Science.gov

Sample records for determining seepage water

  1. Seepage water of northern Utah

    USGS Publications Warehouse

    Fortier, Samuel

    1897-01-01

    The term “seepage water” is used by the irrigators of the West to designate the water which reaches the lowest grounds or the stream channels, swelling the latter by imperceptible degrees and keeping up the flow long after the rains have ceased and the snow has melted. The word “seepage” is applied particularly to the water which begins to appear in spots below irrigation canals and cultivated fields, usually some months or even years after irrigation has been introduced, and which tends to convert the lowlands into marshes and gives rise to springs, which in turn may be employed in watering other fields.The importance of a thorough knowledge of the behavior of seepage water is obvious when consideration is given to the close relationship which exists between the available water supply and the material prosperity of the arid region where irrigation is practiced. This is particularly true of Utah, where every readily available source of supply has long since been utilized and where the rapidly increasing agricultural population necessitates the complete utilization of all fresh waters.

  2. A seepage meter designed for use in flowing water

    USGS Publications Warehouse

    Rosenberry, D.O.

    2008-01-01

    Seepage meters provide one of the most direct means to measure exchange of water across the sediment-water interface, but they generally have been unsuitable for use in fluvial settings. Although the seepage bag can be placed inside a rigid container to minimize velocity head concerns, the seepage cylinder installed in the sediment bed projects into and disrupts the flow field, altering both the local-scale fluid exchange as well as measurement of that exchange. A low-profile seepage meter designed for use in moving water was tested in a seepage meter flux tank where both current velocity and seepage velocity could be controlled. The conical seepage cylinder protrudes only slightly above the sediment bed and is connected via tubing to a seepage bag or flowmeter positioned inside a rigid shelter that is located nearby where current velocity is much slower. Laboratory and field tests indicate that the net effect of the small protrusion of the seepage cylinder into the surface water flow field is inconsequentially small for surface water currents up to 65 cm s-1. Current velocity affects the variability of seepage measurements; seepage standard deviation increased from ???2 to ???6 cm d-1 as current velocity increased from 9 to 65 cm s-1. Substantial bias can result if the shelter is not placed to minimize hydraulic gradient between the bag and the seepage cylinder.

  3. Determination of the hole drain position in dams and hydraulic structures in order to reduce the seepage in water structures by Geo studio model

    NASA Astrophysics Data System (ADS)

    Kahkesh, Ismaeil; Esmaeili, Kazem; Salehi, Saeid

    2017-04-01

    Stability Analysis of Cutoff Walls, Foundations and Concrete Dams Under the Uplift Force is Very Important. Hole Drain is Considered as Effective Measures to Reduce Seepage, Uplift Pressure and Exit Gradient Under the Foundation of Hydraulic Structures Which Made Up to Vertical Pipes With Different Diameters. Physical Model in The Ferdowsi University of Mashhad Was Applied in Order to Study The Effect of Hole Drains in Estimating Uplift Pressure, Seepage Discharge and Exit Gradient. The Uplift Pressure Was Measured By 14 Piezometers. In Each Experiment, The Seepage Discharge Was Measured For The Located Hole Drains, Separately. Water Head Was at Maximum Level. Results Showed That The Best Position Of Controlling Seepage and Exit Gradient by Vertical Drainages Were A/L =0.4 (A=Distance From Dam Heel, L=Dam Length). And Finally Validated Data and the Results by Geo Studio. Key words:earth dam, Geo studio, Gradiant

  4. Seepage Reduction from Unlined Irrigation Canals: Water Quality and Seepage Reduction Effectiveness

    NASA Astrophysics Data System (ADS)

    Susfalk, R. B.; Epstein, B. J.; Schmidt, M.; Goreham, J.; Fitzgerald, B.; Young, M. H.; Martin, C.; Swihart, J.; Smith, D.

    2006-12-01

    Polyacrylamide is a class of long-chain synthetic polymers that is used extensively in food packaging, paper manufacturing, wastewater treatment, and as a soil amendment to reduce erosion. More recently, linear, anionic polyacrylamides (LA-PAM) have been used to reduce seepage from unlined irrigation canals in the western United States. A diverse set of experiments spanning multiple scales has been initiated to understand the efficacy of LA-PAM usage in canal environments. The physical application of granular LA-PAM to flowing canals is straightforward. However, granular PAM requires time to hydrate and react with sediment suspended in the water column, complicating the targeting of a specific canal reach for treatment. Factors that influence PAM's ability to reduce seepage will be discussed, and can include: water temperature, water velocity, and the cation balance and suspended sediment concentration in the canal water. The application method and mass of PAM that are applied are also important considerations. If the ability of PAM to form flocs with suspended sediment is overestimated, PAM will travel further downstream, potentially having an adverse impact on water quality and/or ecology. Negative impacts include livestock drinking out of the canal, the unintentional reduction of seepage water feeding adjacent wetlands or sensitive areas, and impacts on receiving waters. A combination of results from working canals and small scale, artificial Test Troughs will be used to address the impacts that different LA-PAM applications can have on water quality and seepage reduction effectiveness.

  5. 132. Credit JTL. Smaller feeder pipes collecting seepage and water ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    132. Credit JTL. Smaller feeder pipes collecting seepage and water from springs for the Eagle Canyon flume. - Battle Creek Hydroelectric System, Battle Creek & Tributaries, Red Bluff, Tehama County, CA

  6. A system for calibrating seepage meters used to measure flow between ground water and surface water

    USGS Publications Warehouse

    Rosenberry, Donald O.; Menheer, Michael A.

    2006-01-01

    The in-line flowmeter used with this system is incapable of measuring seepage rates below about 7 centimeters per day. Smaller seepage rates can be measured manually. The seepage- control system also can be modified for measuring slower seepage rates with the use of two flowmeters and a slightly different water-routing system, or a fluid-metering pump can be used to control flow through the flux tank instead of an adjustable-height reservoir.

  7. The solution of unconfined water seepage problem in saturated-unsaturated soil using Bathe algorithm and Signorini condition

    NASA Astrophysics Data System (ADS)

    Dou, Zhongsi; Wu, Jiwen; Zhang, Hongmei; Huang, Kai

    2017-06-01

    Bathe algorithm converts problem of determining inner infiltration face into a material nonlinearity problem, and Signorini condition coverts outflow boundary into conventional water boundary. Because an unsaturated seepage problem is also a nonlinear flow problem, through the joint application of this 2 methods, solving variational inequalities is avoided. In conventional material nonlinearity finite element framework with small modification, using NR algorithm, the solving of unconfined water seepage problems including unsteady and unsaturated water seepage problems is realized. The followings are discussed: (1) the improvement of convergence of Bathe method and its generalized form in a three-dimensional model; (2) use Switching Algorithm of Signorini condition to solve water seepage problems; (3) the under-relaxation methods of improving the convergence and mass conservation when solving unsaturated and unsteady water seepage problems. At last, through classic calculation examples, the calculating accuracy and application fields of the proposed methods are evaluated.

  8. Water quality effects of seepage from earthen dams

    USGS Publications Warehouse

    Yost, C.; Naney, J.W.

    1974-01-01

    Analyses of surface and seepage waters from selected floodwater retarding structures in west-central Oklahoma, U.S.A. show the salinity of seepage to be several times greater than that of the impounded waters. The increases in concentration of the several chemical components are not proportional. This phenomenon appears to be caused largely by simple solution, which is closely related to the chemical character of the geologic formation that provides the reservoir site and the earth fill of the dam. Concentration of certain chemical components in the seepage water progressively decreases as the structure ages. This is probably a function of depletion, which is related to the amounts and solubility of the parent materials subjected to solution. In contrast, the concentration of certain other components, such as iron and calcium, increases with time. The chemical activities within the accumulating mud on the bottom of the reservoir apparently cause these increases. ?? 1974.

  9. Variability and comparison of hyporheic water temperatures and seepage fluxes in a small Atlantic salmon stream.

    PubMed

    Alexander, Matthew D; Caissie, Daniel

    2003-01-01

    Ground water discharge is often a significant factor in the quality of fish spawning and rearing habitat and for highly biologically productive streams. In the present study, water temperatures (stream and hyporheic) and seepage fluxes were used to characterize shallow ground water discharge and recharge within thestreambed of Catamaran Brook, a small Atlantic salmon (Salmo salar) stream in central New Brunswick, Canada. Three study sites were instrumented using a total of 10 temperature sensors and 18 seepage meters. Highly variable mean seepage fluxes, ranging from 1.7 x 10(-4) to 2.5 cm3 m(-2) sec(-1), and mean hyporheic water temperatures, ranging from 10.5 degrees to 18.0 degrees C, at depths of 20 to 30 cm in the streambed were dependent on streambed location (left versus right stream bank and site location) and time during the summer sampling season. Temperature data were usefulfor determining if an area of the streambed was under discharge (positive flux), recharge (negative flux), or parallel flow (no flux) conditions and seepage meters were used to directly measure the quantity of water flux. Hyporheic water temperature measurements and specific conductance measurements of the seepage meter sample water, mean values ranging from 68.8 to 157.9 microS/cm, provided additional data for determining flux sources. Three stream banks were consistently under discharge conditions, while the other three stream banks showed reversal from discharge to recharge conditions over the sampling season. Results indicate that the majority of the water collected in the seepage meters was composed of surface water. The data obtained suggests that even though a positive seepage flux is often interpreted as ground water discharge, this discharging water may be of stream water origin that has recently entered the hyporheic zone.The measurement of seepage flux in conjunction with hyporheic water temperature or other indicators of water origin should be considered when attempting to

  10. Comparative Analysis of Seepage Losses From Nighttime Water Level Changes and Water Balance Methods

    NASA Astrophysics Data System (ADS)

    Shukla, A.; Shukla, S.; Wu, C.

    2013-12-01

    Several techniques including Darcy's theory of one and two dimensional groundwater flow, seepage meters, and water balance have been used in the past to estimate seepage from impoundments such as reservoirs, ponds, and constructed wetlands. These methods result in varying level of errors in seepage estimates depending on method and biogeophysical setting to which they are applied. In this study, we explore a simple yet effective method of estimating groundwater fluxes for two stormwater impoundments (SIs) and a partially drained wetland located in agricultural areas using diurnal changes in surface water levels inside these systems. Days with no inflow, outflow, and rainfall were selected to minimize the effect of the error associated water balance components on seepage estimation. Difference in water levels between 20:00 hrs and 5:00 hrs was calculated for the selected days. Only nighttime change was considered keeping in mind the fact that evapotranspiration is negligible during night and hence, the change in water levels can be attributed to seepage alone. Seepage from the analysis of night-time change in the water levels was compared to the estimates from the water balance method with seepage being the residual component of the balance. Results show that seepage constitutes a large part of total outflow from the impoundments (29% and 17% for SI1 during 2008-2009 and 2009-2010 respectively, 30% for SI2 during 2009-2010 and seepage was greater than the total surface water outflow from SI2 during 2010-2011). Accuracy of this method varied from 5% to 41% for first and 4% to 29% for the second SI. Considering that errors as high as 100% have been reported with the use of Darcy's approach, the errors from our method are lower. The lower errors combined with ease of application without using the hydraulic conductivity values makes our approach feasible for other similar systems. Improved seepage estimate from the proposed method will result in quantification of

  11. Uncertainty of canal seepage losses estimated using flowing water balance with acoustic Doppler devices

    NASA Astrophysics Data System (ADS)

    Martin, Chad A.; Gates, Timothy K.

    2014-09-01

    Seepage losses from unlined irrigation canals amount to a large fraction of the total volume of water diverted for agricultural use, posing problems to both water conservation and water quality. Quantifying these losses and identifying areas where they are most prominent are crucial for determining the severity of seepage-related complications and for assessing the potential benefits of seepage reduction technologies and materials. A relatively easy and inexpensive way to estimate losses over an extensive segment of a canal is the flowing water balance, or inflow-outflow, method. Such estimates, however, have long been considered fraught with ambiguity due both to measurement error and to spatial and temporal variability. This paper presents a water balance analysis that evaluates uncertainty in 60 tests on two typical earthen irrigation canals. Monte Carlo simulation is used to account for a number of different sources of uncertainty. Issues of errors in acoustic Doppler flow measurement, in water level readings, and in evaporation estimates are considered. Storage change and canal wetted perimeter area, affected by variability in the canal prism, as well as lagged vs. simultaneous measurements of discharge at the inflow and outflow ends also are addressed. Mean estimated seepage loss rates for the tested canal reaches ranged from about -0.005 (gain) to 0.110 m3 s-1 per hectare of canal wetted perimeter (or -0.043 to 0.95 m d-1) with estimated probability distributions revealing substantial uncertainty. Across the tests, the average coefficient of variation was about 240% and the average 90th inter-percentile range was 0.143 m3 s-1 per hectare (1.24 m d-1). Sensitivity analysis indicates that while the predominant influence on seepage uncertainty is error in measured discharge at the upstream and downstream ends of the canal test reach, the magnitude and uncertainty of storage change due to unsteady flow also is a significant influence. Recommendations are

  12. Geohydrologic setting of and seepage from a water-supply canal, Indianapolis, Marion County, Indiana

    USGS Publications Warehouse

    Meyer, William R.

    1979-01-01

    The Indianapolis Water Company Canal is underlain by alluvial and outwash deposits. The water level in the canal on July 21, 1978, was above the water table along the entire reach of the canal upstream from the Fall Creek aqueduct, and, therefore, water was seeping downward from the canal into these deposits along this entire reach. Because of the highly variable lithology of the deposits underlying the canal, the seepage rate was probably also highly variable. Discharge measurements were made at selected points along the canal, and differences between successive measurements were calculated to determine the rate of water loss. The differences were smaller than the potential error in any of the measurements, however, and thus do not directly substantiate that water is being lost. The rate of water loss over the Fall Creek aqueduct by the skimming process could be as high as 43 cubic feet per second, assuming a 5% potential error for discharge measurements made at both ends of the aqueduct. Lower stages and water temperatures would decrease the rate of water loss. Observed ground-water levels were above the canal bottom at three locations along the canal. Lowering these levels below the bottom would increase seepage by approximately 9 cubic feet per second.

  13. Methane gas seepage - Disregard of significant water column filter processes?

    NASA Astrophysics Data System (ADS)

    Schneider von Deimling, Jens; Schmale, Oliver

    2016-04-01

    Marine methane seepage represents a potential contributor for greenhouse gas in the atmosphere and is discussed as a driver for climate change. The ultimate question is how much methane is released from the seafloor on a global scale and what fraction may reach the atmosphere? Dissolved fluxes from methane seepage sites on the seabed were found to be very efficiently reduced by benthic microbial oxidation, whereas transport of free gas bubbles from the seabed is considered to bypass the effective benthic methane filter. Numerical models are available today to predict the fate of such methane gas bubble release to the water column in regard to gas exchange with the ambient water column, respective bubble lifetime and rise height. However, the fate of rising gas bubbles and dissolved methane in the water column is not only governed by dissolution, but is also affected by lateral oceanographic currents and vertical bubble-induced upwelling, microbial oxidation, and physico-chemical processes that remain poorly understood so far. According to this gap of knowledge we present data from two study sites - the anthropogenic North Sea 22/4b Blowout and the natural Coal Oil point seeps - to shed light into two new processes gathered with hydro-acoustic multibeam water column imaging and microbial investigations. The newly discovered processes are hereafter termed Spiral Vortex and Bubble Transport Mechanism. Spiral Vortex describes the evolution of a complex vortical fluid motion of a bubble plume in the wake of an intense gas release site (Blowout, North Sea). It appears very likely that it dramatically changes the dissolution kinetics of the seep gas bubbles. Bubble Transport Mechanism prescribes the transport of sediment-hosted bacteria into the water column via rising gas bubbles. Both processes act as filter mechanisms in regard to vertical transport of seep related methane, but have not been considered before. Spiral Vortex and Bubble Transport Mechanism represent the

  14. Development of a benthic-flux chamber for measurement of ground-water seepage and water sampling for mercury analysis at the sediment-water interface

    USGS Publications Warehouse

    Menheer, M.A.

    2004-01-01

    A benthic-flux chamber was constructed to collect data to determine the relation between ground- and surface-water interaction and mercury concentrations in water at the sediment- water interface. The benthic-flux chamber was successfully used to measure the rate of ground water seeping to surface water or surface water seeping to ground water, and to collect water samples for mercury analysis from the sedimentwater interface in a lake setting. The benthic-flux chamber was designed to be deployed in relatively calm fresh water lakes, in areas of water less than 2 meters deep. The groundwater seepage rate data were comparable to data from an in-line flow meter in a calibration tank and with data from two 55-gallon drum seepage meters concurrently deployed in two different lakes. The benthic-flux chamber was used to collect possible water samples for analysis of total mercury and methylmercury concentrations.

  15. Using self-potential housing technique to model water seepage at the UNHAS housing Antang area

    NASA Astrophysics Data System (ADS)

    Syahruddin, Muhammad Hamzah

    2017-01-01

    The earth's surface has an electric potential that is known as self-potentiall (SP). One of the causes of the electrical potential at the earth's surface is water seepage into the ground. Electrical potential caused by water velocity seepage into the ground known as streaming potential. How to model water seepage into the ground at the housing Unhas Antang? This study was conducted to answer these questions. The self-potential measurements performed using a simple digital voltmeter Sanwa brand PC500 with a precision of 0.01 mV. While the coordinates of measurements points are self-potential using Global Positioning System. Mmeasurements results thus obtained are plotted using surfer image distribution self-potential housing Unhas Antang. The self-potential data housing Unhas Antang processed by Forward Modeling methods to get a model of water infiltration into the soil. Housing Unhas Antang self-potential has a value of 5 to 23 mV. Self-potential measurements carried out in the rainy season so it can be assumed that the measurement results caused by the velocity water seepage into the ground. The results of modeling the velocity water seepage from the surface to a depth of 3 meters was 2.4 cm/s to 0.2 cm /s. Modeling results showed that the velocity water seepage of the smaller with depth.

  16. Integrating seepage heterogeneity with the use of ganged seepage meters

    USGS Publications Warehouse

    Rosenberry, D.O.

    2005-01-01

    The usefulness of standard half-barrel seepage meters for measurement of fluxes between groundwater, and surface water is limited by the small bed area that each measurement represents and the relatively large associated labor costs. Standard half-barrel cylinders were ganged together to allow one measurement of the summed seepage through all of the meters, reducing labor cost and increasing the representative area of measurement. Comparisons of ganged versus individual-meter measurements at two lakes, under both inseepage and outseepage conditions, indicate little loss of efficiency resulting from routing seepage water through the ganging system. Differences between summed and ganged seepage rates were not significant for all but the fastest rates of seepage. At flow rates greater than about 250 mL min-1, ganged values were as low as 80% of summed values. Ganged-meter head losses also were calculated to determine their significance relative to hydraulic-head gradients measured at the field sites. The calculated reduction in hydraulic gradient beneath the seepage meters was significant only for the largest measured seepage rates. A calibration tank was used to determine single-meter and ganged-meter efficiencies compared to known seepage rates. Single-cylinder seepage meters required an average correction factor of 1.05 to convert measured to actual values, whereas the ganged measurements made in the tank required a larger correction factor of 1.14. Although manual measurements were used in these tests, the concept of ganging seepage cylinders also would be useful when used in conjunction with automated flowmeters. ?? 2005, by the American Society of Limnology and Oceanography, Inc.

  17. Pond-aquifer flow and water availability in the vicinity of two coastal area seepage ponds, Glynn and Bulloch Counties, Georgia

    USGS Publications Warehouse

    Clarke, John S.; Rumman, Malek Abu

    2005-01-01

    Pond-aquifer flow and water availability at excavated seepage pond sites in Glynn County and in southern Bulloch County, Georgia, were evaluated to determine their potential as sources of water supply for irrigation. Excavated seepage ponds derive water primarily from ground water seeping into the pond, in a manner similar to a dug well completed in a surficial aquifer. The availability of water from seepage ponds is controlled by the permeability of surficial deposits, the amount of precipitation recharging the ground-water system, and the volume of water stored in the pond. The viability of seepage ponds as supplies for irrigation is limited by low seepage rates and high dependence on climatic conditions. Ponds will not refill unless there is adequate precipitation to recharge the surficial aquifer, which subsequently drains (seeps) into the pond. Ground-water seepage was estimated using a water-budget approach that utilized on-site climatic and hydrologic measurements, computing pond-volume changes during pond pumping tests, and by digital simulation using steady-state and transient ground-water flow models. From August 1999 to May 2000, the Glynn County pond was mostly losing water (as indicated by negative net seepage); whereas from October 2000 to June 2001, the Bulloch County pond was mostly gaining water. At both sites, most ground-water seepage entered the pond following major rainfall events that provided recharge to the surficial aquifer. Net ground-water seepage, estimated using water-budget analysis and simulation, ranged from -11.5 to 15 gallons per minute (gal/min) at the Glynn County pond site and from -55 to 31 gal/min at the Bulloch County pond site. Simulated values during pumping tests indicate that groundwater seepage to both ponds increases with decreased pond stage. At the Glynn County pond, simulated net ground-water seepage varied between 7.8 gal/min at the beginning of the test (high pond stage and low hydraulic gradient) and 103 gal

  18. Polyacrylamide and biopolymer effects on flocculation, aggregate stability, and water seepage in a silt loam

    USDA-ARS?s Scientific Manuscript database

    Researcher’s seek a more renewable and natural alternative for water soluble anionic polyacrylamide (PAM), a highly-effective, petroleum-derived polymer used in agriculture to control erosion and reduce water seepage from unlined irrigation structures. This study evaluated two anionic polymers: a ba...

  19. Numerical simulation experiments on water seepage patterns in heterogeneous, unsaturated rock fractures

    SciTech Connect

    Pruess, K.

    1996-05-01

    Water seepage has been numerically simulated in heterogeneous fractures, which were conceptualized as two-dimensional heterogeneous porous media. Flow was found to proceed in dendritic patterns along preferential paths, giving rise to such features as localized ponding and bypassing. Limited parameter variation studies have shown strong dependence of seepage patterns on fracture permeability and applied flow rate. The temporal evolution of seeps proceeds on a vast range of time scales. This casts doubt on the applicability of steady-state concepts for water migration in thick unsaturated zones of fractured rock where infiltration is episodic. An approximate invariance of seepage behavior was derived for simultaneous space-and-time scaling. Numerical simulation experiments have confirmed this invariance, as well as its limits of applicability.

  20. Purification of organic contaminants in seepage water of a landfill by UV/ozone technique

    NASA Astrophysics Data System (ADS)

    Vollmuth, S.; Wenzel, A.; Niessner, Reinhard

    1995-10-01

    Seepage water of landfills, where toxic waste is deposited, has high concentrations of chlorinated phenols (CP), polychlorinated biphenyls (PCB), and polycyclic aromatic hydrocarbons (PAH). The concentrations of polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF) are usually found at ppq-level. Typical purification methods based on physical techniques produce highly contaminated residues, which have to be removed by combustion or deposition in a landfill. An alternative way is to destruct these contaminants by biological and chemical treatment. The behavior of the trace contaminants during UV/ozone treatment is described. Results show no significant effect for PCB and PCDD/PCDF. The CP and PAH were mostly reduced by UV/ozone treatment to a degradation ratio greater than 90%. An influence of the pH value on the UV/ozone treatment of seepage water could not be detected. A further experiment showed the degradability of PCDD/PCDF in pure water solution. To reach better results for the degradation of organic trace contaminants the seepage water first can be treated with biological methods. Thus the high TOC-concentration of 3 g/l is reduced to 50 - 70%. A combination of biological and oxidative techniques diminishes the treatment costs and better exploitation of the oxidants is reached. Because of high light absorbance of the seepage water between 200 nm and 300 nm we developed a falling-film- photo-reactor to ensure, that every volume of the solution is exposed to UV-radiation.

  1. Purification of organic contaminants in seepage water of a landfill by UV/ozone-technique

    SciTech Connect

    Vollmuth, S.; Wenzel, A.; Niessner, R.

    1995-12-31

    Seepage water of landfills, where toxic waste is deposited, has a high concentrations of chlorinated phenols (CP), polychlorinated biphenyls (PCB) and polycyclic aromatic hydrocarbons (PAH). The concentrations of polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF) are usually found at ppq-level. Typical purification methods based on physical techniques produce highly contaminated residues, which have to be removed by combustion or depositing in a landfill. An alternative way is to destruct these contaminants by biological and chemical treatment. The behavior of the trace contaminants during UV/Ozone treatment is described. Results show no significant effect for PCB and PCDD/PCDF. The CP and PAH were mostly reduced by UV/ozone treatment to a degradation ratio greater than 90%. An influence of the pH value on the UV/ozone treatment of seepage water could not be detected. A further experiment showed the desirability of PCDD/PCDF in pure water solution. To reach better results for the degradation of organic trace contaminants the seepage water first can be treated with biological methods. Thus the high TOC-concentration of 3 g/l is reduced to 50--70%. A combination of biological and oxidative techniques diminishes the treatment costs and better exploitation of the oxidants is reached. Because of the high light absorbance of the seepage water between 200 nm and 300 nm the authors developed a falling-film-photo-reactor to ensure, that every volume part of the solution will be expose to UV-radiation.

  2. Preliminary studies of water seepage through rough-walled fractures

    SciTech Connect

    Geller, J.T.; Su, G.; Pruess, K.

    1996-07-01

    For groundwater aquifers in fractured rock, fractures play a significant role in the transport of water and contaminants through the unsaturated zone to the groundwater table. Fractures can provide preferential flow paths for infiltrating liquids that dramatically accelerate contaminant transport compared to predictions based upon spatially uniform infiltration. The actual liquid distribution during infiltration determines the contact area between the flowing water and rock, and liquid residence time, which in turn affects the potential for rock-water and rock-solute interaction, as well as mass transfer between liquid and gas phases. This report summarizes flow- visualization experiments of water percolation through transparent replicas of a natural rock fracture. We have focused on phenomenological and exploratory experiments that can lead to a conceptual model which incorporates the important physical mechanisms that control flow.

  3. Simulation of Sub-Drains Performance Using Visual MODFLOW for Slope Water Seepage Problem

    NASA Astrophysics Data System (ADS)

    Baharuddin, M. F. T.; Tajudin, S. A. A.; Abidin, M. H. Z.; Yusoff, N. A.

    2016-07-01

    Numerical simulation technique was used for investigating water seepage problem at the Botanic Park Kuala Lumpur. A proposed sub-drains installation in problematic site location was simulated using Modular Three-Dimensional Finite Difference Groundwater Flow (MODFLOW) software. The results of simulation heads during transient condition showed that heads in between 43 m (water seepage occurred at level 2) until 45 m (water seepage occurred at level 4) which heads measurement are referred to mean sea level. However, elevations measurements for level 2 showed the values between 41 to 42 m from mean sea level and elevations for level 4 between 42 to 45 m from mean sea level. These results indicated an increase in heads for level 2 and level 4 between 1 to 2 m when compared to elevations slope at the level 2 and level 4. The head increases surpass the elevation level of the slope area that causing water seepage at level 2 and level 4. In order to overcome this problems, the heads level need to be decrease to 1 until 2 m by using two options of sub-drain dimension size. Sub-drain with the dimension of 0.0750 m (diameter), 0.10 m (length) and using 4.90 m spacing was the best method to use as it was able to decrease the heads to the required levels of 1 to 2 m.

  4. Processes of bedrock groundwater seepage and their effects on soil water fluxes in a foot slope area

    NASA Astrophysics Data System (ADS)

    Masaoka, Naoya; Kosugi, Ken'ichirou; Yamakawa, Yosuke; Tsutsumi, Daizo

    2016-04-01

    The impact of bedrock groundwater seepage on surface hydrological processes in a foot slope area is an important issue in hillslope hydrology. However, properties of water flux vectors around a seepage area are poorly understood because previous studies have lacked sufficient spatial resolution to capture detailed water movements. Here, we conducted hydrometric observations using unprecedented high-resolution and three-dimensional tensiometer nests in the mountainous foot slope area of the Hirudani experimental basin (Japan). Our findings are summarized as follows: (1) a considerable quantity of groundwater seeped from the bedrock surface in the study site. A groundwater exfiltration flux occurred constantly from a seepage area regardless of rainfall conditions. Saturated lateral flow over the bedrock surface occurred constantly in the region downslope of the seepage area. Groundwater was likely to mixed with soil water infiltration and flowed toward the lower end of the slope. (2) During the wet season, the seepage area expanded ∼3 m in the upslope direction along the bedrock valley in a single season. (3) The pressure head waveform observed in the seepage area showed gradual and significant increases after large rainfall events. However, the seepage pressure propagated within a relatively narrow area: a slope distance of ∼4 m from the seepage point in the downslope direction due to the damping of seepage pressure. (4) Within the whole study area, groundwater seeped from a narrow area located at the bottom of the valley line of the bedrock surface. The shape of the seepage area changed along the valley line in the wet season. Overall, we reveal spatial and temporal variations in bedrock groundwater seepage under the soil mantle and the effects on soil water fluxes. These findings should improve the accuracy of models for predicting surface hydrogeomorphological processes in mountainous hillslopes.

  5. Estimating seepage flux from ephemeral stream channels using surface water and groundwater level data

    NASA Astrophysics Data System (ADS)

    Noorduijn, Saskia L.; Shanafield, Margaret; Trigg, Mark A.; Harrington, Glenn A.; Cook, Peter G.; Peeters, L.

    2014-02-01

    Seepage flux from ephemeral streams can be an important component of the water balance in arid and semiarid regions. An emerging technique for quantifying this flux involves the measurement and simulation of a flood wave as it moves along an initially dry channel. This study investigates the usefulness of including surface water and groundwater data to improve model calibration when using this technique. We trialed this approach using a controlled flow event along a 1387 m reach of artificial stream channel. Observations were then simulated using a numerical model that combines the diffusion-wave approximation of the Saint-Vénant equations for streamflow routing, with Philip's infiltration equation and the groundwater flow equation. Model estimates of seepage flux for the upstream segments of the study reach, where streambed hydraulic conductivities were approximately 101 m d-1, were on the order of 10-4 m3 d-1 m-2. In the downstream segments, streambed hydraulic conductivities were generally much lower but highly variable (˜10-3 to 10-7 m d-1). A Latin Hypercube Monte Carlo sensitivity analysis showed that the flood front timing, surface water stage, groundwater heads, and the predicted streamflow seepage were most influenced by specific yield. Furthermore, inclusion of groundwater data resulted in a higher estimate of total seepage estimates than if the flood front timing were used alone.

  6. Periodic seepage face formation and water pressure distribution along a vertical boundary of an aquifer

    NASA Astrophysics Data System (ADS)

    Jazayeri Shoushtari, Seyed Mohammad Hossein; Nielsen, Peter; Cartwright, Nick; Perrochet, Pierre

    2015-04-01

    Detailed measurements of the piezometric head from sand flume experiments of an idealised coastal aquifer forced by a simple harmonic boundary condition across a vertical boundary are presented. The measurements focus on the pore pressures very close to the interface (x = 0.01m) and throw light on the details of the boundary condition, particularly with respect to meniscus suction and seepage face formation during the falling tide. Between the low and the mean water level, the response is consistent with meniscus suction free models in terms of both the vertical mean head and oscillation amplitude profiles and is consistent with the observation that this area of the interface was generally within the seepage face. Above the mean water level, the influence of meniscus formation is significant with the mean pressure head being less than that predicted by capillary free theory and oscillation amplitudes decaying faster than predicted by suction free models. The reduced hydraulic conductivity in this area due to partial drainage of pores on the falling tide also causes a delay in the response to the rising tide. The combined influence of seepage face formation, meniscus suction and reduced hydraulic conductivity generate higher harmonics with amplitudes of up to 26% of the local main harmonic. To model the influence of seepage face formation and meniscus suction a numerical solution of the Richards' equation was developed and evaluated against the data. The model-data comparison shows a good agreement with the behaviour high above the water table sensitive to the choice of moisture retention parameters.

  7. ABSTRACTION OF DRIFT SEEPAGE

    SciTech Connect

    Michael L. Wilson

    2001-02-08

    Drift seepage refers to flow of liquid water into repository emplacement drifts, where it can potentially contribute to degradation of the engineered systems and release and transport of radionuclides within the drifts. Because of these important effects, seepage into emplacement drifts is listed as a ''principal factor for the postclosure safety case'' in the screening criteria for grading of data in Attachment 1 of AP-3.15Q, Rev. 2, ''Managing Technical Product Inputs''. Abstraction refers to distillation of the essential components of a process model into a form suitable for use in total-system performance assessment (TSPA). Thus, the purpose of this analysis/model is to put the information generated by the seepage process modeling in a form appropriate for use in the TSPA for the Site Recommendation. This report also supports the Unsaturated-Zone Flow and Transport Process Model Report. The scope of the work is discussed below. This analysis/model is governed by the ''Technical Work Plan for Unsaturated Zone Flow and Transport Process Model Report'' (CRWMS M&O 2000a). Details of this activity are in Addendum A of the technical work plan. The original Work Direction and Planning Document is included as Attachment 7 of Addendum A. Note that the Work Direction and Planning Document contains tasks identified for both Performance Assessment Operations (PAO) and Natural Environment Program Operations (NEPO). Only the PAO tasks are documented here. The planning for the NEPO activities is now in Addendum D of the same technical work plan and the work is documented in a separate report (CRWMS M&O 2000b). The Project has been reorganized since the document was written. The responsible organizations in the new structure are the Performance Assessment Department and the Unsaturated Zone Department, respectively. The work plan for the seepage abstraction calls for determining an appropriate abstraction methodology, determining uncertainties in seepage, and providing

  8. Past methane seepage and linked deep-water anoxia are logged in methane-derived carbonates

    NASA Astrophysics Data System (ADS)

    Stadnitskaia, A.; Liebetrau, V.; Eisenhauer, A.; Sinninghe Damsté, J. S.

