH, which indicates an increased stability of surface hydroxyl groups on these Ni-modified surfaces.« less

Investigation of Water Dissociation and Surface Hydroxyl Stability on Pure and Ni-Modified CoOOH by Ambient Pressure Photoelectron Spectroscopy

DOE PAGES

Chen, Zhu; Kronawitter, Coleman X.; Waluyo, Iradwikanari; ...

2017-09-07

Water adsorption and reaction on pure and Ni-modified CoOOH nanowires were investigated using ambient pressure photoemission spectroscopy (APPES). The unique capabilities of APPES enable us to observe water dissociation and monitor formation of surface species on pure and Ni-modified CoOOH under elevated pressures and temperatures for the first time. Over a large range of pressures (UHV to 1 Torr), water dissociates readily on the pure and Ni-modified CoOOH surfaces at 27 °C. With an increase in H 2O pressure, a greater degree of surface hydroxylation was observed for all samples. At 1 Torr H 2O, ratios of different oxygen speciesmore » indicate a transformation of CoOOH to CoO xH y in pure and Ni-modified CoOOH. In temperature dependent studies, desorption of weakly bound water and surface dehydroxylation were observed with increasing temperature. In conclusion, larger percentages of surface hydroxyl groups at higher temperatures were observed on Ni-modified CoOOH compared to pure CoOOH, which indicates an increased stability of surface hydroxyl groups on these Ni-modified surfaces.« less

Simulated peak flows and water-surface profiles for Scott Creek near Sylva, North Carolina

USGS Publications Warehouse

Pope, B.F.

1996-01-01

Peak flows were simulated for Scott Creek, just upstream from Sylva, in Jackson County, North Carolina, in order to provide Jackson County officials with information that can be used to improve preparation for and response to flash floods along the reach of Scott Creek that flows through Sylva. A U.S. Geological Survey rainfall-runoff model was calibrated using observed rainfall and streamflow data collected from March 1994 through September 1995. Standard errors for calibration were 34 percent for runoff volumes and 21 percent for peak flows. The calibrated model was used to simulate peak flows resulting from syn- thetic rainfall amounts of 1.0, 2.5, 5.0, and 7.5 inches in 24-hour periods. For each rainfall amount, peak flows were simulated under low-, moderate-, and high-antecedent soil-moisture conditions, represented by selected 3-month periods of daily rainfall and evaporation record from nearby climatic-data measuring stations. Simulated peak flows ranged from 89 to 10,100 cubic feet per second. Profiles of water-surface elevations for selected observed and simu- lated peak flows were computed for the reach of Scott Creek that flows through Sylva, North Carolina. The profiles were computed using the U.S. Army Corps of Engineers HEC-2 Water Surface Profiles computer program and channel cross-section data collected by the Tennessee Valley Authority. The stage-discharge relation for Scott Creek at the simulation site has changed since the collection of the cross-section data. These changes, however, are such that the water-surface profiles presented in this report likely overestimate the true water-surface elevations at the simulation site for a given peak flow

Mathematical Modelling of Arctic Polygonal Tundra with Ecosys : 1. Microtopography Determines How Active Layer Depths Respond to Changes in Temperature and Precipitation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grant, R. F.; Mekonnen, Z. A.; Riley, W. J.

Microtopographic variation that develops among features (troughs, rims, and centers) within polygonal landforms of coastal arctic tundra strongly affects movement of surface water and snow and thereby affects soil water contents (θ) and active layer depth (ALD). Spatial variation in ALD among these features may exceed interannual variation in ALD caused by changes in climate and so needs to be represented in projections of changes in arctic ALD. For this study, increases in near-surface θ with decreasing surface elevation among polygon features at the Barrow Experimental Observatory (BEO) were modeled from topographic effects on redistribution of surface water and snowmore » and from lateral water exchange with a subsurface water table during a model run from 1981 to 2015. These increases in θ caused increases in thermal conductivity that in turn caused increases in soil heat fluxes and hence in ALD of up to 15 cm with lower versus higher surface elevation which were consistent with increases measured at BEO. The modeled effects of θ caused interannual variation in maximum ALD that compared well with measurements from 1985 to 2015 at the Barrow Circumpolar Active Layer Monitoring (CALM) site (R 2 = 0.61, RMSE = 0.03 m). For higher polygon features, interannual variation in ALD was more closely associated with annual precipitation than mean annual temperature, indicating that soil wetting from increases in precipitation may hasten permafrost degradation beyond that caused by soil warming from increases in air temperature. This degradation may be more rapid if increases in precipitation cause sustained wetting in higher features.« less

Mathematical Modelling of Arctic Polygonal Tundra with Ecosys : 1. Microtopography Determines How Active Layer Depths Respond to Changes in Temperature and Precipitation

DOE PAGES

Grant, R. F.; Mekonnen, Z. A.; Riley, W. J.; ...

2017-11-17

Microtopographic variation that develops among features (troughs, rims, and centers) within polygonal landforms of coastal arctic tundra strongly affects movement of surface water and snow and thereby affects soil water contents (θ) and active layer depth (ALD). Spatial variation in ALD among these features may exceed interannual variation in ALD caused by changes in climate and so needs to be represented in projections of changes in arctic ALD. For this study, increases in near-surface θ with decreasing surface elevation among polygon features at the Barrow Experimental Observatory (BEO) were modeled from topographic effects on redistribution of surface water and snowmore » and from lateral water exchange with a subsurface water table during a model run from 1981 to 2015. These increases in θ caused increases in thermal conductivity that in turn caused increases in soil heat fluxes and hence in ALD of up to 15 cm with lower versus higher surface elevation which were consistent with increases measured at BEO. The modeled effects of θ caused interannual variation in maximum ALD that compared well with measurements from 1985 to 2015 at the Barrow Circumpolar Active Layer Monitoring (CALM) site (R 2 = 0.61, RMSE = 0.03 m). For higher polygon features, interannual variation in ALD was more closely associated with annual precipitation than mean annual temperature, indicating that soil wetting from increases in precipitation may hasten permafrost degradation beyond that caused by soil warming from increases in air temperature. This degradation may be more rapid if increases in precipitation cause sustained wetting in higher features.« less

Spatial Variability of Wet Troposphere Delays Over Inland Water Bodies

NASA Astrophysics Data System (ADS)

Mehran, Ali; Clark, Elizabeth A.; Lettenmaier, Dennis P.

2017-11-01

Satellite radar altimetry has enabled the study of water levels in large lakes and reservoirs at a global scale. The upcoming Surface Water and Ocean Topography (SWOT) satellite mission (scheduled launch 2020) will simultaneously measure water surface extent and elevation at an unprecedented accuracy and resolution. However, SWOT retrieval accuracy will be affected by a number of factors, including wet tropospheric delay—the delay in the signal's passage through the atmosphere due to atmospheric water content. In past applications, the wet tropospheric delay over large inland water bodies has been corrected using atmospheric moisture profiles based on atmospheric reanalysis data at relatively coarse (tens to hundreds of kilometers) spatial resolution. These products cannot resolve subgrid variations in wet tropospheric delays at the spatial resolutions (of 1 km and finer) that SWOT is intended to resolve. We calculate zenith wet tropospheric delays (ZWDs) and their spatial variability from Weather Research and Forecasting (WRF) numerical weather prediction model simulations at 2.33 km spatial resolution over the southwestern U.S., with attention in particular to Sam Rayburn, Ray Hubbard, and Elephant Butte Reservoirs which have width and length dimensions that are of order or larger than the WRF spatial resolution. We find that spatiotemporal variability of ZWD over the inland reservoirs depends on climatic conditions at the reservoir location, as well as distance from ocean, elevation, and surface area of the reservoir, but that the magnitude of subgrid variability (relative to analysis and reanalysis products) is generally less than 10 mm.

Ohio River backwater flood-inundation maps for the Saline and Wabash Rivers in southern Illinois

USGS Publications Warehouse

Murphy, Elizabeth A.; Sharpe, Jennifer B.; Soong, David T.

2012-01-01

Digital flood-inundation maps for the Saline and Wabash Rivers referenced to elevations on the Ohio River in southern Illinois were created by the U.S. Geological Survey (USGS). The inundation maps, accessible through the USGS Flood Inundation Mapping Science Web site at http://water.usgs.gov/osw/flood_inundation/, depict estimates of the areal extent of flooding corresponding to selected water levels (gage heights) at the USGS streamgage at Ohio River at Old Shawneetown, Illinois-Kentucky (station number 03381700). Current gage height and flow conditions at this USGS streamgage may be obtained on the Internet at http://waterdata.usgs.gov/usa/nwis/uv?03381700. In addition, this streamgage is incorporated into the Advanced Hydrologic Prediction Service (AHPS) flood warning system (http://water.weather.gov/ahps/) by the National Weather Service (NWS). The NWS forecasts flood hydrographs at many places that are often co-located at USGS streamgages. That NWS forecasted peak-stage information, also shown on the Ohio River at Old Shawneetown inundation Web site, may be used in conjunction with the maps developed in this study to show predicted areas of flood inundation. In this study, eight water-surface elevations were mapped at 5-foot (ft) intervals referenced to the streamgage datum ranging from just above the NWS Action Stage (31 ft) to above the maximum historical gage height (66 ft). The elevations of the water surfaces were compared to a Digital Elevation Model (DEM) by using a Geographic Information System (GIS) in order to delineate the area flooded at each water level. These maps, along with information on the Internet regarding current gage heights from USGS streamgages and forecasted stream stages from the NWS, provide emergency management personnel and residents with information that is critical for flood response activities such as evacuations and road closures, as well as for post-flood recovery efforts.

Velocity and stage data collected in a laboratory flume for water-surface slope determination using a pipe manometer

USGS Publications Warehouse

Lee, Jonathan K.; Visser, H.M.; Jenter, H.L.; Duff, M.P.

2000-01-01

U.S. Geological Survey (USGS) hydrologists and ecologist are conducting studies to quantify vegetative flow resistance in order to improve numerical models of surface-water flow in the Florida Everglades. Water-surface slope is perhaps the most difficult of the flow resistance parameters to measure in the Everglades due to the very low gradients of the topography and flow. In an effort to measure these very small slopes, a unique pipe manometer was developed for the local measurement of water-surface slopes on the order of 1 centimeter per kilometer (cm/km). According to theory, a very precise measurement of centerline velocity obtained inside the pipe manometer should serve as a unique proxy for water-surface slope in the direction of the pipe axis. In order to confirm this theoretical relationship and calibrate the pipe manometer, water-surface elevation and pipe centerline velocity data were simultaneously measured in a set of experiments carried out in the tilting flume at the USGS Hydraulic Laboratory Facility at Stennis Space Center, Mississippi. A description of the instrumentation and methods used to evaluate this technique for measuring water-surface slope as well as a summary of the entire data set is presented.

Fate of individual sewage disposal system wastewater within regolith in mountainous terrain

NASA Astrophysics Data System (ADS)

Dano, Kathleen; Poeter, Eileen; Thyne, Geoff

2008-06-01

In order to improve understanding of the fate of septic tank or individual sewage disposal system (ISDS) effluent in regolith overlying fractured-rock aquifers, effluent from an ISDS in such a setting was tracked via geophysical, hydrological, and geochemical methods. Under typical precipitation conditions, the effluent entered the fractured bedrock within 5 m of the boundary of the constructed infiltration area. During a period of unusually high spring recharge, the plume migrated between 50 and 100 m within the regolith before infiltrating the fractured bedrock. The chemical signature of the effluent is similar to that required to account for the decline in water quality, suggesting a causative relationship (as estimated from mass-balance models of the surface-water chemistry near the mouth of the basin). The elevated salt content of the effluent during periods of high natural recharge to the infiltration area correlates with elevated salt concentrations in surface and groundwater at the basin scale, suggesting that some of the effluent salt load may be stored in the unsaturated zone during dry periods and flushed during periods of elevated natural recharge.

Occurrence of Diatoms in Lakeside Wells in Northern New Jersey as an Indicator of the Effect of Surface Water on Ground-Water Quality

USGS Publications Warehouse

Reilly, Timothy J.; Walker, Christopher E.; Baehr, Arthur L.; Schrock, Robin M.; Reinfelder, John R.

2006-01-01

In a novel approach for detecting ground-water/surface-water interaction, diatoms were used as an indicator that surface water affects ground-water quality in lakeside communities in northern New Jersey. The presence of diatoms, which are abundant in lakes, in adjacent domestic wells demonstrated that ground water in these lakeside communities was under the direct influence of surface water. Entire diatom frustules were present in 17 of 18 water samples collected in August 1999 from domestic wells in communities surrounding Cranberry Lake and Lake Lackawanna. Diatoms in water from the wells were of the same genus as those found in the lakes. The presence of diatoms in the wells, together with the fact that most static and stressed water levels in wells were below the elevation of the lake surfaces, indicates that ground-water/surface-water interaction is likely. Ground-water/surface-water interaction also probably accounts for the previously documented near-ubiquitous presence of methyl tertiary-butyl ether in the ground-water samples. Recreational use of lakes for motor boating and swimming, the application of herbicides for aquatic weed control, runoff from septic systems and roadways, and the presence of waterfowl all introduce contaminants to the lake. Samples from 4 of the 18 wells contained Navicula spp., a documented significant predictor of Giardia and Cryptosporidium. Because private well owners in New Jersey generally are not required to regularly monitor their wells, and tests conducted by public-water suppliers may not be sensitive to indicators of ground-water/surface-water interaction, these contaminants may remain undetected. The presence of diatoms in wells in similar settings can warn of lake/well interactions in the absence of other indicators.

Water resources data Virginia water year 2005 Volume 1. Surface-water discharge and surface-water quality records

USGS Publications Warehouse

Wicklein, Shaun M.; Powell, Eugene D.; Guyer, Joel R.; Owens, Joseph A.

2006-01-01

Water-resources data for the 2005 water year for Virginia includes records of stage, discharge, and water quality of streams and stage, contents, and water quality of lakes and reservoirs. This volume contains records for water discharge at 172 gaging stations; stage only at 2 gaging stations; elevation at 2 reservoirs and 2 tide gages; contents at 1 reservoir, and water quality at 25 gaging stations. Also included are data for 50 crest-stage partial-record stations. Locations of these sites are shown on figures 4A-B and 5A-B. Miscellaneous hydrologic data were collected at 128 measuring sites and 19 water-quality sampling sites not involved in the systematic data-collection program. The data in this report represent that part of the National Water Data System collected by the U.S. Geological Survey and cooperating State and Federal agencies in Virginia.

Flood of May 2006 in York County, Maine

USGS Publications Warehouse

Stewart, Gregory J.; Kempf, Joshua P.