    2012-04-01

    The precipitation of carbonate in methane saturated environments is a common phenomenon that is caused by the increase of alkalinity due to the microbial process of anaerobic oxidation of methane (AOM) accomplished by a consortium of sulfate reducing bacteria and methanotrophic archaea (Boetius et al., 2000). Since the formation of such carbonates is irrespective to climate changes and to the depth of the carbonate compensation, they represent unique archives of the time and duration of methane seepage, adjacent sedimentary/water column environments and associated bionetwork. The Nile Deep Sea Fan basin is known for the widespread occurrence of seabed methane/fluid seepage linked to mud volcanoes and pock marks. Massive accumulations of methane-derived carbonate pavements and up to one meter buildups were often encountered in the vicinity or even within mud volcano structures. Here we analyzed at high resolution the differences in stable carbon and oxygen isotope compositions and lipid biomarker composition, accompanied with U/Th dating of the topmost part of a ~1 m-high carbonate edifice sited at the margin of the Amon mud volcano. The uppermost part of the edifice has been dated at ~7.8 - 9.1 kyr B.P. This is synchronous with the increase of fresh-water fluxes in the Eastern Mediterranean resulting in density stratification of the water column (~ 10.5 - 5.0 14C kyr B.P.), with the formation of S1 sapropel (~9.7 - 5.7 14C kyr B.P.; De Lange et al., 2008), and with the Holocene warm climatic optimum (Rohling and Hilgen, 1991). Significant changes of ^13CCaCO3 values, from -32 to -9‰ (VPDB), indicate swings in methane flux, which affected rates of AOM and the consequent production of 13C-depleted HCO3-. Lipid biomarkers revealed the presence of methanotrophic archaea of the ANME-2 group due to the dominance of sn-2-hydroxyarchaeol over archaeol and the low abundance of tetraether lipids (Blumenberg et al., 2004). Ecologically these archaea are associated with

  9. Influence of particle size on non-Darcy seepage of water and sediment in fractured rock.

    PubMed

    Liu, Yu; Li, Shuncai

    2016-01-01

    Surface water, groundwater and sand can flow into mine goaf through the fractured rock, which often leads to water inrush and quicksand movement. It is important to study the mechanical properties of water and sand in excavations sites under different conditions and the influencing factors of the water and sand seepage system. The viscosity of water-sand mixtures under different particle sizes, different concentration was tested based on the relationship between the shear strain rate and the surface viscosity. Using the self-designed seepage circuit, we tested permeability of water and sand in fractured rock. The results showed that (1) effective fluidity is in 10(-8)-10(-5) m(n+2) s(2-n)/kg, while the non-Darcy coefficient ranges from 10(5) to 10(8) m(-1) with the change of particle size of sand; (2) effective fluidity decreases as the particle size of sand increased; (3) the non-Darcy coefficient ranges from 10(5) to 10(8) m(-1) depending on particle size and showed contrary results. Moreover, the relationship between effective fluidity and the particle size of sand is fitted by the exponential function. The relationship between the non-Darcy coefficient and the particle size of sand is also fitted by the exponential function.

  10. Estimation of lateral water flow and bromide transport in a subsurface seepage irrigation system.

    PubMed

    Ouyang, Y

    2009-01-01

    Subsurface seepage irrigation is a common method used by growers in the Tri-County Agricultural Area (TCAA), Florida, USA, owing to its cost-effectiveness and low maintenance requirements. This study investigated the lateral flow of the perched water and the lateral transport of bromide (Br-) in this irrigation system in the TCAA and estimated the potential discharge of Br- into the drainage canals at the edges of the field, using the Visual MODFLOW/ MT3DMS models in conjunction with field experiments. Simulations showed that the perched water flowed from the northeast to the southwest of the field. Migration of the Br- plume from the source areas toward the canals was very slow and varied depending on the selection of the outer Br- concentration contour levels. However, the lateral transport of Br- from the perched water into the canals occurred after about 61 days. The simulations further revealed that the rate of perched water Br- discharge into the canals averaged 8.6 g day(-1) during a 30-day discharge period (from 61 to 91 days). This rate is very important for estimating Br- discharge into the canals and could also provide useful information for evaluating dissolved nutrient discharge into canals from the subsurface seepage irrigation system.

  11. Temporal variability of exchange between groundwater and surface water based on high-frequency direct measurements of seepage at the sediment-water interface

    USGS Publications Warehouse

    Rosenberry, Donald O.; Sheibley, Rich W.; Cox, Stephen E.; Simonds, Frederic W.; Naftz, David L.

    2013-01-01

    Seepage at the sediment-water interface in several lakes, a large river, and an estuary exhibits substantial temporal variability when measured with temporal resolution of 1 min or less. Already substantial seepage rates changed by 7% and 16% in response to relatively small rain events at two lakes in the northeastern USA, but did not change in response to two larger rain events at a lake in Minnesota. However, seepage at that same Minnesota lake changed by 10% each day in response to withdrawals from evapotranspiration. Seepage increased by more than an order of magnitude when a seiche occurred in the Great Salt Lake, Utah. Near the head of a fjord in Puget Sound, Washington, seepage in the intertidal zone varied greatly from −115 to +217 cm d−1 in response to advancing and retreating tides when the time-averaged seepage was upward at +43 cm d−1. At all locations, seepage variability increased by one to several orders of magnitude in response to wind and associated waves. Net seepage remained unchanged by wind unless wind also induced a lake seiche. These examples from sites distributed across a broad geographic region indicate that temporal variability in seepage in response to common hydrological events is much larger than previously realized. At most locations, seepage responded within minutes to changes in surface-water stage and within minutes to hours to groundwater recharge associated with rainfall. Likely implications of this dynamism include effects on water residence time, geochemical transformations, and ecological conditions at and near the sediment-water interface.

  12. Analysis of a mesoscale infiltration and water seepage test in unsaturated fractured rock: Spatial variabilities and discrete fracture patterns.

    PubMed

    Zhou, Quanlin; Salve, Rohit; Liu, Hui-Hai; Wang, Joseph S Y; Hudson, David

    2006-09-10

    A mesoscale (21 m in flow distance) infiltration and seepage test was recently conducted in a deep, unsaturated fractured rock system at the crossover point of two underground tunnels. Water was released from a 3 mx4 m infiltration plot on the floor of an alcove in the upper tunnel, and seepage was collected from the ceiling of a niche in the lower tunnel. Significant temporal and (particularly) spatial variabilities were observed in both measured infiltration and seepage rates. To analyze the test results, a three-dimensional unsaturated flow model was used. A column-based scheme was developed to capture heterogeneous hydraulic properties reflected by these spatial variabilities observed. Fracture permeability and van Genuchten alpha parameter [van Genuchten, M.T., 1980. A closed-form equation for predicting the hydraulic conductivity of unsaturated soils. Soil Sci. Soc. Am. J. 44, 892-898] were calibrated for each rock column in the upper and lower hydrogeologic units in the test bed. The calibrated fracture properties for the infiltration and seepage zone enabled a good match between simulated and measured (spatially varying) seepage rates. The numerical model was also able to capture the general trend of the highly transient seepage processes through a discrete fracture network. The calibrated properties and measured infiltration/seepage rates were further compared with mapped discrete fracture patterns at the top and bottom boundaries. The measured infiltration rates and calibrated fracture permeability of the upper unit were found to be partially controlled by the fracture patterns on the infiltration plot (as indicated by their positive correlations with fracture density). However, no correlation could be established between measured seepage rates and density of fractures mapped on the niche ceiling. This lack of correlation indicates the complexity of (preferential) unsaturated flow within the discrete fracture network. This also indicates that continuum

  13. Strong seepage of shallow groundwater shifts the timing of the annual thermal signals in stream water

    NASA Astrophysics Data System (ADS)

    Briggs, M. A.; Johnson, Z. C.; Snyder, C.; Hitt, N. P.; White, E. A.; Lane, J. W., Jr.; Nelms, D. L.

    2016-12-01

    Conventional wisdom indicates that while short-term (e.g. diurnal) thermal variance in streams may be attenuated by groundwater seepage, annual temperature swings will essentially track the local air temperature signal. However, the temperature of shallow (less than 5 m depth) groundwater from seepage zones may not be constant and near the local mean air temperature, but instead will fluctuate seasonally, and show a pronounced phase lag from the annual air signal. The degree of phase lag will be dependent on the rate of vertical fluid and heat exchange through shallow aquifer sediments. Gaining headwater streams might be expected to adopt similar phase lags to local seepage zones. We explore these dynamics through 9 mountain watersheds in Shenandoah National Park, VA, USA that harbor critical habitat for cold-water brook trout (Salvelinus fontinalis). Daily paired air and stream water temperature records were collected for up to 5 years at several stream locations along each watershed. Sinusoids fit to multiple-year data from more than 100 total locations indicate an average phase shift from air to surface water of approximately 10 d; this may primarily be due to strong conductive exchange with the rocky alluvial aquifer in generally incised and shaded channels. A subset of these transects (n=4) showed phase-lags greater than 20 d, coinciding with locations of particularly pronounced diurnal variance attenuation, indicating strong groundwater influence. Shallow bedrock, evaluated throughout the watersheds with passive seismic methods, restricts downward infiltration of precipitation in the mountain bedrock aquifers. Numerical 1D vertical aquifer models indicate similar phase lags in shallow groundwater at the bedrock contact to that observed in stream seepage zones. Therefore, contrary to conventional wisdom, shaded mountain streams with strong groundwater influence may adopt the annual thermal signature of the adjacent aquifer, shifting the stream thermal maxima

  14. Metal concentrations in soil and seepage water due to infiltration of roof runoff by long term numerical modelling.

    PubMed

    Zimmermann, J; Dierkes, C; Göbel, P; Klinger, C; Stubbe, H; Coldewey, W G

    2005-01-01

    The qualitative effects of stormwater infiltration on soil and seepage water are investigated with long term numerical modelling. The retention behaviour of different soils and materials used in infiltration devices is determined with batch and column tests. Results of the laboratory tests are adsorption isotherms which represent input data for numerical transport modelling. The long term simulations are performed with combinations of different solutions (types of roof runoff) and infiltration devices (swale and trench) under different hydrogeological conditions. The presented results contain the infiltration of low polluted roof runoff, runoff from a roof with zinc sheets and from a roof with copper sheets concerning the heavy metals zinc, copper and lead. The increase of concentrations in the infiltration body is high. For the infiltrated water, the results show a migration to groundwater only for the low adsorbing soil.

  15. Toxicity of Water Samples Collected in the Vicinity of F and H Seepage Basin 1990-1995

    SciTech Connect

    Specht, W.L.; Bowers, B.

    1996-09-01

    Water and contaminants from the F- and H-Area Seepage Basins outcrop as shallow groundwater seeps down gradient from the basins. In 1990, 1991, 1993, 1994, and 1995, toxicity tests were performed on water collected from a number of these seeps, as well as from several locations in Fourmile Branch and several uncontaminated reference locations.

  16. High mobilization of arsenic, metals and rare earth elements in seepage waters driven by respiration of old allochthonous organic carbon.

    PubMed

    Weiske, Arndt; Schaller, Jörg; Hegewald, Tilo; Machill, Susanne; Werner, Ingo; Dudel, E Gert

    2013-12-01

    Metal and metalloid mobilization processes within seepage water are of major concern in a range of water reservoir systems. The mobilization process of arsenic and heavy metals within a dam and sediments of a drinking water reservoir was investigated. Principle component analysis (PCA) on time series data of seepage water showed a clear positive correlation of arsenic with iron and DOC (dissolved organic carbon), and a negative correlation with nitrate due to respiratory processes. A relationship of reductive metal and metalloid mobilization with respiration of old carbon was shown. The system is influenced by sediment layers as well as a recent DOC input from degraded ombrotrophic peatbogs in the catchment area. The isotopic composition ((12)C, (13)C and (14)C) of DOC is altered along the path from basin to seepage water, but no significant changes in structural parameters (LC-OCD-OND, FT-IR) could be seen. DIC (dissolved inorganic carbon) in seepage water partly originates from respiratory processes, and a higher relationship of it with sediment carbon than with the DOC inventory of infiltrating water was found. This study revealed the interaction of respiratory processes with metal and metalloid mobilization in sediment water flows. In contrast to the presumption that emerging DOC via respiratory processes mainly controls arsenic and metal mobilization it could be shown that the presence of aged carbon compounds is essential. The findings emphasize the importance of aged organic carbon for DOC, DIC, arsenic and metal turnover.

  17. Groundwater-Seepage Meter

    NASA Technical Reports Server (NTRS)

    Walthall, Harry G.; Reay, William G.

    1993-01-01

    Instrument measures seepage of groundwater into inland or coastal body of water. Positioned at depth as great as 40 meters, and measures flow at low rate and low pressure differential. Auxiliary pressure meter provides data for correlation of flow of groundwater with tides and sea states. Seepage meter operates independently for several weeks. Its sampling rate adjusted to suit hydrologic conditions; to measure more frequently when conditions changing rapidly. Used in water-quality management and for biological and geological research. Potential industrial uses include measurement of seepage of caustic and corrosive liquids.

  18. Groundwater-Seepage Meter

    NASA Technical Reports Server (NTRS)

    Walthall, Harry G.; Reay, William G.

    1993-01-01

    Instrument measures seepage of groundwater into inland or coastal body of water. Positioned at depth as great as 40 meters, and measures flow at low rate and low pressure differential. Auxiliary pressure meter provides data for correlation of flow of groundwater with tides and sea states. Seepage meter operates independently for several weeks. Its sampling rate adjusted to suit hydrologic conditions; to measure more frequently when conditions changing rapidly. Used in water-quality management and for biological and geological research. Potential industrial uses include measurement of seepage of caustic and corrosive liquids.

  19. Geochemical characterisation of seepage and drainage water quality from two sulphide mine tailings impoundments: Acid mine drainage versus neutral mine drainage

    USGS Publications Warehouse

    Heikkinen, P.M.; Raisanen, M.L.; Johnson, R.H.

    2009-01-01

    Seepage water and drainage water geochemistry (pH, EC, O2, redox, alkalinity, dissolved cations and trace metals, major anions, total element concentrations) were studied at two active sulphide mine tailings impoundments in Finland (the Hitura Ni mine and Luikonlahti Cu mine/talc processing plant). The data were used to assess the factors influencing tailings seepage quality and to identify constraints for water treatment. Changes in seepage water quality after equilibration with atmospheric conditions were evaluated based on geochemical modelling. At Luikonlahti, annual and seasonal changes were also studied. Seepage quality was largely influenced by the tailings mineralogy, and the serpentine-rich, low sulphide Hitura tailings produced neutral mine drainage with high Ni. In contrast, drainage from the high sulphide, multi-metal tailings of Luikonlahti represented typical acid mine drainage with elevated contents of Zn, Ni, Cu, and Co. Other factors affecting the seepage quality included weathering of the tailings along the seepage flow path, process water input, local hydrological settings, and structural changes in the tailings impoundment. Geochemical modelling showed that pH increased and some heavy metals were adsorbed to Fe precipitates after net alkaline waters equilibrated with the atmosphere. In the net acidic waters, pH decreased and no adsorption occurred. A combination of aerobic and anaerobic treatments is proposed for Hitura seepages to decrease the sulphate and metal loading. For Luikonlahti, prolonged monitoring of the seepage quality is suggested instead of treatment, since the water quality is still adjusting to recent modifications to the tailings impoundment.

  20. Abstraction of Drift Seepage

    SciTech Connect

    J.T. Birkholzer

    2004-11-01

    This model report documents the abstraction of drift seepage, conducted to provide seepage-relevant parameters and their probability distributions for use in Total System Performance Assessment for License Application (TSPA-LA). Drift seepage refers to the flow of liquid water into waste emplacement drifts. Water that seeps into drifts may contact waste packages and potentially mobilize radionuclides, and may result in advective transport of radionuclides through breached waste packages [''Risk Information to Support Prioritization of Performance Assessment Models'' (BSC 2003 [DIRS 168796], Section 3.3.2)]. The unsaturated rock layers overlying and hosting the repository form a natural barrier that reduces the amount of water entering emplacement drifts by natural subsurface processes. For example, drift seepage is limited by the capillary barrier forming at the drift crown, which decreases or even eliminates water flow from the unsaturated fractured rock into the drift. During the first few hundred years after waste emplacement, when above-boiling rock temperatures will develop as a result of heat generated by the decay of the radioactive waste, vaporization of percolation water is an additional factor limiting seepage. Estimating the effectiveness of these natural barrier capabilities and predicting the amount of seepage into drifts is an important aspect of assessing the performance of the repository. The TSPA-LA therefore includes a seepage component that calculates the amount of seepage into drifts [''Total System Performance Assessment (TSPA) Model/Analysis for the License Application'' (BSC 2004 [DIRS 168504], Section 6.3.3.1)]. The TSPA-LA calculation is performed with a probabilistic approach that accounts for the spatial and temporal variability and inherent uncertainty of seepage-relevant properties and processes. Results are used for subsequent TSPA-LA components that may handle, for example, waste package corrosion or radionuclide transport.

  1. Failure Behavior of Granite Affected by Confinement and Water Pressure and Its Influence on the Seepage Behavior by Laboratory Experiments

    PubMed Central

    Cheng, Cheng; Li, Xiao; Li, Shouding; Zheng, Bo

    2017-01-01

    Failure behavior of granite material is paramount for host rock stability of geological repositories for high-level waste (HLW) disposal. Failure behavior also affects the seepage behavior related to transportation of radionuclide. Few of the published studies gave a consistent analysis on how confinement and water pressure affect the failure behavior, which in turn influences the seepage behavior of the rock during the damage process. Based on a series of laboratory experiments on NRG01 granite samples cored from Alxa area, a candidate area for China’s HLW disposal, this paper presents some detailed observations and analyses for a better understanding on the failure mechanism and seepage behavior of the samples under different confinements and water pressure. The main findings of this study are as follows: (1) Strength reduction properties were found for the granite under water pressure. Besides, the complete axial stress–strain curves show more obvious yielding process in the pre-peak region and a more gradual stress drop in the post-peak region; (2) Shear fracturing pattern is more likely to form in the granite samples with the effect of water pressure, even under much lower confinements, than the predictions from the conventional triaxial compressive results; (3) Four stages of inflow rate curves are divided and the seepage behaviors are found to depend on the failure behavior affected by the confinement and water pressure. PMID:28773157

  2. Failure Behavior of Granite Affected by Confinement and Water Pressure and Its Influence on the Seepage Behavior by Laboratory Experiments.

    PubMed

    Cheng, Cheng; Li, Xiao; Li, Shouding; Zheng, Bo

    2017-07-14

    Failure behavior of granite material is paramount for host rock stability of geological repositories for high-level waste (HLW) disposal. Failure behavior also affects the seepage behavior related to transportation of radionuclide. Few of the published studies gave a consistent analysis on how confinement and water pressure affect the failure behavior, which in turn influences the seepage behavior of the rock during the damage process. Based on a series of laboratory experiments on NRG01 granite samples cored from Alxa area, a candidate area for China's HLW disposal, this paper presents some detailed observations and analyses for a better understanding on the failure mechanism and seepage behavior of the samples under different confinements and water pressure. The main findings of this study are as follows: (1) Strength reduction properties were found for the granite under water pressure. Besides, the complete axial stress-strain curves show more obvious yielding process in the pre-peak region and a more gradual stress drop in the post-peak region; (2) Shear fracturing pattern is more likely to form in the granite samples with the effect of water pressure, even under much lower confinements, than the predictions from the conventional triaxial compressive results; (3) Four stages of inflow rate curves are divided and the seepage behaviors are found to depend on the failure behavior affected by the confinement and water pressure.

  3. Characteristics of the ground-water seepage into Great South Bay. Special Report 35

    SciTech Connect

    Bokuniewicz, H.J.; Zeitlin, M.J.

    1980-03-01

    The water quality and salinity in Great South Bay represent a balance between the amount of seawater that enters the bay through its inlets and the amount of freshwater that is supplied from Long Island. Streamflow accounts for most of the freshwater supplied to the bay. The second largest contribution is the submarine outflow of ground water across the bay floor. Direct measurements of this source are reported here. Preliminary work showed that much of the seepage occurred within 100 meters of the shore. Submarine outflow rates were as high as 150 liters/day/square meter. The outflow near the shore was typically 50 liters/day/square meter and decreased to about 30 liters/day/square meter at a distance of 100 meters offshore. Variations in the outflow rate due to tidal changes in the water level could not be detected. The flow rate did appear to be sensitive to coastal flooding and rainfall, however. In order to calculate the total submarine outflow, the data were described as decreasing exponentially with distance from shore. The typical value of the submarine outflow was calculated to be 4.1 x 10/sup 8/ liters/day. This calculation excluded measurements made near Fire Island, but they suggest that significant amounts of ground water may enter the bay far from shore due to sustained, upward leakage from deep aquifers. As a result, the calculated value is an underestimate. The outflow rates are relatively large and should significantly affect the pore water chemistry.

  4. Analysis of a mesoscale infiltration and water seepage test in unsaturated fractured rock: Spatial variabilities and discrete fracture patterns

    USGS Publications Warehouse

    Zhou, Q.; Salve, R.; Liu, H.-H.; Wang, J.S.Y.; Hudson, D.

    2006-01-01

    A mesoscale (21??m in flow distance) infiltration and seepage test was recently conducted in a deep, unsaturated fractured rock system at the crossover point of two underground tunnels. Water was released from a 3??m ?? 4??m infiltration plot on the floor of an alcove in the upper tunnel, and seepage was collected from the ceiling of a niche in the lower tunnel. Significant temporal and (particularly) spatial variabilities were observed in both measured infiltration and seepage rates. To analyze the test results, a three-dimensional unsaturated flow model was used. A column-based scheme was developed to capture heterogeneous hydraulic properties reflected by these spatial variabilities observed. Fracture permeability and van Genuchten ?? parameter [van Genuchten, M.T., 1980. A closed-form equation for predicting the hydraulic conductivity of unsaturated soils. Soil Sci. Soc. Am. J. 44, 892-898] were calibrated for each rock column in the upper and lower hydrogeologic units in the test bed. The calibrated fracture properties for the infiltration and seepage zone enabled a good match between simulated and measured (spatially varying) seepage rates. The numerical model was also able to capture the general trend of the highly transient seepage processes through a discrete fracture network. The calibrated properties and measured infiltration/seepage rates were further compared with mapped discrete fracture patterns at the top and bottom boundaries. The measured infiltration rates and calibrated fracture permeability of the upper unit were found to be partially controlled by the fracture patterns on the infiltration plot (as indicated by their positive correlations with fracture density). However, no correlation could be established between measured seepage rates and density of fractures mapped on the niche ceiling. This lack of correlation indicates the complexity of (preferential) unsaturated flow within the discrete fracture network. This also indicates that continuum

  5. Method to Determine the Global Thermogenic Methane Seepage Rate from the Helium Flux of the Continents

    NASA Astrophysics Data System (ADS)

    Hornafius, J. S.

    2012-12-01

    Bottom-up assessments of the contribution of natural hydrocarbon seepage from the earth to the global methane budget have quantified the emissions from small areas and attempted to extrapolate those measurements to a cumulative global emission rate, resulting in estimates of 18-48 Tg/yr (3-9% of the global methane budget). An alternative top-down method using helium is proposed to estimate the total emission rate of methane from natural hydrocarbon seepage worldwide from the equation: Qseeps = 4J 4 f g-1 f b c m c T c a where Qseeps is the quantity of methane emitted to the atmosphere annually (in Tg yr-1). 4J is the average flux of 4He atoms from the surface of the continents (4.18 x 1010atoms m-2 s-1), 4 f g-1 is the inverse of the global average fraction of natural hydrocarbon gases comprised of 4He in the subsurface, expressed as CH 4 (vol) / 4He (vol). The other variable is the fraction of the continents that are covered by sedimentary basins (f b ~0.4), which reduces the helium flux to the fraction that migrates through hydrocarbon reservoirs on the way to the surface. The constants convert 4He atoms m-2 s-1into 4He mass flux per m2 per year (c m = 2.11 x 10-16), 4He grams into CH 4 Teragrams (c T = 4.0 x 10-12) and c a is the area of the continents (1.53 x 1014 m2). This approach assumes the 4He flux from the continents is the same from basement shield areas as from sedimentary basins, and that the average 4He content of natural hydrocarbon seeps is the same as the 4He content of natural gases in subsurface reservoirs exploited for hydrocarbons worldwide. An internally consistent estimate of the 4He content of these gases can be determined from the increase in the 4He content of the atmosphere in the past 30 years, because this would be attributable to the worldwide hydrocarbon production during that period. A most likely increase of 4 x 1010 4He mol yr-1 and a maximum increase of 1.3 x 1011 4He mol y-1 has been measured at the experimental limit from the

  6. Ground-water seepage and sulfur diagenesis in acidified lake sediments

    SciTech Connect

    McIntire, P.E.

    1988-01-01

    Most sulfur diagenesis models predict that porewater SO{sub 4}{sup 2{minus}} concentrations will decrease exponentially with increasing sediment depth and will be lower than that of the overlying water throughout the sediments. Sulfate concentrations below 0.2 mM are common in Lake Anna sediments which receive acid mine drainage; however, sediment porewater containing up to 29 mM SO{sub 4}{sup 2{minus}} is also seen at about 20 cm below the sediment surface in this section of the lake. A decision tree was used to investigate the cause of the high SO{sub 4}{sup 2{minus}} concentrations at depth (HSD) in the sediment. The first hypothesis was that increased ground-water flow through Lake Anna HSD sediments, relative to the non-HSD sediments, increases groundwater advection of SO{sub 4}{sup 2{minus}} or of oxygen which would induce sulfide oxidation. Stations having HSD profiles did not have higher groundwater flow than other sites samples. Alternative explanations for the HSD profiles were that the region in which they occurred had (1) unusual sediment chemical compositions; (2) groundwater seepage containing unusually high sulfate concentrations; or (3) a lateral intrusion of high SO{sub 4}{sup 2{minus}} water from the sulfide mines which supplied SO{sub 4}{sup 2{minus}} to the HSD region before the lake was impounded.

  7. Simplified measurement method for dissolved radio-Cs in litter and soil seepage water using copper-substituted Prussian blue.

    PubMed

    Takada, Momo; Yasutaka, Tetsuo; Okuda, Toshinori

    2016-11-01

    We developed a simple and rapid method for detecting dissolved radio-Cs in litter and/or soil seepage water using nonwoven fabrics impregnated with copper-substituted Prussian blue (Cu-NF). In laboratory and field experiments, litter and/or soil seepage water including dissolved radio-Cs were passed through traditional lysimeter systems combined with seven sheets of the Cu-NF. We then examined the recovery ratios of dissolved (137)Cs in the Cu-NF. In the laboratory experiments with faster flow rates (11-2200 mm h(-1)), over 86% of the total dissolved (137)Cs in litter seepage water was detected in the Cu-NF and over 82% of the collected (137)Cs was present in the first three sheets. In the field experiments, 99% of the total dissolved (137)Cs litter seepage water was collected in the Cu-NF and more than 96% of the collected (137)Cs was present in the first three sheets. Furthermore, the recovery ratio of dissolved (137)Cs increased with increasing installation Cu-NF length, probably because the packed soil in the Cu-NF lysimeter become more stable over time. Finally, because only the Cu-NF is measured, it is not necessary to undertake traditional measurement preparations such as filtration to remove particulate radio-Cs materials and evaporative concentration for low concentration of radio-Cs. As a result, we can save time and effort in measurement preparation by using the Cu-NF lysimeter method. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Relation between proposed developments of water resources and seepage from the All-American Canal, eastern Imperial Valley, California

    USGS Publications Warehouse

    Loeltz, Omar J.; Leake, S.A.

    1979-01-01

    A two-layer digital model designed for this study indicated that sealing of the Coachella branch of the All-American Canal would cause an eventual increase in seepage from the All-American Canal of about 15,000 acre-feet annually. Sealing of both the Coachella Canal and the segment of the All-American Canal between Pilot Knob and Drop 1 would result in a lessening of seepage rates from the All-American Canal of 57,000 acre-feet in 1985, but of only 39,000 acre-feet in 2030. Sealing both the Coachella and the All-American Canals would reduce the outflow to Mexicali Valley from 120,000 acre-feet in 1980 to less than 9 ,000 acre-feet in 2030. The model also indicated that if only the Coachella Canal was sealed, a little less than 40% of water pumped from proposed well fields near the All-American Canal ultimately would be derived from increased seepage from the All-American Canal; between 50 and 60% of the water pumped would be water that otherwise would flow to Mexicali Valley. (USGS)

  9. Seepage between a Regional Aquifer and a Flow-through Lake in a Melt Water Outwash Plain: Evidence of off-shore exchange

    NASA Astrophysics Data System (ADS)

    Kidmose, J.; Engesgaard, P. K.; Nilsson, B.; Looms, M. C.; Boldreel, L.

    2009-12-01

    Groundwater discharge to lakes is often completely neglected or misrepresented in the lake water balance, mainly because of difficulties in quantifying the spatial distribution. Furthermore, knowledge of the spatial discharge pattern is important for tracing contaminant sources to the lake. Former studies have suggested that the primary discharge zone is near the shore line at shallow depths. However, discharge zones can also be linked with topographical breaks in slopes both at the shoreline and in the deeper parts of the lake. Numerical investigations corroborate these flow patterns for homogeneous systems. Lake Hampen in Western Denmark is a flow-through lake located in a geological homogeneous melt-water outwash plain. The lake consists of a deep (maximum depth of 13 m) and shallow basin (mean depth of 1.5 m). The complexity of the groundwater-lake water interaction was resolved by an integrated use of different methods performed at three different scales in order to determine direction and rates; 1) Near shore lines with water depths up to 1 m, 2) Off-shore in shallow to intermediate water depths (1-5 m), and 3) Off-shore in deeper parts of the lake with water depths of 3-13 m. Lake sedimentology was investigated using geophysical methods (Multi Electrode Profiling, seismic profiling and Ground Penetrating Radar) and these guided the choice of locations for measuring the spatial distribution of seepage. Direct and indirect methods were used to measure seepage; hydraulic gradients and seepage meter measurements and stable oxygen isotope profiles. The results show clear evidence of off-shore exchange between the regional aquifer and the lake. Discharge rates, ranging from 0.03-10.6 cm/day in the near shore zone, cannot account for all seepage to the lake. This suggests that a significant part of the discharge takes place further off-shore, which is also supported by observations of gradients in the shallow to intermediate zone and the deeper parts. Recharge is

  10. Lake Okeechobee seepage monitoring network

    USGS Publications Warehouse

    McKenzie, Donald J.

    1973-01-01

    This report summarizes the data collected at the five original monitoring sites along the south shore of Lake Okeechobee from January 29, 1970 to June 28, 1972. In order to use the hydrographs in this report to full advantage, they should be studied in conjunction with Meyer's graphs and text (1971). During steady-state conditions, water seeps from the lake through the filtercake and through the aquifers beneath the dike. At those sites where the filtercake is missing, or has about the same permeability as the aquifers, the seepage from the lake is about equivalent to the flow through the aquifers. Present data are insufficient to determine whether or not filtercake buildup has reduced seepage. No appreciable change in drainage occurred during the observed period.

  11. Evidence for Recent Liquid Water on Mars: Seepage Sites in 'Aerobraking Crater' Revisited

    NASA Technical Reports Server (NTRS)

    2000-01-01

    (A) [figure removed for brevity, see original site] (B) [figure removed for brevity, see original site] (C) (D) You will need 3D glasses to view this anaglyph

    The first clue that there might be places on Mars where liquid groundwater seeps out onto the surface came from a picture taken by the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) during the pre-mapping Orbit Insertion Phase of the mission. The picture, shown in (A)above, was taken at the end of December 1997 while the spacecraft was still in the midst of aerobraking maneuvers to put it into the circular orbit needed for the Mapping Phase of the project. The Aerobraking 1 image, AB1-07707, showed dark, v-shaped scars on the western wall of a 50 kilometer-(31 mile)-diameter impact crater in southern Noachis Terra at 65oS, 15oW (see B, above, for context). The v-shaped features taper downslope to form narrow, somewhat curved channels. The relationship seen here was interpreted by MOC scientists to be similar to seepage landforms on Earth that form where springs emerge on a slope and water runs downhill.