2008-01-01

A stalled low-pressure system over coastal New England on Mother's Day weekend, May 13-15, 2006, released rainfall in excess of 15 inches. This flood (sometimes referred to as the 'Mother's Day flood') caused widespread damage to homes, businesses, roads, and structures in southern Maine. The damage to public property in York County was estimated to be $7.5 million. As a result of these damages, a presidential disaster declaration was enacted on May 25, 2006, for York County, Maine. Peak-flow recurrence intervals for eight of the nine streams studied were calculated to be greater than 500 years. The peak-flow recurrence interval of the remaining stream was calculated to be between a 100-year and a 500-year interval. This report provides a detailed description of the May 2006 flood in York County, Maine. Information is presented on peak streamflows and peak-flow recurrence intervals on nine streams, peak water-surface elevations for 80 high-water marks at 25 sites, hydrologic conditions before and after the flood, comparisons with published Flood Insurance Studies, and places the May 2006 flood in context with historical floods in York County. At sites on several streams, differences were observed between peak flows published in the Flood Insurance Studies and those calculated for this study. The differences in the peak flows from the published Flood Insurance Studies and the flows calculated for this report are within an acceptable range for flows calculated at ungaged locations, with the exception of those for the Great Works River and Merriland River. For sites on the Mousam River, Blacksmith Brook, Ogunquit River, and Cape Neddick River, water-surface elevations from Flood Insurance Studies differed with documented water-surface elevations from the 2006 flood.

ICESat-2 bathymetry: an empirical feasibility assessment using MABEL

NASA Astrophysics Data System (ADS)

Forfinski, Nick; Parrish, Christopher

2016-10-01

The feasibility of deriving bathymetry from data acquired with ATLAS, the photon-counting lidar on NASA's upcoming ICESat-2 satellite, is assessed empirically by examining data from NASA's airborne ICESat-2 simulator, MABEL. The primary objectives of ICESat-2 will be to measure ice-sheet elevations, sea-ice thickness, and global biomass. However, the 6-beam, green-wavelength photon-counting lidar, combined with the 91-day repeat period and near-polar orbit, may provide unique opportunities to measure coastal bathymetry in remote, poorly-mapped areas of the globe. The study focuses on high-probability bottom returns in Keweenaw Bay, Lake Superior, acquired during the "Transit to KPMD" MABEL mission in August, 2012 at an AGL altitude of 20,000 m. Water-surface and bottom returns were identified and manually classified using MABEL Viewer, an in-house prototype data-explorer web application. Water-surface returns were observed in 12 green channels, and bottom returns were observed in 10 channels. Comparing each channel's mean water-surface elevation to a regional NOAA Nowcast water-level estimate revealed channel-specific elevation biases that were corrected for in our bathymetry estimation procedure. Additionally, a first-order refraction correction was applied to each bottom return. Agreement between the refraction-corrected depth profile and NOAA data acquired two years earlier by Fugro LADS with the LADS Mk II airborne system indicates that MABEL reliably detected bathymetry in depths up to 8 m, with an RMS difference of 0.7 m. In addition to feeding coastal bathymetry models, MABEL (and potentially ICESat-2 ATLAS) has the potential to seed algorithms for bathymetry retrieval from passive, multispectral satellite imagery by providing reference depths.

Effects of lake surface elevation on shoreline-spawning Lost River Suckers

USGS Publications Warehouse

Burdick, Summer M.; Hewitt, David A.; Rasmussen, J.E.; Hayes, Brian; Janney, Eric; Harris, Alta C.

2015-01-01

We analyzed remote detection data from PIT-tagged Lost River Suckers Deltistes luxatus at four shoreline spawning areas in Upper Klamath Lake, Oregon, to determine whether spawning of this endangered species was affected by low water levels. Our investigation was motivated by the observation that the surface elevation of the lake during the 2010 spawning season was the lowest in 38 years. Irrigation withdrawals in 2009 that were not replenished by subsequent winter-spring inflows caused a reduction in available shoreline spawning habitat in 2010. We compared metrics of skipped spawning, movement among spawning areas, and spawning duration across 8 years (2006-2013) that had contrasting spring water levels. Some aspects of sucker spawning were similar in all years, including few individuals straying from the shoreline areas to spawning locations in lake tributaries and consistent effects of increasing water temperatures on the accumulation of fish at the spawning areas. During the extreme low water year of 2010, 14% fewer female and 8% fewer male suckers joined the shoreline spawning aggregation than in the other years. Both males and females visited fewer spawning areas within Upper Klamath Lake in 2010 than in other years, and the median duration at spawning areas in 2010 was at least 36% shorter for females and 20% shorter for males relative to other years. Given the imperiled status of the species and the declining abundance of the population in Upper Klamath Lake, any reduction in spawning success and egg production could negatively impact recovery efforts. Our results indicate that lake surface elevations above 1,262.3-1,262.5 m would be unlikely to limit the number of spawning fish and overall egg production.

Groundwater flood of a river terrace in southwest Wisconsin, USA

NASA Astrophysics Data System (ADS)

Gotkowitz, Madeline B.; Attig, John W.; McDermott, Thomas

2014-09-01

Intense rainstorms in 2008 resulted in wide-spread flooding across the Midwestern United States. In Wisconsin, floodwater inundated a 17.7-km2 area on an outwash terrace, 7.5 m above the mapped floodplain of the Wisconsin River. Surface-water runoff initiated the flooding, but results of field investigation and modeling indicate that rapid water-table rise and groundwater inundation caused the long-lasting flood far from the riparian floodplain. Local geologic and geomorphic features of the landscape lead to spatial variability in runoff and recharge to the unconfined sand and gravel aquifer, and regional hydrogeologic conditions increased groundwater discharge from the deep bedrock aquifer to the river valley. Although reports of extreme cases of groundwater flooding are uncommon, this occurrence had significant economic and social costs. Local, state and federal officials required hydrologic analysis to support emergency management and long-term flood mitigation strategies. Rapid, sustained water-table rise and the resultant flooding of this high-permeability aquifer illustrate a significant aspect of groundwater system response to an extreme precipitation event. Comprehensive land-use planning should encompass the potential for water-table rise and groundwater flooding in a variety of hydrogeologic settings, as future changes in climate may impact recharge and the water-table elevation.

Applications of Future NASA Decadal Missions for Observing Earth's Land and Water Processes

NASA Technical Reports Server (NTRS)

Luvall, Jeffrey C.; Hook, Simon; Brown, Molly E.; Tzortziou, Maria A.; Carroll, Mark; Escobar, Vanessa M.; Omar, Ali

2013-01-01

Misson Objective: To collect altimetry data of the Earth's surface optimized to measure ice sheet elevation change and sea ice thickness, while also generating an estimate of global vegetation biomass.

Base of principal aquifer for parts of the North Platte, South Platte, and Twin Platte Natural Resources Districts, western Nebraska

USGS Publications Warehouse

Hobza, Christopher M.; Abraham, Jared D.; Cannia, James C.; Johnson, Michaela R.; Sibray, Steven S.

2014-01-01

Water resources in the North and South Platte River valleys of Nebraska, including the valley of Lodgepole Creek, are critical to the social and economic health of the area, and for the recovery of threatened and endangered species in the Platte River Basin. Groundwater and surface water are heavily used resources, and uses are regulated in the study area. Irrigation is the dominant water use and, in most instances, is supplied by both groundwater and surface-water sources. The U.S. Geological Survey and its partners have collaborated to use airborne geophysical surveys for areas of the North and South Platte River valleys including the valley of Lodgepole Creek in western Nebraska. The objective of the surveys was to map the aquifers and underlying bedrock topography of selected areas to help improve the understanding of groundwater–surface-water relations to guide water-management decisions. This project was a cooperative study involving the North Platte Natural Resources District, the South Platte Natural Resources District, the Twin Platte Natural Resources District, the Conservation and Survey Division of the University of Nebraska-Lincoln, and the Nebraska Environmental Trust. This report presents the interpreted base-of-aquifer surface for part of the area consisting of the North Platte Natural Resources District, the South Platte Natural Resources District, and the Twin Platte Natural Resources District. The interpretations presented herein build on work done by previous researchers from 2008 to 2009 by incorporating additional airborne electromagnetic survey data collected in 2010 and additional test holes from separate, related studies. To make the airborne electromagnetic data useful, numerical inversion was used to convert the measured data into a depth-dependent subsurface resistivity model. An interpretation of the elevation and configuration of the base of aquifer was completed in a geographic information system that provided x, y, and z coordinates. The process of interpretation involved manually picking locations (base-of-aquifer elevations) on the displayed airborne electromagnetic-derived resistivity profile by the project geophysicist, hydrologist, and geologist. These locations, or picks, of the base-of-aquifer elevation (typically the top of the Brule Formation of the White River Group) were then stored in a georeferenced database. The pick was made by comparing the inverted airborne electromagnetic-derived resistivity profile to the lithologic descriptions and borehole geophysical logs from nearby test holes. The database of interpretive picks of the base-of-aquifer elevation was used to create primary input for interpolating the new base-of-aquifer contours. The automatically generated contours were manually adjusted based on the interpreted location of paleovalleys eroded into the base-of-aquifer surface and associated bedrock highs, many of which were unmapped before this study. When contours are overlain by the water-table surface, the saturated thickness of the aquifer can be computed, which allows an estimate of total water in storage. The contours of the base-of-aquifer surface presented in this report may be used as the lower boundary layer in existing and future groundwater-flow models. The integration of geophysical data into the contouring process facilitated a more continuous and spatially comprehensive view of the hydrogeologic framework.

Army Net Zero Installation Initiative and Cost Benefit Analysis Activity

DTIC Science & Technology

2011-10-31

freshwater resources and returns water back to the same watershed so not to deplete the groundwater and surface water resources of that... freshwater resources & returns water back to the same watershed so not to deplete the groundwater & surface water resources of that region in quantity...Goals: Reduce freshwater demand through water efficiency & conservation Access/develop alternate water sources to offset freshwater demand Develop

U.S. Geological Survey Subsidence Interest Group Conference : proceedings of the Technical Meeting, Galveston, Texas, November 27-29, 2001

USGS Publications Warehouse

Prince, Keith R.; Galloway, Devin L.

2003-01-01

InSAR is a powerful technique that uses radar data acquired at different times to measure land-surface deformation, or displacement, over large areas at a high level of spatial detail and a high degree of measurement resolution. InSAR displacement maps (interferograms), in conjunction with other hydrogeologic data, have been used to determine aquifer-system characteristics for areas where surface deformation is the result of stress induced changes in the granular skeleton of the aquifer system. Interferograms and measurements of aquifer-system compaction from borehole extensometers, and ground-water levels in wells in Santa Clara Valley, California, have shown that land-surface changes caused by aquifer-system deformation for September 23, 1992-August 2, 1997, are elastic (reversible): During the summer when water levels are declining, the land surface subsides, and during the winter when water levels are recovering, the land surface uplifts, resulting in no net surface deformation. Interferograms used with fault maps of Santa Clara Valley and of Las Vegas Valley, Nevada, have shown that the extent of regional land-surface changes caused by aquifer-system deformation may be partially controlled by faults. Interferograms of Yucca Flat, Nevada, show subsidence associated with the recovery of elevated hydraulic heads caused by underground weapons testing at depths of more than 600 meters. For these selected case studies, continuing or renewed deformation of the aquifer system is coupled with pore-fluid-pressure changes. When applied stresses (water-level changes) can be measured accurately for periods that the interferograms show displacement, stress-strain relations, and thus bulk storage properties, can be evaluated. For areas where additional ground-water-level, land-surface-elevation, aquifer-system-compaction, or other environmental data are needed, the interferograms can be used as a guide for designing appropriate monitoring networks. Aquifer-system properties derived from stress-strain relations and identification of hidden faults, other structural or stratigraphic controls on deformation and ground-water flow, and other hydrogeologic boundaries in the flow system can be used to constrain numerical ground-water flow and subsidence simulations. Managing aquifer systems within optimal limits may be possible if regions susceptible to ground-water depletion and the accompanying land subsidence can be identified and characterized.

Preliminary Investigation of Paleochannels and Groundwater Specific Conductance using Direct-Current Resistivity and Surface-Wave Seismic Geophysical Surveys at the Standard Chlorine of Delaware, Inc., Superfund Site, Delaware City, Delaware, 2008

USGS Publications Warehouse

Degnan, James R.; Brayton, Michael J.

2010-01-01

The U.S. Geological Survey (USGS), in cooperation with Region III of the U.S. Environmental Protection Agency (USEPA) and the State of Delaware, is conducting an ongoing study of the water-quality and hydrogeologic properties of the Columbia and Potomac aquifers and the extent of cross-aquifer contamination with benzene; chlorobenzene; 1,2-dichlorobenzene; 1,4-dichlorobenzene; and hydrogen chloride (hydrochloric acid when dissolved in water) in the vicinity of the Standard Chlorine of Delaware, Inc. (SCD), Superfund Site, Delaware City, Delaware. Surface geophysical surveys and well data were used to identify and correlate low-permeability units (clays) across the site and to search for sand and gravel filled paleochannels that are potential conduits and receptors of contaminated groundwater and (or) Dense Non-Aqueous Phase Liquid (DNAPL) contaminants. The combined surveys and well data were also used to characterize areas of the site that have groundwater with elevated (greater than 1,000 microsiemens per centimeter) specific conductance (SC) as a result of contamination. The most electrically conductive features measured with direct-current (DC) resistivity at the SCD site are relatively impermeable clays and permeable sediment that are associated with elevated SC in groundwater. Many of the resistive features include paleochannel deposits consisting of coarse-grained sediments that are unsaturated, have low (less than 200 microsiemens per centimeter) SC pore water, or are cemented. Groundwater in uncontaminated parts of the Columbia aquifer and of the Potomac aquifer has a low SC. Specific-conductance data from monitoring wells at the site were used to corroborate the DC-resistivity survey results. For comparison with DC-resistivity surveys, multi-channel analysis of surface wave (MASW) surveys were used and were able to penetrate deep enough to measure the Columbia aquifer, which is known to have elevated SC in some places. MASW survey results respond to solid material stiffness; clays and cemented sediments will have a higher velocity than silts, sands, and gravels (in order of increasing hydraulic conductivity). Geophysical surveys detected elevated SC associated with contamination of the surficial Columbia aquifer. Groundwater with elevated SC over ambient (by an order of magnitude) produced a decrease in measured resistivity at the SCD site. Where SC data are not available from wells, it is not known if a low resistivity value measured with DC resistivity alone results from the geologic material (clay) or elevated SC in groundwater (in sand or gravel). Seismic surface waves used as part of the MASW technique are not affected by water content or quality and are used herein to distinguish between sand and clay when SC is high. Through concurrent interpretation of MASW and DC-resistivity surveys, information was gained about water quality and lithology over large areas at the SCD site.