    Once MGS achieved its Mapping Orbit in March 1999, the MOC was in a better position to take pictures of 10 times higher resolution than the Aerobraking AB1-07707 image. The opportunity to take a new picture of the proposed 'seepage' sites on the wall of the crater in southern Noachis finally arose in January 2000. The result is MOC image M11-00530, shown above in (top) and (C). This new close-up shows that the darkly-shaped scars host many small channels of only a few meters (yards) across. These small channels run downslope and coalesce at the apex (or point) of each 'v'. Amid the small channels are many large boulders, some of them the size of houses, that have eroded out of the crater wall. A 3-D view created using the AB1 and M11 images is shown in (D). The stereo picture (red-blue '3D' glasses required) emphasizes the presence of small channels and valleys, and shows that these valleys start

  12. Evidence for Recent Liquid Water on Mars: Seepage Sites in 'Aerobraking Crater' Revisited

    NASA Technical Reports Server (NTRS)

    2000-01-01

    (A) [figure removed for brevity, see original site] (B) [figure removed for brevity, see original site] (C) (D) You will need 3D glasses to view this anaglyph

    The first clue that there might be places on Mars where liquid groundwater seeps out onto the surface came from a picture taken by the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) during the pre-mapping Orbit Insertion Phase of the mission. The picture, shown in (A)above, was taken at the end of December 1997 while the spacecraft was still in the midst of aerobraking maneuvers to put it into the circular orbit needed for the Mapping Phase of the project. The Aerobraking 1 image, AB1-07707, showed dark, v-shaped scars on the western wall of a 50 kilometer-(31 mile)-diameter impact crater in southern Noachis Terra at 65oS, 15oW (see B, above, for context). The v-shaped features taper downslope to form narrow, somewhat curved channels. The relationship seen here was interpreted by MOC scientists to be similar to seepage landforms on Earth that form where springs emerge on a slope and water runs downhill.

    Once MGS achieved its Mapping Orbit in March 1999, the MOC was in a better position to take pictures of 10 times higher resolution than the Aerobraking AB1-07707 image. The opportunity to take a new picture of the proposed 'seepage' sites on the wall of the crater in southern Noachis finally arose in January 2000. The result is MOC image M11-00530, shown above in (top) and (C). This new close-up shows that the darkly-shaped scars host many small channels of only a few meters (yards) across. These small channels run downslope and coalesce at the apex (or point) of each 'v'. Amid the small channels are many large boulders, some of them the size of houses, that have eroded out of the crater wall. A 3-D view created using the AB1 and M11 images is shown in (D). The stereo picture (red-blue '3D' glasses required) emphasizes the presence of small channels and valleys, and shows that these valleys start

  13. Benefits and Risks of using Linear Anionic Polyacrylamide (LA-PAM) for Seepage Reduction in Unlined Water Delivery Canals

    NASA Astrophysics Data System (ADS)

    Susfalk, R. B.; Martin, C.; Sada, D.; Young, M.; Gates, T.; Shanafield, M.; Fitzgerald, B.; Smith, D.

    2008-12-01

    As water resources continue to be constrained in the arid western United States, there is a need to improve the efficiency in how water is transported from its sources to end-users. In particular, there is a growing need for cost-effective technologies capable of reducing undesirable seepage from water delivery canals where traditional canal sealing methods, such as concrete and geomembranes, are not suitable or cost-prohibitive. One alternative is the use of a linear, anionic polyacrylamide (LA-PAM) applied as granular solid to a flowing canal. The benefits and risks of LA-PAM use in unlined water delivery canals will be discussed in context of a diverse set of experiments that were conducted in the laboratory, at the furrow-scale, and in working water delivery canals. When properly used, the application of LA-PAM reduced seepage rates between 28 and 87 percent at a cost of 78 to 213 km-1. LA-PAM provided a cost-effective tool for canal operators to better manage the volume, timing, and extent of water losses from their canals. However, these benefits must be weighed against potential risks associated with LA-PAM use. Potential risks included the release of small concentrations of residual acrylamide (AMD) monomer, a cumulative neurotoxin and a suspected human carcinogen, and potential impacts on aquatic communities and downstream users.

  14. Local-scale variability of seepage and hydraulic conductivity in a shallow gravel-bed river

    USGS Publications Warehouse

    Rosenberry, D.O.; Pitlick, J.

    2009-01-01

    Seepage rate and direction measured with a seepage metre modified for use in flowing water were greatly variable along a 300-m reach of a shallow, gravel-bed river and depended primarily on the local-scale bed topography. The median value of seepage measured at 24 locations was 24 cm/day, but seepage measured at specific sites ranged from -340 to +237 cm/day. Seepage also varied substantially over periods of hours to days and occasionally reversed direction in response to evolution of the sediment bed. Vertical hydraulic conductivity was related to seepage direction and was larger during upward seepage than during downward seepage; with differences ranging from 4 to 40% in areas of active sediment transport to more than an order of magnitude in areas where current was too slow to mobilize bed sediment. Seepage was poorly related to hydraulic gradient measured over vertical distances of 0.3 m and appeared to be opposite the hydraulic gradient at 18% of the locations where both parameters were measured. Results demonstrate the scale dependence of these measurements in coarse-grained hyporheic settings and indicate that hydraulic gradients should be determined over a much shorter vertical increment if used to indicate exchange across the sediment-water interface. Published in 2009 by John Wiley & Sons, Ltd.

  15. Characterization of Preferential Ground-Water Seepage From a Chlorinated Hydrocarbon-Contaminated Aquifer to West Branch Canal Creek, Aberdeen Proving Ground, Maryland, 2002-04

    USGS Publications Warehouse

    Majcher, Emily H.; Phelan, Daniel J.; Lorah, Michelle M.; McGinty, Angela L.

    2007-01-01

    , relatively low concentrations of chlorinated daughter compounds, and insignificant concentrations of methane in shallow pore water samples. These seeps were primarily along the creek edge or formed a dendritic-like pattern between the wetland and creek channel. In contrast, seep locations characterized as diffuse seeps contained relatively high concentrations of chlorinated daughter compounds (or a mixture of daughter and parent compounds) and detectable methane concentrations in shallow pore water samples. These seeps were primarily along the wetland boundary. Qualitative thermal infrared surveys coupled with quantitative verification of temperature differences, and screening for volatile organic compound and methane concentrations proved to be effective tools in determining the overall extent of preferential seepage. Hydrologic and physical properties of wetland sediments were characterized at two focused and one diffuse seep location. In the seeps with focused discharge, measured seepage was consistent over the tidal cycle, whereas more variability with tidal fluctuation was measured in the diffuse seep location. At all locations, areas were identified within the general seep boundaries where discharge was minimal. In all cases, the geometric mean of non-zero vertical flux measurements was greater than those previously reported in the non-seep wetland sediments using flow-net analysis. Flux was greater in the focused discharge areas than in the diffuse discharge area, and all fluxes were within the range reported in the literature for wetland discharge. Vertical hydraulic conductivity estimated from seepage flux and a mean vertical gradient at seeps with focused discharge resulted in a minimum hydraulic conductivity two orders of magnitude greater than those estimated in the non-seep sediment. In contrast, vertical conductivity estimates at a diffuse seep were similar to estimates along a nearby line of section through a non-seep area. Horizontal hydraulic cond

  16. Review of water demand and water utilization studies for the Provo River drainage basin, and review of a study of the effects of the proposed Jordanelle Reservoir on seepage to underground mines, Bonneville unit of the central Utah project

    USGS Publications Warehouse

    Waddell, K.M.; Freethey, G.W.; Susong, D.D.; Pyper, G.E.

    1991-01-01

    Problem: Questions have been raised concerning the adequacy of available water to fulfill the needs of storage, exchanges, diversions, and instream flows, pursuant to existing water rights in the Provo River drainage basin part of the Bonneville Unit. Also, concern has been expressed about the potential for seepage of water from Jordanelle Reservoir to underground mines. The Utah Congressional Delegation requested that the U.S. Geological Survey (USGS) review the results of analyses performed by and for the USBR.Purpose and Scope: The purpose of this report is to present the results of the USGS review of (1) the hydrologic data, techniques, and model used by the USBR in their hydrologic analyses of the Provo River drainage basin and (2) the results of a study of the potential for seepage from the Jordanelle Reservoir to nearby underground mines.The USGS reviewed USBR-supplied water demands, water utilization studies, and models of seepage from Jordanelle Reservoir. The USBR estimated that about 90 percent of the water supply for Jordanelle Reservoir will be water from Strawberry Reservoir exchanged for water from the Provo River stored in Utah Lake. If the Utah State Engineer allows the USBR to claim an estimated 19,700 acre-feet of return flows from the CUP, only about 77 percent of the supply would be derived from exchange of existing water rights in Utah Lake. The USGS assumed that planned importations of water from the Uinta Basin will be available and deliverable to fulfill the proposed exchanges.Water rights and demands are important for determining water availability. The USGS did not conduct an independent review of water rights and demands. The USSR and Utah Division of Water Rights use different methods in some areas for determining stress on the system based on past records. The USSR used "historical observed diversions" and the Utah Division of Water Rights use "diversion entitlements", which may not be equal to the historical diversions. The USGS

  17. Regeneration of mature Norway spruce stands: early effects of selective cutting and clear cutting on seepage water quality and soil fertility.

    PubMed

    Weis, W; Huber, C; Göttlein, A

    2001-11-10

    The cutting of trees influences element turnover in the forest ecosystem. The reduction of plant uptake, as well as an increased mineralization and nitrification due to higher soil temperature and soil moisture, can lead to considerable losses of nutrients from the main rooting zone. This may result in a reduced soil fertility and a decrease in drinking water quality due to high nitrate concentrations in the seepage water. In Bavaria (Germany) selective cutting is preferred to clear cutting when initiating the regeneration of Norway spruce stands with European beech. This paper summarizes the early effects of both forest management practices on soil fertility and seepage water quality for three different sites. Shown are the concentrations of nitrogen and base cations in the seepage water as well as the water and ion fluxes during the first year after tree cut. Nutrient inputs decreased on thinned plots and even more at clear-cuts. Nitrate concentrations in the seepage water are hardly affected by moderate thinning; however, on clear-cuts, the nitrate concentration increases significantly, and base cations are lost from the upper mineral soil. This effect is less obvious at sites where a dense ground vegetation, which is able to take up excess nitrogen, exists.

  18. Drift-Scale THC Seepage Model

    SciTech Connect

    C.R. Bryan

    2005-02-17

    The purpose of this report (REV04) is to document the thermal-hydrologic-chemical (THC) seepage model, which simulates the composition of waters that could potentially seep into emplacement drifts, and the composition of the gas phase. The THC seepage model is processed and abstracted for use in the total system performance assessment (TSPA) for the license application (LA). This report has been developed in accordance with ''Technical Work Plan for: Near-Field Environment and Transport: Coupled Processes (Mountain-Scale TH/THC/THM, Drift-Scale THC Seepage, and Post-Processing Analysis for THC Seepage) Report Integration'' (BSC 2005 [DIRS 172761]). The technical work plan (TWP) describes planning information pertaining to the technical scope, content, and management of this report. The plan for validation of the models documented in this report is given in Section 2.2.2, ''Model Validation for the DS THC Seepage Model,'' of the TWP. The TWP (Section 3.2.2) identifies Acceptance Criteria 1 to 4 for ''Quantity and Chemistry of Water Contacting Engineered Barriers and Waste Forms'' (NRC 2003 [DIRS 163274]) as being applicable to this report; however, in variance to the TWP, Acceptance Criterion 5 has also been determined to be applicable, and is addressed, along with the other Acceptance Criteria, in Section 4.2 of this report. Also, three FEPS not listed in the TWP (2.2.10.01.0A, 2.2.10.06.0A, and 2.2.11.02.0A) are partially addressed in this report, and have been added to the list of excluded FEPS in Table 6.1-2. This report has been developed in accordance with LP-SIII.10Q-BSC, ''Models''. This report documents the THC seepage model and a derivative used for validation, the Drift Scale Test (DST) THC submodel. The THC seepage model is a drift-scale process model for predicting the composition of gas and water that could enter waste emplacement drifts and the effects of mineral alteration on flow in rocks surrounding drifts. The DST THC submodel uses a drift

  19. Seasonal seepage investigation on an urbanized reach of the lower Boise River, southwestern Idaho, water year 2010

    USGS Publications Warehouse

    Williams, Marshall L.

    2011-01-01

    The U.S. Geological Survey in cooperation with the Idaho Department of Water Resources Treasure Valley Comprehensive Aquifer Management Planning effort investigated seasonal groundwater gains and losses on the Boise River, Idaho, starting in November 2009 through August 2010. The investigation was conducted using seepage runs in 11 subreaches over a 14-mile reach from downstream of the inactive streamgage, Boise River below Diversion Dam (U.S. Geological Survey station No. 13203510) to the active Boise River at Glenwood Bridge streamgage (U.S. Geological Survey station No. 13206000). The seepage runs measured mainstem discharge, and significant tributary contributions and diversions along the reach. In addition, an evaluation of the groundwater hydraulic gradient was simultaneously conducted through shallow groundwater mini-piezometers adjacent to the river during February (low stream discharge) and May (high stream discharge) measurement timeframes. November discharge estimates, representative of autumn, had gains and losses that varied by subreach with an overall net gain of 42 ± 8 cubic feet per second (ft3/s). This finding compares favorably to a previous U.S. Geological Survey seepage investigation in November 1996 that found a gaining reach with an estimated gain of 52 ft3/s. This finding also is supported by a U.S. Geological Survey investigation in the study reach in November 1971 that estimated a gain of 74 ft3/s, which largely came from groundwater. The February discharge estimates, representative of winter conditions, showed variability in the reach with a net gain of 52 ft3/s with an uncertainty estimate of ± 7 ft3/s, which is consistent with the low stream discharge findings from November 2009. This finding is further supported by the differential hydraulic head measured at transect sites that qualitatively indicated groundwater to surface-water movement with few exceptions. The May discharge estimates, representative of the spring-time conditions

  20. Cycling of mercury across the sediment-water interface in seepage lakes: Chapter 13, Advances in Chemistry

    USGS Publications Warehouse

    Hurley, James P.; Krabbenhoft, David P.; Babiarz, C.L.; Andren, Anders

    1994-01-01

    The magnitude and direction of Hg fluxes across the sediment—water interface were estimated by groundwater, dry bulk sediment, sediment pore water, sediment trap, and water-column analyses in two northern Wisconsin seepage lakes. Little Rock Lake (Treatment Basin) received no groundwater discharge during the study period (1988—1990), and Follette Lake received continuous groundwater discharge. In Little Rock Lake, settling of particulate matter accounted for the major Hg delivery mechanism to the sediment—water interface. Upward diffusion of Hg from sediment pore waters below 2—4-cm sediment depth was apparently a minor source during summer stratification. Time-series comparisons suggested that the observed buildup of Hg in the hypolimnion of Little Rock Lake was attributable to dissolution and diffusion of Hg from recently fallen particulate matter close to the sediment—water interface. Groundwater inflow represented an important source of new Hg, and groundwater outflow accounted for significant removal of Hg from Pallette Lake. Equilibrium speciation calculations revealed that association of Hg with organic matter may control solubility in well-oxygenated waters, whereas in anoxic environments sulfur (polysulfide and bisulfide) complexation governs dissolved total Hg levels.

  1. Hydrogeologic setting, water budget, and preliminary analysis of ground-water exchange at Lake Starr, a seepage lake in Polk County, Florida

    USGS Publications Warehouse

    Swancar, Amy; Lee, T.M.; O'Hare, T. M.

    2000-01-01

    Lake Starr, a 134-acre seepage lake of multiple-sinkhole origin on the Lake Wales Ridge of central Florida, was the subject of a detailed water-budget study from August 1996 through July 1998. The study monitored the effects of hydrogeologic setting, climate, and ground-water pumping on the water budget and lake stage. The hydrogeologic setting of the Lake Starr basin differs markedly on the two sides of the lake. Ground water from the surficial aquifer system flows into the lake from the northwest side of the basin, and lake water leaks out to the surficial aquifer system on the southeast side of the basin. Lake Starr and the surrounding surficial aquifer system recharge the underlying Upper Floridan aquifer. The rate of recharge to the Upper Floridan aquifer is determined by the integrity of the intermediate confining unit and by the downward head gradient between the two aquifers. On the inflow side of the lake, the intermediate confining unit is more continuous, allowing ground water from the surficial aquifer system to flow laterally into the lake. Beneath the lake and on the southeast side of the basin, breaches in the intermediate confining unit enhance downward flow to the Upper Floridan aquifer, so that water flows both downward and laterally away from the lake through the ground-water flow system in these areas. An accurate water budget, including evaporation measured by the energy-budget method, was used to calculate net ground-water flow to the lake, and to do a preliminary analysis of the relation of net ground-water fluxes to other variables. Water budgets constructed over different timeframes provided insight on processes that affect ground-water interactions with Lake Starr. Weekly estimates of net ground-water flow provided evidence for the occurrence of transient inflows from the nearshore basin, as well as the short-term effects of head in the Upper Floridan aquifer on ground-water exchange with the lake. Monthly water budgets showed the effects

  2. Abstraction of Seepage into Drifts

    SciTech Connect

    M.L. Wilson; C.K. Ho

    2000-09-26

    A total-system performance assessment (TSPA) for a potential nuclear-waste repository requires an estimate of the amount of water that might contact waste. This paper describes the model used for part of that estimation in a recent TSPA for the Yucca Mountain site. The discussion is limited to estimation of how much water might enter emplacement drifts; additional considerations related to flow within the drifts, and how much water might actually contact waste, are not addressed here. The unsaturated zone at Yucca Mountain is being considered for the potential repository, and a drift opening in unsaturated rock tends to act as a capillary barrier and divert much of the percolating water around it. For TSPA, the important questions regarding seepage are how many waste packages might be subjected to water flow and how much flow those packages might see. Because of heterogeneity of the rock and uncertainty about the future (how the climate will evolve, etc.), it is not possible to predict seepage amounts or locations with certainty. Thus, seepage is treated as a stochastic quantity in TSPA simulations, with the magnitude and spatial distribution of seepage sampled from uncertainty distributions. The distillation of the essential components of process modeling into a form suitable for use in TSPA simulations is referred to as abstraction. In the following sections, seepage process models and abstractions will be summarized and then some illustrative results are presented.

  3. Using noble gases in the pore water of ocean sediments to characterize CH4 seepage off the coast of New Zealand

    NASA Astrophysics Data System (ADS)

    Tomonaga, Yama; Brennwald, Matthias S.; Kipfer, Rolf

    2013-04-01

    Newly developed analytical techniques to determine the abundances of noble gases in sediment pore water [1, 5] allow noble-gas concentrations and isotope ratios to be measured easily and routinely in unconsolidated lacustrine sediments [6, 7]. We applied these techniques for the first time to ocean sediments to investigate an active cold methane seepage system located in the South Pacific off the coast of New Zealand using 3He-4He ratios determined in the sediment pore water. Our results [8] show that more 3He-rich fluids are released in the vicinity of the Pacific-Australian subduction zone than at the forearc stations located closer to the New Zealand coast. However, the 3He-4He isotope signature in the sediment column indicates that only a minor part of the He emanating from deeper strata originates from a (depleted) mantle source. Hence, most He in the pore water is produced locally by the radioactive decay of U and Th in the sediment minerals or in the underlying crustal rocks. Such an occurrence of isotopically heavy crustal He also suggests that the source of the largest fraction of methane is a near-surface geochemical reservoir. This finding is in line with a previous δ13C study in the water column which concluded that the emanating methane is most likely of biological origin and is formed in the upper few meters of the sediment column [2]. The prevalence of isotopically heavy He agrees well with the outcome of other previous studies on island arc systems [3, 4] which indicate that the forearc regions are characterized by crustal He emission, whereas the volcanic arc region is characterized by the presence of mantle He associated with rising magma. References [1] Brennwald, M. S., Hofer, M., Peeters, F., Aeschbach-Hertig, W., Strassmann, K., Kipfer, R., and Imboden, D. M. (2003). Analysis of dissolved noble gases in the pore water of lacustrine sediments. Limnol. Oceanogr.: Methods 1, 51-62. [2] Faure, K., Greinert, J., Schneider von Deimling, J., Mc

  4. Interaction between hydrocarbon seepage, chemosynthetic communities and bottom water redox at cold seeps of the Makran accretionary prism: insights from habitat-specific pore water sampling and modeling

    NASA Astrophysics Data System (ADS)

    Fischer, D.; Sahling, H.; Nöthen, K.; Bohrmann, G.; Zabel, M.; Kasten, S.

    2011-09-01

    The interaction between fluid seepage, bottom water redox, and chemosynthetic communities was studied at cold seeps across one of the world's largest oxygen minimum zones (OMZ) located at the Makran convergent continental margin. Push cores were obtained from seeps within and at the lower boundary of the core-OMZ with a remotely operated vehicle. Extracted pore water was analyzed for sulfide and sulfate contents. Depending on oxygen availability, seeps were either colonized by microbial mats or by mats and macrofauna. The latter, including ampharetid polychaetes and vesicomyid clams, occurred in distinct benthic habitats which were arranged in a concentric fashion around gas orifices. At most sites colonized by microbial mats, hydrogen sulfide was exported into the bottom water. Where macrofauna was widely abundant, hydrogen sulfide was consumed within the sediment. Numerical modeling of pore water profiles was performed in order to assess rates of fluid advection and bioirrigation. While the magnitude of upward fluid flow decreased from 11 cm yr-1 to <1 cm yr-1 and the sulfate/methane transition zone (SMTZ) deepened with increasing distance from the central gas orifice, the fluxes of sulfate into the SMTZ did not significantly differ (6.6-9.3 mol m-2 yr-1). Depth-integrated rates of bioirrigation increased from 162 cm yr-1 in central habitats characterized by microbial mats and sparse macrofauna to 348 cm yr-1 in habitats of large and small vesicomyid clams. These results reveal that chemosynthetic macrofauna inhabiting the outer seep habitats at the lower boundary of the OMZ efficiently bioirrigate and thus transport sulfate into the upper 10 to 15 cm of the sediment. In this way bioirrigation compensates for the lower upward flux of methane in outer habitats and stimulates rates of anaerobic oxidation of methane (AOM) with sulfate high enough to provide sulfide for chemosynthesis. Through bioirrigation macrofauna engineer their geochemical environment and fuel

  5. Investigation of Seepage Meter Measurements in Steady Flow and Wave Conditions.

    PubMed

    Russoniello, Christopher J; Michael, Holly A

    2015-01-01

    Water exchange between surface water and groundwater can modulate or generate ecologically important fluxes of solutes across the sediment-water interface. Seepage meters can directly measure fluid flux, but mechanical resistance and surface water dynamics may lead to inaccurate measurements. Tank experiments were conducted to determine effects of mechanical resistance on measurement efficiency and occurrence of directional asymmetry that could lead to erroneous net flux measurements. Seepage meter efficiency was high (average of 93%) and consistent for inflow and outflow under steady flow conditions. Wave effects on seepage meter measurements were investigated in a wave flume. Seepage meter net flux measurements averaged 0.08 cm/h-greater than the expected net-zero flux, but significantly less than theoretical wave-driven unidirectional discharge or recharge. Calculations of unidirectional flux from pressure measurements (Darcy flux) and theory matched well for a ratio of wave length to water depth less than 5, but not when this ratio was greater. Both were higher than seepage meter measurements of unidirectional flux made with one-way valves. Discharge averaged 23% greater than recharge in both seepage meter measurements and Darcy calculations of unidirectional flux. Removal of the collection bag reduced this net discharge. The presence of a seepage meter reduced the amplitude of pressure signals at the bed and resulted in a nearly uniform pressure distribution beneath the seepage meter. These results show that seepage meters may provide accurate measurements of both discharge and recharge under steady flow conditions and illustrate the potential measurement errors associated with dynamic wave environments.

  6. Simulation procedure of unconfined seepage with an inner seepage face in a heterogeneous field

    NASA Astrophysics Data System (ADS)

    Wu, MengXi; Yang, LianZhi; Yu, Ting

    2013-06-01

    An inner seepage face phenomenon is given and a numerical simulation procedure has been developed. It may appear at the interface of two materials when an unconfined seepage flows from a porous media to a coarser porous media with a higher permeability. Inaccuracy and divergent problems may arise both in a saturated-only and in a variably saturated analysis while an inner seepage face is not simulated with a special procedure. The position of the seepage face is determined during the nonlinear iteration process and the flux of the inner seepage face nodes is transferred to the downstream side nodes. Validity and efficiency of the procedure are illustrated by the simulation of two dimensional steady state seepage examples of heterogeneous zoned dams which is usually used to validate algorithms. An analysis of a three-dimensional earth core rockfill dam is also presented here. The procedure can also be applied to general transient seepage problems.

  7. Influence of Groundwater Seepage on Water Quality and Ecological Health of the Ria Formosa Lagoon, Southern Portugal (Invited)

    NASA Astrophysics Data System (ADS)

    Kontar, A. Y.; Newton, A.

    2009-12-01

    Groundwater seepage from coastal aquifers has recently been recognized as an overlooked major source of nutrients (N, P) and contaminants to the coastal environment (Biddanda et al., 2009; Fear, Paerl and Braddy, 2007; Kluge et al., 2007; Kroeger and Charette, 2008). Nutrient and contaminants concentrations in groundwater are often much higher than those in river water, compensating for the lower flux of groundwater relative to the lagoon surface water. The Ria Formosa is a coastal lagoon located in the south of Portugal (Algarve, Faro) and surrounded by an intensely farmed area. We hypothesize that water quality and ecological health of the Ria Formosa environments are influenced by past and on-going contamination of terrestrial groundwaters with nutrients from fertilizer, sewage and industry. According to Leote, Ibanhez and Rocha (2005) estimated submarine groundwater discharge (SGD) into the lagoon to be 3.6 m3 day-1 per linear meter of coastline with freshwater contributions (per volume) ranging from 10% to 50%. SGD as an important nutrient source to the Ria Formosa, estimating annual loads of 36.2 mol (0.507 kg) of Nitrogen, 1.1 mol (0.034 kg) of Phosphorus and 18.6 mol (0.522 kg) of Silicon per meter of coastline. Based on these results, it was suggested that SGD is a potential contributor to the observed nutrification status of the Ria Formosa lagoon. We are testing the following two hypotheses: (1) Anthropogenically impacted sites of the Ria Formosa having higher concentration of inorganic nutrients in groundwater will be characterized by higher density of Aquatic Invasive Species (AIS) distribution, and higher chlorophyll and phycocyanin concentration, oxygen demand, and sediment organic carbon than the pristine site; (2) Anthropogenically impacted sites of the Ria Formosa having higher concentration of contaminants in groundwater will be characterized by lower AIS dispersal and colonization, and lower chlorophyll and phycocyanin concentration, oxygen

  8. Seepage meters and Bernoulli's revenge

    USGS Publications Warehouse

    Shinn, E.A.; Reich, C.D.; Hickey, T.D.

    2002-01-01

    Evaluation of seepage data from a network of 50 permanently deployed submarine seepage meters, specially constructed from fiberglass, indicates that the devices artificially advect (Bernoulli effect) shallow ground water. Reverse flow into the rock was not observed even when adjacent piezometers installed 2-m to 20-m below the rock-water interface indicated negative groundwater heads. Quantitative testing of five different designs, including conventional end-of-oil-drum designs, indicates that meters presenting positive relief on the sea floor are subject to the Bernoulli effect when placed in areas where there are waves and/or currents. Advection does not appear to be caused by flexing of the collection bags.

  9. Seepage Calibration Model and Seepage Testing Data

    SciTech Connect

    P. Dixon

    2004-02-17

    The purpose of this Model Report is to document the Seepage Calibration Model (SCM). The SCM is developed (1) to establish the conceptual basis for the Seepage Model for Performance Assessment (SMPA), and (2) to derive seepage-relevant, model-related parameters and their distributions for use in the SMPA and seepage abstraction in support of the Total System Performance Assessment for License Application (TSPA-LA). The SCM is intended to be used only within this Model Report for the estimation of seepage-relevant parameters through calibration of the model against seepage-rate data from liquid-release tests performed in several niches along the Exploratory Studies Facility (ESF) Main Drift and in the Cross Drift. The SCM does not predict seepage into waste emplacement drifts under thermal or ambient conditions. Seepage predictions for waste emplacement drifts under ambient conditions will be performed with the SMPA (see upcoming REV 02 of CRWMS M&O 2000 [153314]), which inherits the conceptual basis and model-related parameters from the SCM. Seepage during the thermal period is examined separately in the Thermal Hydrologic (TH) Seepage Model (see BSC 2003 [161530]). The scope of this work is (1) to evaluate seepage rates measured during liquid-release experiments performed in several niches in the Exploratory Studies Facility (ESF) and in the Cross Drift, which was excavated for enhanced characterization of the repository block (ECRB); (2) to evaluate air-permeability data measured in boreholes above the niches and the Cross Drift to obtain the permeability structure for the seepage model; (3) to use inverse modeling to calibrate the SCM and to estimate seepage-relevant, model-related parameters on the drift scale; (4) to estimate the epistemic uncertainty of the derived parameters, based on the goodness-of-fit to the observed data and the sensitivity of calculated seepage with respect to the parameters of interest; (5) to characterize the aleatory uncertainty of

  10. R Reactor seepage basins soil moisture and resistivity field investigation using cone penetrometer technology, Savannah River Site, Aiken, South Carolina

    SciTech Connect

    Harris, M.K.

    2000-02-17

    The focus of this report is the summer 1999 investigation of the shallow groundwater system using cone penetrometer technology characterization methods to determine if the water table is perched beneath the R Reactor Seepage Basins (RRSBs).

  11. Evaluation of 2D resistivity imaging technique for delineating subsurface seepage of hydrocarbon-contaminated water southeast of Karbala city, Iraq.

    PubMed

    Al-Menshed, Firas H; Thabit, Jassim M

    2017-03-01

    2D imaging technique was applied in (8) transects near a pit of contaminated water near contaminated well southeast of Karbala city, Iraq. Each transect was 30 m long with 1 m electrode spacing. Data acquisition was fulfilled by using Wenner electrode array. The resistivity of water-contaminated zone is found less than 3Ω.m and the top dry zone recorded relatively high resistivity (more than 170Ω.m). It is found that the greatest amount of seepage was found moving towards northeast direction coincided with groundwater movement direction, whereas there was no movement towards northwest and southeast directions and restricted on the closest areas to the pit location. The outcomes suggested that the 2D imaging technique is a successful and powerful tool in separating contaminated zone from clear one and in detecting underground seepage depth and moving direction.

  12. Active seepage and water infiltration in Lake Baikal sediments: new thermal data from TTR-Baikal 2014 (Class@Baikal)

    NASA Astrophysics Data System (ADS)

    Poort, Jeffrey; Khlystov, Oleg M.; Akhmanov, Grigorii G.; Khabuev, Andrei V.; Belousov, Oleg V.

    2015-04-01

    New thermal data from the sediments of Lake Baikal were collected in July 2014 during the first Training-Through-Research cruise on Lake Baikal (Class@Baikal) organized by MGU and LIN. TTR-Baikal is a comprehensive multidisciplinary program to train students on the field on pertinent scientific topics. The cruise program focused on seafloor sampling, acoustic investigations and heat flow measurements of gas seeps, flares, mud volcanoes, slumps and debris flows, canyons and channels in the coastal proximity. The thermal data were acquired using autonomous temperature sensors on a 3 meter long gravity corer that allowed analysis at the same spot of sediments, pore fluids, hydrates and microbiology. A total of eight thermal measurements were performed in five structures located on the lake floor of the Central Baikal Basin at 333-1530 meter water depths: 3 mud volcanoes (Novosibirsk, Unshuy and Krest), 1 seep site (Seep 13), and one fault outcrop in the Selenga transfer zone. All studied structures show signals of active seepage, water infiltration and/or hydrate dynamics. The strongest thermal gradient has been measured in Seep 13, suggesting a strong upflow of warm fluids similar to the Gorevoy Utes seep. At the three mud volcanoes, hydrate presence have been evidenced and both enhanced and reduced thermal gradients have been observed. This is similar to the hydrate-bearing K-2 mud volcano in Baikal (Poort et al., 2012). A strongly reduced thermal gradient was observed in the Krest mud volcano where the presence of oxidized channels at 30-40 cm under the sediment surface indicate an infiltration of cold lake water. The water infiltration process at hydrate bearing seep sites will be discussed and compared with other seep areas in the world.

  13. Influence of evaporation, ground water, and uncertainty in the hydrologic budget of Lake Lucerne, a seepage lake in Polk County, Florida

    USGS Publications Warehouse

    Lee, Terrie Mackin; Swancar, Amy

    1997-01-01

    A detailed hydrologic budget was constructed of a seepage lake of sinkhole origin in the karst terrain of central Florida. During the drought period studied, lake evaporation computed by the energy-budget and mass-transfer methods was the largest component in the budget, followed by rainfall. Ground-water inflow contributed about one-third of the total inflow. Lake leakage was about one-fourth of the evaporative losses and was increased substantially by pumping from the Upper Floridan aquifer.

  14. Effects on ground-water quality of seepage from a phosphatic clayey waste settling pond, north-central Florida

    USGS Publications Warehouse

    Hunn, J.D.; Seaber, P.R.

    1986-01-01

    Water samples were taken from test wells drilled near an inactive phosphatic clayey waste storage settling pond, from the settling pond and its perimeter ditch, and from an active settling pond near White Springs, Hamilton County, in north-central Florida. The purpose was to document the seepage of chemical constituents from the inactive settling pond and ditch into the adjacent surficial groundwater system, and to assess the potential for movement of these constituents into the deeper Floridan aquifer system which is the major source of public supply in the area. The study area is underlain by a 2 ,500-ft-thick sequence of Coastal Plain sediments of Early Cretaceous to Holocene age. The rocks of Tertiary and Quaternary age that underlie the test site area can be grouped into three major geohydrologic units. In descending order, these units are: surficial aquifer, Hawthorn confining unit, and Floridan aquifer system. Phosphate deposits occur in the upper part of the surficial aquifer. Water in the active settling pond is a calcium magnesium sulfate type with a dissolved solids concentration of 250 mg/L, containing greater amounts of phosphorus, iron, aluminum, barium, zinc, and chromium than the other surface waters. Water in the perimeter ditch is a calcium sulfate type with a dissolved solids concentration of 360 to 390 mg/L, containing greater amounts of calcium, sulfate, nitrogen, and fluoride than other surface waters. Water from the inactive settling pond is a calcium magnesium bicarbonate type with a dissolved solids concentration of 140 mg/L, containing more bicarbonate than the other surface waters. Large amounts of chemical constituents in the phosphate waste disposal slurry are apparently trapped in the sediments of the settling ponds. The quality of water in the upper part of the surficial aquifer from wells within 200 to 400 ft of the inactive settling pond shows no signs of chemical contamination from phosphate industry operations. The horizontal

  15. SEEPAGE/BACKFILL INTERACTIONS

    SciTech Connect

    P. Mariner

    2000-04-14

    As directed by written development plan (CRWMS M&O 1999a), a sub-model of seepage/backfill interactions is developed and presented in this document to support the Engineered Barrier System (EBS) Physical and Chemical Environment Model. The purpose of this analysis is to assist Performance Assessment Operations (PAO) and the Engineered Barrier Performance Department in modeling the geochemical environment within a repository drift. In this analysis, a conceptual model is developed to provide PAO a more detailed and complete in-drift geochemical model abstraction and to answer the key technical issues (KTI) raised in the NRC Issue Resolution Status Report (IRSR) for the Evolution of the Near Field Environment (NFE) Revision 2 (NRC 1999). The development plan calls for a sub-model that evaluates the effect on water chemistry of chemical reactions between water that enters the drift and backfill materials in the drift. The development plan specifically requests an evaluation of the following important chemical reaction processes: dissolution-precipitation, aqueous complexation, and oxidation-reduction. The development plan also requests the evaluation of the effects of varying seepage and drainage fluxes, varying temperature, and varying evaporation and condensation fluxes. Many of these effects are evaluated in a separate Analysis/Model Report (AMR), ''Precipitates Salts Analysis AMR'' (CRWMS M&O 2000), so the results of that AMR are referenced throughout this AMR.

  16. Modeling research on the response of geoelectric fields in a porous media seepage process

    NASA Astrophysics Data System (ADS)

    Zhou, Haitao; Gong, Xulong; Sun, Qiang; Yao, Yahui; Zhang, Rui

    2017-03-01

    Water seepage in rock and soil is a main inducing factor of accidents in many engineering fields such as tunnel engineering, mineral resource exploitation, and rock slopes. Water migration in rock and soil can lead to abnormal geoelectric fields due to the effects of diffusion, adsorption, filtration, and oxidation. This makes it possible to research the seepage law in porous media by measuring the response of geoelectric fields in this process. In this work, we carry out a physical simulation experiment to study the geoelectric field response occurring in the water-migration process. By analyzing the response of first electric potential, spontaneous potentials, and exciting current, we find that both the spontaneous potential and exciting current can reflect the change of seepage flow during the water-infiltration process. The exciting current and first electric potential is applicable to the seepage research on heterogeneous rock and soil, for they can accurately determine the position and velocity of the seepage. Real-time apparent resistivity not only indicates the infiltration area but also reflects the relative water content, i.e., the seepage reached saturation along with the reduction of the apparent resistivity.

  17. Nitrate-nitrogen concentrations in the perched ground water under seepage-irrigated potato cropping systems.

    PubMed

    Munoz-Arboleda, F; Mylavarapu, R; Hutchinson, C; Portier, K

    2008-01-01

    Excessive nitrogen rates for potato production in northeast Florida have been declared as a potential source of nitrate pollution in the St. Johns River watershed. This 3-yr study examined the effect of N rates (0, 168, and 280 kg ha(-1)) split between planting and 40 d after planting on the NO(3)-N concentration in the perched ground water under potato (Solanum tuberosum cv. Atlantic) in rotation with sorghum sudan grass hybrid (Sorghum vulgare x Sorghum vulgare var. sudanese, cv. SX17), cowpea (Vigna unguiculata cv. Iron Clay), and greenbean (Phaseolus vulgare cv. Espada). Soil solution from the root zone and water from the perched ground water under potato were sampled periodically using lysimeters and wells, respectively. Fertilization at planting increased the NO(3)-N concentration in the perched ground water, but no effect of the legumes in rotation with potatoes on nitrate leaching was detected. Fertilization of green bean increased NO(3)-N concentration in the perched ground water under potato planted in the following season. The NO(3)-N concentration in the soil solution within the potato root zone followed a similar pattern to that of the perched ground water but with higher initial values. The NO(3)-N concentration in the perched ground water was proportional to the rainfall magnitude after potato planting. A significant increase in NO(3)-N concentration in the perched ground water under cowpea planted in summer after potato was detected for the side-dressing of 168 kg ha(-1) N applied to potato 40 d after planting but not at the 56 kg ha(-1) N side-dress. Elevation in NO(3)-N concentration in the perched ground water under sorghum was not significant, supporting its use as an effective N catch crop.

  18. Seepage Calibration Model and Seepage Testing Data

    SciTech Connect

    S. Finsterle

    2004-09-02

    The purpose of this Model Report is to document the Seepage Calibration Model (SCM). The SCM was developed (1) to establish the conceptual basis for the Seepage Model for Performance Assessment (SMPA), and (2) to derive seepage-relevant, model-related parameters and their distributions for use in the SMPA and seepage abstraction in support of the Total System Performance Assessment for License Application (TSPA-LA). This Model Report has been revised in response to a comprehensive, regulatory-focused evaluation performed by the Regulatory Integration Team [''Technical Work Plan for: Regulatory Integration Evaluation of Analysis and Model Reports Supporting the TSPA-LA'' (BSC 2004 [DIRS 169653])]. The SCM is intended to be used only within this Model Report for the estimation of seepage-relevant parameters through calibration of the model against seepage-rate data from liquid-release tests performed in several niches along the Exploratory Studies Facility (ESF) Main Drift and in the Cross-Drift. The SCM does not predict seepage into waste emplacement drifts under thermal or ambient conditions. Seepage predictions for waste emplacement drifts under ambient conditions will be performed with the SMPA [''Seepage Model for PA Including Drift Collapse'' (BSC 2004 [DIRS 167652])], which inherits the conceptual basis and model-related parameters from the SCM. Seepage during the thermal period is examined separately in the Thermal Hydrologic (TH) Seepage Model [see ''Drift-Scale Coupled Processes (DST and TH Seepage) Models'' (BSC 2004 [DIRS 170338])]. The scope of this work is (1) to evaluate seepage rates measured during liquid-release experiments performed in several niches in the Exploratory Studies Facility (ESF) and in the Cross-Drift, which was excavated for enhanced characterization of the repository block (ECRB); (2) to evaluate air-permeability data measured in boreholes above the niches and the Cross-Drift to obtain the permeability structure for the seepage model

  19. H-Area Seepage Basins

    SciTech Connect

    Stejskal, G.

    1990-12-01

    During the third quarter of 1990 the wells which make up the H-Area Seepage Basins (H-HWMF) monitoring network were sampled. Laboratory analyses were performed to measure levels of hazardous constituents, indicator parameters, tritium, nonvolatile beta, and gross alpha. A Gas Chromatograph Mass Spectrometer (GCMS) scan was performed on all wells sampled to determine any hazardous organic constituents present in the groundwater. The primary contaminants observed at wells monitoring the H-Area Seepage Basins are tritium, nitrate, mercury, gross alpha, nonvolatile beta, trichloroethylene (TCE), tetrachloroethylene, lead, cadmium, arsenic, and total radium.

  20. Sediment and water column geochemistry related to methane seepage along the northern US Atlantic margin

    NASA Astrophysics Data System (ADS)

    Pohlman, J.; Ruppel, C. D.; Colwell, F. S.; Krause, S.; Treude, T.; Graw, M.; Casso, M.; Boze, L. G.; Buczkowski, B.; Brankovits, D.

    2015-12-01

    Many of the more than 550 gas plumes recently identified along the northern US Atlantic margin (USAM) using multibeam water-column backscatter data lie at, or shallower than, the upper limit of gas hydrate stability on the continental slope. Important questions remain unanswered regarding the gas sources feeding these seeps, the export of carbon from the seafloor and the fundamental biogeochemical processes that regulate the flux and transformation of carbon along this margin. In addition, few programs have ever systematically studied the dynamics across the upper slope transition from no hydrate to hydrate. In September 2015, the US Geological Survey, Oregon State University, Geomar and UCLA conducted a multidisciplinary study aboard the R/V Sharp that included piston coring, multicoring, seafloor heat flow measurements, imaging of sub-seafloor sediments and water column methane plumes, and sampling of methane plumes in the water column. This presentation provides some of the basic geochemical results from the cruise, focusing on the pore water characteristics in upper slope gas hydrate provinces that will be used to constrain the fundamental biogeochemical processes operating at methane seeps, including data on the origin of seep methane at sites with and without a possible association with gas hydrate degradation. Water column profiling of methane and other biogeochemically relevant species (e.g., dissolved inorganic and organic carbon) are also used to establish how carbon exported from the seeps affects ocean chemistry and carbon availability in the deep ocean.

  1. Impact of aquifer desaturation on steady-state river seepage

    NASA Astrophysics Data System (ADS)

    Morel-Seytoux, Hubert J.; Miracapillo, Cinzia; Mehl, Steffen

    2016-02-01

    Flow exchange between surface and ground water is of great importance be it for beneficial allocation and use of the water resources or for the proper exercise of water rights. That exchange can take place under a saturated or unsaturated flow regime. Which regimes occur depend on conditions in the vicinity of the interactive area. Withdrawals partially sustained by seepage may not bring about desaturation but greater amounts eventually will. The problem considered in this paper deals only with the steady-state case. It is meant as a first step toward a simple, yet accurate and physically based treatment of the transient situation. The primary purpose of the article is to provide simple criteria for determination of the initiation of desaturation in an aquifer originally in saturated hydraulic connection with a river or a recharge area. The extent of the unsaturated zone in the aquifer will increase with increasing withdrawals while at the same time the seepage rate from the river increases. However the seepage increase will stop once infiltration takes place strictly by gravity in the aquifer and is no longer opposed by the capillary rise from the water table below the riverbed. Following desaturation simple criteria are derived and simple analytical formulae provided to estimate the river seepage based on the position of the water table mound below the clogging layer and at some distance away from the river bank. They fully account for the unsaturated flow phenomena, including the existence of a drainage entry pressure. Two secondary objectives were to verify that (1) the assumption of uniform vertical flow through a clogging layer and that (2) the approximation of the water table mound below the seepage area as a flat surface were both reasonably legitimate. This approach will be especially advantageous for the implementation of the methodology in large-scale applications of integrated hydrologic models used for management.

  2. Effects of seepage from fly-ash settling ponds and construction dewatering on ground-water levels in the Cowles unit, Indiana Dunes National Lakeshore, Indiana

    USGS Publications Warehouse

    Meyer, William R.; Tucci, Patrick

    1979-01-01

    Part of the Indiana Dunes National Lakeshore shares a common boundary with the Northern Indiana Public Service Company (NIPSCO). This area is underlain by unconsolidated deposits approximately 180 feet thick. NIPSCO accumulates fly ash from the burning of coal in electric-power generating units in settling ponds. Seepage from the ponds has raised ground-water levels above natural levels approximately 15 feet under the ponds and more than 10 feet within the Lakeshore. NIPSCO is presently (1977) constructing a nuclear powerplant, and construction activities include pumping ground water to dewater the construction site. The company has installed a slurry wall around the site to prevent lowering of ground-water levels within the Lakeshore. Plans call for continuous pumping through at least December 1979. A multilayered digital flow model was constructed to simulate the ground-water system. The model was used to demonstrate the effects of seepage from the fly-ash ponds on ground-water levels. Also, the model indicated a decline of 3 feet or less in the upper sand unit and 5 feet or less in the lower sand unit within the Lakeshore.

  3. Water chemistry, seepage investigation, streamflow, reservoir storage, and annual availability of water for the San Juan-Chama Project, northern New Mexico, 1942-2010

    USGS Publications Warehouse

    McKean, Sarah E.; Anderholm, Scott K.

    2014-01-01

    The Albuquerque Bernalillo County Water Utility Authority supplements the municipal water supply for the Albuquerque metropolitan area, in central New Mexico, with surface water diverted from the Rio Grande. The U.S. Geological Survey, in cooperation with the Albuquerque Bernalillo County Water Utility Authority, undertook this study in which water-chemistry data and historical streamflow were compiled and new water-chemistry data were collected to characterize the water chemistry and streamflow of the San Juan-Chama Project (SJCP). Characterization of streamflow included analysis of the variability of annual streamflow and comparison of the theoretical amount of water that could have been diverted into the SJCP to the actual amount of water that was diverted for the SJCP. Additionally, a seepage investigation was conducted along the channel between Azotea Tunnel Outlet and the streamflow-gaging station at Willow Creek above Heron Reservoir to estimate the magnitude of the gain or loss in streamflow resulting from groundwater interaction over the approximately 10-mile reach. Generally, surface-water chemistry varied with streamflow throughout the year. Streamflow ranged from high flow to low flow on the basis of the quantity of water diverted from the Rio Blanco, Little Navajo River, and Navajo River for the SJCP. Vertical profiles of the water temperature over the depth of the water column at Heron Reservoir indicated that the reservoir is seasonally stratified. The results from the seepage investigations indicated a small amount of loss of streamflow along the channel. Annual variability in streamflow for the SJCP was an indication of the variation in the climate parameters that interact to contribute to streamflow in the Rio Blanco, Little Navajo River, Navajo River, and Willow Creek watersheds. For most years, streamflow at Azotea Tunnel Outlet started in March and continued for approximately 3 months until the middle of July. The majority of annual streamflow

  4. Use of an Electromagnetic Seepage Meter to Investigate Temporal Variability in Lake Seepage

    USGS Publications Warehouse

    Rosenberry, D.O.; Morin, R.H.

    2004-01-01

    A commercially available electromagnetic flowmeter is attached to a seepage cylinder to create an electromagnetic seepage meter (ESM) for automating measurement of fluxes across the sediment/water interface between ground water and surface water. The ESM is evaluated through its application at two lakes in New England, one where water seeps into the lake and one where water seeps out of the lake. The electromagnetic flowmeter replaces the seepage-meter bag and provides a continuous series of measurements from which temporal seepage processes can be investigated. It provides flow measurements over a range of three orders of magnitude, and contains no protruding components or moving parts. The ESM was used to evaluate duration of seepage disturbance following meter installation and indicated natural seepage rates resumed approximately one hour following meter insertion in a sandy lakebed. Lakebed seepage also varied considerably in response to lakebed disturbances, near-shore waves, and rain-falls, indicating hydrologic processes are occurring in shallow lakebed settings at time scales that have largely gone unobserved.

  5. Use of an electromagnetic seepage meter to investigate temporal variability in lake seepage.

    PubMed

    Rosenberry, Donald O; Morin, Roger H

    2004-01-01

    A commercially available electromagnetic flowmeter is attached to a seepage cylinder to create an electromagnetic seepage meter (ESM) for automating measurement of fluxes across the sediment/water interface between ground water and surface water. The ESM is evaluated through its application at two lakes in New England, one where water seeps into the lake and one where water seeps out of the lake. The electromagnetic flowmeter replaces the seepage-meter bag and provides a continuous series of measurements from which temporal seepage processes can be investigated. It provides flow measurements over a range of three orders of magnitude, and contains no protruding components or moving parts. The ESM was used to evaluate duration of seepage disturbance following meter installation and indicated natural seepage rates resumed approximately one hour following meter insertion in a sandy lakebed. Lakebed seepage also varied considerably in response to lakebed disturbances, near-shore waves, and rainfalls, indicating hydrologic processes are occurring in shallow lakebed settings at time scales that have largely gone unobserved.

  6. Use of geophysical methods to map subsurface features at levee seepage locations

    NASA Astrophysics Data System (ADS)

    Brackett, Thomas C.

    The Great Flood of 2011 caused moderate to severe seepage and piping along the Mississippi River levees in Northwest Mississippi. The aim of this thesis was to implement geophysical techniques at two seepage locations in order to give a better understanding of the causes of underseepage and information on how to mitigate the problem. Sites near Rena Lara in Coahoma County and near Francis in Bolivar County were chosen to conduct this survey. Electrical Resistivity Tomography (ERT) and Electromagnetic Induction (EM) surveys were conducted on and adjacent to levees to identify seepage pathways and any dominant geological features at the sites. Results from geophysical surveys revealed that Francis and Rena Laura each had a prominent geomorphologic feature that was attributing to underseepage. Seepage at Francis was the result of a sand filled channel capped by a clay overburden. Permeable materials at the base of the channel served as a conduit for transporting river water beneath the levee. The seepage surfaced as sand boils where the overlying clay overburden was thin or non-existent. Investigations at the Rena Lara site revealed a large, clay-filled swale extending beneath the levee. The clay within the swale has relatively low horizontal permeability, and concentrated the seepage flow towards more permeable zones on the flanks of the swale. This resulted in the formation of sand boils at the base of the levee. Both geomorphic features at Francis and Rena Lara were identified as surface drainages using remote sensing data. With the assistance of borehole and elevation data, geophysics was successfully used to characterize the features at each site. Properties such as permeability and clay content were derived from responses in electrical conductivity and used to build seepage models at each site. These models will hopefully be considered when determining seepage conditions and mitigation techniques at other sites along the levee.

  7. Synoptic estimates of diffuse groundwater seepage to a spring-fed karst river at high spatial resolution using an automated radon measurement technique

    NASA Astrophysics Data System (ADS)

    Khadka, Mitra B.; Martin, Jonathan B.; Kurz, Marie J.

    2017-01-01

    Groundwater (GW) seepage can provide a major source of water, solutes, and contaminants to rivers, but identifying magnitudes, directions and locations of seepage is complicated by its diffuse and heterogeneous distributions. However, such information is necessary to develop programs and policies for protecting ecosystems and managing water resources. Here, we assess GW seepage to the Ichetucknee River, a spring-fed, low gradient, gaining stream in north-central Florida, through automated longitudinal surveys of radon (222Rn) activities at three different flow conditions. A 222Rn mass balance model, which integrates groundwater and spring water end member 222Rn activities and longitudinal 222Rn distributions in river water, shows that diffuse groundwater seepage represents about 16% of the total river baseflow, consistent with previous results obtained from ion (Ca2+, Cl-, SRP and Fe) mass balances and dye tracer methods. During high river stage, the contribution from seepage increases to 18-23% of the river flow. The spatial distribution of GW seepage is more variable in the upper 2.2-km reach of the river than the lower 2.8-km reach, regardless of river flow conditions. The upper reach has a narrower flood plain than the lower reach, which limits evapotranspiration and increases hydraulic gradients toward the river following storm events. Seepage in the lower reach is also limited by hydrologic damming by the receiving river, which inundates the floodplain during high flow conditions, and reduces the hydraulic head gradient. These results demonstrate the variable nature of seepage to a gaining river in both time and space and indicate that multiple synoptic analyses of GW seepage are required to assess seepage rates, determine time-averaged solute fluxes, and develop optimal management policies for riverine ecosystems.

  8. Use of hydrologic budgets and hydrochemistry to determine ground-water and surface-water interactions for Rapid Creek, Western South Dakota

    USGS Publications Warehouse

    Anderson, Mark T.

    1995-01-01

    The study of ground-water and surface-water interactions often employs streamflow-gaging records and hydrologic budgets to determine ground-water seepage. Because ground-water seepage usually is computed as a residual in the hydrologic budget approach, all uncertainty of measurement and estimation of budget components is associated with the ground-water seepage. This uncertainty can exceed the estimate, especially when streamflow and its associated error of measurement, is large relative to other budget components. In a study of Rapid Creek in western South Dakota, the hydrologic budget approach with hydrochemistry was combined to determine ground-water seepage. The City of Rapid City obtains most of its municipal water from three infiltration galleries (Jackson Springs, Meadowbrook, and Girl Scout) constructed in the near-stream alluvium along Rapid Creek. The reach of Rapid Creek between Pactola Reservoir and Rapid City and, in particular the two subreaches containing the galleries, were studied intensively to identify the sources of water to each gallery. Jackson Springs Gallery was found to pump predominantly ground water with a minor component of surface water. Meadowbrook and Girl Scout Galleries induce infiltration of surface water from Rapid Creek but also have a significant component of ground water.

  9. Geophysical and Hydrologic Studies of Lake Seepage Variability.

    PubMed

    Toran, Laura; Nyquist, Jonathan; Rosenberry, Donald; Gagliano, Michael; Mitchell, Natasha; Mikochik, James

    2015-01-01

    Variations in lake seepage were studied along a 130 m shoreline of Mirror Lake NH. Seepage was downward from the lake to groundwater; rates measured from 28 seepage meters varied from 0 to -282 cm/d. Causes of this variation were investigated using electrical resistivity surveys and lakebed sediment characterization. Two-dimensional (2D) resistivity surveys showed a transition in lakebed sediments from outwash to till that correlated with high- and low-seepage zones, respectively. However, the 2D survey was not able to predict smaller scale variations within these facies. In the outwash, fast seepage was associated with permeability variations in a thin (2 cm) layer of sediments at the top of the lakebed. In the till, where seepage was slower than that in the outwash, a three-dimensional resistivity survey mapped a point of high seepage associated with heterogeneity (lower resistivity and likely higher permeability). Points of focused flow across the sediment-water interface are difficult to detect and can transmit a large percentage of total exchange. Using a series of electrical resistivity geophysical methods in combination with hydrologic data to locate heterogeneities that affect seepage rates can help guide seepage meter placement. Improving our understanding of the causes and types of heterogeneity in lake seepage will provide better data for lake budgets and prediction of mass transfer of solutes or contaminants between lakes and groundwater.

  10. Geophysical and hydrologic studies of lake seepage variability

    USGS Publications Warehouse

    Toran, Laura; Nyquist, Jonathan E.; Rosenberry, Donald O.; Gagliano, Michael P.; Mitchell, Natasha; Mikochik, James

    2014-01-01

    Variations in lake seepage were studied along a 130 m shoreline of Mirror Lake NH. Seepage was downward from the lake to groundwater; rates measured from 28 seepage meters varied from 0 to −282 cm/d. Causes of this variation were investigated using electrical resistivity surveys and lakebed sediment characterization. Two-dimensional (2D) resistivity surveys showed a transition in lakebed sediments from outwash to till that correlated with high- and low-seepage zones, respectively. However, the 2D survey was not able to predict smaller scale variations within these facies. In the outwash, fast seepage was associated with permeability variations in a thin (2 cm) layer of sediments at the top of the lakebed. In the till, where seepage was slower than that in the outwash, a three-dimensional resistivity survey mapped a point of high seepage associated with heterogeneity (lower resistivity and likely higher permeability). Points of focused flow across the sediment–water interface are difficult to detect and can transmit a large percentage of total exchange. Using a series of electrical resistivity geophysical methods in combination with hydrologic data to locate heterogeneities that affect seepage rates can help guide seepage meter placement. Improving our understanding of the causes and types of heterogeneity in lake seepage will provide better data for lake budgets and prediction of mass transfer of solutes or contaminants between lakes and groundwater.

  11. Seepage through a hazardous-waste trench cover

    USGS Publications Warehouse

    Healy, R.W.

    1989-01-01

    Water movement through a waste-trench cover under natural conditions at a low-level radioactive waste disposal site in northwestern Illinois was studied from July 1982 to June 1984, using tensiometers, a moisture probe, and meteorological instruments. Four methods were used to estimate seepage: the Darcy, zero-flux plane, surface-based water-budget, and groundwater-based water-budget methods. Annual seepage estimates ranged from 48 to 216 mm (5-23% of total precipitation), with most seepage occurring in spring. The Darcy method, although limited in accuracy by uncertainty in hydraulic conductivity, was capable of discretizing seepage in space and time and indicated that seepage varied by almost an order of magnitude across the width of the trench. Lowest seepage rates occurred near the center of the cover, where seepage was gradual. Highest rates occurred along the edge of the cover, where seepage was highly episodic, with 84% of the total there being traced to wetting fronts from 28 individual storms. Limitations of the zero-flux-plane method were severe enough for the method to be judged inappropriate for use in this study.Water movement through a waste-trench cover under natural conditions at a low-level radioactive waste disposal site in northwestern Illinois was studied from July 1982 to June 1984, using tensiometers, a moisture probe, and meteorological instruments. Four methods were used to estimate seepage: the Darcy, zero-flux plane, surface-based water-budget, and groundwater-based water-budget methods. Annual seepage estimates ranged from 48 to 216mm (5-23% of total precipitation), with most seepage occurring in spring. The Darcy method, although limited in accuracy by uncertainty in hydraulic conductivity, was capable of discretizing seepage in space and time and indicated that seepage varied by almost an order of magnitude across the width of the trench. Lowest seepage rates occurred near the center of the cover, where seepage was gradual. Highest

  12. Potential incremental seepage losses in an alluvial channel in the Rio Grande Basin, New Mexico

    USGS Publications Warehouse

    Gold, R.L.

    1985-01-01

    A two-dimensional, digital, cross-sectional model was used to simulate seepage of water from an alluvial channel, which had the general characteristic of the Rio Grande channel, into the underlying alluvium within the reach from Cochiti Dam to Elephant Butte Reservoir. Seepage rates were determined for losing and gaining reaches, and reaches affected by pumping of ground water. The seepage rates were computed for stream surcharges (height of additional water applied on top of base flow) ranging from 0.5 foot to 3 feet and for application periods ranging from 1 to 100 days. The net seepage rates, which were nearly identical for each type of reach, ranged from 0.0 cubic foot per second per mile of channel length for a 0.5 foot surcharge applied for 1 day to 0.37 cubic foot per second per mile of channel length for a 3 feet surcharge applied for 100 days, followed by a 180 day seepage return flow from the aquifer. (USGS)

  13. Field Analogues of Shallow-water Hydrocarbon Seepages in the Pleistocene Argille Azzurre Formation: the Chimneys Field of Enza River, Northern Apennines, Italy

    NASA Astrophysics Data System (ADS)

    Oppo, D.; Capozzi, R.; Dinelli, E.; Negri, A.; Montagna, P.; Picotti, V.; Scarponi, D.; Taviani, M.

    2012-12-01

    The geologically young Northern Apennines contain various natural seeps documenting a variability of reservoirs and fluids in terms of origin, age and evolution. Hydrocarbon and saline water seepages are controlled by the structures of the chain and the foredeep. In the geological record, the witness of these natural seepages are represented by authigenic carbonates. Their isotopic content allows to understand the carbon source and the processes of carbonate precipitation. The better known regional examples of Methane Derived Authigenic Carbonates (MDAC) and chemoherm build-ups, clustered in the Upper Miocene and Lower-Upper Pliocene successions, are formed in deep water (> 300 m) sediments. Occurrences in shallow water (shelf) settings have never been reported. Our case study describes the palisade chimneys field, recently exposed along the Enza riverbanks in the Northern Apennines in the Argille Azzurre Formation (blue mudstones) of Pleistocene age. The paleontological content (mainly bivalves) documents that this unit was deposited in an open marine muddy shelfal setting, in a bathymetric range of about 50-70 m, with local anoxic condition, documented by benthic foraminifer assemblages. The succession is biostratigraphically dated at the Early Pleistocene (Calabrian, nannoplancton zone MNN19e). A number of subvertical, metric-high columnar chimneys, ranging in diameter from 10 to 35 cm, in association with discontinuous planar carbonate concretions, intervening along the bedding planes, outcrop within the mudstones. Such concretions are clearly formed by the moderate cementation of the hosting pelitic sediments. The tubular concretions show central conduits running along the whole length, locally filled by sediments. The grain size within the concretions is homogeneous, both in the chimneys and planar concretions and irrespective of the bedding planes, suggesting a process of transport and homogenization prior to the cementation. Within the Enza river succession

  14. SEEPAGE, a new MODFLOW DRAIN package.

    PubMed

    Batelaan, O; De Smedt, F

    2004-01-01

    The prediction of the location of ground water discharge areas is a key aspect for the protection and (re)development of ground water-dependent wetlands. Ground water discharge areas can be simulated with MODFLOW using the DRAIN package by setting the drain level equal to the topography, while the conductance is mostly set to an arbitrary high value. However, conceptual and practical problems arise in the calculation of the ground water discharge by the DRAIN package as calculated water tables above the land surface, difficult parameterization of the conductance, and large water balance errors. To overcome these problems, a new SEEPAGE package for MODFLOW is proposed. The basic idea of this package is an adaptable constant head cell. It has a variable head, unless the ground water rises above the seepage level, in which case it has a constant head cell. The estimation of the ground water discharge location along a homogeneous, isotropic, linear sloping profile is used to verify the model and to compare it to the DRAIN solution. In an application to three basins in Belgium, it is shown that the SEEPAGE package can be used in combination with the DRAIN package in situations where an upper boundary for a free water table and additional resistance for drainage is required. It is clearly demonstrated that the identification and delineation of regional ground water discharge areas is more accurate using the SEEPAGE package.

  15. POST-PROCESSING ANALYSIS FOR THC SEEPAGE

    SciTech Connect

    Y. SUN

    2004-09-29

    This report describes the selection of water compositions for the total system performance assessment (TSPA) model of results from the thermal-hydrological-chemical (THC) seepage model documented in ''Drift-Scale THC Seepage Model'' (BSC 2004 [DIRS 169856]). The selection has been conducted in accordance with ''Technical Work Plan for: Near-Field Environment and Transport: Coupled Processes (Mountain-Scale TH/THC/THM, Drift-Scale THC Seepage, and Post-Processing Analysis for THC Seepage) Report Integration'' (BSC 2004 [DIRS 171334]). This technical work plan (TWP) was prepared in accordance with AP-2.27Q, ''Planning for Science Activities''. Section 1.2.3 of the TWP describes planning information pertaining to the technical scope, content, and management of this report. The post-processing analysis for THC seepage (THC-PPA) documented in this report provides a methodology for evaluating the near-field compositions of water and gas around a typical waste emplacement drift as these relate to the chemistry of seepage, if any, into the drift. The THC-PPA inherits the conceptual basis of the THC seepage model, but is an independently developed process. The relationship between the post-processing analysis and other closely related models, together with their main functions in providing seepage chemistry information for the Total System Performance Assessment for the License Application (TSPA-LA), are illustrated in Figure 1-1. The THC-PPA provides a data selection concept and direct input to the physical and chemical environment (P&CE) report that supports the TSPA model. The purpose of the THC-PPA is further discussed in Section 1.2. The data selection methodology of the post-processing analysis (Section 6.2.1) was initially applied to results of the THC seepage model as presented in ''Drift-Scale THC Seepage Model'' (BSC 2004 [DIRS 169856]). Other outputs from the THC seepage model (DTN: LB0302DSCPTHCS.002 [DIRS 161976]) used in the P&CE (BSC 2004 [DIRS 169860

  16. Groundwater quality assessment/corrective action feasibility plan: New TNX Seepage Basin

    SciTech Connect

    Nichols, R.L.

    1989-12-05

    The New TNX Seepage Basin is located across River Road east of the TNX Area at the Savannah River Site. Currently the basin is out of service and is awaiting closure in accordance with the Consent Decree settled under Civil Act No. 1:85-2583. Groundwater monitoring data from the detection monitoring network around the New TNX Seepage Basin was recently analyzed using South Carolina Hazardous Waste Management Regulations R.61-79.264.92 methods to determine if groundwater downgradient of the New TNX Seepage Basin had been impacted. Results from the data analysis indicate that the groundwater has been impacted by inorganic constituents with no associated health risks. The impacts resulting from elevated levels of inorganic constituents, such as Mn, Na, and Total PO{sub 4} in the water table, do not pose a threat to human health and the environment.