Subsurface Scattered Photons: Friend or Foe? Improving visible light laser altimeter elevation estimates, and measuring surface properties using subsurface scattered photons

NASA Astrophysics Data System (ADS)

Greeley, A.; Kurtz, N. T.; Neumann, T.; Cook, W. B.; Markus, T.

2016-12-01

Photon counting laser altimeters such as MABEL (Multiple Altimeter Beam Experimental Lidar) - a single photon counting simulator for ATLAS (Advanced Topographical Laser Altimeter System) - use individual photons with visible wavelengths to measure their range to target surfaces. ATLAS, the sole instrument on NASA's upcoming ICESat-2 mission, will provide scientists a view of Earth's ice sheets, glaciers, and sea ice with unprecedented detail. Precise calibration of these instruments is needed to understand rapidly changing parameters such as sea ice freeboard, and to measure optical properties of surfaces like snow covered ice sheets using subsurface scattered photons. Photons that travel through snow, ice, or water before scattering back to an altimeter receiving system travel farther than photons taking the shortest path between the observatory and the target of interest. These delayed photons produce a negative elevation bias relative to photons scattered directly off these surfaces. We use laboratory measurements of snow surfaces using a flight-tested laser altimeter (MABEL), and Monte Carlo simulations of backscattered photons from snow to estimate elevation biases from subsurface scattered photons. We also use these techniques to demonstrate the ability to retrieve snow surface properties like snow grain size.

Water-surface profile and flood boundaries for the computed 100-year flood, lower Salt River, Lincoln County, Wyoming

USGS Publications Warehouse

Miller, Kirk A.; Mason, John P.

2000-01-01

The water-surface profile and flood boundaries for the computed 100-year flood were determined for a part of the lower Salt River in Lincoln County, Wyoming. Channel cross-section data were provided by Lincoln County. Cross-section data for bridges and other structures were collected and compiled by the U.S. Geological Survey. Roughness coefficients ranged from 0.034 to 0.100. The 100-year flood was computed using standard methods, ranged from 5,170 to 4,120 cubic feet per second through the study reach, and was adjusted proportional to contributing drainage area. Water-surface elevations were determined by the standard step-backwater method. Flood boundaries were plotted on digital basemaps.

Great Basin riparian and aquatic ecosystems

Treesearch

Don Sada

2008-01-01

Most Great Basin riparian and aquatic ecosystems are associated with streams and springs that are comparatively small and isolated from one another because of the naturally arid climate. There are few rivers and lakes in the region. Surface waters and aquifers that support springs provide the only water available to humans and wildlife. Springs occur at all elevations...

Causal Chains Arising from Climate Change in Mountain Regions: the Core Program of the Mountain Research Initiative

NASA Astrophysics Data System (ADS)

Greenwood, G. B.

2014-12-01

Mountains are a widespread terrestrial feature, covering from 12 to 24 percent of the world's terrestrial surface, depending of the definition. Topographic relief is central to the definition of mountains, to the benefits and costs accruing to society and to the cascade of changes expected from climate change. Mountains capture and store water, particularly important in arid regions and in all areas for energy production. In temperate and boreal regions, mountains have a great range in population densities, from empty to urban, while tropical mountains are often densely settled and farmed. Mountain regions contain a wide range of habitats, important for biodiversity, and for primary, secondary and tertiary sectors of the economy. Climate change interacts with this relief and consequent diversity. Elevation itself may accentuate warming (elevationi dependent warming) in some mountain regions. Even average warming starts complex chains of causality that reverberate through the diverse social ecological mountain systems affecting both the highlands and adjacent lowlands. A single feature of climate change such as higher snow lines affect the climate through albedo, the water cycle through changes in timing of release , water quality through the weathering of newly exposed material, geomorphology through enhanced erosion, plant communities through changes in climatic water balance, and animal and human communities through changes in habitat conditions and resource availabilities. Understanding these causal changes presents a particular interdisciplinary challenge to researchers, from assessing the existence and magnitude of elevation dependent warming and monitoring the full suite of changes within the social ecological system to climate change, to understanding how social ecological systems respond through individual and institutional behavior with repercussions on the long-term sustainability of these systems.

Methods of Real Time Image Enhancement of Flash LIDAR Data and Navigating a Vehicle Using Flash LIDAR Data

NASA Technical Reports Server (NTRS)

Vanek, Michael D. (Inventor)

2014-01-01

A method for creating a digital elevation map ("DEM") from frames of flash LIDAR data includes generating a first distance R(sub i) from a first detector i to a first point on a surface S(sub i). After defining a map with a mesh THETA having cells k, a first array S(k), a second array M(k), and a third array D(k) are initialized. The first array corresponds to the surface, the second array corresponds to the elevation map, and the third array D(k) receives an output for the DEM. The surface is projected onto the mesh THETA, so that a second distance R(sub k) from a second point on the mesh THETA to the detector can be found. From this, a height may be calculated, which permits the generation of a digital elevation map. Also, using sequential frames of flash LIDAR data, vehicle control is possible using an offset between successive frames.

Data on surface-water, streambed-interstitial water, and bed-sediment quality for selected locations in the small arms impact area of central Fort Gordon, Georgia, September 4-6, 2001

USGS Publications Warehouse

Priest, Sheryln; Stamey, Timothy C.; Lawrence, Stephen J.

2002-01-01

In September 2001, the U.S. Geological Survey, in cooperation with the Environmental and Natural Resources Management Office of the U.S. Army Signal Center and Fort Gordon (U.S. Department of the Army), conducted a chemical assessment of surface water, streambed-interstitial water, and bed sediments within the small arms impact area of Fort Gordon Military Installation. The study was conducted in support of the development of an Integrated Natural Resources Management Plan (INRMP) for Fort Gordon, Georgia. An effective INRMP ensures that natural resources conservation measures and U.S. Army activities on the military base are integrated and consistent with Federal requirements to manage military installations on an ecosystem basis. Filtered water samples were collected from five sites along South Prong Creek and three sites along Marcum Branch Creek for chemical analyses of major ions, nutrients, and selected trace elements. On-site measurements of pH, temperature, specific conductance, and dissolved oxygen were made at the eight sites. Filtered water collected showed varying concentrations in both surface- and streambed-interstitial water. Bed-sediment samples collected from South Prong Creek contain elevated levels of arsenic, barium, beryllium, cadmium, chromium, cobalt, copper, iron, lead, manganese, nickel, selenium, vanadium, and total organic carbon relative to previous concentrations (McConnell and others, 2000). Bed-sediment samples collected from Marcum Branch Creek contain elevated levels of beryllium, copper, lead, manganese, mercury, selenium, and total organic carbon relative to previous concentrations (McConnell and others, 2000).

The influence of vegetation on the hydrodynamics and geomorphology of a tree island in Everglades National Park (Florida, United States)

USGS Publications Warehouse

Sullivan, Pamela L.; Engel, Victor C.; Ross, Michael S.; Price, René M.

2013-01-01

Transpiration-driven nutrient accumulation has been identified as a potential mechanism governing the creation and maintenance of wetland vegetation patterning. This process may contribute to the formation of nutrient-rich tree islands within the expansive oligotrophic marshes of the Everglades (Florida, United States). This study presents hydrogeochemical data indicating that tree root water uptake is a primary driver of groundwater ion accumulation across one of these islands. Sap flow, soil moisture, water level, water chemistry, and rainfall were measured to identify the relationships between climate, transpiration, and groundwater uptake by phreatophytes and to examine the effect this uptake has on groundwater chemistry and mineral formation in three woody plant communities of differing elevations. During the dry season, trees relied more on groundwater for transpiration, which led to a depressed water table and the advective movement of groundwater and dissolved ions, including phosphorus, from the surrounding marsh towards the centre of the island. Ion exclusion during root water uptake led to elevated concentrations of all major dissolved ions in the tree island groundwater compared with the adjacent marsh. Groundwater was predominately supersaturated with respect to aragonite and calcite in the lower-elevation woody communities, indicating the potential for soil formation. Elevated groundwater phosphorous concentrations detected in the highest-elevation woody community were associated with the leaching of inorganic sediments (i.e. hydroxyapatite) in the vadose zone. Understanding the complex feedback mechanisms regulating plant/groundwater/surface water interactions, nutrient dynamics, and potential soil formation is necessary to manage and restore patterned wetlands such as the Everglades.

Topography and flooding of coastal ecosystems on the Yukon-Kuskokwim Delta, Alaska: Implications for sea level rise

USGS Publications Warehouse

Jorgenson, Torre; Ely, Craig R.

2001-01-01

We measured surface elevations, stage of annual peak flooding, and sedimentation along 10 toposequences across coastal ecosystems on the Yukon-Kuskokwim (Y-K) Delta in western Alaska during 1994-1998 to assess some of the physical processes affecting ecosystem distribution. An ecotype was assigned to each of 566 points, and differences in elevations among 24 ecotypes were analyzed within individual toposequences and across the 40 x 40-km study area. Elevations of vegetated ecotypes along the longest toposequence rose only ~1 m over a distance of 7.5 km, and mean elevations of most ecotype across the study area were within 0.5 m of mean higher-high water (1.47 m). During 1994 to 1998, monitoring of annual peak stage using crest gauges revealed flooding from the highest fall storm surge reached 2.58 m (1.11 m above mean higher-high tide). In each year, only the highest surface was unaffected by flooding. Mean annual sedimentation rates for the various ecotypes were 8.0 ram/y on tidal flats, 1.4 to 3.8 mm/y on the active floodplain, 0.1-0.2 mm/y on the inactive floodplain, and 0 mm/ on the abandoned floodplain. If sea levels in the Bering Sea rise ~0.5 m by 2100, as predicted by some on a global basis, large portions of the coastal margin of the delta could be regularly inundated by water during high tides, and even the highest ecotypes could be affected by storm surges. Predicting the extent of future inundation is difficult, however, because of the changes in the ground-surface elevation through sedimentation, organic matter accumulation, and permafrost development.

Impacts of elevated CO2 concentration on the productivity and surface energy budget of the soybean and maize agroecosystem in the Midwest US

USDA-ARS?s Scientific Manuscript database

The physiological response of vegetation to increasing atmospheric carbon dioxide concentration ([CO2]) modifies productivity and surface energy and water fluxes. Quantifying this response is required for assessments of future climate change. Many global climate models account for this response; how...

Networked Thermodynamic Boundary Layer Profiling with AERIs during the PECAN Field Campaign

NASA Astrophysics Data System (ADS)

Gero, P. J.; Turner, D. D.; Hackel, D.; Phillips, C.; Smith, N.; Wagner, T.

2015-12-01

The Plains Elevated Convection at Night (PECAN) campaign was a large-scale field experiment in the Great Plains region of the U.S. that was conducted in June-July 2015. Nocturnal storms provide the majority of the precipitation in the Great Plains, yet the initiation and evolution of nocturnal convection is not understood to the same level as daytime surface-based convection, and thus provides significant challenges for operational weather forecasters. PECAN's objectives were to study elevated nocturnal convection initiation and the lifecycle of nocturnal convection. Specific research areas that were studied were the evolution of mesoscale convective systems, the structure and evolution of nocturnal low-level jets, atmospheric bores, and elevated convection initiation. A broad range of fixed and mobile observing systems were deployed by several agencies and organizations in a domain centered around Kansas. The Atmospheric Emitted Radiance Interferometer (AERI) is a ground-based instrument that measures downwelling infrared radiance from the atmosphere. AERI observations can be used to obtain vertical profiles of tropospheric temperature and water vapor in the lowest 3 km of the troposphere, as well as measurements of the concentration of various trace gases and microphysical and optical properties of clouds and aerosols. A network of eight AERIs was deployed in the domain during PECAN, with six at fixed sites and two in mobile facilities. One of the goals of the campaign was a demonstration of the use of real-time high-temporal-resolution boundary layer profiles from the network of AERIs for characterizing the mesoscale environment and its evolution during the weather events sampled during PECAN. If successful, a future network could be implemented across CONUS and thermodynamic profiles in the boundary layer data assimilated to help improve numerical weather prediction. We present an overview of the AERI deployments, a summary of the technique used to retrieve thermodynamic profiles from the AERI's observed radiances, and results from the AERI retrievals in different atmospheric conditions.

Drainage Water Filtration

USDA-ARS?s Scientific Manuscript database

Tile drainage discharge from managed turf is known to carry elevated concentrations of agronomic fertilizers and chemicals. One approach being considered to reduce the transport is end-of-tile-filters. Laboratory and field studies have been initiated to address the efficacy of this approach. Result...

Development of a universal water signature for the LANDSAT-3 Multispectral Scanner, part 1

NASA Technical Reports Server (NTRS)

Schlosser, E. H.

1980-01-01

A generalized four channel hyperplane to discriminate water from nonwater was developed using LANDSAT-3 multispectral scaner (MSS) scenes and matching same/next day color infrared aerial photography. The MSS scenes varied in sun elevation angle from 40 to 58 deg. The 28 matching air photo frames contained over 1400 water bodies larger than one surface acre. A preliminary water discriminant, was used to screen the data and eliminate from further consideration all pixels distant from water in MSS spectral space. A linear discriminant was iteratively fitted to the labelled pixels. This discriminant correctly classified 98.7% of the water pixels and 98.6% of the nonwater pixels. The discriminant detected 91.3% of the 414 water bodies over 10 acres in surface area, and misclassified as water 36 groups of contiguous nonwater pixels.

Source or Sink: Investigating the role of storm water retention ponds in the urban landscape (Invited)

NASA Astrophysics Data System (ADS)

Lev, S.; Casey, R.; Ownby, D.; Snodgrass, J.