  17. Effect of ground-water recharge on configuration of the water table beneath sand dunes and on seepage in lakes in the sandhills of Nebraska, U.S.A.

    USGS Publications Warehouse

    Winter, T.C.

    1986-01-01

    Analysis of water-level fluctuations in about 30 observation wells and 5 lakes in the Crescent Lake National Wildlife Refuge in the sandhills of Nebraska indicates water-table configuration beneath sand dunes in this area varies considerably, depending on the configuration of the topography of the dunes. If the topography of an interlake dunal area is hummocky, ground-water recharge is focused at topographic lows causing formation of water-table mounds. These mounds prevent ground-water movement from topographically high lakes to adjacent lower lakes. If a dune ridge is sharp, the opportunity for focused recharge does not exist, resulting in water-table troughs between lakes. Lakes aligned in descending altitudes, parallel to the principal direction of regional ground-water movement, generally have seepage from higher lakes toward lower lakes. ?? 1986.

  18. Solution of AntiSeepage for Mengxi River Based on Numerical Simulation of Unsaturated Seepage

    PubMed Central

    Ji, Youjun; Zhang, Linzhi; Yue, Jiannan

    2014-01-01

    Lessening the leakage of surface water can reduce the waste of water resources and ground water pollution. To solve the problem that Mengxi River could not store water enduringly, geology investigation, theoretical analysis, experiment research, and numerical simulation analysis were carried out. Firstly, the seepage mathematical model was established based on unsaturated seepage theory; secondly, the experimental equipment for testing hydraulic conductivity of unsaturated soil was developed to obtain the curve of two-phase flow. The numerical simulation of leakage in natural conditions proves the previous inference and leakage mechanism of river. At last, the seepage control capacities of different impervious materials were compared by numerical simulations. According to the engineering actuality, the impervious material was selected. The impervious measure in this paper has been proved to be effectible by hydrogeological research today. PMID:24707199

  19. Hydrogeochemistry of seepage water collected within the Youngcheon diversion tunnel, Korea: source and evolution of SO4-rich groundwater in sedimentary terrain

    NASA Astrophysics Data System (ADS)

    Chae, Gi-Tak; Yun, Seong-Taek; Kim, Sang-Ryul; Hahn, Chan

    2001-06-01

    In the Youngcheon Diversion Tunnel area, South Korea, 46 samples of tunnel seepage water (TSW) and borehole groundwater were collected from areas with sedimentary rocks (mainly sandstone and shale) and were examined for hydrogeochemical characteristics. The measured SO4 concentrations range widely from 7·7 to 942·0 mg/l, and exceed the Korean Drinking Water Standard (200 mg/l) in about half the samples. The TDS (total dissolved solid) content generally is high (171-1461 mg/l) from more shale-rich formations and also reflects varying degrees of water-rock interaction. The water is classified into three groups: Ca SO4 type (61% of the samples collected), Ca SO4 HCO3 type (15%) and Ca HCO3 type (24%). The Ca HCO3 type water (mean concentrations=369 mg/l Ca, 148 mg/l HCO3 and 23 mg/l SO4) reflected the simple reaction between CO2-recharged water and calcite, whereas the more SO4-rich nature of Ca SO4 type water (mean concentrations=153 mg/l Ca, 66 mg/l HCOwater was enhanced by the diffusion of oxygenated air through the fractures related to the tunnel's construction. The subsequent outgassing of CO

  20. Determining TOC in Waters

    ERIC Educational Resources Information Center

    Kehoe, Thomas J.

    1977-01-01

    The instrumental method for detecting total organic carbon (TOC) in water samples is detailed. The method's limitations are discussed and certain precautions that must be taken are emphasized. The subject of TOC versus COD and BOD is investigated and TOC is determined to be a valid indication of biological demand. (BT)

  1. Determining TOC in Waters

    ERIC Educational Resources Information Center

    Kehoe, Thomas J.

    1977-01-01

    The instrumental method for detecting total organic carbon (TOC) in water samples is detailed. The method's limitations are discussed and certain precautions that must be taken are emphasized. The subject of TOC versus COD and BOD is investigated and TOC is determined to be a valid indication of biological demand. (BT)

  2. The air-water exchange of C{sub 15}-C{sub 31} n-alkanes in a precipitation-dominated seepage lake.

    SciTech Connect

    Doskey, P. V.; Environmental Research

    2000-01-01

    The air-water exchange of semivolatile n-alkanes in Crystal Lake, a small precipitation-dominated seepage lake in northern Wisconsin, was investigated with modeling and mass balance approaches. The results suggest that atmospheric deposition contributes approximately 80% of the allochthonous input of n-alkanes to Crystal Lake. Atmospheric deposition accounts for about 50% of the total annual input of n-alkanes to Crystal Lake, and an additional 30% is contributed by in situ production of planktonic n-alkanes ({Sigma}C{sub 15}, C{sub 17}, C{sub 19}). Contributions to the particle dry flux of terrestrial n-alkanes ({Sigma}C{sub 25}, C{sub 27}, C{sub 29}, C{sub 31}) by pine pollen dispersal and by dry deposition of particles containing leaf waxes are similar in magnitude and constitute about 60% of the atmospheric input, with particle wet deposition being responsible for the remainder. Approximately 30% of the atmospheric input of the n-alkanes occurs during a two-week episode of pine pollen dispersal in spring. Concentration gradients between gaseous n-alkanes in the atmosphere and dissolved n-alkanes in the water column of Crystal Lake favor volatilization of n-alkanes from the lake surface; however, distributions of dissolved n-alkanes are characteristic of bacteria, and therefore are contained in organic matter and not available for air-water exchange. The estimated net atmospheric input of terrestrial n-alkanes is about 20% less than the settling sediment flux. Additional allochthonous sources of the terrestrial n-alkanes might include diffuse surface runoff or episodes of coarse-particle deposition. The discrepancies in the results from the modeling and mass balance approaches indicate that direct measurements of air-water exchange rates and measurements of the seasonal variations of particle size distributions in air and rain would greatly improve our ability to quantify air-water exchange rates of n-alkanes.

  3. H-Area Seepage Basins groundwater monitoring report

    SciTech Connect

    Not Available

    1992-09-01

    During second quarter 1992, tritium, nitrate, nonvolatile beta, total alpha-emitting radium (radium-224 and radium-226), gross alpha, mercury, lead, tetrachloroethylene, arsenic, and cadmium exceeded the US Environmental Protection Agency Primary Drinking Water Standards (PDWS) in groundwater samples from monitoring wells at the H-Area Seepage Basins (HASB) at the Savannah River Plant. This report gives the results of the analyses of groundwater from the H-Area Seepage Basin.

  4. Seepage to Collection Gallery Near Seacoast

    NASA Astrophysics Data System (ADS)

    Hunt, B.

    1985-03-01

    Conformal mapping is used to obtain a solution for seepage to a collection gallery (a horizontal ditch or slotted pipe) that is parallel to a seacoast. The solution permits calculation of the gallery drawdown that is required to withdraw any given flow rate and also allows calculation of the maximum flow rate that can be abstracted without causing sea water intrusion. The results are applied to a numerical example.

  5. Flow rate logging seepage meter

    NASA Technical Reports Server (NTRS)

    Reay, William G. (Inventor); Walthall, Harry G. (Inventor)

    1996-01-01

    An apparatus for remotely measuring and logging the flow rate of groundwater seepage into surface water bodies. As groundwater seeps into a cavity created by a bottomless housing, it displaces water through an inlet and into a waterproof sealed upper compartment, at which point, the water is collected by a collection bag, which is contained in a bag chamber. A magnet on the collection bag approaches a proximity switch as the collection bag fills, and eventually enables the proximity switch to activate a control circuit. The control circuit then rotates a three-way valve from the collection path to a discharge path, enables a data logger to record the time, and enables a pump, which discharges the water from the collection bag, through the three-way valve and pump, and into the sea. As the collection bag empties, the magnet leaves the proximity of the proximity switch, and the control circuit turns off the pump, resets the valve to provide a collection path, and restarts the collection cycle.

  6. Hydrological and Geological Features Contributing to a Seepage Event at Yucca Mountain

    NASA Astrophysics Data System (ADS)

    Fedors, R. W.; Smart, K. J.; Parrott, J. D.

    2006-05-01

    depressions or gullies). Analyses of the geological characteristics associated with the seepage location suggest the contributing factors that constrained seepage to this particular portion of the tunnel include (i) distance to the surface (i.e., ~60 m [200 ft]), (ii) gently dipping strata with distinct lithological contacts that may have laterally diverted water, (iii) faults and fractures, and (iv) downslope capping by rock units with different hydrological characteristics. This is an independent product of the CNWRA and does not necessarily reflect the views of regulatory positions of the NRC. The NRC staff views expressed herein are preliminary and do not constitute a final judgment or determination of the matters addressed or of the acceptability of a license application for a geologic repository at Yucca Mountain.

  7. Identifying the Cause of Toxicity of a Saline Mine Water

    PubMed Central

    van Dam, Rick A.; Harford, Andrew J.; Lunn, Simon A.; Gagnon, Marthe M.

    2014-01-01

    Elevated major ions (or salinity) are recognised as being a key contributor to the toxicity of many mine waste waters but the complex interactions between the major ions and large inter-species variability in response to salinity, make it difficult to relate toxicity to causal factors. This study aimed to determine if the toxicity of a typical saline seepage water was solely due to its major ion constituents; and determine which major ions were the leading contributors to the toxicity. Standardised toxicity tests using two tropical freshwater species Chlorella sp. (alga) and Moinodaphnia macleayi (cladoceran) were used to compare the toxicity of 1) mine and synthetic seepage water; 2) key major ions (e.g. Na, Cl, SO4 and HCO3); 3) synthetic seepage water that were modified by excluding key major ions. For Chlorella sp., the toxicity of the seepage water was not solely due to its major ion concentrations because there were differences in effects caused by the mine seepage and synthetic seepage. However, for M. macleayi this hypothesis was supported because similar effects caused by mine seepage and synthetic seepage. Sulfate was identified as a major ion that could predict the toxicity of the synthetic waters, which might be expected as it was the dominant major ion in the seepage water. However, sulfate was not the primary cause of toxicity in the seepage water and electrical conductivity was a better predictor of effects. Ultimately, the results show that specific major ions do not clearly drive the toxicity of saline seepage waters and the effects are probably due to the electrical conductivity of the mine waste waters. PMID:25180579

  8. Identifying the cause of toxicity of a saline mine water.

    PubMed

    van Dam, Rick A; Harford, Andrew J; Lunn, Simon A; Gagnon, Marthe M

    2014-01-01

    Elevated major ions (or salinity) are recognised as being a key contributor to the toxicity of many mine waste waters but the complex interactions between the major ions and large inter-species variability in response to salinity, make it difficult to relate toxicity to causal factors. This study aimed to determine if the toxicity of a typical saline seepage water was solely due to its major ion constituents; and determine which major ions were the leading contributors to the toxicity. Standardised toxicity tests using two tropical freshwater species Chlorella sp. (alga) and Moinodaphnia macleayi (cladoceran) were used to compare the toxicity of 1) mine and synthetic seepage water; 2) key major ions (e.g. Na, Cl, SO4 and HCO3); 3) synthetic seepage water that were modified by excluding key major ions. For Chlorella sp., the toxicity of the seepage water was not solely due to its major ion concentrations because there were differences in effects caused by the mine seepage and synthetic seepage. However, for M. macleayi this hypothesis was supported because similar effects caused by mine seepage and synthetic seepage. Sulfate was identified as a major ion that could predict the toxicity of the synthetic waters, which might be expected as it was the dominant major ion in the seepage water. However, sulfate was not the primary cause of toxicity in the seepage water and electrical conductivity was a better predictor of effects. Ultimately, the results show that specific major ions do not clearly drive the toxicity of saline seepage waters and the effects are probably due to the electrical conductivity of the mine waste waters.

  9. Infiltration and Seepage Through Fractured Welded Tuff

    SciTech Connect

    T.A. Ghezzehei; P.F. Dobson; J.A. Rodriguez; P.J. Cook

    2006-06-20

    The Nopal I mine in Pena Blanca, Chihuahua, Mexico, contains a uranium ore deposit within fractured tuff. Previous mining activities exposed a level ground surface 8 m above an excavated mining adit. In this paper, we report results of ongoing research to understand and model percolation through the fractured tuff and seepage into a mined adit both of which are important processes for the performance of the proposed nuclear waste repository at Yucca Mountain. Travel of water plumes was modeled using one-dimensional numerical and analytical approaches. Most of the hydrologic properly estimates were calculated from mean fracture apertures and fracture density. Based on the modeling results, we presented constraints for the arrival time and temporal pattern of seepage at the adit.

  10. Seepage and seepage gradients in an homogeneous, isotropic aquifer with drains as a function of soil properties and flow region geometry

    USDA-ARS?s Scientific Manuscript database

    Seepage and seepage gradients are important parameters in soil erosion processes and water quality problems on agricultural land. Traditionally, surface overland flow is viewed as one of the major soil erosive agents on those areas. In recent years, the role of the subsurface flow regime is increasi...

  11. Modeling Coupled Evaporation and Seepage in Ventilated Cavities

    SciTech Connect

    T. Ghezzehei; R. Trautz; S. Finsterle; P. Cook; C. Ahlers

    2004-07-01

    Cavities excavated in unsaturated geological formations are important to activities such as nuclear waste disposal and mining. Such cavities provide a unique setting for simultaneous occurrence of seepage and evaporation. Previously, inverse numerical modeling of field liquid-release tests and associated seepage into cavities were used to provide seepage-related large-scale formation properties by ignoring the impact of evaporation. The applicability of such models was limited to the narrow range of ventilation conditions under which the models were calibrated. The objective of this study was to alleviate this limitation by incorporating evaporation into the seepage models. We modeled evaporation as an isothermal vapor diffusion process. The semi-physical model accounts for the relative humidity, temperature, and ventilation conditions of the cavities. The evaporation boundary layer thickness (BLT) over which diffusion occurs was estimated by calibration against free-water evaporation data collected inside the experimental cavities. The estimated values of BLT were 5 to 7 mm for the open underground drifts and 20 mm for niches closed off by bulkheads. Compared to previous models that neglected the effect of evaporation, this new approach showed significant improvement in capturing seepage fluctuations into open cavities of low relative humidity. At high relative-humidity values (greater than 85%), the effect of evaporation on seepage was very small.

  12. Chemical Properties of Pore Water and Sediment at Three Wetland Sites Near the F- and H-Area Seepage Basins, Savannah River Site

    SciTech Connect

    Friday, G.P.

    2001-05-15

    In 1980, vegetative stress and arboreal mortality in wetland plant communities down-gradient from the F- and H-Area seepage basins were detected using aerial imagery. By 1988, approximately six acres in H-Area and four acres in F-Area had been adversely impacted. Today, wetland plant communities have become well established at the H-Area tree-kill zone.

  13. Impact of Rock Bolts on Seepage

    SciTech Connect

    F. C. Ahlers

    2001-06-01

    Characterization of seepage into drifts in unsaturated fractured tuff is a key factor for assessing the long-term viability of the proposed high level nuclear waste repository at Yucca Mountain. Rock bolts are among the methods proposed for ground control in the emplacement drifts. They may provide a conduit whereby percolating water that would otherwise bypass the drift will seep into the drift. The objective of this study is to assess the impact that the use of rock bolts may have on seepage. The impact of rock bolts on seepage is studied using a numerical model that is finely discretized around the rock bolt. There are several sources of uncertainty and variability with respect to the flow system around the drift and rock bolt. There is uncertainty about the capillary strength of the fractures around the drift. There is also uncertainty about how the permeability and capillary strength of the grout used to cement the steel rock bolts into the bolt holes will change over time. There is variability expected in the percolation rates incident upon the drifts depending on location. The uncertainty and variability of these parameters are approached by evaluating the rock bolt impact over a range of values for several model parameters. It is also important to consider where the last fracture capable of carrying flow away from the rock bolt intersects the rock bolt. Three models are used where the last fracture is 0, 10 and 50 cm above the drift.

  14. Role of tectonic stress in seepage evolution along the gas hydrate-charged Vestnesa Ridge, Fram Strait

    NASA Astrophysics Data System (ADS)

    Plaza-Faverola, A.; Bünz, S.; Johnson, J. E.; Chand, S.; Knies, J.; Mienert, J.; Franek, P.

    2015-02-01

    Methane expulsion from the world ocean floor is a broadly observed phenomenon known to be episodic. Yet the processes that modulate seepage remain elusive. In the Arctic offshore west Svalbard, for instance, seepage at 200-400 m water depth may be explained by ocean temperature-controlled gas hydrate instabilities at the shelf break, but additional processes are required to explain seepage in permanently cold waters at depths >1000 m. We discuss the influence of tectonic stress on seepage evolution along the ~100 km long hydrate-bearing Vestnesa Ridge in Fram Strait. High-resolution P-Cable 3-D seismic data revealed fine-scale (>10 m width) near-vertical faults and fractures controlling seepage distribution. Gas chimneys record multiple seepage events coinciding with glacial intensification and active faulting. The faults document the influence of nearby tectonic stress fields in seepage evolution along this deepwater gas hydrate system for at least the last ~2.7 Ma.

  15. Hydrological and chemical estimates of the water balance of a closed-basin lake in north central Minnesota

    USGS Publications Warehouse

    LaBaugh, J.W.; Winter, T.C.; Rosenberry, D.O.; Schuster, P.F.; Reddy, M.M.; Aiken, G.R.

    1997-01-01

    Chemical mass balances for sodium, magnesium, chloride, dissolved organic carbon, and oxygen 18 were used to estimate groundwater seepage to and from Williams Lake, Minnesota, over a 15-month period, from April 1991 through June 1992. Groundwater seepage to the lake and seepage from the lake to groundwater were determined independently using a flow net approach using data from water table wells installed as part of the study. Hydrogeological analysis indicated groundwater seepage to the lake accounted for 74% of annual water input to the lake; the remainder came from atmospheric precipitation, as determined from a gage in the watershed and from nearby National Weather Service gages. Seepage from the lake accounted for 69% of annual water losses from the lake; the remainder was removed by evaporation, as determined by the energy budget method. Calculated annual water loss exceeded calculated annual water gain, and this imbalance was double the value of the independently measured decrease in lake volume. Seepage to the lake determined from oxygen 18 was larger (79% of annual water input) than that determined from the flow net approach and made the difference between calculated annual water gain and loss consistent with the independently measured decrease in lake volume. Although the net difference between volume of seepage to the lake and volume of seepage from the lake was 1% of average lake volume, movement of water into and out of the lake by seepage represented an annual exchange of groundwater with the lake equal to 26-27% of lake volume. Estimates of seepage to the lake from sodium, magnesium, chloride, and dissolved organic carbon did not agree with the values determined from flow net approach or oxygen 18. These results indicated the importance of using a combination of hydrogeological and chemical approaches to define volume of seepage to and from Williams Lake and identify uncertainties in chemical fluxes.

  16. Air Compressibility Effect on Bouwer and Rice Seepage Meter.

    PubMed

    Peng, Xin; Zhan, Hongbin

    2017-07-17

    Measuring a disconnected streambed seepage flux using a seepage meter can give important streambed information and help understanding groundwater-surface water interaction. In this study, we provide a correction for calculating the seepage flux rate with the consideration of air compressibility inside the manometer of the Bouwer and Rice seepage meter. We notice that the effect of air compressibility in the manometer is considerably larger when more air is included in the manometer. We find that the relative error from neglecting air compressibility can be constrained within 5% if the manometer of the Bouwer and Rice seepage meter is shorter than 0.8 m and the experiment is done in a suction mode in which air is pumped out from the manometer before the start of measurement. For manometers longer than 0.8 m, the relative error will be larger than 5%. It may be over 10% if the manometer height is longer than 1.5 m and the experiment is done in a no-suction mode, in which air is not pumped out from the manometer before the start of measurement. © 2017, National Ground Water Association.

  17. Water Quality and Hydrology of Whitefish (Bardon) Lake, Douglas County, Wisconsin, With Special Emphasis on Responses of an Oligotrophic Seepage Lake to Changes in Phosphorus Loading and Water Level

    USGS Publications Warehouse

    Robertson, Dale M.; Rose, William J.; Juckem, Paul F.

    2009-01-01

    Whitefish Lake, which is officially named Bardon Lake, is an oligotrophic, soft-water seepage lake in northwestern Wisconsin, and classified by the Wisconsin Department of Natural Resources as an Outstanding Resource Water. Ongoing monitoring of the lake demonstrated that its water quality began to degrade (increased phosphorus and chlorophyll a concentrations) around 2002 following a period of high water level. To provide a better understanding of what caused the degradation in water quality, and provide information to better understand the lake and protect it from future degradation, the U.S. Geological Survey did a detailed study from 2004 to 2008. The goals of the study were to describe the past and present water quality of the lake, quantify water and phosphorus budgets for the lake, simulate the potential effects of changes in phosphorus inputs on the lake's water quality, analyze changes in the water level in the lake since 1900, and relate the importance of changes in climate and changes in anthropogenic (human-induced) factors in the watershed to the water quality of the lake. Since 1998, total phosphorus concentrations increased from near the 0.005-milligrams per liter (mg/L) detection limit to about 0.010 mg/L in 2006, and then decreased slightly in 2007-08. During this time, chlorophyll a concentrations and Secchi depths remained relatively stable at about 1.5 micrograms per liter (ug/L) and 26 feet, respectively. Whitefish Lake is typically classified as oligotrophic. Because the productivity in Whitefish Lake is limited by phosphorus, phosphorus budgets were constructed for the lake. Because it was believed that much of its phosphorus comes from the atmosphere, phosphorus deposition was measured in this study. Phosphorus input from the atmosphere was greater than computed based on previously reported wetfall phosphorus concentrations. The concentrations and deposition rates can be used to estimate atmospheric loading in future lake studies. The

  18. Seepage into an Underground Opening Constructed in Unsaturated Fractured Rock Under Evaporative Conditions

    SciTech Connect

    R. C. Trautz; Joseph S. Y. Wang

    2001-06-07

    Liquid-release tests, performed in boreholes above an underground opening constructed in unsaturated fractured rock, are used in this study to evaluate seepage into a waste emplacement drift. Evidence for the existence of a capillary barrier at the ceiling of the drift is presented, based on field observations (including spreading of the wetting front across the ceiling and water movement up fractures exposed in the ceiling before seepage begins). The capillary barrier mechanism has the potential to divert water around the opening, resulting in no seepage when the percolation flux is at or below the seepage threshold flux. Liquid-release tests are used to demonstrate that a seepage threshold exists and to measure the magnitude of the seepage threshold flux for three test zones that seeped. The seepage data are interpreted using analytical techniques to estimate the test-specific strength of the rock capillary forces ({alpha}{sup -1}) that prevent water from seeping into the drift. Evaporation increases the seepage threshold flux making it more difficult for water to seep into the drift and producing artificially inflated {alpha}{sup -1} values. With adjustments for evaporation, the minimum test-specific threshold is 1,600 mm/yr with a corresponding {alpha}{sup -1} of 0.027 m.

  19. Temporal constraints on hydrate-controlled methane seepage off Svalbard.

    PubMed

    Berndt, C; Feseker, T; Treude, T; Krastel, S; Liebetrau, V; Niemann, H; Bertics, V J; Dumke, I; Dünnbier, K; Ferré, B; Graves, C; Gross, F; Hissmann, K; Hühnerbach, V; Krause, S; Lieser, K; Schauer, J; Steinle, L

    2014-01-17

    Methane hydrate is an icelike substance that is stable at high pressure and low temperature in continental margin sediments. Since the discovery of a large number of gas flares at the landward termination of the gas hydrate stability zone off Svalbard, there has been concern that warming bottom waters have started to dissociate large amounts of gas hydrate and that the resulting methane release may possibly accelerate global warming. Here, we corroborate that hydrates play a role in the observed seepage of gas, but we present evidence that seepage off Svalbard has been ongoing for at least 3000 years and that seasonal fluctuations of 1° to 2°C in the bottom-water temperature cause periodic gas hydrate formation and dissociation, which focus seepage at the observed sites.

  20. Geoelectric monitoring of seepage in porous media with engineering applications to earthen dams

    NASA Astrophysics Data System (ADS)

    Ikard, Scott

    A monitoring methodology is developed for investigating seepage and internal erosion in earthen dams with time-lapse measurements of self-potential anomalies associated with conservative salt and non-conservative heat tracer migration in the subsurface. The method allows for 1) detecting seepage zones in earthen dams and determining the preferential flow paths through seepage zones in a non-invasive manner from the ground surface, 2) monitoring the transient evolution of seepage path geometry, flow velocity, and permeability in real-time if high frequency measurements can be made, and 3) long-term non-invasive monitoring with wired or wireless sensors The method is first theoretically developed and tested in a laboratory using a conservative tracer, and then demonstrated at a 12 m high, 100 m long leaking earthen dam with complex, unknown seepage paths. The method is shown to be capable of rapidly detecting seepage zones discovered during a reconnaissance survey, and delineates the predominant seepage directions through the dam from the time-lapse self-potential anomalies. The time-lapse monitoring approach ensures improved spatial resolution, increased measurement frequencies, and improved data analysis capabilities relative to traditional approaches to seepage detection, and a cost-reduction for the application of this methodology is anticipated to follow advancements in wireless sensing and monitoring technologies. This method is designed to be a more cost-effective means of interrogating earthen dams and levees to answer questions such as: Is the dam safe? What are the geometries of the seepage zones inside of the dam, and over what spatial scale does anomalous seepage occur? What are preferential paths through the seepage zones? Is internal erosion actively occurring? At what rates are the geometries, permeabilities and flow rates of preferential seepage paths evolving?

  1. Liquid chromatographic determination of water

    DOEpatents

    Fortier, Nancy E.; Fritz, James S.

    1990-11-13

    A sensitive method for the determination of water in the presence of common interferences is presented. The detection system is based on the effect of water on the equilibrium which results from the reaction aryl aldehydes, such as cinnamaldehyde and methanol in the eluent to form cinnamaldehyde dimethylacetal, plus water. This equilibrium is shifted in a catalytic atmosphere of a hydrogen ion form past column reactor. The extent of the shift and the resulting change in absorbance are proportional to the amount of water present.

  2. Liquid chromatographic determination of water

    DOEpatents

    Fortier, N.E.; Fritz, J.S.

    1990-11-13

    A sensitive method for the determination of water in the presence of common interferences is presented. The detection system is based on the effect of water on the equilibrium which results from the reaction aryl aldehydes, such as cinnamaldehyde and methanol in the eluent to form cinnamaldehyde dimethylacetal, plus water. This equilibrium is shifted in a catalytic atmosphere of a hydrogen ion form past column reactor. The extent of the shift and the resulting change in absorbance are proportional to the amount of water present. 1 fig.

  3. An evaluation of seepage gains and losses in Indian Creek Reservoir, Ada County, Idaho, April 2010–November 2011

    USGS Publications Warehouse

    Williams, Marshall L.; Etheridge, Alexandra B.

    2013-01-01

    The U.S. Geological Survey, in cooperation with the Idaho Department of Water Resources, conducted an investigation on Indian Creek Reservoir, a small impoundment in east Ada County, Idaho, to quantify groundwater seepage into and out of the reservoir. Data from the study will assist the Idaho Water Resources Department’s Comprehensive Aquifer Management Planning effort to estimate available water resources in Ada County. Three independent methods were utilized to estimate groundwater seepage: (1) the water-budget method; (2) the seepage-meter method; and (3) the segmented Darcy method. Reservoir seepage was quantified during the periods of April through August 2010 and February through November 2011. With the water-budget method, all measureable sources of inflow to and outflow from the reservoir were quantified, with the exception of groundwater; the water-budget equation was solved for groundwater inflow to or outflow from the reservoir. The seepage-meter method relies on the placement of seepage meters into the bottom sediments of the reservoir for the direct measurement of water flux across the sediment-water interface. The segmented-Darcy method utilizes a combination of water-level measurements in the reservoir and in adjacent near-shore wells to calculate water-table gradients between the wells and the reservoir within defined segments of the reservoir shoreline. The Darcy equation was used to calculate groundwater inflow to and outflow from the reservoir. Water-budget results provided continuous, daily estimates of seepage over the full period of data collection, while the seepage-meter and segmented Darcy methods provided instantaneous estimates of seepage. As a result of these and other difference in methodologies, comparisons of seepage estimates provided by the three methods are considered semi-quantitative. The results of the water-budget derived estimates of seepage indicate seepage to be seasonally variable in terms of the direction and magnitude

  4. Drift natural convection and seepage at the Yucca Mountain repository

    NASA Astrophysics Data System (ADS)

    Halecky, Nicholaus Eugene

    The decay heat from radioactive waste that is to be disposed in the once proposed geologic repository at Yucca Mountain (YM) will significantly influence the moisture conditions in the fractured rock near emplacement tunnels (drifts). Additionally, large-scale convective cells will form in the open-air drifts and will serve as an important mechanism for the transport of vaporized pore water from the fractured rock, from the hot drift center to the cool drift end. Such convective processes would also impact drift seepage, as evaporation could reduce the build up of liquid water at the tunnel wall. Characterizing and understanding these liquid water and vapor transport processes is critical for evaluating the performance of the repository, in terms of water- induced canister corrosion and subsequent radionuclide containment. To study such processes, we previously developed and applied an enhanced version of TOUGH2 that solves for natural convection in the drift. We then used the results from this previous study as a time-dependent boundary condition in a high-resolution seepage model, allowing for a computationally efficient means for simulating these processes. The results from the seepage model show that cases with strong natural convection effects are expected to improve the performance of the repository, since smaller relative humidity values, with reduced local seepage, form a more desirable waste package environment.

  5. H-Area Seepage Basins: Groundwater quality assessment report, Savannah River Site. Second quarter, 1990

    SciTech Connect

    Not Available

    1990-09-01

    During the second quarter of 1990 the wells which make up the H-Area Seepage Basins (H-HWMF) monitoring network were sampled. Laboratory analyses were performed to measure levels of hazardous constituents, indicator parameters, tritium, nonvolatile beta, and gross alpha. A Gas Chromatograph Mass Spectrometer (GCMS) scan was performed on all wells sampled to determine any hazardous organic constituents present in the groundwater. The primary contaminants observed at wells monitoring the H-Area Seepage Basins are tritium, nitrate, mercury, gross alpha, nonvolatile beta, trichloroethylene (TCE), tetrachloroethylene, lead, cadmium, arsenic, and total radium. Concentrations of at least one of the following constituents: tritium, nitrate, total radium, gross alpha, nonvolatile beta, mercury, lead, cadmium, trichloroethylene chromium, and arsenic in excess of the primary drinking water standard (PDWS) were observed in at least one well monitoring the H-Area Seepage Basins. Elevated levels of tritium above the PDWS were exhibited in seventy-seven of the 105 (73%) groundwater monitoring wells. Elevated levels of nitrate in excess of the PDWS were exhibited in forty-four of the 105 (42%) monitoring wells.

  6. H-Area Seepage Basins: Groundwater quality assessment report, Savannah River Site

    SciTech Connect

    Not Available

    1990-09-01

    During the second quarter of 1990 the wells which make up the H-Area Seepage Basins (H-HWMF) monitoring network were sampled. Laboratory analyses were performed to measure levels of hazardous constituents, indicator parameters, tritium, nonvolatile beta, and gross alpha. A Gas Chromatograph Mass Spectrometer (GCMS) scan was performed on all wells sampled to determine any hazardous organic constituents present in the groundwater. The primary contaminants observed at wells monitoring the H-Area Seepage Basins are tritium, nitrate, mercury, gross alpha, nonvolatile beta, trichloroethylene (TCE), tetrachloroethylene, lead, cadmium, arsenic, and total radium. Concentrations of at least one of the following constituents: tritium, nitrate, total radium, gross alpha, nonvolatile beta, mercury, lead, cadmium, trichloroethylene chromium, and arsenic in excess of the primary drinking water standard (PDWS) were observed in at least one well monitoring the H-Area Seepage Basins. Elevated levels of tritium above the PDWS were exhibited in seventy-seven of the 105 (73%) groundwater monitoring wells. Elevated levels of nitrate in excess of the PDWS were exhibited in forty-four of the 105 (42%) monitoring wells.

  7. Method for estimating spatially variable seepage loss and hydraulic conductivity in intermittent and ephemeral streams

    USGS Publications Warehouse

    Niswonger, R.G.; Prudic, D.E.; Fogg, G.E.; Stonestrom, D.A.; Buckland, E.M.

    2008-01-01

    A method is presented for estimating seepage loss and streambed hydraulic conductivity along intermittent and ephemeral streams using streamflow front velocities in initially dry channels. The method uses the kinematic wave equation for routing streamflow in channels coupled to Philip's equation for infiltration. The coupled model considers variations in seepage loss both across and along the channel. Water redistribution in the unsaturated zone is also represented in the model. Sensitivity of the streamflow front velocity to parameters used for calculating seepage loss and for routing streamflow shows that the streambed hydraulic conductivity has the greatest sensitivity for moderate to large seepage loss rates. Channel roughness, geometry, and slope are most important for low seepage loss rates; however, streambed hydraulic conductivity is still important for values greater than 0.008 m/d. Two example applications are presented to demonstrate the utility of the method. Copyright 2008 by the American Geophysical Union.

  8. Seepage investigation of the Rio Grande from below Leasburg Dam, Leasburg, New Mexico, to above American Dam, El Paso, Texas, 2014

    USGS Publications Warehouse

    Briody, Alyse C.; Robertson, Andrew J.; Thomas, Nicole

    2016-03-22

    Seepage investigations have been conducted annually by the U.S. Geological Survey from 1988 to 1998 and from 2004 to the present (2014) along a 64-mile reach of the Rio Grande from below Leasburg Dam, Leasburg, New Mexico, to above American Dam, El Paso, Texas, as part of the Mesilla Basin monitoring program. Results of the investigation conducted in 2014 are presented in this report. The 2014 seepage investigation was conducted on February 11, 2014, during the low-flow conditions of the non-irrigation season. During the 2014 investigation, discharge was measured at 23 sites along the main-stem Rio Grande and 19 inflow sites within the study reach. Because of extended drought conditions affecting the basin, many sites along the Rio Grande (17 main-stem and 9 inflow) were observed to be dry in February 2014. Water-quality samples were collected during the seepage investigation at sites with flowing water as part of a long-term monitoring effort in the region.Net seepage gain or loss was computed for each subreach (the interval between two adjacent measurement locations along the river) by subtracting the discharge measured at the upstream location from the discharge measured at the closest downstream location along the river and then subtracting any inflow to the river within the subreach. An estimated gain or loss was determined to be meaningful when it exceeded the cumulative measurement uncertainty associated with the net seepage computation. The cumulative seepage loss in the 64-mile study reach in 2014 was 16.0 plus or minus 2.9 cubic feet per second.

  9. Remote semi-continuous flow rate logging seepage meter

    NASA Astrophysics Data System (ADS)

    Reay, William G.; Walthall, Harry G.

    1991-12-01

    The movement of groundwater and its associated solutes from upland regions was implicated in the degradation of receiving surface water bodies. Current efforts to directly measure this influx of water incorporate manually operated seepage meters which are hindered by severe limitations. A prototype seepage meter was developed by NASA Langley Research Center and Virginia Polytechnic Institute and State University that will allow for the semi-continuous collection and data logging of seepage flux across the sediment water interface. The meter is designed to operate at depths to 40 meters, and alleviate or minimize all disadvantages associated with traditional methods while remaining cost effective. The unit was designed to operate independently for time periods on the order of weeks with adjustable sample sequences depending upon hydrologic conditions. When used in conjunction with commercially available pressure transducers, this seepage meter allows for correlations to be made between groundwater discharge and tidal/sea state conditions in coastal areas. Field data from the Chesapeake Bay and Florida Bay systems are presented.

  10. Remote semi-continuous flow rate logging seepage meter

    NASA Technical Reports Server (NTRS)

    Reay, William G.; Walthall, Harry G.

    1991-01-01

    The movement of groundwater and its associated solutes from upland regions was implicated in the degradation of receiving surface water bodies. Current efforts to directly measure this influx of water incorporate manually operated seepage meters which are hindered by severe limitations. A prototype seepage meter was developed by NASA Langley Research Center and Virginia Polytechnic Institute and State University that will allow for the semi-continuous collection and data logging of seepage flux across the sediment water interface. The meter is designed to operate at depths to 40 meters, and alleviate or minimize all disadvantages associated with traditional methods while remaining cost effective. The unit was designed to operate independently for time periods on the order of weeks with adjustable sample sequences depending upon hydrologic conditions. When used in conjunction with commercially available pressure transducers, this seepage meter allows for correlations to be made between groundwater discharge and tidal/sea state conditions in coastal areas. Field data from the Chesapeake Bay and Florida Bay systems are presented.

  11. Incorporating seepage losses into the unsteady streamflow equations for simulating intermittent flow along mountain front streams

    USGS Publications Warehouse

    Niswonger, R.G.; Prudic, D.E.; Pohll, G.; Constantz, J.

    2005-01-01

    Seepage losses along numerous mountain front streams that discharge intermittently onto alluvial fans and piedmont alluvial plains are an important source of groundwater in the Basin and Range Province of the Western United States. Determining the distribution of seepage loss along mountain front streams is important when assessing groundwater resources of the region. Seepage loss along a mountain front stream in northern Nevada was evaluated using a one-dimensional unsteady streamflow model. Seepage loss was incorporated into the spatial derivatives of the streamflow equations. Because seepage loss from streams is dependent on stream depth, wetted perimeter, and streambed properties, a two-dimensional variably saturated flow model was used to develop a series of relations between seepage loss and stream depth for each reach. This method works when streams are separated from groundwater by variably saturated sediment. Two periods of intermittent flow were simulated to evaluate the modeling approach. The model reproduced measured flow and seepage losses along the channel. Seepage loss in the spring of 2000 was limited to the upper reaches on the alluvial plain and totaled 196,000 m3, whereas 64% of the seepage loss in the spring of 2004 occurred at the base of the alluvial plain and totaled 273,000 m3. A greater seepage loss at the base of the piedmont alluvial plain is attributed to increased streambed hydraulic conductivity caused by less armoring of the channel. The modeling approach provides a method for quantifying and distributing seepage loss along mountain front streams that cross alluvial fans or piedmont alluvial plains. Copyright 2005 by the American Geophysical Union.

  12. Determination of radium in water

    USGS Publications Warehouse

    Barker, Franklin Butt; Johnson, J.O.

    1964-01-01

    Radium isotopes are common radioactive constituents of natural waters. The concentration of radium-226 in potable water is of particular significance because this isotope is generally considered the most hazardous of all radionuclides with respect to ingestion. The approximate concentration of radium-226 is determined after coprecipitating radium with barium sulfate. The short-lived daughters of radium are allowed to grow for 10-12 days, then the alpha activity of the precipitate is measured and compared with that of a precipitate containing a known amount of radium-226. Concentrations of the individual alpha-emitting isotopes of radium-223, radium-224, and radium-226, are determined by coprecipitating radium first with lead sulfate, then with barium chloride, and finally with barium sulfate. This final precipitate is initially free of other alpha-emitting nuclides, thus permitting the isotopic composition to be determined by measuring the growth and decay of the alpha activity of the precipitate.

  13. Seepage investigation for Leap, South Ash, Wet Sandy, and Leeds creeks in the Pine Valley Mountains, Washington County, Utah, 1998

    USGS Publications Warehouse

    Wilberg, Dale E.; Swenson, Robert L.; Slaugh, Bradely A.; Howells, James H.; Christiansen, Howard K.

    2001-01-01

    Seepage loss-gain data were collected along four creeks (Leap, South Ash, Wet Sandy, and Leeds) that drain the eastern flank of the Pine Valley Mountains in southwestern Utah. Streamflow was measured at a minimum of eight sites on each of the four creeks during each of three (four on South Ash) seepage investigations at higher streamflows in May and June, and at lower streamflows during August, October, and November 1998. Only two reaches on Leap and Leeds Creeks showed a significant reversal of loss or gain trends between high and low streamflow where the difference in streamflow exceeded the measurement error. Error analyses were computed both for individual reaches between consecutive measurement sites and for composite reaches between specified, nonconsecutive measurement sites to determine if seepage losses or gains exceed the error associated with measurement of streamflow. Computed losses or gains at 31 individual reaches exceed the normalized measurement error; 16 were along channel reaches that traverse unconsolidated deposits, 7 were associated with reaches that traverse sedimentary rocks other than Navajo Sandstone, 6 were associated with reaches that traverse the Navajo Sandstone, and 2 were associated with reaches that traverse rocks of igneous origin. Composite reaches that encompass the outcrop of one of four hydrogeologic units (Navajo Sandstone, unconsolidated deposits, igneous rocks, or sedimentary rocks other than Navajo Sandstone) were used to compute the loss or gain based on the amount measured at the upstream and downstream nonconsecutive sites. For composite reaches that traverse outcrops of Navajo Sandstone, less water was measured at (or near) the downstream contact than at (or near) the upstream contact for 11 of the 13 seepage investigations. Of those 11 investigations with computed losses, the normalized difference (N d) was greater than the normalized error (Ne) for 6 investigations and confirms that a source of recharge to the Navajo

  14. Experimental study on the deterioration and natural remediation of the Ariake Sea tidal mud caused by the sea laver treatment acid practice and the upward seepage of pore water liquid

    NASA Astrophysics Data System (ADS)

    Du, Yan-Jun; Liu, Song-Yu; Hayashi, Shigenori

    2008-08-01

    This study presents a laboratory study of the following two aspects: (1) the influence of sea laver treatment acid on the geoenvironmental properties of Ariake Sea tidal mud, and (2) the natural remediation effect on the sea laver treatment acid contaminated Ariake Sea tidal mud caused by the upward seepage of pore water liquid in the mud. Firstly, the mechanisms of the transport of sea laver treatment acid in the Ariake Sea tidal mud and the generation mechanisms of the upward seepage flow in the Ariake Sea tidal mud are discussed. Secondly, a series of one-dimensional laboratory infiltration tests were carried out to investigate the deterioration of the Ariake Sea tidal mud caused by the sea laver acid treatment practice. Test results reveal that the acid treatment practice caused considerable change in the geochemical properties of the mud in terms of increase in sulfide content and decrease in pH value. After the treatment by the sea laver treatment acid, the sulfide content of the mud even exceeded the safe limit value for the benthos, which represents undesirable living condition for benthos. Thirdly, series of laboratory fresh seawater infiltration tests for the deteriorated Iida site mud were conducted to illustrate this natural remediation efficiency. It is found that with the infiltration of the fresh seawater, the sulfide content of the Iida site mud was considerably reduced and pH value increased to an acceptable range for benthos living in the tidal flat mud. With the increase in the infiltration time and the hydraulic gradient, the remediation efficiency could be increased.

  15. Seepage study of McLeod Creek and East Canyon Creek near Park City, Summit County, Utah, 2004

    USGS Publications Warehouse

    Wilkowske, C.D.

    2005-01-01

    Seepage investigations on McLeod Creek downstream of U.S. Geological Survey streamflow-gaging station McLeod Creek near Park City, Utah, and its confluence with Kimball Creek during the summer of 2004 indicate that this section of the creek is a gaining reach. The total seepage gains ranged from 1.8 to 2.7 cubic feet per second, or a 32 to 55 percent gain. The apparent average total seepage gain was 2.2 cubic feet per second, or an average 42 percent gain. Seepage investigations from the U.S. Geological Survey streamflow-gaging station at East Canyon Creek below I-80 Rest Stop near Park City, Utah, to the station at East Canyon Creek near Jeremy Ranch, Utah, indicate that this section of East Canyon Creek is a slightly losing reach. The total seepage losses ranged from -1.2 to -2.0 cubic feet per second. This is a loss of between -18 and -27 percent from discharge measured at the upstream gaging station. The apparent average total seepage loss for the reach was -1.0 cubic feet per second, or -18 percent. Seepage information also was obtained along East Canyon Creek by using water-temperature data recorded in three shallow streambed piezometers. Surface-water temperature also was recorded at these locations. These water-temperature profiles indicate a seepage loss at all three locations along East Canyon Creek. This seepage loss appears to decrease in September and October.

  16. Geophysical investigation of seepage beneath an earthen dam.

    PubMed

    Ikard, S J; Rittgers, J; Revil, A; Mooney, M A

    2015-01-01

    A hydrogeophysical survey is performed at small earthen dam that overlies a confined aquifer. The structure of the dam has not shown evidence of anomalous seepage internally or through the foundation prior to the survey. However, the surface topography is mounded in a localized zone 150 m downstream, and groundwater discharges from this zone periodically when the reservoir storage is maximum. We use self-potential and electrical resistivity tomography surveys with seismic refraction tomography to (1) determine what underlying hydrogeologic factors, if any, have contributed to the successful long-term operation of the dam without apparent indicators of anomalous seepage through its core and foundation; and (2) investigate the hydraulic connection between the reservoir and the seepage zone to determine whether there exists a potential for this success to be undermined. Geophysical data are informed by hydraulic and geotechnical borehole data. Seismic refraction tomography is performed to determine the geometry of the phreatic surface. The hydro-stratigraphy is mapped with the resistivity data and groundwater flow patterns are determined with self-potential data. A self-potential model is constructed to represent a perpendicular profile extending out from the maximum cross-section of the dam, and self-potential data are inverted to recover the groundwater velocity field. The groundwater flow pattern through the aquifer is controlled by the bedrock topography and a preferential flow pathway exists beneath the dam. It corresponds to a sandy-gravel layer connecting the reservoir to the downstream seepage zone.

  17. Mine seepage problems in drift mine operations

    SciTech Connect

    DeRossett, C.; Johnson, D.E.; Bradshaw, D.B.

    1996-12-31

    Extensive mining in the Eastern Kentucky Coal Region has occurred in coal deposits located above valley floors. Underground mines present unique stability problems resulting from the creation of mine pools in abandoned works. {open_quotes}Blowouts{close_quotes} occur when hydrostatic pressures result in the cataclysmic failure of an outcrop-barrier. Additionally, seepage from flooded works results in saturation of colluvium, which may ultimately mobilize as landslides. Several case studies of both landslides and blowouts illustrate that considerations should be taken into account to control or prevent these problems. Underground mine maps and seepage conditions at the individual sites were examined to determine the mine layouts, outcrop-barrier widths, and structure of the mine floors. Discharge monitoring points were established in and near the landslides. These studies depict how mine layout, operation, and geology influence drainage conditions. The authors suggest that mine designs should incorporate drainage control to insure long-term stability and limit liability. The goal of the post-mining drainage plan is control of the mine drainage, which will reduce the size of mine pools and lower the hydrostatic pressure. Recommendations are made as to several methods that may be useful in controlling mine drainage.

  18. Determination of radium in water

    SciTech Connect

    Hohorst, F.A.; Huntley, M.W.; Hartenstein, S.D.

    1995-10-01

    These detailed work instructions (DWIs) are tailored for the analysis of radium-226 and radium-228 in drinking water supplies from ground water and surface water sources and composites derived from them. The instructions have been adapted from several sources, including a draft EPA method. One objective was to minimize the generation of mixed wastes. Quantitative determinations of actinium-228 are made at 911 keV. The minimum detection level (MDL) for the gamma spectrometric measurements at this energy vary with matrix, volume, geometry, detector, background, and counting statistics. The range of MDL`s for current detectors is 0.07 to 0.5 Bq/sample. Quantitative determinations of radium-226 are made by counting the high energy alpha particles which radium-226 progeny emit using liquid scintillation counting (LSC). The minimum detectable activity (MDA) is 3.8 E-3 Bq/sample. The maximum concentration which may be counted on available instruments without dilution is about 2 E + 5 Bq/sample. Typically, this determination of radium in a 2 L sample has a yield of 80%. If radium-228 is determined using a 16 h count after 50 h grow-in, the typical MDL is 1 E-9 to 8 E-9 {mu}Ci/mL (1 to 8 pCi/L). If radium-226 is determined using a 2.5 h count after 150 h grow-in, the typical MDA is about 1 E-10 {mu}Ci/mL (0. 1 pCi/L).

  19. Electric-field response based experimental investigation of unsaturated soil slope seepage

    NASA Astrophysics Data System (ADS)

    Geng, Jishi; Sun, Qiang; Zhang, Yuchun; Yan, Changgen; Zhang, Weiqiang

    2017-03-01

    Rainfall is one of the important factors causing the failure of slope, such as the occurrence of transverse cracks and localized slumps. The process of rainfall seepage was studied with an indoor soil slope model based on the Network Parallel Electrical Method. The responses of geoelectric-field parameters were analyzed to infer the evolution process of rainfall seepage path. The variations of geoelectric-field parameters also contribute to our understanding of the behavior of groundwater seepage. The results show that the seepage velocity and seepage position of groundwater can be obtained according to the exciting current and primary field potential response characteristics of seepage field. The primary field potential, exciting current, spontaneous potential and apparent resistivity are sensitive to the water flow. When the position of the seepage surface reaches a certain electrode, the spontaneous potential, primary field potential and exciting current rapidly increase, while the apparent resistivity decreases gradually. The result of apparent resistivity can reflect the variation of the water content in the 3D structural soil slope and the position of infiltration surface. The results of study can provide the theoretical basis for studying the behavior of moisture flow in soil slope under rainfall condition.

  20. A seepage erosion sediment transport function and geometric headcut relationships for predicting seepage erosion undercutting

    USDA-ARS?s Scientific Manuscript database

    Seepage erosion is an important factor in hillslope instability and failure. However, predicting erosion by subsurface flow or seepage and incorporating its effects into stability models remain a challenge. Limitations exist with all existing seepage erosion sediment transport functions, including n...

  1. Simulating seepage into mine shafts and tunnels with MODFLOW.

    PubMed

    Zaidel, Jacob; Markham, Bradley; Bleiker, David

    2010-01-01

    In cases when an equivalent porous medium assumption is suitable for simulating groundwater flow in bedrock aquifers, estimation of seepage into underground mine workings (UMWs) can be achieved by specifying MODFLOW drain nodes at the contact between water bearing rock and dewatered mine openings. However, this approach results in significant numerical problems when applied to simulate seepage into an extensive network of UMWs, which often exist at the mine sites. Numerical simulations conducted for individual UMWs, such as a vertical shaft or a horizontal drift, showed that accurate prediction of seepage rates can be achieved by either applying grid spacing that is much finer than the diameter/width of the simulated openings (explicit modeling) or using coarser grid with cell sizes exceeding the characteristic width of shafts or drifts by a factor of 3. Theoretical insight into this phenomenon is presented, based on the so-called well-index theory. It is demonstrated that applying this theory allows to minimize numerical errors associated with MODFLOW simulation of seepage into UMWs on a relatively coarse Cartesian grid. Presented examples include simulated steady-state groundwater flow from homogeneous, heterogeneous, and/or anisotropic rock into a vertical shaft, a horizontal drift/cross-cut, a ramp, two parallel drifts, and a combined system of a vertical shaft connected to a horizontal drift.

  2. Shallow bedrock limits groundwater seepage-based headwater climate refugia

    USGS Publications Warehouse

    Briggs, Martin; Lane, John; Snyder, Craig D.; White, Eric A.; Johnson, Zachary; Nelms, David L.; Hitt, Nathaniel P.

    2017-01-01

    Groundwater/surface-water exchanges in streams are inexorably linked to adjacent aquifer dynamics. As surface-water temperatures continue to increase with climate warming, refugia created by groundwater connectivity is expected to enable cold water fish species to survive. The shallow alluvial aquifers that source groundwater seepage to headwater streams, however, may also be sensitive to seasonal and long-term air temperature dynamics. Depth to bedrock can directly influence shallow aquifer flow and thermal sensitivity, but is typically ill-defined along the stream corridor in steep mountain catchments. We employ rapid, cost-effective passive seismic measurements to evaluate the variable thickness of the shallow colluvial and alluvial aquifer sediments along a headwater stream supporting cold water-dependent brook trout (Salvelinus fontinalis) in Shenandoah National Park, VA, USA. Using a mean depth to bedrock of 2.6 m, numerical models predicted strong sensitivity of shallow aquifer temperature to the downward propagation of surface heat. The annual temperature dynamics (annual signal amplitude attenuation and phase shift) of potential seepage sourced from the shallow modeled aquifer were compared to several years of paired observed stream and air temperature records. Annual stream water temperature patterns were found to lag local air temperature by ∼8–19 d along the stream corridor, indicating that thermal exchange between the stream and shallow groundwater is spatially variable. Locations with greater annual signal phase lag were also associated with locally increased amplitude attenuation, further suggestion of year-round buffering of channel water temperature by groundwater seepage. Numerical models of shallow groundwater temperature that incorporate regional expected climate warming trends indicate that the summer cooling capacity of this groundwater seepage will be reduced over time, and lower-elevation stream sections may no longer serve as larger

  3. Evaluation of seepage from Chester Morse Lake and Masonry Pool, King County, Washington

    USGS Publications Warehouse

    Hidaka, F.T.; Garrett, Arthur Angus

    1967-01-01

    Hydrologic data collected in the Cedar and Snoqualmie River basins on the west slope of the Cascade Range have been analyzed to determine the amount of water lost by seepage from Chester Morse Lake and Masonry Pool and the. consequent gain by seepage to the Cedar and South Fork Snoqualmie Rivers. For water years 1957-64, average losses were about 220 cfs (cubic feet per second) while average gains were about 180 cfs in the Cedar River and 50 cfs in the South Fork Snoqualmie River. Streamflow and precipitation data for water years 1908-26 and 1930-F2 indicate that a change in runoff regimen occurred in Cedar and South Fork Snoqualmie Rivers after the Boxley Creek washout in December 1918. For water years 1919-26 and 1930-32, the flow of Cedar River near Landsburg averaged about 80 cfs less than it would have if the washout had not occurred. In contrast, the flow of South Fork Snoqualmie River at North Bend averaged about 60 cfs more than it would have.

  4. Utilizing Continuous Resistivity Profiling for Assessment and Characterization of Canal Seepage in El Paso's Lower Valley Irrigation Network System

    NASA Astrophysics Data System (ADS)

    Brown, W. A.; Sheng, Z.

    2009-12-01

    Annually, billions of gallons of water are lost through seepage along sections of the irrigation network. To conserve water, El Paso County Water Improvement District has been assessing seepage losses and investigating measures for reducing such losses. Resistivity techniques were used to identify areas of high seepage and provide information on locations along canals that need to be structurally modified in an effort to curb water lost through seepage. Several half mile sections were selected along canals with varying seepage rates to conduct electric resistivity surveys in order generate soil profiles during the non-irrigation and irrigation seasons. Two different multiple channel resistivity meters (The“OhmMapper and the Super Sting R8”) were used, which both allow a vertical resistivity profile to be collected using a single current transmission. The results presented are preliminary and we believe that upon completion findings will serve multiple purposes. Firstly, a better understanding of seepage patterns, seepage rate and its spatial variation can be obtained. Secondly, our findings could be used to produce geological profiles associated with seepage areas which will enable the irrigation district to develop guidelines for improving delivery efficiency, especially during drought. And thirdly, our results will be transferable to other areas of the state and will have a positive impact on the environment and the overall quality of life.

  5. The geochemistry characteristic and dating of cold seepage carbonates of the Pearl River Mouth Basin, eastern of South China Sea

    NASA Astrophysics Data System (ADS)

    Fang, Yunxin; Fu, Shaoying

    2015-04-01

    Cold seepage carbonates are usually formed by the interaction of methane oxidizing archaea, sulfate reducing bacteria and cold seepage which contain abundant venting hydrocarbon gases. The presence of cold seepage carbonates on the seabed is one of the evidences that the area exist venting hydrocarbon gases, which are usually result by the dissociation of gas hydrate. The cold seepage property and fluid flow rate can influence the oxidation-deoxidation environment of the bottom water and sediment. Many previous studies focused on the mineral composition, microstructure, elemental composition, isotope composition of the cold seepage carbonates and isotopic dating for the cold seepage carbonates. The isotopic dating for the cold seepage carbonates can provide the information of the gas hydrate formation and dissociation in some area of the South China Sea. High precision TIMS-U dating and 14C dating are used as routine method for the dating of the Quaternary carbonates and fossils. The cold seepage carbonates in the study include the samples collected by ROV on the seabed and the drilling for gas hydrate in the Pearl River Mouth Basin, eastern of the South China Sea. The authigenic carbonate occurred in different depth in the A, B and C drilling site. They may be represent different events of gas hydrate formation and dissociation in the Quaternary. The dating study for all the cold seepage carbonates can provide the relative accurate eras of the gas hydrate dissociation events in certain area of the South China Sea.

  6. Seepage and settlement monitoring for earth embankment dams using fully distributed sensing along optical fibers

    NASA Astrophysics Data System (ADS)

    Zhu, P. Y.; Zhou, Y.; Thévenaz, Luc; Jiang, G. L.

    2008-12-01

    A method for seepage and settlement monitoring in earth embankment dams using fully distributed sensing along optical fibres is proposed. A model is developed for simulating and monitoring seepage and settlement systems. This model relates the strains and the temperature changes to the fiber Brillouin gain spectrum in the embankment dam embedding the optical fiber sensors. The model consists of two parts. Submodel 1 addresses the simulation of seepage inside the embankment dam. Submodel 2 relates the measurement of the fiber Brillouin gain spectrum to the changes in temperature and strain inside the embankment dam. Both the changes in temperature and strain during the process are used to reveal serious seepages and settlements occurring inside the embankment dam. The continuously decreasing temperature curve shows an abrupt dramatic increasing rate, which shows that the change is not caused by the temperature of the seepage water but the strain. In this paper, as an example, a model filled with the soil from Yellow River is built and bare optical fibers are embedded under different soil layers near the seepage path. The simulated seepage flows under various flow rates are monitored using the optical fibers and measured by a DiTeSt -STA202 distributed temperature and strain analyzer. A partial settlement within the embankment dam model is observed.

  7. Fluid venting and seepage at accretionary ridges: the Four Way Closure Ridge offshore SW Taiwan

    NASA Astrophysics Data System (ADS)

    Klaucke, Ingo; Berndt, Christian; Crutchley, Gareth; Chi, Wu-Cheng; Lin, Saulwood; Muff, Sina

    2016-06-01

    Within the accretionary prism offshore SW Taiwan, widespread gas hydrate accumulations are postulated to occur based on the presence of a bottom simulating reflection. Methane seepage, however, is also widespread at accretionary ridges offshore SW Taiwan and may indicate a significant loss of methane bypassing the gas hydrate system. Four Way Closure Ridge, located in 1,500 m water depth, is an anticlinal ridge that would constitute an ideal trap for methane and consequently represents a site with good potential for gas hydrate accumulations. The analysis of high-resolution bathymetry, deep-towed sidescan sonar imagery, high-resolution seismic profiling and towed video observations of the seafloor shows that Four Way Closure Ridge is and has been a site of intensive methane seepage. Continuous seepage is mainly evidenced by large accumulations of authigenic carbonate precipitates, which appear to be controlled by the creation of fluid pathways through faulting. Consequently, Four Way Closure Ridge is not a closed system in terms of fluid migration and seepage. A conceptual model of the evolution of gas hydrates and seepage at accretionary ridges suggests that seepage is common and may be a standard feature during the geological development of ridges in accretionary prisms. The observation of seafloor seepage alone is therefore not a reliable indicator of exploitable gas hydrate accumulations at depth.

  8. Heterogeneous seepage at the Nopal I natural analogue site, Chihuahua, Mexico

    SciTech Connect

    Dobson, Patrick F.; Cook, Paul J.; Ghezzehei, Teamrat A.; Rodriguez, J. Alfredo; Villalba, Lourdes; de la Garza, Rodrigo

    2008-10-25

    An integrated field, laboratory, and modeling study of the Pena Blanca (Chihuahua, Mexico) natural analogue site is being conducted to evaluate processes that control the mobilization and transport of radionuclides from a uranium ore deposit. One component of this study is an evaluation of the potential for radionuclide transport through the unsaturated zone (UZ) via a seepage study in an adit at the Nopal I uranium mine, excavated 10 m below a mined level surface. Seasonal rainfall on the exposed level surface infiltrates into the fractured rhyolitic ash-flow tuff and seeps into the adit. An instrumented seepage collection system and local automated weather station permit direct correlation between local precipitation events and seepage within the Nopal I +00 adit. Monitoring of seepage within the adit between April 2005 and December 2006 indicates that seepage is highly heterogeneous with respect to time, location, and quantity. Within the back adit area, a few zones where large volumes of water have been collected are linked to fast flow path fractures (0-4 h transit times) presumably associated with focused flow. In most locations, however, there is a 1-6 month time lag between major precipitation events and seepage within the adit, with longer residence times observed for the front adit area. Seepage data obtained from this study will be used to provide input to flow and transport models being developed for the Nopal I hydrogeologic system.

  9. Three-dimensional imaging, change detection, and stability assessment during the centerline trench levee seepage experiment using terrestrial light detection and ranging technology, Twitchell Island, California, 2012

    USGS Publications Warehouse

    Bawden, Gerald W.; Howle, James; Bond, Sandra; Shriro, Michelle; Buck, Peter

    2014-01-01

    A full scale field seepage test was conducted on a north-south trending levee segment of a now bypassed old meander belt on Twitchell Island, California, to understand the effects of live and decaying root systems on levee seepage and slope stability. The field test in May 2012 was centered on a north-south trench with two segments: a shorter control segment and a longer seepage test segment. The complete length of the trench area measured 40.4 meters (m) near the levee centerline with mature trees located on the waterside and landside of the levee flanks. The levee was instrumented with piezometers and tensiometers to measure positive and negative porewater pressures across the levee after the trench was flooded with water and held at a constant hydraulic head during the seepage test—the results from this component of the experiment are not discussed in this report. We collected more than one billion three-dimensional light detection and ranging (lidar) data points before, during, and after the centerline seepage test to assess centimeter-scale stability of the two trees and the levee crown. During the seepage test, the waterside tree toppled (rotated 20.7 degrees) into the water. The landside tree rotated away from the levee by 5 centimeters (cm) at a height of 2 m on the tree. The paved surface of the levee crown had three regions that showed subsidence on the waterside of the trench—discussed as the northern, central, and southern features. The northern feature is an elongate region that subsided 2.1 cm over an area with an average width of 1.35 m that extends 15.8 m parallel to the trench from the northern end of the trench to just north of the trench midpoint, and is associated with a crack 1 cm in height that formed during the seepage test on the trench wall. The central subsidence feature is a semicircular region on the waterside of the trench that subsided by as much as 6.2 cm over an area 3.4 m wide and 11.2 m long. The southern feature is an elongate

  10. Estimated seepage rates from selected ditches, ponds, and lakes at the Camas National Wildlife Refuge, eastern Idaho.

    PubMed

    Rattray, Gordon W

    2017-12-01

    The Camas National Wildlife Refuge (Refuge) in eastern Idaho, established in 1937, contains wetlands, ponds, and wet meadows that are essential resting and feeding habitat for migratory birds and nesting habitat for waterfowl. Initially, natural sources of water supported these habitats. However, during the past few decades, changes in climate and surrounding land use have altered and reduced natural groundwater and surface-water inflows, resulting in a 5-meter decline in the water table and an earlier, and more frequent, occurrence of no flow in Camas Creek at the Refuge. Due to these changes in water availability, water management that includes extensive groundwater pumping is now necessary to maintain the wetlands, ponds, and wet meadows. These water management activities have proven to be inefficient and expensive, and the Refuge is seeking alternative water-management options that are more efficient and less expensive. More efficient water management at the Refuge may be possible through knowledge of the seepage rates from ditches, ponds, and lakes at the Refuge. With this knowledge, water-management efficiency may be improved by natural means through selective use of water bodies with the smallest seepage rates or through engineering efforts to minimize seepage losses from water bodies with the largest seepage rates. The U.S. Geological Survey performed field studies in 2015 and 2016 to estimate seepage rates for selected ditches, ponds, and lakes at the Refuge. Estimated seepage rates from ponds and lakes ranged over an order of magnitude, from 3.4 ± 0.2 to 103.0 ± 0.5 mm/d, with larger seepage rates calculated for Big Pond and Redhead Pond, intermediate seepage rates calculated for Two-way Pond, and smaller seepages rates calculated for the south arm of Sandhole Lake. Estimated seepage losses from two reaches of Main Diversion Ditch were 21 ± 2 and 17 ± 2 percent/km. These losses represent seepage rates of about 890 and 860 mm/d, which are one

  11. Estimated seepage rates from selected ditches, ponds, and lakes at the Camas National Wildlife Refuge, eastern Idaho

    USGS Publications Warehouse

    Rattray, Gordon W.