2009-12-01

The impact of human activities on surface water, groundwater and soil is nowhere more apparent than in urban and suburban systems. Dramatic changes to watersheds in urbanizing areas have led to changes in hydrology and an associated increase in the flux of sediment and contaminants to surface and ground waters. In an effort to mediate these impacts, Best Management Practices (BMP) have been established in order to increase infiltration of runoff and trap sediment and particulates derived from impervious surfaces before they enter surface waters. Perhaps the most ubiquitous BMP are storm water retention ponds. While these structures are designed to reduce runoff and particulate loading to urban streams, their addition to the urban landscape has created a large number of new wetland habitats. In the Red Run watershed, just outside of Baltimore, Maryland, 186 discrete natural or man-made wetland areas have been identified. Of these 186 wetland areas, 165 were created to manage stormwater and most were specifically designed as stormwater management ponds (i.e., human-created basins or depressions that hold runoff for some period during the annual hydrological year). Despite their abundance in the landscape, very little is known about how these systems impact the flux of stormwater pollutants or affect the organisms using these ponds as habitat. Results from a series of related projects in the Red Run watershed are presented here in an effort to summarize the range of issues associated with stormwater management ponds. The Red Run watershed is situated inside the Urban-Rural Demarcation Line (URDL) around Baltimore City and has been identified as a smart growth corridor by Baltimore County. This region is one of two areas in Baltimore County where new development is focused. In a series of investigations of soils, surface and ground waters, and amphibian and earthworm use of 68 randomly selected stormwater retention ponds from the Red Run watershed, a range of hydrologic, ecologic, and geochemical conditions have been identified. Results from these investigations suggest that pollutant conditions, specifically trace metals and chloride, limit the use of these ponds by amphibians and effect the distribution of earthworms within ponds. The soils in ponds associated with high use roadways contain elevated levels of PAHs, Zn and Cu and the groundwater beneath these same ponds tends to have elevated chloride levels year round. Pond and associated flood plain soils in these systems have been altered and exhibit elevated Na+ or Ca2+ concentrations suggesting years of interaction with road salt contaminated discharge. These Na+ and Ca2+ form soils affect the retention of dissolved trace metals with Ca-enriched soils potentially increasing the dissolved metal concentrations of surface and pore waters and enabling the transport of roadway derived metals to surface waters and Na-enriched soils scavenging trace metals from incoming runoff. The increase in dissolved metals may also increase the toxicity to amphibians and other organisms inhabiting the storm water ponds and ultimately, streams fed by ground water recharge from ponds. Our results to date suggest both the intended and unintended function of storm water ponds in urban landscapes are complicated and deserving of more attention.

Seasonally-Active Water on Mars: Vapour, Ice, Adsorbate, and the Possibility of Liquid

NASA Astrophysics Data System (ADS)

Richardson, M. I.

2002-12-01

Seasonally-active water can be defined to include any water reservoir that communicates with other reservoirs on time scales of a year or shorter. It is the interaction of these water reservoirs, under the influence of varying solar radiation and in conjunction with surface and atmospheric temperatures, that determines the phase-stability field for water at the surface, and the distribution of water in various forms below, on, and above the surface. The atmosphere is the critical, dynamical link in this cycling system, and also (fortunately) one of the easiest to observe. Viking and Mars Global Surveyor observations paint a strongly asymmetric picture of the global seasonal water cycle, tied proximately to planetary eccentricity, and the existence of residual ice caps of different composition at the two poles. The northern summer experiences the largest water vapour columns, and is associated with sublimation from the northern residual water ice cap. The southern summer residual carbon dioxide ice cap is cold trap for water. Asymmetry in the water cycle is an unsolved problem. Possible solutions may involve the current timing of perihelion (the water cap resides at the pole experiencing the longer but cooler summer), the trapping of water ice in the northern hemisphere by tropical water ice clouds, and the bias in the annual-average, zonal-mean atmospheric circulation resulting from the zonal-mean difference in the elevation of the northern and southern hemispheres. Adsorbed and frozen water have proven harder to constrain. Recent Odyssey Gamma Ray Spectrometer results suggest substantial ground ice in the mid- and high-latitudes, but this water is likely below the seasonal skin depth for two reasons: the GRS results are best fit with such a model, and GCM models of the water cycle produce dramatically unrealistic atmospheric vapour distributions when such a very near surface, GRS-like distribution is initialized - ultimately removing the water to the northern and southern caps. Similar climate-models of the water cycle also do not need much exchangeable adsorbed water in order to explain the observed vapour distributions. The possibility of liquid water is tantalizing, but difficult to definitively judge. On scales greater than a meter or so, Mars is most definitely well away from the water triple point--although the surface pressure can exceed 6.1 mbars, the partial pressure of water vapor (to which the triple point refers) is at best orders of magnitude lower. Several careful studies have shown, however, that locally transient (meta-stable) liquid is possible, if the net heating of ice deposits is high enough. This process is aided if the total surface pressure exceeds 6.1mbar (this prevents boiling, or the explosive loss of vapour into the atmosphere) or if the liquid is covered by a thin ice shell, and is only possible if surface temperatures exceed 273K (for pure water, or the appropriate eutectic for brines) and if ice is present. The former challenge is much easier to meet than the latter. The melt scenario requires that ice deposited in winter must be protected from sublimation as surface temperatures increase in spring, but then exposed to the peak of solar heating in summer. Available spacecraft observations of seasonal water will be discussed with the aid of GCM model simulations, and examined in the context of water distributions and phases.

Mercury emission and distribution: Potential environmental risks at a small-scale gold mining operation, Phichit Province, Thailand.

PubMed

Pataranawat, Poranee; Parkpian, Preeda; Polprasert, Chongrak; Delaune, R D; Jugsujinda, A

2007-07-01

Mercury (Hg) contamination was assessed in environment near an amalgamation gold recovery operation located at a small scale mining operation (Phanom Pha) in Phichit Province, Thailand. Total mercury (THg) concentrations was determined in water, sediment, bivalves in the aquatic environment and as dry deposition or atmospheric fallout on surface soil and leaves of Neem tree (Azadirachta indica Juss. var. siamensis Valeton) near the mining operation. THg in surface soil, Neem flowers (edible part) and rice grain in surrounding terrestrial habitat and with distance from the mining area were also evaluated for possible contamination. Potential environmental risks were evaluated using the hazard quotient equation. Hg analyses conducted in the aquatic habitat showed that THg in water, sediment and bivalves (Scabies cripata Gould) ranged from 0.4 to 4 microg L(-1), 96 to 402 microg kg(-1)dry weight (dw) and 15 to 584 microg kg(-1) wet weight (ww), respectively. High concentrations of THg in water, sediment and bivalves were observed in the receiving stream near the mining operation which was located near the Khao Chet Luk Reservoir. Whereas the THg concentration in water, sediment and bivalves from monitoring stations outside the gold mining operation (upstream and downstream), were considerably lower with the values of 0.4-0.8 microg L(-1), 96-140 microg kg(-1) dw and 88-658 microg kg(-1) dw, respectively. The elevated concentration of Hg found in the sediment near the mining operation was consistent with Hg accumulation measured in bivalves. The elevated Hg levels found in living bivalves collected from highly contaminated sites suggested that the sediment bound Hg was bioavailable. THg in surface soils, brown rice grain (Jasmine rice #105) and Neem flowers of terrestrial habitats were in the range of 16 to 180 microg kg(-1) dw, 190 to 300 microg kg(-1) dw, and 622 to 2150 microg kg(-1) dw, respectively. Elevated concentrations of mercury were found in Neem flowers with the concentration greater than 600 microg kg(-1) ww, which exceeds the maximum permissible concentration reported for biota tissue (500 microg kg(-1) ww). An evaluation of air and soil pollution near the mining operations showed high concentrations of THg in dry deposit from atmospheric fallout (139 microg m(-2) d(-1)), and in surface soil (10,564 microg kg(-1) dw) at station near where open burning of gold ore extracts using the amalgamation process occurred. High or elevated concentration of THg (1172-1301 microg kg(-1) dw) in leaves of Neem tree was also measured near the mining operations. A survey of Hg in surface soil showed elevated Hg concentrations near the site which corresponded to the elevated THg concentration in dry deposition. These results suggested that atmospheric fallout is a major source of Hg to the area surrounding the mining or gold ore extraction. Results also suggest that Hg emitted into the air (estimated to be 60-150 g d(-1)) from the gold mining activities (over the past 10 years) contaminated air, the aquatic environment, surface soil and biota in the area surrounding the gold mining operation.

Updated one-dimensional hydraulic model of the Kootenai River, Idaho-A supplement to Scientific Investigations Report 2005-5110

USGS Publications Warehouse

Czuba, Christiana R.; Barton, Gary J.

2011-01-01

The Kootenai Tribe of Idaho, in cooperation with local, State, Federal, and Canadian agency co-managers and scientists, is assessing the feasibility of a Kootenai River habitat restoration project in Boundary County, Idaho. The restoration project is focused on recovery of the endangered Kootenai River white sturgeon (Acipenser transmontanus) population, and simultaneously targets habitat-based recovery of other native river biota. River restoration is a complex undertaking that requires a thorough understanding of the river and floodplain landscape prior to restoration efforts. To assist in evaluating the feasibility of this endeavor, the U.S. Geological Survey developed an updated one-dimensional hydraulic model of the Kootenai River in Idaho between river miles (RMs) 105.6 and 171.9 to characterize the current hydraulic conditions. A previously calibrated model of the study area, based on channel geometry data collected during 2002 and 2003, was the basis for this updated model. New high-resolution bathymetric surveys conducted in the study reach between RMs 138 and 161.4 provided additional detail of channel morphology. A light detection and ranging (LIDAR) survey was flown in the Kootenai River valley in 2005 between RMs 105.6 and 159.5 to characterize the floodplain topography. Six temporary gaging stations installed in 2006-08 between RMs 154.1 and 161.2, combined with five permanent gaging stations in the study reach, provided discharge and water-surface elevations for model calibration and verification. Measured discharges ranging from about 4,800 to 63,000 cubic feet per second (ft3/s) were simulated for calibration events, and calibrated water-surface elevations ranged from about 1,745 to 1,820 feet (ft) throughout the extent of the model. Calibration was considered acceptable when the simulated and measured water-surface elevations at gaging stations differed by less than (+/-)0.15 ft. Model verification consisted of simulating 10 additional events with measured discharges ranging from about 4,900 to 52,000 ft3/s, and comparing simulated and measured water-surface elevations at gaging stations. Average water-surface-elevation error in the verification simulations was 0.05 ft, with the error ranging from -1.17 to 0.94 ft over the range of events and gaging stations. Additional verification included a graphical comparison of measured average velocities that range from 1.0 to 6.2 feet per second to simulated velocities at four sites within the study reach for measured discharges ranging from about 7,400 to 46,600 ft3/s. The availability of high-resolution bathymetric and LIDAR data, along with the additional gaging stations in the study reach, allowed for more detail to be added to the model and a more thorough calibration, sensitivity, and verification analysis to be conducted. Model resolution and performance is most improved between RMs 140 and 160, which includes the 18.3-mile reach of the Kootenai River white sturgeon critical habitat.

Determination of the origin of elevated uranium at a Former Air Force Landfill using non-parametric statistics analysis and uranium isotope ratio analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weismann, J.; Young, C.; Masciulli, S.

2007-07-01

Lowry Air Force Base (Lowry) was closed in September 1994 as part of the Base Realignment and Closure (BRAC) program and the base was transferred to the Lowry Redevelopment Authority in 1995. As part of the due diligence activities conducted by the Air Force, a series of remedial investigations were conducted across the base. A closed waste landfill, designated Operable Unit 2 (OU 2), was initially assessed in a 1990 Remedial Investigation (RI; [1]). A Supplemental Remedial Investigation was conducted in 1995 [2] and additional studies were conducted in a 1998 Focused Feasibility Study. [3] The three studies indicated thatmore » gross alpha, gross beta, and uranium concentrations were consistently above regulatory standards and that there were detections of low concentrations other radionuclides. Results from previous investigations at OU 2 have shown elevated gross alpha, gross beta, and uranium concentrations in groundwater, surface water, and sediments. The US Air Force has sought to understand the provenance of these radionuclides in order to determine if they could be due to leachates from buried radioactive materials within the landfill or whether they are naturally-occurring. The Air Force and regulators agreed to use a one-year monitoring and sampling program to seek to explain the origins of the radionuclides. Over the course of the one-year program, dissolved uranium levels greater than the 30 {mu}g/L Maximum Contaminant Level (MCL) were consistently found in both up-gradient and down-gradient wells at OU 2. Elevated Gross Alpha and Gross Beta measurements that were observed during prior investigations and confirmed during the LTM were found to correlate with high dissolved uranium content in groundwater. If Gross Alpha values are corrected to exclude uranium and radon contributions in accordance with US EPA guidance, then the 15 pCi/L gross alpha level is not exceeded. The large dataset also allowed development of gross alpha to total uranium correlation factors so that gross alpha action levels can be applied to future long-term landfill monitoring to track radiological conditions at lower cost. Ratios of isotopic uranium results were calculated to test whether the elevated uranium displayed signatures indicative of military use. Results of all ratio testing strongly supports the conclusion that the uranium found in groundwater, surface water, and sediment at OU 2 is naturally-occurring and has not undergone anthropogenic enrichment or processing. U-234:U-238 ratios also show that a disequilibrium state, i.e., ratio greater than 1, exists throughout OU 2 which is indicative of long-term aqueous transport in aged aquifers. These results all support the conclusion that the elevated uranium observed at OU 2 is due to the high concentrations in the regional watershed. Based on the results of this monitoring program, we concluded that the elevated uranium concentrations measured in OU 2 groundwater, surface water, and sediment are due to the naturally-occurring uranium content of the regional watershed and are not the result of waste burials in the former landfill. Several lines of evidence indicate that natural uranium has been naturally concentrated beneath OU 2 in the geologic past and the higher of uranium concentrations in down-gradient wells is the result of geochemical processes and not the result of a uranium ore disposal. These results therefore provide the data necessary to support radiological closure of OU 2. (authors)« less

Effect of turbidity on chlorination efficiency and bacterial persistence in drinking water.

PubMed Central

LeChevallier, M W; Evans, T M; Seidler, R J

1981-01-01

To define interrelationships between elevated turbidities and the efficiency of chlorination in drinking water, experiments were performed to measure bacterial survival, chlorine demand, and interference with microbiological determinations. Experiments were conducted on the surface water supplies for communities which practice chlorination as the only treatment. Therefore, the conclusions of this study apply only to such systems. Results indicated that disinfection efficiency (log10 of the decrease in coliform numbers) was negatively correlated with turbidity and was influenced by season, chlorine demand of the samples, and the initial coliform level. Total organic carbon was found to be associated with turbidity and was shown to interfere with maintenance of a free chlorine residual by creating a chlorine demand. Interference with coliform detection in turbid waters could be demonstrated by the recovery of typical coliforms from apparently negative filters. The incidence of coliform masking in the membrane filter technique was found to increase as the turbidity of the chlorinated samples increased. the magnitude of coliform masking in the membrane filter technique increased from less than 1 coliform per 100 ml in water samples of less than 5 nephelometric turbidity units to greater than 1 coliform per 100 ml in water samples of greater than 5 nephelometric turbidity units. Statistical models were developed to predict the impact of turbidity on drinking water quality. The results justify maximum contaminant levels for turbidity in water entering a distribution system as stated in the National Primary Drinking Water Regulations of the Safe Drinking Water Act. Images PMID:7259162

Serological responses to Cryptosporidium antigens in inhabitants of Hungary using conventionally filtered surface water and riverbank filtered drinking water.