    2017-01-01

    The Camas National Wildlife Refuge (Refuge) in eastern Idaho, established in 1937, contains wetlands, ponds, and wet meadows that are essential resting and feeding habitat for migratory birds and nesting habitat for waterfowl. Initially, natural sources of water supported these habitats. However, during the past few decades, changes in climate and surrounding land use have altered and reduced natural groundwater and surface-water inflows, resulting in a 5-meter decline in the water table and an earlier, and more frequent, occurrence of no flow in Camas Creek at the Refuge. Due to these changes in water availability, water management that includes extensive groundwater pumping is now necessary to maintain the wetlands, ponds, and wet meadows.These water management activities have proven to be inefficient and expensive, and the Refuge is seeking alternative water-management options that are more efficient and less expensive. More efficient water management at the Refuge may be possible through knowledge of the seepage rates from ditches, ponds, and lakes at the Refuge. With this knowledge, water-management efficiency may be improved by natural means through selective use of water bodies with the smallest seepage rates or through engineering efforts to minimize seepage losses from water bodies with the largest seepage rates.The U.S. Geological Survey performed field studies in 2015 and 2016 to estimate seepage rates for selected ditches, ponds, and lakes at the Refuge. Estimated seepage rates from ponds and lakes ranged over an order of magnitude, from 3.4 ± 0.2 to 103.0 ± 0.5 mm/d, with larger seepage rates calculated for Big Pond and Redhead Pond, intermediate seepage rates calculated for Two-way Pond, and smaller seepages rates calculated for the south arm of Sandhole Lake. Estimated seepage losses from two reaches of Main Diversion Ditch were 21 ± 2 and 17 ± 2 percent/km. These losses represent seepage rates of about 890 and 860 mm/d, which are one

  12. H-Area Seepage Basins groundwater monitoring report. Second quarter 1992

    SciTech Connect

    Not Available

    1992-09-01

    During second quarter 1992, tritium, nitrate, nonvolatile beta, total alpha-emitting radium (radium-224 and radium-226), gross alpha, mercury, lead, tetrachloroethylene, arsenic, and cadmium exceeded the US Environmental Protection Agency Primary Drinking Water Standards (PDWS) in groundwater samples from monitoring wells at the H-Area Seepage Basins (HASB) at the Savannah River Plant. This report gives the results of the analyses of groundwater from the H-Area Seepage Basin.

  13. Lagoon Seepage Testing Report for Central Facilities Area (CFA) Sewage Lagoons at Idaho National Laboratory, Butte County, Idaho

    SciTech Connect

    Morrison, Bridger

    2014-09-01

    J-U-B ENGINEERS, Inc. (J-U-B) performed seepage tests on the CFA Wastewater Lagoons 1, 2, and 3 between August 26th and September 22nd, 2014. The lagoons were tested to satisfy the Idaho Department of Environmental Quality (DEQ) Rules (IDAPA 58.01.16) that require all lagoons be tested at a frequency of every 10 years and the Compliance Activity CA-141-03 in the DEQ Wastewater Reuse Permit for the CFA Sewage Treatment Plant (LA-000141-03). The lagoons were tested to determine if the average seepage rates are less than 0.25 in/day, the maximum seepage rate allowed for lagoons built prior to April 15, 2007. The average seepage rates were estimated for each lagoon and are given in Table-ES1. The average seepage rates for Lagoons 1 and 2 are less than the allowable seepage rate of 0.25 in/day. Lagoon 1 and 2 passed the seepage test and will not have to be tested again until the year 20241. However, the average seepage rate for Lagoon 3 appears to exceed the allowable seepage rate of 0.25 in/day which means the potential source for the excessive leakage should be investigated further.

  14. H-Area Seepage Basins groundwater monitoring report

    SciTech Connect

    Thompson, C.Y.

    1992-06-01

    During first quarter 1992, tritium, nitrate, nonvolatile beta, total alpha-emitting radium (radium-224 and radium-226), gross alpha, antimony, mercury, lead, tetrachloroethylene, arsenic, and cadmium exceeded the US Environmental Protection Agency Primary Drinking Water Standards (PDWS) in groundwater samples from monitoring wells at the H-Area Seepage Basins (HASB) at the Savannah River Site. This report presents and discusses the groundwater monitoring results in the H-Area for first quarter 1992.

  15. Impact of quaternary climate on seepage at Yucca Mountain, Nevada

    USGS Publications Warehouse

    Whelan, J.F.; Paces, J.B.; Neymark, L.A.; Schmitt, A.K.; Grove, M.

    2006-01-01

    Uranium-series ages, oxygen-isotopic compositions, and uranium contents were determined in outer growth layers of opal and calcitefrom 0.5- to 3-centimeter-thick mineral coatings hosted by lithophysal cavities in the unsaturated zone at Yucca Mountain, Nevada, the proposed site of a permanent repository for high-level radioactive waste. Micrometer-scale growth layering in the minerals was imaged using a cathodoluminescence detector on a scanning electron microscope. Determinations of the chemistry, ages, and delta oxygen-18 (??18O) values of the growth layers were conducted by electron microprobe analysis and secondary ion mass spectrometry techniques at spatial resolutions of 2 to about 20 micrometers (??m) and 25 to 40 ??m, respectively. Growth rates for the last 300 thousand years (k.y.) calculated from about 300 new high-resolution uranium-series ages range from approximately 0.5 to 1.5 ??m/k.y. for 1- to 3-centimeter-thick coatings, whereas coatings less than about 1-centimeter-thick have growth rates less than 0.5 ??m/k.y. At the depth of the proposed repository, correlations of uranium concentration and ??18O values with regional climate records indicate that unsaturated zone percolation and seepage water chemistries have responded to changes in climate during the last several hundred thousand years.

  16. Impact of Quaternary Climate on Seepage at Yucca Mountain, Nevada

    SciTech Connect

    J.F. Whelan; J.B. Paces; L.A. Neymark; A.K. Schmitt; M. Grove

    2006-03-17

    Uranium-series ages, oxygen-isotopic compositions, and uranium contents were determined in outer growth layers of opal and calcite from 0.5- to 3-centimeter-thick mineral coatings hosted by lithophysal cavities in the unsaturated zone at Yucca Mountain, Nevada, the proposed site of a permanent repository for high-level radioactive waste. Micrometer-scale growth layering in the minerals was imaged using a cathodoluminescence detector on a scanning electron microscope. Determinations of the chemistry, ages, and delta oxygen-18 values of the growth layers were conducted by electron microprobe analysis and secondary ion mass spectrometry techniques at spatial resolutions of 1 to about 20 micrometers ({micro}m) and 25 to 40 micrometers, respectively. Growth rates for the last 300 thousand years (k.y.) calculated from about 300 new high-resolution uranium-series ages range from approximately 0.5 to 1.5 {micro}m/k.y. for 1- to 3-centimeter-thick coatings, whereas coatings less than about I-centimeter-thick have growth rates less than 0.5 {micro}m/k.y. At the depth of the proposed repository, correlations of uranium concentration and delta oxygen-18 values with regional climate records indicate that unsaturated zone percolation and seepage water chemistries have responded to changes in climate during the last several hundred thousand years.

  17. Effects of recharge, Upper Floridan aquifer heads, and time scale on simulated ground-water exchange with Lake Starr, a seepage lake in central Florida

    USGS Publications Warehouse

    Swancar, Amy; Lee, Terrie Mackin

    2003-01-01

    Lake Starr and other lakes in the mantled karst terrain of Florida's Central Lake District are surrounded by a conductive surficial aquifer system that receives highly variable recharge from rainfall. In addition, downward leakage from these lakes varies as heads in the underlying Upper Floridan aquifer change seasonally and with pumpage. A saturated three-dimensional finite-difference ground-water flow model was used to simulate the effects of recharge, Upper Floridan aquifer heads, and model time scale on ground-water exchange with Lake Starr. The lake was simulated as an active part of the model using high hydraulic conductivity cells. Simulated ground-water flow was compared to net ground-water flow estimated from a rigorously derived water budget for the 2-year period August 1996-July 1998. Calibrating saturated ground-water flow models with monthly stress periods to a monthly lake water budget will result in underpredicting gross inflow to, and leakage from, ridge lakes in Florida. Underprediction of ground-water inflow occurs because recharge stresses and ground-water flow responses during rainy periods are averaged over too long a time period using monthly stress periods. When inflow is underestimated during calibration, leakage also is underestimated because inflow and leakage are correlated if lake stage is maintained over the long term. Underpredicted leakage reduces the implied effect of ground-water withdrawals from the Upper Floridan aquifer on the lake. Calibrating the weekly simulation required accounting for transient responses in the water table near the lake that generated the greater range of net ground-water flow values seen in the weekly water budget. Calibrating to the weekly lake water budget also required increasing the value of annual recharge in the nearshore region well above the initial estimate of 35 percent of the rainfall, and increasing the hydraulic conductivity of the deposits around and beneath the lake. To simulate the total

  18. Drift-Scale Coupled Processes (DST and THC Seepage) Models

    SciTech Connect

    P. Dixon

    2004-04-05

    The purpose of this Model Report (REV02) is to document the unsaturated zone (UZ) models used to evaluate the potential effects of coupled thermal-hydrological-chemical (THC) processes on UZ flow and transport. This Model Report has been developed in accordance with the ''Technical Work Plan for: Performance Assessment Unsaturated Zone'' (Bechtel SAIC Company, LLC (BSC) 2002 [160819]). The technical work plan (TWP) describes planning information pertaining to the technical scope, content, and management of this Model Report in Section 1.12, Work Package AUZM08, ''Coupled Effects on Flow and Seepage''. The plan for validation of the models documented in this Model Report is given in Attachment I, Model Validation Plans, Section I-3-4, of the TWP. Except for variations in acceptance criteria (Section 4.2), there were no deviations from this TWP. This report was developed in accordance with AP-SIII.10Q, ''Models''. This Model Report documents the THC Seepage Model and the Drift Scale Test (DST) THC Model. The THC Seepage Model is a drift-scale process model for predicting the composition of gas and water that could enter waste emplacement drifts and the effects of mineral alteration on flow in rocks surrounding drifts. The DST THC model is a drift-scale process model relying on the same conceptual model and much of the same input data (i.e., physical, hydrological, thermodynamic, and kinetic) as the THC Seepage Model. The DST THC Model is the primary method for validating the THC Seepage Model. The DST THC Model compares predicted water and gas compositions, as well as mineral alteration patterns, with observed data from the DST. These models provide the framework to evaluate THC coupled processes at the drift scale, predict flow and transport behavior for specified thermal-loading conditions, and predict the evolution of mineral alteration and fluid chemistry around potential waste emplacement drifts. The DST THC Model is used solely for the validation of the THC

  19. Seepage into drifts with mechanical degradation.

    PubMed

    Li, Guomin; Tsang, Chin-Fu

    2003-01-01

    Seepage into drifts in unsaturated tuff is an important issue for the long-term performance of the proposed nuclear waste repository at Yucca Mountain, Nevada. Drifts in which waste packages will be emplaced are subject to degradation in the form of rockfall from the drift ceiling, induced by stress-relief, seismic, or thermal effects. The objective of this study is to calculate seepage rates, for various drift-degradation scenarios and for different values of percolation flux, in the Topopah Spring middle nonlithophysal (Tptpmn) and the Topopah Spring lower lithophysal (Tptpll) units at Yucca Mountain. Seepage calculations are conducted by (1) defining a heterogeneous drift-scale permeability model with field data, (2) selecting calibrated parameters associated with the Tptpmn and Tptpll units, and (3) simulating seepage, based on detailed degraded-drift profiles obtained from a separate rock mechanics engineering analysis. The simulation results indicate (1) that the seepage threshold (i.e., the percolation flux at which seepage first occurs) is not significantly changed by drift degradation and (2) the degradation-induced increase in seepage above the threshold is influenced probably more by the shape of the cavity created by rockfall than by rockfall volume.

  20. Seepage study of six canals in Salt Lake County, Utah, 1982-1983

    USGS Publications Warehouse

    Herbert, L.R.; Cruff, R.W.; Waddell, K.M.

    1985-01-01

    A study of selected reaches of the Utah and Salt Lake, Utah Lake Distributing, Provo Reservoir, Draper Irrigation, East Jordan, and Jordan and Salt Lake City Canals in Salt Lake County, Utah, was made to determine gains or losses of flow in those reaches. Three to five sets of seepage measurements were made on each canal during 1982 or 1983. Adjustments for fluctuations in flow were made from information obtained from water-stage recorders operated at selected locations during the time of each seepage run.The study showed an overall net loss of about 9.5 cubic feet per second in the Utah and Salt Lake Canal, 11.0 cubic feet per second in the Utah Lake Distributing canal, 20.5 cubic feet per second in the Provo Reservoir canal, 1.5 cubic feet per second in the Draper Irrigation Canal, and 4.0 cubic feet per second in the East Jordan canal. It also showed a net gain of about 6.0 cubic feet per second in the Jordan and Salt Lake City Canal. The gains and losses are attributed primarily to the relation of the canals to the depth of the water table near the canals.

  1. Field measurement of seepage and evapotranspiration rate for a soil under plant cover: A comparison of soil water balance and tritium labeling procedure

    NASA Astrophysics Data System (ADS)

    Kreutzer, K.; Strebel, O.; Renger, M.

    1980-08-01

    Vertical water flux at 90 cm depth and evapotranspiration were measured in a loess Parabraunerde soil profile, under spring wheat and sugar beets, respectively, during a time period of nearly 21 months. Two field methods were compared: the HTO-tracer method (labeling soil water at a depth of 60 cm followed by core sampling) and the soil water balance method (measuring soil water suction and water content as a function of depth and time). Outside the vegetation season the results of the two methods agreed well, but not during the vegetation season. The reason is that the reference soil compartment, with its reference depth of 90 cm, lies within the root zone and the HTO-method does not correctly reflect the water flux through the roots and the water withdrawal by the roots from this reference compartment. It is shown, that after correcting the HTO-values for these root-activity-dependent effects, a good agreement between the two methods was found also during periods with root activity. Investigations with the HTO-method lead to inaccurate results if the reference depth or the median value of the tracer distribution lie within the zone of active roots.

  2. An Integrated Approach to Determine Ground-water Surface Water Flux in a Contaminated Aquifer-Wetland System at the Norman Landfill Research Site, Oklahoma

    NASA Astrophysics Data System (ADS)

    Mendoza-Sanchez, I.; Phanikumar, M.; McGuire, J. T.; Masoner, J.; Cozzarelli, I.

    2008-12-01

    An area of research in progress at the Norman Landfill Research Site in Oklahoma involves a small wetland that overlies a landfill leachate plume. The wetland-aquifer system actively exchanges contaminants and nutrients. These chemicals move from the wetland to the aquifer and vice versa depending on the ground- water/surface-water exchange rate and flow direction. The ground-water/surface-water flow has to be quantified in order to better understand the influence of contaminants and nutrients on the transport and fate of landfill leachates. Different types of data have been collected at the site over a period of ten years including isotopic composition of water samples, ion concentrations, water levels, evaporative and seepage fluxes and meteorological variables. After identifying key processes influencing the water exchange between the wetland and ground-water based on time series analysis, we used process-based modeling to determine the ground-water/surface-water flow rates in the system using an integrated water balance model. Other methods used to constrain processes and parameters in the study include: (a) ground-water inflow calculation with stable environmental isotopes mass balance (b) ground-water input to the wetland with solute mass balance, and (c) Darcy's flow calculation of ground-water/surface-water exchange based on measurements from a network of piezometers. Preliminary results show that it is possible to differentiate between regional and local ground-water influences, as well as precipitation and evapotranspiration contributions in the exchange behavior.

  3. Evaluation Of The Physical Stability, Ground Water Seepage Control, And Faunal Changes Associated With An AquaBlok® Sediment Cap

    EPA Science Inventory

    Active sediment caps are being considered for addressing contaminated sediment areas in surface-water bodies. A demonstration of an active cap designed to reduce advective transport of contaminants using AquaBlok® (active cap material) was initiated in a small study a...

  4. Evaluation Of The Physical Stability, Ground Water Seepage Control, And Faunal Changes Associated With An AquaBlok® Sediment Cap

    EPA Science Inventory

    Active sediment caps are being considered for addressing contaminated sediment areas in surface-water bodies. A demonstration of an active cap designed to reduce advective transport of contaminants using AquaBlok® (active cap material) was initiated in a small study a...

  5. Hydrogeochemistry of Maine seepage lakes and related groundwaters

    NASA Astrophysics Data System (ADS)

    Stauffer, Robert E.; Wittchen, Bruce D.

    1992-10-01

    Southeastern Maine contains numerous small seepage lakes (no perennial surface inflows or outflows), set in felsic, glacial deposits (eskers, pitted outwash, glacio-marine deltaic terraces) dating from the Wisconsin glacial retreat ca. 12 500 years B.P. The modern landscape is either forested or maintained as low blueberry heath by semi-annual mowing and burning. Although local precipitation is currently moderately acidic (volume-weighted pH ≈ 4.5), spring waters issuing from the glacial deposits are only weakly acidic (6.1 < pH < 7.0), and bicarbonate-buffered (120 to 300 mmol m -3) on account of tertiary weathering by dissolved CO 2. The order of mobility (denudation rate) for base cations (BC) is: Ca > Na > Mg > K, the same as for upland granitic terrane in the same region. Springwater composition is temporally stable but geographically variable. The most dilute springwaters drain blueberry barrens. Here, chemical weathering is limited by available acidity as evidenced by the relatively high final pHs (> 6.3) and low concentrations of strong oxy-anions (nitrate, sulfate) and dissolved inorganic carbon (DIC < 250 μM). Closely neighboring lakes often range widely in alkalinity, BC, and F, depending on their connection to the local groundwater system. Tracer analysis indicates seepage inflow is equal to 5-50 cm year -1 for typical regional seepage lakes, vs. higher rates (> 100 cm year -1) for groundwater discharge lakes. Approximately 88% of Si inputs to regional seepage lakes is retained in the sediments. Non-marine sulfate is lowest in groundwater discharge lakes containing the highest concentrations of BC and F, and featuring the shortest hydraulic residence times, suggesting that S retention in lake sediments is currently less efficient than in the adjoining terrestrial soils and vegetation.

  6. Percolation testing at the F- and H-Area Seepage Basins. Final report

    SciTech Connect

    McHood, M.D.

    1993-10-18

    The design of the F- and H-Area Seepage Basin contaminated groundwater remediation system requires information from multiple well pump tests (Reference 1). Soil percolation rates are needed in order to support the multiple well pump test planning. The objective of this task was to determine characteristic percolation rates for soils in four select areas where infiltration galleries are proposed. These infiltration galleries will be temporary installations built on the ground surface and used to disposes of water from the multiple well pump tests. A procedure defining the specific work process for collecting percolation rate data is contained in Appendix 3. Results from these percolation tests will be used in the design of infiltration galleries for the disposal of well water extracted during the multiple well pump tests.

  7. Use of Polyacrylamide to Reduce Seepage From Unlined Irrigation Canals: Initial Results From Small Scale Test Troughs

    NASA Astrophysics Data System (ADS)

    Susfalk, R. B.; Young, M. H.; Schmidt, M.; Epstein, B. J.; Goreham, J.; Swhihart, J.; Smith, D.

    2005-12-01

    Polyacrylamide (PAM) is a class of long-chain synthetic polymers that are used extensively in food packaging, paper manufacturing, wastewater treatment, and as a soil amendment to reduce erosion. Recent empirical evidence has shown that applying linear, anionic PAM seepage can also reduce seepage from unlined irrigation canals. A diverse set of experiments has been initiated to understand the efficacy of PAM usage in ditch environments. The experiments span multiple scales, from small-scale bench top and artificial furrow experiments, to larger engineered furrows and irrigation ditches. Our objective was to assess the effectiveness of different PAM application methods and concentrations on seepage reductions in small scale, artificial Test Troughs (TT). The TT consists of two 24 m long, 10 cm deep furrows formed from native ASTM C-33 sand. During water application, inflows, outflows, and seepage from under the furrows were continuously measured. PAM in either granular or partially hydrated form was applied at various rates. The results presented here cover one facet of the research program. The application of granular PAM to the TT reduced seepage from 49 L/min to less than 22 L/min, depending on treatment. A PAM application rate of 44 kg/(canal ha) reduced seepage by 69+/-9 percent, and was more effective than an application rate of 11 kg/(canal ha) that reduced seepage by 56+/-22 percent. Seepage reduction was calculated using flow rates between 400 and 600 elapsed minutes. Inclusion of later data (up to 1440 min) into seepage calculations was complicated by a reduction in seepage at the control trough caused either by a reduction in head or deposition of suspended sediment. We hypothesize that the PAM-sediment layer present in the treated trough exerted a greater control on seepage than sediment deposition alone. However, heavy suspended sediment loads associated with hydrologic events reduced seepage rates within both the control and treated troughs, somewhat

  8. Terrestrial Laser Scanning of a Stream Bank During Naturally and Experimentally Induced Erosion by Groundwater Seepage

    NASA Astrophysics Data System (ADS)

    Lyons, N. J.; Mitasova, H.; Starek, M. J.; Wegmann, K. W.

    2012-12-01

    Bank erosion was characterized and quantified with a terrestrial laser scanner (TLS) and an in situ experiment for a stream that is incising into historic millpond sediment in the piedmont region of the southeastern United States. The volume removed from pre-millpond, millpond, and post-millpond bank layers during a 22-month period were determined with a series of TLS surveys. A total of approximately 12 m3 of bank material was eroded, stemming predominantly from groundwater seepage, from an 11.5 m length of surveyed bank. The mechanisms and rate of failure stemming from groundwater seepage was then examined with an in-situ experiment. The experiment involved wetting the ground above the bank with pressure-regulated water emitters installed along a hose parallel to the bank. The response of the bank face to wetting was assessed with periodic TLS surveys and subsurface pore pressure measurements obtained with tensiometers installed to multiple depths parallel to the bank face. Based on the TLS surveys and experiment results, we present a comparison of (1) the natural and experimentally induced bank erosion, and (2) erosion mechanism characteristics in the pre-millpond, millpond, and post-millpond bank layers.

  9. Preliminary assessment of tree mortality near F- and H-area seepage basins

    SciTech Connect

    Loehle, C; Gladden, J

    1988-01-28

    A preliminary assessment was conducted to evaluate factors that may have been responsible for the vegetation damage that has occurred in groundwater seeps downslope from the F- and H-area seepage basins. The factors that were considered included altered hydrology, toxicity from hazardous chemical constituents associated with seepage basin operation, and toxicity from non-hazardous constituents associated with basin operation. It was concluded that the observed damage was not likely to have resulted from altered hydrologic conditions or hazardous constituents associated with basin operation. Insufficient information is currently available to determine definitively which of the non-hazardous constituents, alone or in concert, were responsible for the observed vegetation damage. The most likely explanation, however, is that elevated Na, pH, and conductivity is outcropping seep water are responsible for tree mortality. All three of these factors will return to ambient levels over a period of several years when basin operation ceases. Faster remediation can be achieved using lime at the seep line.

  10. Experimental study of bentonite-soil mixtures as anti-seepage materials of constructed wetlands.

    PubMed

    Chen, Jing; Li, Zifu; Zhao, Xin; Li, Haihan

    2011-01-01

    In this study, mixtures of different kinds of bentonite and soil were used and tested in order to find a cheap alternative to current anti-seepage materials for constructed wetlands. The anti-seepage layer of constructed wetlands was simulated in the experimental study and the permeability coefficient of the mixed materials was determined in order to evaluate the anti-seepage effect of mixtures. The main results are as follows: (i) The minimum mass ratio of bentonite to soil is 10%; (ii) Within a certain range, the more compact and higher the wet density is, then the better anti-seepage effect is (under the condition of certain moisture content). The permeability coefficient of the mixed materials exponentially increased with the increase of wet density; (iii) At the wet density of 1.83 g/cm(3), corresponding with the optimum compactness, the mixture of natural sodium bentonite produced in Wyoming, USA and soil from Cangzhou, Hebei province showed the best anti-seepage performance; (iv) The impermeability of the mixture with smaller particle sizes of bentonite was far better than that with the bigger particle sizes; (v) The hydration effect of bentonite changed the structure of the mixture materials into a special structure that is similar to that of pure bentonite. The particles of the mixture became expanded under SEM investigation and the mixture became more compact, which could have the same or similar effect as pure bentonite for anti-seepage.

  11. Seepage erosion mechanisms of bank collapse: three-dimensional seepage particle mobilization and undercutting

    USDA-ARS?s Scientific Manuscript database

    Seepage flow initiates undercutting, similar to development and headward migration of internal gullies, by liquefaction of soil particles, followed by mass wasting of the bank. Although seepage erosion has three-dimensional characteristics, two-dimensional lysimeters have been used in previous resea...

  12. Natural Oil Seepages : Detection, Monitoring and Relationships with Submarine Morphologies

    NASA Astrophysics Data System (ADS)

    Dhont, D.; Jatiault, R.; Dubucq, D.; Longépé, N.; Nhunfat, B.; Lucas, M.

    2014-12-01

    Detection of hydrocarbon shows in marine areas is of primary importance for oil and gas exploration since they confirm hydrocarbon generation and prove the presence of an active petroleum system. The use of spaceborne Synthetic Aperture Radar (SAR) images serves as an ideal technology for the imaging of hydrocarbon seeps as it is cost effective, provides large ground coverage with continuous acquisitions and operates day and night and in all weather conditions. Here, we present results on the interpretation of radar images for seepage detection on the West African margin. Long-term monitoring of 150 SAR scenes during 20 years allowed the recognition of more than 1400 oil seepages. Seabed morphologies associated to oil leakage correspond to clusters of small sized pockmarks, 50 to 200 m in diameter, and high-reflectivity mounds. The correlation between the location of the impact point of the oil plume at the sea surface with the seabed features reveals that oceanic drift of the oil is less than 1000 m through a water column of 1800 m, with a rising speed of 10 cm/s. In order to address the question of the seeps lifetime, we set up a short-term monitoring through the acquisition of one radar scene every 12 hours during 10 days in a specific area recognized for active oil leaking. Our main observations are: (i) the number of detected seeps varies spatially and temporally, and (ii) oil seep dissipation is effective in less than 12 hours. The variation of the hydrostatic pressure in the water column associated to the oscillation of the tide has been firstly considered as a possible mechanism controlling the expulsion of oil at the seafloor in relation with the number of seeps detected on each image. However, the correlation between the regional mean wind field and the amount of oil seeps strongly suggests that the wind is a primary factor to be considered for seepage detection. In addition, the age of the seepage on the sea surface is undetermined when the SAR imagery

  13. Characterization of seepage in the exploratory studies facility, Yucca Mountain, Nevada

    USGS Publications Warehouse

    Oliver, T.A.; Whelan, J.F.

    2006-01-01

    Following a 5-month period of above-average precipitation during the winter of 2004-2005, water was observed seeping into the South Ramp section of the Exploratory Studies Facility of the proposed repository for high-level radioactive waste at Yucca Mountain, Nevada. Samples of the seepage were collected and analyzed for major ions, trace metals, and delta deuterium and delta oxygen-18 values in an effort to characterize the water and assess the interaction of seepage with anthropogenic materials used in the construction of the proposed repository. As demonstrated by the changes in the chemistry of water dripping from a rock bolt, interaction of seepage with construction materials can alter solution chemistry and oxidation state.

  14. Charecterization of Seepage in the Exploratory Studies Facility, Yucca Mountain, Nevada

    SciTech Connect

    T.A. Oliver; J.F. Whelan

    2006-03-20

    Following a 5-month period of above-average precipitation during the winter of 2004-2005, water was observed seeping into the South Ramp section of the Exploratory Studies Facility of the proposed repository for high-level radioactive waste at Yucca Mountain, Nevada. Samples of the seepage were collected and analyzed for major ions, trace metals, and delta deuterium and delta oxygen-18 values in an effort to characterize the water and assess the interaction of seepage with anthropogenic materials used in the construction of the proposed repository. As demonstrated by the changes in the chemistry of water dripping from a rock bolt, interaction of seepage with construction materials can alter solution chemistry and oxidation state.

  15. Results of a seepage investigation at Bear Creek Valley, Oak Ridge, Tennessee, January through September 1994

    SciTech Connect

    Robinson, J.A.; Johnson, G.C.

    1996-12-31

    A seepage investigation was conducted of 4,600 acres of Bear Creek Valley southwest of the Y-12 Plant, Oak Ridge, Tennessee, for the period of January through September 1994. The data was collected to help the Y-12 Environmental Restoration Program develop a better understanding of ground-water and surface-water interactions, recharge and discharge relations, and ground-water flow patterns. The project was divided into three phases: a reconnaissance and mapping of seeps, springs, and stream-measurement sites; a high base flow seepage investigation; and a low base flow seepage investigation. This report describes the results of the investigation. It includes a map showing measurement site locations and tables that list the coordinates for each site and measurements of discharge, pH, specific conductance, temperature, and dissolved oxygen.

  16. A seepage investigation of an area at and near Oak Ridge National Laboratory, Oak Ridge, Tennessee, March through August 1993

    USGS Publications Warehouse

    Johnson, G.C.

    1996-01-01

    A seepage investigation was conducted of an area surrounding the Oak Ridge National Laboratory from March through August 1993. The project was divided into three phases: a reconnaissance to inventory and map seeps, springs, and stream-measurement sites; a high base flow seepage investigation; and a low base flow seepage investigation. The reconnaissance consisted of following each tributary to its source to inventory each site where water was issuing from the ground. Stream- measurement sites were also located along stream reaches at 500-foot intervals. A total of 822 sites were identified. A global positioning system was used to locate 483 sites to within 3- to 5-meter accuracy. The high base flow seepage investigation was conducted from April 29 through May 3, 1993, and from May 7 through May 10, 1993. During the high base flow seepage investigation, sites identified during the reconnaissance were revisited. At almost all sites with flowing water, discharge, pH, specific conductance, and temperature were recorded. Two hundred and fourteen sites were dry. The low base flow seepage investigation was conducted from August 8 through August 10, 1993, and consisted of revisiting the seeps and springs that were flowing during the high base flow seepage investigation. Stream- measurement sites were not revisited. One hundred and forty-one sites were dry.

  17. A calorimetric method to determine water activity

    NASA Astrophysics Data System (ADS)

    Björklund, Sebastian; Wadsö, Lars

    2011-11-01

    A calorimetric method to determine water activity covering the full range of the water activity scale is presented. A dry stream of nitrogen gas is passed either over the solution whose activity should be determined or left dry before it is saturated by bubbling through water in an isothermal calorimeter. The unknown activity is in principle determined by comparing the thermal power of vaporization related to the gas stream with unknown activity to that with zero activity. Except for three minor corrections (for pressure drop, non-perfect humidification, and evaporative cooling) the unknown water activity is calculated solely based on the water activity end-points zero and unity. Thus, there is no need for calibration with references with known water activities. The method has been evaluated at 30 °C by measuring the water activity of seven aqueous sodium chloride solutions ranging from 0.1 mol kg-1 to 3 mol kg-1 and seven saturated aqueous salt solutions (LiCl, MgCl2, NaBr, NaCl, KCl, KNO3, and K2SO4) with known water activities. The performance of the method was adequate over the complete water activity scale. At high water activities the performance was excellent, which is encouraging as many other methods used for water activity determination have limited performance at high water activities.

  18. Determination of color of turbid waters

    USGS Publications Warehouse

    Lamar, W.L.

    1949-01-01

    A convenient procedure for determining the color of turbid waters, using the principle of precipitation of turbidity by the electrolyte calcium chloride, is described. Because the stable turbidity of many surface waters cannot be completely precipitated by conventional centrifuging alone, this procedure presents a means of flocculating the turbidity without affecting the true color of the water. In the determination of true color of turbid samples one of the most prevalent errors is caused by the reading of color on samples not completely free of turbidity. Pertinent data are presented on color and turbidity of waters as related to the principles involved in the determination of color.

  19. Seepage study of the Sevier Valley-Piute Canal, Sevier County, Utah

    USGS Publications Warehouse

    Cruff, R.W.

    1977-01-01

    A study of the gains or losses of the Sevier Valley-Piute Canal from near Joseph to near Aurora, Sevier County, Utah, was made to aid in water allocation for the canal system. Four sets of seepage measurements were made in 1976, with the three most representative being used in the analysis. Adjustments for fluctuations in flow in the canals were made from information obtained from water-stage recorders operated at selected locations along the canal during the time of each seepage run.

  20. Statistical analysis of interaction between lake seepage rates and groundwater and lake levels

    NASA Astrophysics Data System (ADS)

    Ala-aho, P.; Rossi, P. M.; Klöve, B.

    2012-04-01

    In Finland, the main sources of groundwater are the esker deposits from the last ice age. Small lakes imbedded in the aquifer with no outlets or inlets are typically found in eskers. Some lakes at Rokua esker, in Northern Finland, have been suffering from changes in water stage and quality. A possible permanent decline of water level has raised considerable concern as the area is also used for recreation and tourism. Rare biotypes supported by the oligotrophic lakes can also be endangered by the level decline. Drainage of peatlands located in the discharge zone of the aquifer is a possible threat for the lakes and the whole aquifer. Drainage can potentially lower the aquifer water table which can have an effect on the groundwater-lake interaction. The aim of this study was to understand in more detail the interaction of the aquifer and the lake systems so potential causes for the lake level variations could be better understood and managed. In-depth understanding of hydrogeological system provides foundation to study the nutrient input to lakes affecting lake ecosystems. A small lake imbedded the Rokua esker aquifer was studied in detail. Direct measurements of seepage rate between the lake and the aquifer were carried out using seepage meters. Seepage was measured from six locations for eight times during May 2010 - November 2010. Precipitation was recorded with a tipping bucket rain gauge adjacent to the lake. Lake stage and groundwater levels from three piezometers were registered on an hourly interval using pressure probes. Statistical methods were applied to examine relationship between seepage measurements and levels of lake and groundwater and amount of precipitation. Distinct areas of inseepage and outseepage of the lake were distinguished with seepage meter measurements. Seepage rates showed only little variation within individual measurement locations. Nevertheless analysis revealed statistically significant correlation of seepage rate variation in four

  1. Groundwater seepage controls salinity in a hydrologically terminal basin of semi-arid northwest Australia

    NASA Astrophysics Data System (ADS)

    Skrzypek, Grzegorz; Dogramaci, Shawan; Rouillard, Alexandra; Grierson, Pauline F.