PubMed

Farkas, K; Plutzer, J; Moltchanova, E; Török, A; Varró, M J; Domokos, K; Frost, F; Hunter, P R

2015-10-01

In this study the putative protective seroprevalence (PPS) of IgG antibodies to the 27-kDa and 15/17-kDa Cryptosporidium antigens in sera of healthy participants who were and were not exposed to Cryptosporidium oocysts via surface water-derived drinking water was compared. The participants completed a questionnaire regarding risk factors that have been shown to be associated with infection. The PPS was significantly greater (49-61%) in settlements where the drinking water originated from surface water, than in the control city where riverbank filtration was used (21% and 23%). Logistic regression analysis on the risk factors showed an association between bathing/swimming in outdoor pools and antibody responses to the 15/17-kDa antigen complex. Hence the elevated responses were most likely due to the use of contaminated water. Results indicate that waterborne Cryptosporidium infections occur more frequently than reported but may derive from multiple sources.

An Assessment of the Potential Effects of Aquifer Storage and Recovery on Mercury Cycling in South Florida

USGS Publications Warehouse

Krabbenhoft, David P.; Aiken, George R.; Anderson, Mary P.

2007-01-01

Mercury contamination in the environment is a global concern, especially in areas with abundant wetlands, such as south Florida. As the causal factors of this concern improve, scientists find that many factors that do not necessarily affect mercury concentrations, such as flooding and drying cycles, or changes to carbon and sulfate loading, can profoundly affect net mercury toxicity. Especially important are ecological factors that alter the conversion of mercury to methylmercury, which is the most bioaccumulative and toxic form of mercury in the environment. Resource managers, therefore, need to be aware of possible deleterious affects to mercury toxicity that could result from land and water management decisions. Several aspects of the Comprehensive Everglades Restoration Plan (CERP), including the planned Aquifer Storage and Recovery (ASR) program, have the potential to affect the abundance of methylmercury. In response to these concerns, the U.S. Geological Survey and U.S. Army Corps of Engineers collaborated on a study to evaluate how the proposed ASR program may affect mercury cycling and toxicity. This project was conducted as an initial assessment of the possible effects of the CERP ASR program on mercury in the south Florida environment. A twofold approach was employed: field sampling and controlled laboratory benchmark experiments. The field sampling survey collected ground-water samples from the Floridan and surficial aquifer systems for the ASR program to determine existing levels of mercury and methylmercury. Laboratory experiments, on the other hand, were designed to determine how the injected surface water would interact with the aquifer during storage periods. Overall, very low levels of mercury and methylmercury (mean values of 0.41 and 0.07 nanograms per liter, respectively) were observed in ground-water samples collected from the Floridan and surficial aquifer systems. These results indicate that 'recovered water' from the CERP ASR program would not represent a significant additional direct load of mercury and methyl-mercury to ASR 'receiving waters'. Net production of methylmercury, however, can result from additions of sulfate or natural organic carbon. Thus, because the Upper Floridan aquifer generally has elevated concentrations of sulfate (relative to ambient Everglades conditions) and surface waters near Lake Okeechobee (the assumed target for ASR receiving waters) are elevated in organic carbon and sulfate, at least some potential for increased methylmercury production might arise from the release of recovered ASR water to locations in or near the Everglades.

Analysis and assessment of microbial biofilm-mediated concrete deterioration.

DOT National Transportation Integrated Search

2008-10-01

Inspections of bridge substructures in Texas identified surface deterioration of reinforced concrete columns on : bridges continuously exposed water. Initial hypothesis were that the surface deterioration was a result of the : acidity of the water in...

Restoring marsh elevation in a rapidly subsiding salt marsh by thin-layer deposition of dredged material

USGS Publications Warehouse

Ford, M.A.; Cahoon, D.R.; Lynch, J.C.

1999-01-01

Thin-layer deposition of dredged material on coastal marsh by means of high-pressure spray dredging (Jet-Spray??2) technology has been proposed as a mechanism to minimize wetland impacts associated with traditional bucket dredging technologies and to restore soil elevations in deteriorated marshes of the Mississippi River delta. The impact of spray dredging on vegetated marsh and adjacent shallow-water habitat (formerly vegetated marsh that deteriorated to open water) was evaluated in a 0.5-ha Spartina alterniflora-dominated salt marsh in coastal Louisiana. The thickness of dredged sediment deposits was determined from artificial soil marker horizons and soil elevation change was determined from sedimentation-erosion tables (SET) established prior to spraying in both sprayed and reference marshes. The vertical accretion and elevation change measurements were made simultaneously to allow for calculation of shallow (~5 m depth) subsidence (accretion minus elevation change). Measurements made immediately following spraying in July 1996 revealed that stems of S. alterniflora were knocked down by the force of the spray and covered with 23 mm of dredged material. Stems of S. alterniflora soon recovered, and by July 1997 the percent cover of S. alterniflora had increased three-fold over pre-project conditions. Thus, the layer of dredged material was thin enough to allow for survival of the S. alterniflora plants, with no subsequent colonization by plant species typical of higher marsh zones. By February 1998, 62 mm of vertical accretion accumulated at this site, and little indication of disturbance was noted. Although not statistically significant, soil elevation change was greater than accretion on average at both the spray and reference marshes, suggesting that subsurface expansion caused by increased root biomass production and/or pore water storage influence elevation in this marsh region. In the adjacent shallow water pond, 129 mm of sediment was deposited in July 1996 as a result of spraying, and despite initial shallow subsidence and continual erosion through February 1998, water bottom elevation was raised sufficiently to allow S. alterniflora to invade via rhizome growth from the adjacent marsh. Hence, thin-layer deposition of dredged material at this site was effective at restoring and maintaining marsh elevation after 1.5 years. However, if the open water sediment deposits are not soon completely stabilized via further vegetative colonization, erosion may eventually lower elevations to the level where emergent vegetation cannot persist.

Assessment of Fluctuating Reservoir Elevations Using Hydraulic Models and Impacts to Larval Pacific Lamprey Rearing Habitat in the Bonneville Pool

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mueller, Robert P.; Rakowski, Cynthia L.; Perkins, William A.

2015-02-24

This report presents the results of a modeling assessment of likely lamprey larval habitat that may be impacted by dewatering of the major tributary delta regions in the Bonneville Pool of the Columbia River. This assessment was conducted by the Pacific Northwest National Laboratory (PNNL) for the U.S. Army Corps of Engineers Portland District (CENWP). The goal of the study was to provide baseline data about how the regions of interest would potentially be impacted at three river flows (10, 50, and 90 percent exceedance flow) for four different forebay elevations at Bonneville Dam. Impacts of unsteady flows at Themore » Dalles Dam and changing forebay elevation at Bonneville Dam for a 2-week period were also assessed. The area of dewatered regions was calculated by importing modeled data outputs into a GIS and then calculating the change in inundated area near tributary deltas for the four Bonneville forebay surface elevations. From the modeled output we determined that the overall change in area is less sensitive to elevations changes during higher river discharges. Changing the forebay elevation at Bonneville and the resulting impact to total dewatered regions was greater at the lowest modeled river flow (97 kcfs) and showed the greatest variation at the White Salmon/Hood River delta regions followed by the Wind, Klickitat and the Little White Salmon rivers. To understand how inundation might change on a daily and hourly basis. Unsteady flow models were run for a 2-week period in 2002 and compared to 2014. The water surface elevation in the upstream pool closely follows that of the Bonneville Dam forebay with rapid changes of 1 to 2-ft possible. The data shows that 2.5-ft variation in water surface elevation occurred during this period in 2002 and a 3.7-ft change occurred in 2014. The duration of these changes were highly variable and generally did not stay constant for more than a 5-hr period.« less

Modelling surface-water depression storage in a Prairie Pothole Region

USGS Publications Warehouse

Hay, Lauren E.; Norton, Parker A.; Viger, Roland; Markstrom, Steven; Regan, R. Steven; Vanderhoof, Melanie

2018-01-01

In this study, the Precipitation-Runoff Modelling System (PRMS) was used to simulate changes in surface-water depression storage in the 1,126-km2 Upper Pipestem Creek basin located within the Prairie Pothole Region of North Dakota, USA. The Prairie Pothole Region is characterized by millions of small water bodies (or surface-water depressions) that provide numerous ecosystem services and are considered an important contribution to the hydrologic cycle. The Upper Pipestem PRMS model was extracted from the U.S. Geological Survey's (USGS) National Hydrologic Model (NHM), developed to support consistent hydrologic modelling across the conterminous United States. The Geospatial Fabric database, created for the USGS NHM, contains hydrologic model parameter values derived from datasets that characterize the physical features of the entire conterminous United States for 109,951 hydrologic response units. Each hydrologic response unit in the Geospatial Fabric was parameterized using aggregated surface-water depression area derived from the National Hydrography Dataset Plus, an integrated suite of application-ready geospatial datasets. This paper presents a calibration strategy for the Upper Pipestem PRMS model that uses normalized lake elevation measurements to calibrate the parameters influencing simulated fractional surface-water depression storage. Results indicate that inclusion of measurements that give an indication of the change in surface-water depression storage in the calibration procedure resulted in accurate changes in surface-water depression storage in the water balance. Regionalized parameterization of the USGS NHM will require a proxy for change in surface-storage to accurately parameterize surface-water depression storage within the USGS NHM.

Groundwater Surface Water Interactions in a Gold-Mined Dredged Floodplain of the Merced River

NASA Astrophysics Data System (ADS)

Sullivan, L.; Conklin, M. H.; Ghezzehei, T. A.

2012-12-01

The Merced River, originating in the Sierra Nevada, California, drains a watershed with an area of ~3,305 km2. Merced River has been highly altered due to diversions, mechanically dredged mining, and damming. A year of groundwater-surface water interactions were studied to elucidate the hydrological connection between the Main Canal, an unlined canal that contains Merced River water flows parallel to the river with an average elevation of 89m, the highly conductive previously dredged floodplain, and the Merced River with an average elevation of 84m. Upstream of the study reach, located in an undredged portion, of the floodplain are two fish farms that have been operating for approximately 40 years. This study reach has been historically important for salmon spawning and rearing, where more than 50% of the Chinook salmon of the Merced River spawn. Currently salmon restoration is focusing gravel augmentation and adding side channel and ignoring groundwater influences. Exchanges between the hyporheic and surrounding surface, groundwater, riparian, and alluvial floodplain habitats occur over a wide range of spatial and temporal scales. Pressure transducers were installed in seven wells and four ponds located in the dredged floodplain. All wells were drilled to the Mehrten Formation, a confining layer, and screened for last 3m. These groundwater well water levels as well as the surface water elevations of the Main Canal and the Merced River were used to determine the direction of sublateral surface flows using Groundwater Vistas as a user interface for MODFLOW. The well and pond waters and seepage from the river banks were sampled for anion/cation, dissolved organic carbon, total nitrogen, total iron, and total dissolved iron concentrations to determine water sources and the possibility of suboxic water. Field analysis indicated that water in all wells and ponds exhibit low dissolved oxygen, high conductivity rates, and oxidation/reduction potentials that switched from oxidizing to reductive during the course of the monitoring. Chemical analysis indicates that there are three sources of water for this floodplain: the Merced River and Main Canal, (which are chemically very similar), the waters from the fish hatchery, and precipitation. The well closest to the fish hatcheries had C:N ratio of 1:1, highly carbon-limited system. MODFLOW particle tracer experiments were performed, results indicate that that travel time between the Main Canal and Merced River are approximately 10-15 years. The hydraulic gradient set up by the groundwater connection between Main Canal and the Merced River, insures that any effluent released by the fish farms will be transported to the Merced River. Conclusions of the study are that the waters that seep from the Main Canal to the Merced River in this area can be sub-oxic, which is not conducive to salmon spawning and are detrimental to the developing salmonid embryo. Due to the causal connections between the hydrological system of the Merced River floodplain and the riverine system, habitat rehabilitation must target not only the surface water but also important subsurface hydrological components.

Determination of channel capacity of the Sacramento River between Ordbend and Glenn, Butte and Glenn counties, California

USGS Publications Warehouse

Simpson, R.G.

1976-01-01

The adequacy of an 8.5-mi reach of the Sacramento River to carry flood flows is evaluated. The reach studied is in Butte and Glenn Counties, California, and extends northward from the present east-bank Sacramento River Flood Control Project levee near Glenn upstream to the Ord Ferry gaging station near Ordbend. There is a west-bank levee throughout the study reach. Flows analyzed range from 11,500 to 265,000 cfs. Computed water-surface elevations are based on topography obtained during September through November 1974. The present Sacramento River Flood Control Project levees at the downstream end of the study reach near Glenn are designed to contain flows up to 150,000 cfs. Water-surface elevations computed for flows of this magnitude are about 6 to 8 ft below the top of the existing west-bank levee throughout the study reach. (Woodard-USGS)

Using Levee Setbacks to Increase Floodplain Connectivity and Reduce Flood Risk

NASA Astrophysics Data System (ADS)

Dahl, T. A.; Echevarria-Doyle, W.

2017-12-01

Levees typically constrain flood flows to within the main channel, isolating the river from its natural floodplain. Levees limit the areal and temporal extents of flooding, but can increase flood peaks, alter ecosystems, and cause scour. In order to mitigate these effects, some groups have begun moving portions of levees further away from the main channel, creating setback levees. Here we describe a series of levee setback scenarios for a hypothetical river that were modeled with the unsteady, 2D-hydraulic model AdH. In our scenarios, the water surface elevations were reduced both at the location of the levee setback and for some distance upstream. The models also show that the floodplain roughness can have a greater effect on the reduction in water surface elevation than the size of the levee setback. Groups planning levee setbacks can use these results to help guide their designs.

The Canadian Hydrological Model (CHM): A multi-scale, variable-complexity hydrological model for cold regions

NASA Astrophysics Data System (ADS)

Marsh, C.; Pomeroy, J. W.; Wheater, H. S.

2016-12-01

There is a need for hydrological land surface schemes that can link to atmospheric models, provide hydrological prediction at multiple scales and guide the development of multiple objective water predictive systems. Distributed raster-based models suffer from an overrepresentation of topography, leading to wasted computational effort that increases uncertainty due to greater numbers of parameters and initial conditions. The Canadian Hydrological Model (CHM) is a modular, multiphysics, spatially distributed modelling framework designed for representing hydrological processes, including those that operate in cold-regions. Unstructured meshes permit variable spatial resolution, allowing coarse resolutions at low spatial variability and fine resolutions as required. Model uncertainty is reduced by lessening the necessary computational elements relative to high-resolution rasters. CHM uses a novel multi-objective approach for unstructured triangular mesh generation that fulfills hydrologically important constraints (e.g., basin boundaries, water bodies, soil classification, land cover, elevation, and slope/aspect). This provides an efficient spatial representation of parameters and initial conditions, as well as well-formed and well-graded triangles that are suitable for numerical discretization. CHM uses high-quality open source libraries and high performance computing paradigms to provide a framework that allows for integrating current state-of-the-art process algorithms. The impact of changes to model structure, including individual algorithms, parameters, initial conditions, driving meteorology, and spatial/temporal discretization can be easily tested. Initial testing of CHM compared spatial scales and model complexity for a spring melt period at a sub-arctic mountain basin. The meshing algorithm reduced the total number of computational elements and preserved the spatial heterogeneity of predictions.

Thermal Fluxes and Temperatures in Small Urban Headwater Streams of the BES LTER: Landscape Forest and Impervious Patches and the Importance of Spatial and Temporal Scales

NASA Astrophysics Data System (ADS)

Kim, H.; Belt, K. T.; Welty, C.; Heisler, G.; Pouyat, R. V.; McGuire, M. P.; Stack, W. P.

2006-05-01

Water and material fluxes from urban landscape patches to small streams are modulated by extensive "engineered" drainage networks. Small urban headwater catchments are different in character and function from their larger receiving streams because of their extensive, direct connections to impervious surface cover (ISC) and their sometimes buried nature. They need to be studied as unique functional hydrologic units if impacts on biota are to be fully understood. As part of the Baltimore Ecosystem Study LTER project, continuous water temperature data are being collected at 2-minute intervals at over twenty small catchments representing various mixtures of forest and ISC. Suburban stream sites with greater ISC generally have higher summer water temperatures. Suburban catchments with most of their channel drainage contained within storm drain pipes show subdued diurnal variation and cool temperatures, but with very large spikes in summer runoff events. Conversely, high ISC urban piped streams have elevated "baseline" temperatures that stand well above all the other monitoring sites. There is a pronounced upstream-downstream effect; nested small headwater catchments experience more frequent, larger temperature spikes related to runoff events than downstream sites. Also, runoff-initiated temperature elevations at small stream sites unexpectedly last much longer than the storm runoff hydrographs. These observations suggest that for small headwater catchments, urban landscapes not only induce an ambient, "heat island" effect on stream temperatures, but also introduce thermal disturbance regimes and fluxes that are not trivial to aquatic biota.

connecting the dots between Greenland ice sheet surface melting and ice flow dynamics (Invited)

NASA Astrophysics Data System (ADS)

Box, J. E.; Colgan, W. T.; Fettweis, X.; Phillips, T. P.; Stober, M.

2013-12-01

This presentation is of a 'unified theory' in glaciology that first identifies surface albedo as a key factor explaining total ice sheet mass balance and then surveys a mechanistic self-reinforcing interaction between melt water and ice flow dynamics. The theory is applied in a near-real time total Greenland mass balance retrieval based on surface albedo, a powerful integrator of the competing effects of accumulation and ablation. New snowfall reduces sunlight absorption and increases meltwater retention. Melting amplifies absorbed sunlight through thermal metamorphism and bare ice expansion in space and time. By ';following the melt'; we reveal mechanisms linking existing science into a unified theory. Increasing meltwater softens the ice sheet in three ways: 1.) sensible heating given the water temperature exceeds that of the ice sheet interior; 2.) Some infiltrating water refreezes, transferring latent heat to the ice; 3.) Friction from water turbulence heats the ice. It has been shown that for a point on the ice sheet, basal lubrication increases ice flow speed to a time when an efficient sub-glacial drainage network develops that reduces this effect. Yet, with an increasing melt duration the point where the ice sheet glides on a wet bed increases inland to a larger area. This effect draws down the ice surface elevation, contributing to the ';elevation feedback'. In a perpetual warming scenario, the elevation feedback ultimately leads to ice sheet loss reversible only through much slower ice sheet growth in an ice age environment. As the inland ice sheet accelerates, the horizontal extension pulls cracks and crevasses open, trapping more sunlight, amplifying the effect of melt accelerated ice. As the bare ice area increases, the direct sun-exposed crevassed and infiltration area increases further allowing the ice warming process to occur more broadly. Considering hydrofracture [a.k.a. hydrofracking]; surface meltwater fills cracks, attacking the ice integrity. Because water is 'heavier' than ice, water-filled cracks have unlimited capacity to hydraulically ';jack' open fractures, penetrating, fracturing and disaggregating a solid ice body. This process promotes iceberg calving at more than 150, 1km wide marine terminating Greenland glacier fronts. Resulting from a rising trend of surface melting and sea water temperature, meltwater ejection at the underwater front of marine glaciers drives a an increasing turbulent heat exchange between the glacier front and relatively warm sea water melting it faster. Underwater melting promotes an undercutting of the glacier front leading to ice berg calving. Calving through hydrofracture or marine undercutting provide a direct and immediate ice flow speed response mechanism for surface meltwater production. Ice flow speed reacts because calving reduces flow resistance. The above physical processes interact. Cooling shuts these processes down. Negative feedbacks dampen the warming impulse. Live 21 June, 2013 is a new Danish Web site1 that exploits total mass balance rate of decline as a function of albedo to predict GRACE mass rate of change with 80% explained variance. While surface mass balance explains the mass rate of change slightly higher, surface albedo is an observable quantity as is gravity change.

Integrated diagenetic and sequence stratigraphy of a late Oligocene-early Miocene, mixed-sediment platform (Austral Basin, southern Patagonia): Resolving base-level and paleoceanographic changes, and paleoaquifer characteristics

NASA Astrophysics Data System (ADS)

Dix, George R.; Parras, Ana

2014-06-01

A condensed (~ 20-m-thick) marine transgressive-highstand succession comprises the upper San Julián Formation (upper Oligocene-lower Miocene) of the northern retroarc Austral Basin, southern Patagonia. Mixed-sediment facies identify a shelf-interior setting, part of an overall warm-temperate regional platform of moderate energy. Giant oyster-dominated skeletal-hiatal accumulations along the maximum flooding surface and forming high-energy event beds in the highstand succession preserve relict micrite in protected shelter porosity, and identify periods of reduced sediment accumulation. The stratigraphic distribution of marine-derived glaucony and diagenetic carbonates is spatially related to sequence development. Depositional siderite coincides with prominent marine transgression, defining transient mixing of marine and meteoric waters across coastal-plain deposits. Chemically evolved autochthonous glaucony coincides with periods of extended seafloor exposure and transgressions that bracket the marine succession, and within the oyster-dominated skeletal accumulations. Seafloor cement, likely once magnesian calcite, formed in association with an encrusting/boring biota along the maximum flooding surface in concert with incursion of cool (11-13 °C) water. The cement is present locally in skeletal event beds in the highstand succession suggesting a possible association with high-order base-level change and cooler water. As the highstand succession coincides with elevated global sea level in the late Oligocene-early Miocene, the locally marine-cemented glauconitic skeletal event beds in the highstand succession may identify higher order glacio-eustatic control. Local stratal condensation, however, is best explained by regional differences in basement subsidence. In the burial realm, carbonate diagenesis produced layers of phreatic calcrete coincident with skeletal-rich deposits. Zeolite (clinoptilolite-K) cement is restricted to the lowermost marine transgressive interval probably due to initial elevated metastability of reworked weathered silicates. Clay (illite)-cement is restricted to siliciclastic-rich intervals wherein skeletal carbonate did not buffer pore-water pH. Diagenetic carbonate geochemistry (Sr, Na, and δ18O and δ13C) shows that, with burial, the transgressive and highstand system tracts developed as distinct paleoaquifers resulting from different proximities to meteoric recharge zones.

Modeling of subglacial water pressure on Russell glacier, toward a better understanding of the relation between meltwater availability and ice dynamics.

NASA Astrophysics Data System (ADS)

de Fleurian, Basile; Morlighem, Mathieu; Seroussi, Helene; Rignot, Eric

2016-04-01

Basal sliding is the main control on outlet glaciers velocity. This sliding is mainly driven by the water pressure at the base of the glaciers. The ongoing increase in surface melt of the Greenland Ice Sheet warrants an examination of its impact on basal water pressure and in turn on basal sliding. Here, we examine the case of Russell glacier, West Greenland, where a remarkably extensive set of observations have been gathered. These observations suggest that the increase in runoff has no impact on the annual velocity on the lower part of the drainage basin, but yield an acceleration of ice flow above the Equilibrium Line Altitude (ELA). It is believed that this two distinct behaviours are due to different evolutions of the subglacial draining system during and after the melt season. We use here a high-resolution new generation subglacial hydrological model forced by reconstructed surface runoff for the period 2008 to 2012 to investigate the possible causes of these distinct behaviours. The model results confirm the existence of two distinct behaviours of the subglacial water pressure, an increase in the mean annual water pressure at high elevation and a stagnation of these same mean annual pressures below the ELA. The increase in meltwater at the lower elevation leads to a more developed efficient drainage system and the overall steadiness of the annual velocities, but, at higher elevation the drainage system remains mainly inefficient and is therefore strongly sensitive to the increase in meltwater availability.

Remotely-sensed and field-based observations of glacier change in the Annapurna-Manaslu region, Nepal

NASA Astrophysics Data System (ADS)

Lovell, Arminel; Carr, Rachel; Stokes, Chris

2017-04-01

Himalayan glaciers have shrunk rapidly during the past twenty years. Understanding the factors controlling these losses is vital for forecasting changes in water resources, as the Himalaya houses the headwaters of major river systems, with densely populated catchments downstream. However, our knowledge of Himalayan glaciers is comparatively limited, due to their high-altitude, remote location. This is particularly the case in the Annapurna-Manaslu region, which has received relatively little scientific attention to date. Here, we present initial findings from remotely sensed data analysis, and our first field campaign in October 2016. Feature tracking of Band 8 Landsat imagery demonstrates that velocities in the region reach a maximum of 70-100 m a-1 , which is somewhat faster than those reported in the Khumbu region (e.g. Quincey et al 2009). A number of glaciers have substantial stagnant ice tongues, and most are flowing faster in the upper ablation zone than in the lower sections. The most rapidly flowing glaciers are located in the south-east of the Annapurna-Manaslu region and tend to also be the largest. Interestingly, initial observations suggest that the debris-covered ablation zones in the south-east are flowing more rapidly than the smaller, clean-ice glaciers in the north of the region. Comparison of velocities between 2000-2001 and 2014-2015 suggests deceleration on some glacier tongues. In October 2016, we conducted fieldwork on Annapurna South Glacier, located at the foot of Annapurna I. Here, we collected a number of datasets, with the aim of assessing the relationship between surface elevation change, ice velocities and debris cover. These included: i) installing ablation stakes in areas with varying debris cover; ii) quantifying debris characteristics, using Wolman counting and by measuring thickness; iii) surveying the glacier surface, using a differential GPS; iv) monitoring ice cliff melting, using Structure from Motion and; v) measuring surface and sub-surface temperatures, using i-buttons. Initial results demonstrate large spatial variability in debris characteristics and thickness, which in turn appears to substantially influence melt rates. The surface topography is highly uneven and a number of ice cliffs are present, where melt rates appear to be much higher than in surrounding areas. Interestingly, we observed very few surface melt ponds or surface melt water, which we suggest maybe be due to the basal topography and/or debris characteristics, and aim to further investigate this during our 2017 fieldwork.

Modeling the Salar de Uyuni, Bolivia as an Equipotential Surface of Earth's Gravity Field

NASA Technical Reports Server (NTRS)

Borsa, Adrian; Bills, Bruce

2004-01-01

The salar de Uyuni is a massive dry salt lake that lies at the lowest point of an internal/drainage basin in the Bolivian Altiplano. Its topography is remarkable for its extraordinary flatness over almost a full degree of latitude and longitude. We surveyed a 54 x 45 km region of the salar with kinematic GPS in September, 2002 and found a topographic range of only 80 cm over the entire surveyed area. Furthermore, the survey revealed distinct surface features with several dominant wavelengths and orientations. Some of these appear to be aligned with orographic features that intersect the salar, leading us to conjecture that they are the surface expression of high-density mountains that have been buried by low-density basin sediments. Over the oceans, a similar correspondence between basin bathymetry and surface topography is exploited to map the seafloor using sea-surface satellite altimetry measurements, with the sea surface following geoid undulations due to the underwater mass distribution. On the salar, annual flooding creates a shallow lake whose surface also lies on a equipotential surface shaped by the distribution of underlying mass. The link to the actual salar surface is via the dissolution and redeposition of salt by the lake waters, which appears to push the system to an equilibrium of constant water depth and the coincidence of the shapes of the lake surface and bottom. To test our hypothesis about the origin of the surface features on the salar, we compare our GPS survey elevations with the equipotential surface generated from local gravity measurements in conjunction with gravity and potential values from the EGM96 global geopotential model. 50% of the variance of the GPS elevations can be explained by equipotential surface undulations from the EGM96 model alone, and an additional 40% is explained by the shorter-wavelength equipotential surface derived from local gravity. We examine the unexplained 10% of elevation variance from the standpoint of errors in the equipotential surface calculation and possible unmodelled surface processes.

Developing flood-inundation maps for Johnson Creek, Portland, Oregon

USGS Publications Warehouse

Stonewall, Adam J.; Beal, Benjamin A.

2017-04-14

Digital flood-inundation maps were created for a 12.9‑mile reach of Johnson Creek by the U.S. Geological Survey (USGS). The flood-inundation maps depict estimates of water depth and areal extent of flooding from the mouth of Johnson Creek to just upstream of Southeast 174th Avenue in Portland, Oregon. Each flood-inundation map is based on a specific water level and associated streamflow at the USGS streamgage, Johnson Creek at Sycamore, Oregon (14211500), which is located near the upstream boundary of the maps. The maps produced by the USGS, and the forecasted flood hydrographs produced by National Weather Service River Forecast Center can be accessed through the USGS Flood Inundation Mapper Web site (http://wimcloud.usgs.gov/apps/FIM/FloodInundationMapper.html).Water-surface elevations were computed for Johnson Creek using a combined one-dimensional and two‑dimensional unsteady hydraulic flow model. The model was calibrated using data collected from the flood of December 2015 (including the calculated streamflows at two USGS streamgages on Johnson Creek) and validated with data from the flood of January 2009. Results were typically within 0.6 foot (ft) of recorded or measured water-surface elevations from the December 2015 flood, and within 0.8 ft from the January 2009 flood. Output from the hydraulic model was used to create eight flood inundation maps ranging in stage from 9 to 16 ft. Boundary condition hydrographs were identical in shape to those from the December 2015 flood event, but were scaled up or down to produce the amount of streamflow corresponding to a specific water-surface elevation at the Sycamore streamgage (14211500). Sensitivity analyses using other hydrograph shapes, and a version of the model in which the peak flow is maintained for an extended period of time, showed minimal variation, except for overbank areas near the Foster Floodplain Natural Area.Simulated water-surface profiles were combined with light detection and ranging (lidar) data collected in 2014 to delineate water-surface extents for each of the eight modeled stages. The availability of flood-inundation maps in conjunction with real-time data from the USGS streamgages along Johnson Creek and forecasted hydrographs from the National Weather Service Northwest River Forecast Center will provide residents of the watershed and emergency management personnel with valuable information that may aid in flood response, including potential evacuations, road closures, and mitigation efforts. In addition, these maps may be used for post-flood recovery efforts.

Southern Alaska Glaciers: Spatial and Temporal Variations in Ice Volume

NASA Technical Reports Server (NTRS)

Sauber, J.; Molnia, B. F.; Lutchke, S.; Rowlands, D.; Harding, D.; Carabajal, C.; Hurtado, J. M.; Spade, G.

2004-01-01

Although temperate mountain glaciers comprise less than 1% of the glacier-covered area on Earth, they are important because they appear to be melting rapidly under present climatic conditions and, therefore, make significant contributions to rising sea level. In this study, we use ICESat observations made in the last 1.5 years of southern Alaska glaciers to estimate ice elevation profiles, ice surface slopes and roughness, and bi-annual and/or annual ice elevation changes. We report initial results from the near coastal region between Yakutat Bay and Cape Suckling that includes the Malaspina and Bering Glaciers. We show and interpret ice elevations changes across the lower reaches of the Bagley Ice Valley for the period between October 2003 and May 2004. In addition, we use off-nadir pointing observations to reference tracks over the Bering and Malaspina Glaciers in order to estimate annual ice elevation change. Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and Shuttle Radar Topography Mission (SRTM) derived DEMs are used to estimate across track regional slopes between ICESat data acquisitions. Although the distribution and quantity of ICESat elevation profiles with multiple, exact repeat data is currently limited in Alaska, individual ICESat data tracks, provide an accurate reference surface for comparison to other elevation data (e.g. ASTER and SRTM X- and C-band derived DEMs). Specifically we report the elevation change over the Malaspina Glacier's piedmont lobe between a DEM derived from SRTM C-band data acquired in Feb. 2000 and ICESat Laser #2b data from Feb.-March 2004. We also report use of ICESat elevation data to enhance ASTER derived absolute DEMs. Mountain glaciers generally have rougher surfaces and steeper regional slopes than the ice sheets for which the ICESat design was optimized. Therefore, rather than averaging ICESat observations over large regions or relying on crossovers, we are working with well-located ICESat footprint returns to estimate glacier ice elevations and surface characteristics. Additional information is included in the original extended abstract.

Effect of water depth and water velocity upon the surfacing frequency of the bimodally respiring freshwater turtle, Rheodytes leukops.

PubMed

Gordos, Matthew A; Franklin, Craig E; Limpus, Colin J

2004-08-01

This study examines the effect of increasing water depth and water velocity upon the surfacing behaviour of the bimodally respiring turtle, Rheodytes leukops. Surfacing frequency was recorded for R. leukops at varying water depths (50, 100, 150 cm) and water velocities (5, 15, 30 cm s(-1)) during independent trials to provide an indirect cost-benefit analysis of aquatic versus pulmonary respiration. With increasing water velocity, R. leukops decreased its surfacing frequency twentyfold, thus suggesting a heightened reliance upon aquatic gas exchange. An elevated reliance upon aquatic respiration, which presumably translates into a decreased air-breathing frequency, may be metabolically more efficient for R. leukops compared to the expenditure (i.e. time and energy) associated with air-breathing within fast-flowing riffle zones. Additionally, R. leukops at higher water velocities preferentially selected low-velocity microhabitats, presumably to avoid the metabolic expenditure associated with high water flow. Alternatively, increasing water depth had no effect upon the surfacing frequency of R. leukops, suggesting little to no change in the respiratory partitioning of the species across treatment settings. Routinely long dives (>90 min) recorded for R. leukops indicate a high reliance upon aquatic O2 uptake regardless of water depth. Moreover, metabolic and temporal costs attributed to pulmonary gas exchange within a pool-like environment were likely minimal for R. leukops, irrespective of water depth.

Function of desiccate in gustatory sensilla of drosophila melanogaster.

PubMed

Kawano, Takeshi; Ryuda, Masasuke; Matsumoto, Hitoshi; Ochiai, Masanori; Oda, Yasunori; Tanimura, Teiichi; Csikos, Gyorge; Moriya, Megumi; Hayakawa, Yoichi

2015-11-27

Desiccate (Desi), initially discovered as a gene expressing in the epidermis of Drosophila larvae for protection from desiccation stress, was recently found to be robustly expressed in the adult labellum; however, the function, as well as precise expression sites, was unknown. Here, we found that Desi is expressed in two different types of non-neuronal cells of the labellum, the epidermis and thecogen accessory cells. Labellar Desi expression was significantly elevated under arid conditions, accompanied by an increase in water ingestion by adults. Desi overexpression also promoted water ingestion. In contrast, a knockdown of Desi expression reduced feeding as well as water ingestion due to a drastic decrease in the gustatory sensillar sensitivity for all tested tastants. These results indicate that Desi helps protect insects from desiccation damage by not only preventing dehydration through the integument but also accelerating water ingestion via elevated taste sensitivities of the sensilla.

Simulated and observed 2010 floodwater elevations in selected river reaches in the Pawtuxet River Basin, Rhode Island

USGS Publications Warehouse

Zarriello, Phillip J.; Olson, Scott A.; Flynn, Robert H.; Strauch, Kellan R.; Murphy, Elizabeth A.

2014-01-01

Heavy, persistent rains from late February through March 2010 caused severe flooding that set, or nearly set, peaks of record for streamflows and water levels at many long-term streamgages in Rhode Island. In response to this event, hydraulic models were updated for selected reaches covering about 56 river miles in the Pawtuxet River Basin to simulate water-surface elevations (WSEs) at specified flows and boundary conditions. Reaches modeled included the main stem of the Pawtuxet River, the North and South Branches of the Pawtuxet River, Pocasset River, Simmons Brook, Dry Brook, Meshanticut Brook, Furnace Hill Brook, Flat River, Quidneck Brook, and two unnamed tributaries referred to as South Branch Pawtuxet River Tributary A1 and Tributary A2. All the hydraulic models were updated to Hydrologic Engineering Center-River Analysis System (HEC-RAS) version 4.1.0 using steady-state simulations. Updates to the models included incorporation of new field-survey data at structures, high resolution land-surface elevation data, and updated flood flows from a related study. The models were assessed using high-water marks (HWMs) obtained in a related study following the March– April 2010 flood and the simulated water levels at the 0.2-percent annual exceedance probability (AEP), which is the estimated AEP of the 2010 flood in the basin. HWMs were obtained at 110 sites along the main stem of the Pawtuxet River, the North and South Branches of the Pawtuxet River, Pocasset River, Simmons Brook, Furnace Hill Brook, Flat River, and Quidneck Brook. Differences between the 2010 HWM elevations and the simulated 0.2-percent AEP WSEs from flood insurance studies (FISs) and the updated models developed in this study varied with most differences attributed to the magnitude of the 0.2-percent AEP flows. WSEs from the updated models generally are in closer agreement with the observed 2010 HWMs than with the FIS WSEs. The improved agreement of the updated simulated water elevations to observed 2010 HWMs provides a measure of the hydraulic model performance, which indicates the updated models better represent flooding at other AEPs than the existing FIS models.

Improving Frozen Precipitation Density Estimation in Land Surface Modeling

NASA Astrophysics Data System (ADS)

Sparrow, K.; Fall, G. M.

2017-12-01

The Office of Water Prediction (OWP) produces high-value water supply and flood risk planning information through the use of operational land surface modeling. Improvements in diagnosing frozen precipitation density will benefit the NWS's meteorological and hydrological services by refining estimates of a significant and vital input into land surface models. A current common practice for handling the density of snow accumulation in a land surface model is to use a standard 10:1 snow-to-liquid-equivalent ratio (SLR). Our research findings suggest the possibility of a more skillful approach for assessing the spatial variability of precipitation density. We developed a 30-year SLR climatology for the coterminous US from version 3.22 of the Daily Global Historical Climatology Network - Daily (GHCN-D) dataset. Our methods followed the approach described by Baxter (2005) to estimate mean climatological SLR values at GHCN-D sites in the US, Canada, and Mexico for the years 1986-2015. In addition to the Baxter criteria, the following refinements were made: tests were performed to eliminate SLR outliers and frequent reports of SLR = 10, a linear SLR vs. elevation trend was fitted to station SLR mean values to remove the elevation trend from the data, and detrended SLR residuals were interpolated using ordinary kriging with a spherical semivariogram model. The elevation values of each station were based on the GMTED 2010 digital elevation model and the elevation trend in the data was established via linear least squares approximation. The ordinary kriging procedure was used to interpolate the data into gridded climatological SLR estimates for each calendar month at a 0.125 degree resolution. To assess the skill of this climatology, we compared estimates from our SLR climatology with observations from the GHCN-D dataset to consider the potential use of this climatology as a first guess of frozen precipitation density in an operational land surface model. The difference in model derived estimates and GHCN-D observations were assessed using time-series graphs of 2016-2017 winter season SLR observations and climatological estimates, as well as calculating RMSE and variance between estimated and observed values.

Hemispherical Field-of-View Above-Water Surface Imager for Submarines

NASA Technical Reports Server (NTRS)

Hemmati, Hamid; Kovalik, Joseph M.; Farr, William H.; Dannecker, John D.

2012-01-01

A document discusses solutions to the problem of submarines having to rise above water to detect airplanes in the general vicinity. Two solutions are provided, in which a sensor is located just under the water surface, and at a few to tens of meter depth under the water surface. The first option is a Fish Eye Lens (FEL) digital-camera combination, situated just under the water surface that will have near-full- hemisphere (360 azimuth and 90 elevation) field of view for detecting objects on the water surface. This sensor can provide a three-dimensional picture of the airspace both in the marine and in the land environment. The FEL is coupled to a camera and can continuously look at the entire sky above it. The camera can have an Active Pixel Sensor (APS) focal plane array that allows logic circuitry to be built directly in the sensor. The logic circuitry allows data processing to occur on the sensor head without the need for any other external electronics. In the second option, a single-photon sensitive (photon counting) detector-array is used at depth, without the need for any optics in front of it, since at this location, optical signals are scattered and arrive at a wide (tens of degrees) range of angles. Beam scattering through clouds and seawater effectively negates optical imaging at depths below a few meters under cloudy or turbulent conditions. Under those conditions, maximum collection efficiency can be achieved by using a non-imaging photon-counting detector behind narrowband filters. In either case, signals from these sensors may be fused and correlated or decorrelated with other sensor data to get an accurate picture of the object(s) above the submarine. These devices can complement traditional submarine periscopes that have a limited field of view in the elevation direction. Also, these techniques circumvent the need for exposing the entire submarine or its periscopes to the outside environment.

Subsidence (2004-2009) in and near lakebeds of the Mojave River and Morongo groundwater basins, southwest Mojave Desert, California

USGS Publications Warehouse

Solt, Mike; Sneed, Michelle

2014-01-01

Subsidence, in the vicinity of dry lakebeds, within the Mojave River and Morongo groundwater basins of the southwest Mojave Desert has been measured by Interferometric Synthetic Aperture Radar (InSAR). The investigation has focused on determining the location, extent, and magnitude of changes in land-surface elevation. In addition, the relation of changes in land-surface elevation to changes in groundwater levels and lithology was explored. This report is the third in a series of reports investigating land-surface elevation changes in the Mojave and Morongo Groundwater Basins, California. The first report, U.S. Geological Survey (USGS) Water-Resources Investigations Report 03-4015 by Sneed and others (2003), describes historical subsidence and groundwater-level changes in the southwest Mojave Desert from 1969 to 1999. The second report, U.S. Geological Survey Water-Resources Investigations Report 07-5097, an online interactive report and map, by Sneed and Brandt (2007), describes subsidence and groundwater-level changes in the southwest Mojave Desert from 1999 to 2004. The purpose of this report is to document an updated assessment of subsidence in these lakebeds and selected neighboring areas from 2004 to 2009 as measured by InSAR methods. In addition, continuous Global Positioning System (GPS)(2005-10), groundwater level (1951-2010), and lithologic data, if available, were used to characterize compaction mechanisms in these areas. The USGS California Water Science Center’s interactive website for the Mojave River and Morongo groundwater basins was created to centralize information pertaining to land subsidence and water levels and to allow readers to access available data and related reports online. An interactive map of land subsidence and water levels in the Mojave River and Morongo groundwater basins displays InSAR interferograms, subsidence areas, subsidence contours, hydrographs, well information, and water-level contours. Background information, including a basic description of the mechanics of land subsidence and InSAR, as well as a description of the study area, is presented within the Mojave Water Resources Interactive Map and report.

Low-grazing angle laser scans of foreshore topography, swash and inner surf-zone wave heights, and mean water level: validation and storm response

NASA Astrophysics Data System (ADS)

Brodie, K. L.; McNinch, J. E.; Forte, M.; Slocum, R.

2010-12-01

Accurately predicting beach evolution during storms requires models that correctly parameterize wave runup and inner surf-zone processes, the principle drivers of sediment exchange between the beach and surf-zone. Previous studies that aimed at measuring wave runup and swash zone water levels have been restricted to analyzing water-elevation time series of (1) the shoreward-most swash excursion using video imaging or near-bed resistance wires, or (2) the free water surface at a particular location on the foreshore using pressure sensors. These data are often compared with wave forcing parameters in deeper water as well as with beach topography observed at finite intervals throughout the time series to identify links between foreshore evolution, wave spectra, and water level variations. These approaches have lead to numerous parameterizations and empirical equations for wave runup but have difficulty providing adequate data to quantify and understand short-term spatial and temporal variations in foreshore evolution. As a result, modeling shoreline response and changes in sub-aerial beach volume during storms remains a substantial challenge. Here, we demonstrate a novel technique in which a terrestrial laser scanner is used to continuously measure beach and foreshore topography as well as water elevation (and wave height) in the swash and inner surf-zone during storms. The terrestrial laser scanner is mounted 2-m above the dune crest at the Field Research Facility in Duck, NC in line with cross-shore wave gauges located at 2-m, 3-m, 5-m, 6-m, and 8-m of water depth. The laser is automated to collect hourly, two-dimensional, 20-minute time series of data along a narrow swath in addition to an hourly three-dimensional laser scan of beach and dune topography +/- 250m alongshore from the laser. Low grazing-angle laser scans are found to reflect off of the surface of the water, providing spatially (e.g. dx <= 0.1 m) and temporally (e.g. dt = 3Hz) dense elevation data of the foreshore, swash, and inner-surf zone bore heights. Foreshore elevation precision is observed to be < 0.01m. Sea surface elevation data is confined to the breaking region and is more extensive in rough, fully-dissipative surf zones, with the fronts of breaking waves and dissipated bores resolved most clearly. Time series of swash front (runup) data will be compared with simultaneously collected video-imaged swash timestacks, and wave height data of the inner surf zone will be compared with wave data from an aquadopp in 2m of water depth. In addition, analysis of the water level time series data at 10 cm intervals across the profile enables reconstruction of the shoreline setup profile as well as cross-shore variations in 1D wave spectra. Foreshore beach morphology evolution is analyzed using both the 2D cross-shore profile data, as well as the 3D topographic data during multiple storm events. Potential sources of error in the measurements, such as shadowing of the wave troughs or reflectance off of wave spray is identified and quantified.

Reconstructing initial Mediterranean Outflow from Benthic Foraminifera

NASA Astrophysics Data System (ADS)

Garcia Gallardo, A.; Grunert, P.; Voelker, A. H. L.; Mendes, I.; Piller, W. E.

2016-12-01

The onset of Mediterranean Outflow Water (MOW) takes place after the opening of the Gibraltar Strait (5.33 Ma). Its impact on oceanography and climate in the present is widely studied but its role in the early Pliocene is not well explored yet. Quantitative analysis of benthic foraminifera has been performed on sediment samples from the lower part of IODP Hole U1387C (IODP Expedition 339) in order to reconstruct paleoenvironmental changes during the late Miocene-early Pliocene. Micropaleontological records reveal a shift from reduced oxygenation in the late Miocene to a better ventilated setting during the early Pliocene likely related to the first evidence of Mediterranean-Atlantic exchange. Increased abundances of the functional benthic foraminiferal "elevated epifauna" group have been directly related to MOW in the Gulf of Cadiz since they are adapted to settle on substrates above the sediment surface to catch food particles from strong bottom currents (Schönfeld, 2002). In our study, the elevated epifauna is represented by Planulina ariminensis, Cibicides lobatulus and C. refulgens. However, our early Pliocene records reveal that peak abundances of C. lobatulus and C. refulgens are well correlated with allochthonous shelf taxa and grain-size maxima, suggesting downslope transport to deeper settings. To clarify this issue, stable isotope analyses (δ18O, δ13C) have been performed on shells of shelf dwellers, deep water taxa and elevated epifauna from Pliocene and present-day samples from the Iberian Margin. Preliminary results indicate that some elevated epifaunal elements have a broad bathymetric range and are not always autochthonous to deeper settings. In the early Pliocene Gulf of Cadiz, characterized by frequent turbidite deposition, P. ariminensis would thus remain the only reliable indicator of MOW. Schönfeld, J., 2002. A new benthic foraminiferal proxy for near-bottom current velocities in the Gulf of cadiz, Northeastern Atlantic Ocean. Deep-Sea Res I 49:1853-1875.

Sensitivity of potential evapotranspiration and simulated flow to varying meteorological inputs, Salt Creek watershed, DuPage County, Illinois

USGS Publications Warehouse

Whitbeck, David E.

2006-01-01

The Lamoreux Potential Evapotranspiration (LXPET) Program computes potential evapotranspiration (PET) using inputs from four different meteorological sources: temperature, dewpoint, wind speed, and solar radiation. PET and the same four meteorological inputs are used with precipitation data in the Hydrological Simulation Program-Fortran (HSPF) to simulate streamflow in the Salt Creek watershed, DuPage County, Illinois. Streamflows from HSPF are routed with the Full Equations (FEQ) model to determine water-surface elevations. Consequently, variations in meteorological inputs have potential to propagate through many calculations. Sensitivity of PET to variation was simulated by increasing the meteorological input values by 20, 40, and 60 percent and evaluating the change in the calculated PET. Increases in temperatures produced the greatest percent changes, followed by increases in solar radiation, dewpoint, and then wind speed. Additional sensitivity of PET was considered for shifts in input temperatures and dewpoints by absolute differences of ?10, ?20, and ?30 degrees Fahrenheit (degF). Again, changes in input temperatures produced the greatest differences in PET. Sensitivity of streamflow simulated by HSPF was evaluated for 20-percent increases in meteorological inputs. These simulations showed that increases in temperature produced the greatest change in flow. Finally, peak water-surface elevations for nine storm events were compared among unmodified meteorological inputs and inputs with values predicted 6, 24, and 48 hours preceding the simulated peak. Results of this study can be applied to determine how errors specific to a hydrologic system will affect computations of system streamflow and water-surface elevations.

Elevations of water-worn features on Mars: Implications for circulation of groundwater

USGS Publications Warehouse

Carr, M.H.

2002-01-01

Central to the model of the evolution of the martian hydrosphere by Clifford and Parker [2001] is a permanent freezing of the planet at the end of the Noachian and recharge of the global groundwater system by basal melting of ice-rich polar deposits. Acquisition of MOLA data by Mars Global Surveyor provides a means of testing the model, since discharge of water onto the surface, after development of the cryosphere, is driven by the hydrostatic head created by the difference in elevation between the base of the polar-layered terrain and the discharge site. The new data show that, while most post- Noachian water-worn features are at a lower elevation than the base of the polar-layered terrains, as required by the model, there are exceptions. Prominent among these are possible lacustrine deposits within the canyons, tributaries to the canyons, and valleys on several volcanoes. These high-standing features can be reconciled with the model if volcanic melting of ice within the cryosphere is invoked as a source for water at high elevations. An alternative is that high pressures may have developed below the cryosphere as a result of water being trapped beneath the growing cryosphere and the impermeable basement. Yet another alternative is that, since the end of the Noachian, the groundwater system has been recharged by precipitation during occasional warm periods.

NASA CNES SWOT Agreement

NASA Image and Video Library

2014-05-02

NASA Administrator Charles Bolden, left, and Centre National d'Études Spatiales (CNES) President Jean-Yves Le Gall sign an agreement to move from feasibility studies to implementation of the Surface Water and Ocean Topography (SWOT) mission, Friday, May 2, 2014 at NASA Headquarters in Washington. The SWOT mission will use wide swath altimetry technology to produce high-resolution elevation measurements of the surface of lakes, reservoirs, and wetlands and of the ocean surface. Photo Credit: (NASA/Bill Ingalls)

Buried cold-water coral mounds and contourite deposits in the Atlantic Moroccan Coral Province

NASA Astrophysics Data System (ADS)

Vandorpe, Thomas; Hebbeln, Dierk; Wienberg, Claudia; Van den Berghe, Michèle; Van Rooij, David

2016-04-01

The Atlantic Moroccan Coral Province (AMCP) is situated in the southern Gulf of Cadiz roughly between 34° 50'N to 35°35'N and 6°30'W to 7°15'W. The region displays tectonic (ridges and both large transverse as well as small normal and reverse faults) as well as sedimentological features (drifts deposits and sediment waves). Eleven mud volcanoes are present in the northern part of the region as well (Vandorpe et al., in press). Besides the presence of many surfacing small cold-water coral mounds, hundreds to thousands of mounds were discovered in the subsurface through 2D seismic parasound and sparker seismic profiles. Over 90% of the mounds are situated at water depths between 600 and 1000 meters and most of them occur in clusters. The cold-water coral mounds are rather small in this region (compared to the 100 m high mounds in the Belgica Province in the Porcupine basin (Huvenne et al., 2003)). Their widths vary between 20 and 200 m with a modus around 60 m, while their heights vary between 2 and 40 m with a modus around 10 m. Moreover, ten horizons at which mound growth initiated can be distinguished, compared to the single mound growth event observed in the Porcupine Basin (Huvenne et al., 2003). This points towards rapidly changing environmental conditions in the AMCP which were sometimes favourable for initiation and growth of cold-water coral mounds. These favourable periods rapidly switched to periods when corals were not able to settle and the mounds could get buried. Mound growth initiates mostly at elevated places, e.g. tectonic ridges, outcropping bedrock or even previous cold-water coral mounds. Elevated places deflect bottom currents and increase the amount of food particles and sediments delivered to the corals, but also create sedimentological features such as contourites. The contourite deposits in the region greatly depend on the slope of the topography against which they are present (Vandorpe et al., in press). When mounds were able to reach a certain height at which they did not get buried by sediments during subsequent non-favourable periods, they were usually recolonized, leading to complex mound shapes clearly showing the growth phases of the mound. All of these factors indicate that the AMCP is a very promising region to further unravel the conditions (both geographically and environmentally) favourable for mound initiation and how these mounds in turn influence the local stratigraphy. Huvenne, V.A.I., De Mol, B., Henriet, J.P., 2003. A 3D seismic study of the morphology and spatial distribution of buried coral banks in the Porcupine Basin, SW of Ireland. Marine Geology 198, 5-25. Vandorpe, T., Martins, I., Vitorino, J., hebbeln, D., García, M., Van Rooij, D., in press. Bottom currents and their influence on the sedimentation pattern in the El Arraiche Mud Volcano Province, southern Gulf of Cadiz. Marine Geology.

Geochemistry of Surface and Ground Water in Cement Creek from Gladstone to Georgia Gulch and in Prospect Gulch, San Juan County, Colorado

USGS Publications Warehouse

Johnson, Raymond H.; Wirt, Laurie; Manning, Andrew H.; Leib, Kenneth J.; Fey, David L.; Yager, Douglas B.

2007-01-01

In San Juan County, Colo., the effects of historical mining continue to contribute metals to ground water and surface water. Previous research by the U.S. Geological Survey identified ground-water discharge as a significant pathway for the loading of metals to surface water in the upper Animas River watershed from both acid-mine drainage and acid-rock drainage. In support of this ground-water research effort, Prospect Gulch was selected for further study and the geochemistry of surface and ground water in the area was analyzed as part of four sampling plans: (1) ten streamflow and geochemistry measurements at five stream locations (four locations along Cement Creek plus the mouth of Prospect Gulch from July 2004 through August 2005), (2) detailed stream tracer dilution studies in Prospect Gulch and in Cement Creek from Gladstone to Georgia Gulch in early October 2004, (3) geochemistry of ground water through sampling of monitoring wells, piezometers, mine shafts, and springs, and (4) samples for noble gases and tritium/helium for recharge temperatures (recharge elevation) and ground-water age dating. This report summarizes all of the surface and ground-water data that was collected and includes: (1) all sample collection locations, (2) streamflow and geochemistry, (3) ground-water geochemistry, and (4) noble gas and tritium/helium data.

Flooding Frequency Alters Vegetation in Isolated Wetlands

USGS Publications Warehouse

Haag, Kim H.; Lee, Terrie M.

2006-01-01

Many isolated wetlands in central Florida occur as small, shallow depressions scattered throughout the karst topography of the region. In these wetlands, the water table approaches land surface seasonally, and water levels and flooding frequency are largely determined by differences between precipitation and evapotranspiration. Because much of the region is flat with little topographic relief, small changes in wetland water levels can cause large changes in wetland surface area. Persistent changes in wetland flooding frequencies, as a result of changes in rainfall or human activity, can cause a substantial change in the vegetation of thousands of acres of land. Understanding the effect that flooding frequency has on wetland vegetation is important to assessing the overall ecological status of wetlands. Wetland bathymetric mapping, when combined with water-level data and vegetation assessments, can enable scientists to determine the frequency of flooding at different elevations in a wetland and describe the effects of flooding frequency on wetland vegetation at those elevations. Five cypress swamps and five marshes were studied by the U.S. Geological Survey (USGS) during 2000-2004, as part of an interdisciplinary study of isolated wetlands in central Florida (Haag and others, 2005). Partial results from two of these marshes are described in this report.

CRT--Cascade Routing Tool to define and visualize flow paths for grid-based watershed models

USGS Publications Warehouse

Henson, Wesley R.; Medina, Rose L.; Mayers, C. Justin; Niswonger, Richard G.; Regan, R.S.

2013-01-01

The U.S. Geological Survey Cascade Routing Tool (CRT) is a computer application for watershed models that include the coupled Groundwater and Surface-water FLOW model, GSFLOW, and the Precipitation-Runoff Modeling System (PRMS). CRT generates output to define cascading surface and shallow subsurface flow paths for grid-based model domains. CRT requires a land-surface elevation for each hydrologic response unit (HRU) of the model grid; these elevations can be derived from a Digital Elevation Model raster data set of the area containing the model domain. Additionally, a list is required of the HRUs containing streams, swales, lakes, and other cascade termination features along with indices that uniquely define these features. Cascade flow paths are determined from the altitudes of each HRU. Cascade paths can cross any of the four faces of an HRU to a stream or to a lake within or adjacent to an HRU. Cascades can terminate at a stream, lake, or HRU that has been designated as a watershed outflow location.

ICESat Observations of Arctic Sea Ice: A First Look

NASA Technical Reports Server (NTRS)

Kwok, Ron; Zwally, H. Jay; Yi, Dong-Hui

2004-01-01

Analysis of near-coincident ICESat and RADARSAT imagery shows that the retrieved elevations from the laser altimeter are sensitive to new openings (containing thin ice or open water) in the sea ice cover as well as to surface relief of old and first-year ice. The precision of the elevation estimates, measured over relatively flat sea ice, is approx. 2 cm Using the thickness of thin-ice in recent openings to estimate sea level references, we obtain the sea-ice free-board along the altimeter tracks. This step is necessitated by the large uncertainties in the time-varying sea surface topography compared to that required for accurate determination of free-board. Unknown snow depth introduces the largest uncertainty in the conversion of free-board to ice thickness. Surface roughness is also derived, for the first time, from the variability of successive elevation estimates along the altimeter track Overall, these ICESat measurements provide an unprecedented view of the Arctic Ocean ice cover at length scales at and above the spatial dimension of the altimeter footprint.

Optimization Review: Carson River Mercury Superfund Site, Carson City, Nevada

EPA Pesticide Factsheets

The Carson River Mercury Site (CRMS) (Figure 1) is located in northwest Nevada and was designated a Superfund site in 1990 because of elevated mercury concentrations observed in surface water, sediments and biota inhabiting the site.

The prediction of zenith range refraction from surface measurements of meteorological parameters. [mathematical models of atmospheric refraction used to improve spacecraft tracking space navigation

NASA Technical Reports Server (NTRS)

Berman, A. L.

1976-01-01

In the last two decades, increasingly sophisticated deep space missions have placed correspondingly stringent requirements on navigational accuracy. As part of the effort to increase navigational accuracy, and hence the quality of radiometric data, much effort has been expended in an attempt to understand and compute the tropospheric effect on range (and hence range rate) data. The general approach adopted has been that of computing a zenith range refraction, and then mapping this refraction to any arbitrary elevation angle via an empirically derived function of elevation. The prediction of zenith range refraction derived from surface measurements of meteorological parameters is presented. Refractivity is separated into wet (water vapor pressure) and dry (atmospheric pressure) components. The integration of dry refractivity is shown to be exact. Attempts to integrate wet refractivity directly prove ineffective; however, several empirical models developed by the author and other researchers at JPL are discussed. The best current wet refraction model is here considered to be a separate day/night model, which is proportional to surface water vapor pressure and inversely proportional to surface temperature. Methods are suggested that might improve the accuracy of the wet range refraction model.