    2016-11-01

    Very small groundwater outflows have the potential to significantly impact the hydrochemistry and salt accumulation processes of notionally terminal basins in arid environments. However, this limited groundwater outflow can be very difficult to quantify using classical water budget calculations due to large uncertainties in estimates of evaporation and evapotranspiration rates from the surface of dry lake beds. In this study, we used a dimensionless time evaporation model to estimate the range of groundwater outflow required to maintain salinity levels observed at the Fortescue Marsh (FM), one of the largest wetlands of semi-arid northwest Australia (∼1100 km2). The groundwater outflow from aquifers underlying the FM to the Lower Fortescue catchment is constrained by an extremely low hydraulic gradient of <0.0001 and a small 'alluvial outlet' of 0.35 km2 because of relatively high bedrock elevation. However, FM groundwater salinity is far below saturation with respect to halite (TDS < 160 g/L), episodic flood water is fresh to brackish, and salt efflorescences are very sparse and evident only when the FM is dry. We show that if the FM was 100% ;leakage free; i.e., a true terminal basin, groundwater would have achieved halite saturation (>300 g/L) after ∼45 ka. We calculated that only a very small seepage of ∼2G L/yr (∼0.03% of the FM water volume) is sufficient to maintain current salinity conditions. The minimum time required to develop the current hydrochemical groundwater composition under the FM ranges from ∼60 to ∼165 ka. We conclude that a dimensionless time evaporation model versus inflow over outflow ratio model is likely more suitable than classical water budget calculations for determining outflow from large saline lakes and to estimate groundwater seepage from hydrologically terminal basins.

  2. Estimation of past seepage volumes from calcite distribution in the Topopah Spring Tuff, Yucca Mountain, Nevada

    USGS Publications Warehouse

    Marshall, B.D.; Neymark, L.A.; Peterman, Z.E.

    2003-01-01

    Low-temperature calcite and opal record the past seepage of water into open fractures and lithophysal cavities in the unsaturated zone at Yucca Mountain, Nevada, site of a proposed high-level radioactive waste repository. Systematic measurements of calcite and opal coatings in the Exploratory Studies Facility (ESF) tunnel at the proposed repository horizon are used to estimate the volume of calcite at each site of calcite and/or opal deposition. By estimating the volume of water required to precipitate the measured volumes of calcite in the unsaturated zone, seepage rates of 0.005 to 5 liters/year (l/year) are calculated at the median and 95th percentile of the measured volumes, respectively. These seepage rates are at the low end of the range of seepage rates from recent performance assessment (PA) calculations, confirming the conservative nature of the performance assessment. However, the distribution of the calcite and opal coatings indicate that a much larger fraction of the potential waste packages would be contacted by this seepage than is calculated in the performance assessment.

  3. Estimation of past seepage volumes from calcite distribution in the Topopah Spring Tuff, Yucca Mountain, Nevada.

    PubMed

    Marshall, Brian D; Neymark, Leonid A; Peterman, Zell E

    2003-01-01

    Low-temperature calcite and opal record the past seepage of water into open fractures and lithophysal cavities in the unsaturated zone at Yucca Mountain, Nevada, site of a proposed high-level radioactive waste repository. Systematic measurements of calcite and opal coatings in the Exploratory Studies Facility (ESF) tunnel at the proposed repository horizon are used to estimate the volume of calcite at each site of calcite and/or opal deposition. By estimating the volume of water required to precipitate the measured volumes of calcite in the unsaturated zone, seepage rates of 0.005 to 5 liters/year (l/year) are calculated at the median and 95th percentile of the measured volumes, respectively. These seepage rates are at the low end of the range of seepage rates from recent performance assessment (PA) calculations, confirming the conservative nature of the performance assessment. However, the distribution of the calcite and opal coatings indicate that a much larger fraction of the potential waste packages would be contacted by this seepage than is calculated in the performance assessment.

  4. A Tube Seepage Meter for In Situ Measurement of Seepage Rate and Groundwater Sampling.

    PubMed

    Solder, John E; Gilmore, Troy E; Genereux, David P; Solomon, D Kip

    2016-07-01

    We designed and evaluated a "tube seepage meter" for point measurements of vertical seepage rates (q), collecting groundwater samples, and estimating vertical hydraulic conductivity (K) in streambeds. Laboratory testing in artificial streambeds show that seepage rates from the tube seepage meter agreed well with expected values. Results of field testing of the tube seepage meter in a sandy-bottom stream with a mean seepage rate of about 0.5 m/day agreed well with Darcian estimates (vertical hydraulic conductivity times head gradient) when averaged over multiple measurements. The uncertainties in q and K were evaluated with a Monte Carlo method and are typically 20% and 60%, respectively, for field data, and depend on the magnitude of the hydraulic gradient and the uncertainty in head measurements. The primary advantages of the tube seepage meter are its small footprint, concurrent and colocated assessments of q and K, and that it can also be configured as a self-purging groundwater-sampling device.

  5. Geological records of redox change related to methane seepage in the Ulleung Basin, East Sea

    NASA Astrophysics Data System (ADS)

    Chun, J.; Ryu, B.; Bahk, J.; Choi, J.; Riedel, M.

    2012-12-01

    The sediment mounds related to columnar seismic blanking zone have been reported in the basin plain, reflecting the presence of near-surface gas hydrate and authigenic carbonates in the Ulleung Basin, East Sea. The mounds commonly consist of hemipelagic sediments and buried authigenic carbonates. Recently, exposed carbonate mound (~5 m wide and 2 -3 m high) was found in the site UBGH2-11 at water depth of ~2092 m. Six push cores (70-cm-long) were collected around the area of the exposed carbonate mound using ROV manipulators. The total nitrogen (TN), total carbon (TC), total organic carbon (TOC), and their carbon dioxide (δ13C) and nitrogen (δ15N) isotope values of core sediments were measured to identify the spatial distribution of organic matter related to methane seepages. The trace and rare earth elements of core sediments were analyzed to determine the redox conditions in seafloor sedimentary environments around the area of cold vents. Higher TOC contents (4-8%) were observed in three cores in the area around the exposed carbonate mound, whereas TOC contents ranged from 2-3% in other three cores, about 50 m away from the exposed carbonate mound. Highly negative δ13C values (-40 to -28 ‰) of organic matters show only one core located at the side of exposed carbonate mound. Higher Mn/Ti ratios suggest that the topmost parts of the core sediments outside the exposed carbonate mound were influenced by the effects of oxygenated bottom water. At other locations, there is no evidence of oxygenated bottom water. It suggests that the surface sediments formed under oxygen-depleted condition. Variation of Mo/Al and Co/Al ratios explains by fluctuation of redox conditions around the exposed carbonate mound in the site UBGH2-11. These results indicate that redox conditions of seafloor environments were locally influenced by methane seepages of cold vents associated with columnar seismic blanking zone in the Ulleung Basin.

  6. Turbulent flow statistics of vegetative channel with seepage

    NASA Astrophysics Data System (ADS)

    Devi, Thokchom Bebina; Kumar, Bimlesh

    2015-12-01

    The present study is carried out for studying the impact of submerged, flexible vegetation in a channel where downward seepage occurs. Laboratory experiments on artificial vegetation of two different heights, 8 cm and 6 cm, were conducted for no-seepage, 10% seepage and 15% seepage cases. Vegetation height is an important parameter in influencing the flow characteristics in a vegetated channel, where velocity is reduced near the top of the vegetation. Results show that velocity measured at upstream vegetation section is always higher than the downstream section even with the application of downward seepage. The maximum value of Reynolds stress occurs near the top of the vegetation. When the flow enters the vegetation section, the local effect of the presence of vegetation on sediment transport is more at the upstream vegetation section and then decreases which is shown by higher Reynolds stress at the upstream as compared to downstream vegetation section highlighting the importance of vegetation in providing as an erosion control. The maximum Reynolds stress at no seepage is increased by a percentage of 17% for 10% seepage and average of 30.5% for 15% seepage. The turbulence intensities at no seepage are increased by an average value of 15% for 10% seepage and 25% for 15% seepage. The reduction of Reynolds stress and turbulent intensities along the longitudinal direction implies the importance of using vegetation as a river restoration measure providing considerable stability to channels. Third order moments highlight that downward seepage increases the streamwise flux and decreases the upward flux.

  7. Transient hydrogeological controls on the chemistry of a seepage lake

    USGS Publications Warehouse

    Krabbenhoft, David P.; Webster, Katherine E.

    1995-01-01

    A solute mass balance method was used to estimate groundwater inflow and outflow rates for Nevins Lake, Michigan, a seepage lake in the upper peninsula that historically has shown extremely variable water chemistry compared with most other seepage lakes. A 4-year study (1989–1992) of the hydrology and geochemistry of Nevins Lake and its contiguous groundwater system revealed that changes in the mass of dissolved solutes are the result of annual hydraulic gradient reversals. A pronounced acidification of Nevins Lake from 1986 to 1988 was likely caused by drought-induced diminished groundwater inflow rates. In this study, dissolved calcium (the major cation in water of Nevins Lake, groundwater, and precipitation) was used for estimating mass flow rates. During the 1989–1992 period, Nevins Lake showed a reproducible annual cycle in calcium mass. Immediately following spring snowmelt and the resulting hydraulic gradient reversal, the mass of dissolved calcium in the lake increases rapidly, and then it decreases steadily throughout the summer and early fall, at which time the lake becomes hydraulically mounded and receives no groundwater inflow. Groundwater flow rates estimated by the solute mass balance method are sensitive to assumed solute concentrations in discharging groundwater. Pore water samples from the lake bed are shown to be more representative of water discharging to the lake than are samples from piezometers near the lake shore, but spatial and temporal variability in pore water chemistry must be considered. Stable isotope analyses (18O and 2H) of lake water, groundwater, and pore water samples show that water discharging to Nevins Lake in the spring is entirely recycled lake water, and no groundwater derived from terrestrial recharge reaches the lake. The conceptual model formulated during this study linking lake chemistry and the contiguous groundwater system and general groundwater flow patterns surrounding highly transient lake systems are likely

  8. Potential for seepage erosion of landslide dam

    USGS Publications Warehouse

    Meyer, W.; Schuster, R.L.; Sabol, M.A.

    1994-01-01

    The failure potential of the debris-avalanche dam at Castle Lake near Mount St. Helens, Washington, by three processes of seepage erosion (1) Heave; (2) piping; and (3) internal erosion, is examined. Results indicated that the dam is stable against piping but potentially locally unstable against heave. -from Authors

  9. Gas seepage in the Northern Adriatic Sea

    NASA Astrophysics Data System (ADS)

    Matilde Ferrante, Giulia; Donda, Federica; Volpi, Valentina; Tinivella, Umberta

    2017-04-01

    In the Northern Adriatic Sea, the occurrence of gas seepage has been widely documented. However, the origin of seeping gas was not clearly constrained. Geophysical data with different scale of resolution, i.e. multichannel seismic profiles, CHIRP and morpho-bathymetry data collected in 2009 and 2014 by OGS reveal that several the gas-enriched fluid vents are deeply rooted. In fact, the entire Plio-Quaternary succession is characterized by widespread seismic anomalies represented by wipe-out zones and interpreted as gas chimneys. They commonly root at the base of the Pliocene sequence but also within the Paleogene succession, where they appear to be associated to deep-seated, Mesozoic-to-Paleogene faults. These chimneys originate and terminate at different stratigraphic levels; they also commonly reach the seafloor, where rock outcrops interpreted as authigenic carbonate deposits have been recognized. In places, gas is then capable to escape in the water column as shown by numerous gas flares. On going studies are addressed to: 1. re-examining the structural setting of the study area, in order to verify a possible structural control on chimney distribution and gas migration; 2. performing geochemical analysis on gas which have been sampled in some key emission points; 3. a quantitative analysis of some selected boreholes well logs (made available through the public VidePi database (www.videpi.com)) aimed to estimate the amount of gas present in sediments. This work presents the preliminary results regarding the latter aspect of our research. In a first instance, for each selected borehole the geophysical logs have been digitized. This procedure consists in a manual picking of curves, in a set system of reference. Static corrections for vertical offset are made at this stage. Logs are then divided by type and converted in common scales, amplifications and units. Every log is resampled in order to cut high frequencies not useful in the comparison with seismic data

  10. Seepage study for unnamed tributary to Alder Creek, Stevens County, Washington

    USGS Publications Warehouse

    Carpenter, P.J.; Drost, B.W.

    1979-01-01

    Analysis of seepage measurements in the Alder Creek basin, Stevens County, Wash., shows that approximately 50% of 0.2 cubic foot per second taken from an unnamed tributary and used for the 1978 irrigation season would have reached Alder Creek as surface flow. Differences in discharge and specific conductance are explained by the basin geology, physical characteristics, climate, and water use. Only general conclusions could be made from data collected for five seepage measurements because irrigation activities could not be scheduled to allow the hydrologic system to reach equilibrium. (USGS)

  11. A method to determine plant water source using transpired water

    NASA Astrophysics Data System (ADS)

    Menchaca, L. B.; Smith, B. M.; Connolly, J.; Conrad, M.; Emmett, B.

    2007-04-01

    A method to determine the stable isotope ratio of a plant's water source using the plant's transpired water is proposed as an alternative to standard xylem extraction methods. The method consists of periodically sampling transpired waters from shoots or leaves enclosed in sealed, transparent bags which create a saturated environment, preclude further evaporation and allow the progressive mixing of evaporated transpired water and un-evaporated xylem water. The method was applied on trees and shrubs coexisting in a non-irrigated area where stable isotope ratios of local environmental waters are well characterized. The results show Eucalyptus globulus (tree) and Genista monspessulana (shrub) using water sources of different isotopic ratios congruent with groundwater and soil water respectively. In addition, tritium concentrations indicate that pine trees (Pinus sylvestris) switch water source from soil water in the winter to groundwater in the summer. The method proposed is particularly useful in remote or protected areas and in large scale studies related to water management, environmental compliance and surveillance, because it eliminates the need for destructive sampling and greatly reduces costs associated with laboratory extraction of xylem waters from plant tissues for isotopic analyses.

  12. Seepage regime of the hydraulic fill dam of the Mingechaur hydropower development

    SciTech Connect

    Melent'ev, V.A.; Nosovova, O.N.; Mityushina, I.M.; Sergeeva, N.S.; Chugaeva, G.A.

    1984-07-01

    On-site observations used to monitor the condition of the Mingechaur hydraulic-fill dam on the Kura River, USSR, were initiated in the mid-1950's at the time of construction. These revealed no evidence of seepage until the 1965-70 era, at which time, the readings of individual piezometers monitoring seepage indicated a general rise of the line of seepage. Theoretical and experimental studies were conducted to establish the cause and to determine the stability of the dam slopes and the earthquake resistance of the structure. Anomalous variations in the piezometers were noted and were concluded to be unrelated to intensifications of slope stability and determinations of earthquake resistance show the dam to be safe. 12 references, 4 figures, 1 table.

  13. Drift-Scale Coupled Processes (DST and TH Seepage) Models

    SciTech Connect

    J. Birkholzer; S. Mukhopadhyay

    2004-09-29

    The purpose of this report is to document drift-scale modeling work performed to evaluate the thermal-hydrological (TH) behavior in Yucca Mountain fractured rock close to waste emplacement drifts. The heat generated by the decay of radioactive waste results in rock temperatures elevated from ambient for thousands of years after emplacement. Depending on the thermal load, these temperatures are high enough to cause boiling conditions in the rock, giving rise to water redistribution and altered flow paths. The predictive simulations described in this report are intended to investigate fluid flow in the vicinity of an emplacement drift for a range of thermal loads. Understanding the TH coupled processes is important for the performance of the repository because the thermally driven water saturation changes affect the potential seepage of water into waste emplacement drifts. Seepage of water is important because if enough water gets into the emplacement drifts and comes into contact with any exposed radionuclides, it may then be possible for the radionuclides to be transported out of the drifts and to the groundwater below the drifts. For above-boiling rock temperatures, vaporization of percolating water in the fractured rock overlying the repository can provide an important barrier capability that greatly reduces (and possibly eliminates) the potential of water seeping into the emplacement drifts. In addition to this thermal process, water is inhibited from entering the drift opening by capillary forces, which occur under both ambient and thermal conditions (capillary barrier). The combined barrier capability of vaporization processes and capillary forces in the near-field rock during the thermal period of the repository is analyzed and discussed in this report.

  14. DRIFT-SCALE COUPLED PROCESSES (DST AND TH SEEPAGE) MODELS

    SciTech Connect

    J.T. Birkholzer; S. Mukhopadhyay

    2005-01-13

    The purpose of this report is to document drift-scale modeling work performed to evaluate the thermal-hydrological (TH) behavior in Yucca Mountain fractured rock close to waste emplacement drifts. The heat generated by the decay of radioactive waste results in rock temperatures elevated from ambient for thousands of years after emplacement. Depending on the thermal load, these temperatures are high enough to cause boiling conditions in the rock, giving rise to water redistribution and altered flow paths. The predictive simulations described in this report are intended to investigate fluid flow in the vicinity of an emplacement drift for a range of thermal loads. Understanding the TH coupled processes is important for the performance of the repository because the thermally driven water saturation changes affect the potential seepage of water into waste emplacement drifts. Seepage of water is important because if enough water gets into the emplacement drifts and comes into contact with any exposed radionuclides, it may then be possible for the radionuclides to be transported out of the drifts and to the groundwater below the drifts. For above-boiling rock temperatures, vaporization of percolating water in the fractured rock overlying the repository can provide an important barrier capability that greatly reduces (and possibly eliminates) the potential of water seeping into the emplacement drifts. In addition to this thermal process, water is inhibited from entering the drift opening by capillary forces, which occur under both ambient and thermal conditions (capillary barrier). The combined barrier capability of vaporization processes and capillary forces in the near-field rock during the thermal period of the repository is analyzed and discussed in this report.

  15. Natural convection in tunnels at Yucca Mountain and impact on drift seepage

    SciTech Connect

    Halecky, N.; Birkholzer, J.T.; Peterson, P.

    2010-04-15

    The decay heat from radioactive waste that is to be disposed in the once proposed geologic repository at Yucca Mountain (YM) will significantly influence the moisture conditions in the fractured rock near emplacement tunnels (drifts). Additionally, large-scale convective cells will form in the open-air drifts and will serve as an important mechanism for the transport of vaporized pore water from the fractured rock in the drift center to the drift end. Such convective processes would also impact drift seepage, as evaporation could reduce the build up of liquid water at the tunnel wall. Characterizing and understanding these liquid water and vapor transport processes is critical for evaluating the performance of the repository, in terms of water-induced canister corrosion and subsequent radionuclide containment. To study such processes, we previously developed and applied an enhanced version of TOUGH2 that solves for natural convection in the drift. We then used the results from this previous study as a time-dependent boundary condition in a high-resolution seepage model, allowing for a computationally efficient means for simulating these processes. The results from the seepage model show that cases with strong natural convection effects are expected to improve the performance of the repository, since smaller relative humidity values, with reduced local seepage, form a more desirable waste package environment.

  16. A Field Exercise on Groundwater Flow Using Seepage Meters and Mini-Piezometers.

    ERIC Educational Resources Information Center

    Lee, David R.; Cherry, John A.

    1979-01-01

    Basic principles of physical hydrogeology and the nature of hydrologic interactions between groundwater and surface water can be demonstrated using two devices, the miniature piezometer and the seepage meter which can be cheaply constructed by the teacher and students. Use of the devices and learning activities are presented. (RE)

  17. Influence of riparian seepage zones on nitrate variability in two agricultural headwater streams

    USDA-ARS?s Scientific Manuscript database

    Riparian seepage zones are one of the primary pathways of groundwater transport to headwater streams. While seeps have been recognized for their contributions to streamflow, there is little information on how seeps affect stream water quality. The objective of this study was to examine the influence...

  18. A Field Exercise on Groundwater Flow Using Seepage Meters and Mini-Piezometers.

    ERIC Educational Resources Information Center

    Lee, David R.; Cherry, John A.

    1979-01-01

    Basic principles of physical hydrogeology and the nature of hydrologic interactions between groundwater and surface water can be demonstrated using two devices, the miniature piezometer and the seepage meter which can be cheaply constructed by the teacher and students. Use of the devices and learning activities are presented. (RE)

  19. Characterization of focused seepage through an earthfill dam using geoelectrical methods.

    PubMed

    Ikard, S J; Revil, A; Schmutz, M; Karaoulis, M; Jardani, A; Mooney, M

    2014-01-01

    Resistivity and self-potential tomography can be used to investigate anomalous seepage inside heterogeneous earthen dams. The self-potential (SP) signals provide a unique signature to groundwater flow because the source current density responsible for the SP signals is proportional to the Darcy velocity. The distribution of the SP signals is also influenced by the distribution of the resistivity; therefore, resistivity and SP need to be used in concert to elucidate groundwater flow pathways. In this study, a survey is conducted at a small earthen dam in Colorado where anomalous seepage is observed on the downstream face at the dam toe. The data reveal SP and direct current resistivity anomalies that are used to delineate three anomalous seepage zones within the dam and to estimate the source of the localized seepage discharge. The SP data are inverted in two dimensions using the resistivity distribution to determine the distribution of the Darcy velocity responsible for the observed seepage. The inverted Darcy velocity agrees with an estimation of the Darcy velocity from the hydraulic conductivity obtained from a slug test and the observed head gradient.

  20. Vertical migration of fine-grained sediments from interior to surface of seabed driven by seepage flows-`sub-bottom sediment pump action'

    NASA Astrophysics Data System (ADS)

    Zhang, Shaotong; Jia, Yonggang; Wen, Mingzheng; Wang, Zhenhao; Zhang, Yaqi; Zhu, Chaoqi; Li, Bowen; Liu, Xiaolei

    2017-02-01

    A scientific hypothesis is proposed and preliminarily verified in this paper: under the driving of seepage flows, there might be a vertical migration of fine-grained soil particles from interior to surface of seabed, which is defined as `sub-bottom sediment pump action' in this paper. Field experiments were performed twice on the intertidal flat of the Yellow River delta to study this process via both trapping the pumped materials and recording the pore pressures in the substrate. Experimental results are quite interesting as we did observe yellow slurry which is mainly composed of fine-grained soil particles appearing on the seabed surface; seepage gradients were also detected in the intertidal flat, under the action of tides and small wind waves. Preliminary conclusions are that `sediment pump' occurs when seepage force exceeds a certain threshold: firstly, it is big enough to disconnect the soil particles from the soil skeleton; secondly, the degree of seabed fluidization or bioturbation is big enough to provide preferred paths for the detached materials to migrate upwards. Then they would be firstly pumped from interior to the surface of seabed and then easily re-suspended into overlying water column. Influential factors of `sediment pump' are determined as hydrodynamics (wave energy), degree of consolidation, index of bioturbation (permeability) and content of fine-grained materials (sedimentary age). This new perspective of `sediment pump' may provide some implications for the mechanism interpretation of several unclear geological phenomena in the Yellow River delta area.

  1. The need to consider temporal variability when modelling exchange at the sediment-water interface

    USGS Publications Warehouse

    Rosenberry, Donald O.

    2011-01-01

    Most conceptual or numerical models of flows and processes at the sediment-water interface assume steady-state conditions and do not consider temporal variability. The steady-state assumption is required because temporal variability, if quantified at all, is usually determined on a seasonal or inter-annual scale. In order to design models that can incorporate finer-scale temporal resolution we first need to measure variability at a finer scale. Automated seepage meters that can measure flow across the sediment-water interface with temporal resolution of seconds to minutes were used in a variety of settings to characterize seepage response to rainfall, wind, and evapotranspiration. Results indicate that instantaneous seepage fluxes can be much larger than values commonly reported in the literature, although seepage does not always respond to hydrological processes. Additional study is needed to understand the reasons for the wide range and types of responses to these hydrologic and atmospheric events.

  2. Quantitative determination of engine water ingestion

    NASA Technical Reports Server (NTRS)

    Parikh, P.; Hernan, M.; Sarohia, V.

    1986-01-01

    This paper describes a novel non-intrusive optical technique for determination of liquid mass flux in a droplet laden airstream. The technique was developed for quantitative determination of engine water ingestion resulting from heavy rain or wheel spray. Independent measurements of the liquid water content (LWC) of the droplet laden aircraft and of the droplet velocities were made at the simulated nacelle inlet plane for the liquid mass flux determination. The liquid water content was measured by illuminating and photographing the droplets contained within a thin slice of the flow field by means of a sheet of light from a pulsed YAG laser. A fluorescent dye introduced in the water greatly improved the droplet image definition. The droplet velocities were determined from double exposed photographs of the moving droplet field. The technique was initially applied to a steady spray generated in a wind tunnel. It was found that although the spray was initially steady, the aerodynamic breakup process was inherently unsteady. This resulted in a wide variation of the instantaneous liquid water content of the droplet laden airstream. The standard deviation of ten separate LWC measurements was 31 percent of the average. However, the liquid mass flux calculated from the average LWC and droplet velocities came within 10 percent of the known water ingestion rate.

  3. On leakage and seepage from geological carbon sequestration sites

    SciTech Connect

    Oldenburg, C.M.; Unger, A.J.A.; Hepple, R.P.; Jordan, P.D.

    2002-07-18

    Geologic carbon sequestration is one strategy for reducing the rate of increase of global atmospheric carbon dioxide (CO{sub 2} ) concentrations (IEA, 1997; Reichle, 2000). As used here, the term geologic carbon sequestration refers to the direct injection of supercritical CO{sub 2} deep into subsurface target formations. These target formations will typically be either depleted oil and gas reservoirs, or brine-filled permeable formations referred to here as brine formations. Injected CO{sub 2} will tend to be trapped by one or more of the following mechanisms: (1) permeability trapping, for example when buoyant supercritical CO{sub 2} rises until trapped by a confining caprock; (2) solubility trapping, for example when CO{sub 2} dissolves into the aqueous phase in water-saturated formations, or (3) mineralogic trapping, such as occurs when CO{sub 2} reacts to produce stable carbonate minerals. When CO{sub 2} is trapped in the subsurface by any of these mechanisms, it is effectively sequestered away from the atmosphere where it would otherwise act as a greenhouse gas. The purpose of this report is to summarize our work aimed at quantifying potential CO{sub 2} seepage due to leakage from geologic carbon sequestration sites. The approach we take is to present first the relevant properties of CO{sub 2} over the range of conditions from the deep subsurface to the vadose zone (Section 2), and then discuss conceptual models for how leakage might occur (Section 3). The discussion includes consideration of gas reservoir and natural gas storage analogs, along with some simple estimates of seepage based on assumed leakage rates. The conceptual model discussion provides the background for the modeling approach wherein we focus on simulating transport in the vadose zone, the last potential barrier to CO{sub 2} seepage (Section 4). Because of the potentially wide range of possible properties of actual future geologic sequestration sites, we carry out sensitivity analyses by

  4. A steady state solution for ditch drainage problem with special reference to seepage face and unsaturated zone flow contribution: Derivation of a new drainage spacing eqaution

    NASA Astrophysics Data System (ADS)

    Yousfi, Ammar; Mechergui, Mohammed

    2016-04-01

    al. (2001). In this work, a novel solution based on theoretical approach will be adapted to incorporate both the seepage face and the unsaturated zone flow contribution for solving ditch drained aquifers problems. This problem will be tackled on the basis of the approximate 2D solution given by Castro-Orgaz et al. (2012). This given solution yields the generalized water table profile function with a suitable boundary condition to be determined and provides a modified DF theory which permits as an outcome the analytical determination of the seepage face. To assess the ability of the developed equation for water-table estimations, the obtained results were compared with numerical solutions to the 2-D problem under different conditions. It is shown that results are in fair agreement and thus the resulting model can be used for designing ditch drainage systems. With respect to drainage design, the spacings calculated with the newly derived equation are compared with those computed from the DF theory. It is shown that the effect of the unsaturated zone flow contribution is limited to sandy soils and The calculated maximum increase in drain spacing is about 30%. Keywords: subsurface ditch drainage; unsaturated zone; seepage face; water-table, ditch spacing equation

  5. Removal site evaluation report for the SRL seepage basins

    SciTech Connect

    Palmer, E.R.

    1997-08-01

    Removal Site Evaluation Reports are prepared in accordance with Section 300.410 and 300.415 of the National Contingency Plan (NCP) and Section X of the Federal Facility Agreement (FFA). The Savannah River Laboratory (SRL) Seepage Basins is one of the units that is listed in the Appendix C. Resource Conservation and Recovery Act (RCRA)/Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) Units List, of the FFA. The purpose of this investigation is to report information concerning conditions at this unit sufficient to assess the threat (if any) posed to human health and the environment and to determine the need for additional CERCLA action. The scope of the investigation included recent surveys and sampling data, reviews of historical data, and visits to the unit. Through the investigation, unacceptable conditions of radioactive contaminant uptake in on-site vegetation were identified. This has resulted in introduction of contamination into the local ecological food chain and probable contaminant migration through biotic pathways. As a result, the Savannah River Site (SRS) will initiate a time critical removal action to remove and dispose of contaminated vegetation from the SRL Seepage Basins. Potential erosion in affected areas will be inhibited by implementation of the SCDHEC approved Stormwater Management and Sediment Reduction Plan/Pollution Prevention Plan, Permit {number_sign} SCR-100221. This report addresses the removal of the vegetation within the SRL Seepage Basin fence and, if necessary, the vegetation immediately outside the fence. The remediation of the waste unit will be addressed in other CERCLA documentation.

  6. GEOCHEMICAL MODELING OF F AREA SEEPAGE BASIN COMPOSITION AND VARIABILITY

    SciTech Connect

    Millings, M.; Denham, M.; Looney, B.

    2012-05-08

    From the 1950s through 1989, the F Area Seepage Basins at the Savannah River Site (SRS) received low level radioactive wastes resulting from processing nuclear materials. Discharges of process wastes to the F Area Seepage Basins followed by subsequent mixing processes within the basins and eventual infiltration into the subsurface resulted in contamination of the underlying vadose zone and downgradient groundwater. For simulating contaminant behavior and subsurface transport, a quantitative understanding of the interrelated discharge-mixing-infiltration system along with the resulting chemistry of fluids entering the subsurface is needed. An example of this need emerged as the F Area Seepage Basins was selected as a key case study demonstration site for the Advanced Simulation Capability for Environmental Management (ASCEM) Program. This modeling evaluation explored the importance of the wide variability in bulk wastewater chemistry as it propagated through the basins. The results are intended to generally improve and refine the conceptualization of infiltration of chemical wastes from seepage basins receiving variable waste streams and to specifically support the ASCEM case study model for the F Area Seepage Basins. Specific goals of this work included: (1) develop a technically-based 'charge-balanced' nominal source term chemistry for water infiltrating into the subsurface during basin operations, (2) estimate the nature of short term and long term variability in infiltrating water to support scenario development for uncertainty quantification (i.e., UQ analysis), (3) identify key geochemical factors that control overall basin water chemistry and the projected variability/stability, and (4) link wastewater chemistry to the subsurface based on monitoring well data. Results from this study provide data and understanding that can be used in further modeling efforts of the F Area groundwater plume. As identified in this study, key geochemical factors affecting basin

  7. Microbial community changes along the active seepage site of one cold seep in the Red Sea.

    PubMed

    Cao, Huiluo; Zhang, Weipeng; Wang, Yong; Qian, Pei-Yuan

    2015-01-01

    The active seepage of the marine cold seeps could be a critical process for the exchange of energy between the submerged geosphere and the sea floor environment through organic-rich fluids, potentially even affecting surrounding microbial habitats. However, few studies have investigated the associated microbial community changes. In the present study, 16S rRNA genes were pyrosequenced to decipher changes in the microbial communities from the Thuwal seepage point in the Red Sea to nearby marine sediments in the brine pool, normal marine sediments and water, and benthic microbial mats. An unexpected number of reads from unclassified groups were detected in these habitats; however, the ecological functions of these groups remain unresolved. Furthermore, ammonia-oxidizing archaeal community structures were investigated using the ammonia monooxygenase subunit A (amoA) gene. Analysis of amoA showed that planktonic marine habitats, including seeps and marine water, hosted archaeal ammonia oxidizers that differed from those in microbial mats and marine sediments, suggesting modifications of the ammonia oxidizing archaeal (AOA) communities along the environmental gradient from active seepage sites to peripheral areas. Changes in the microbial community structure of AOA in different habitats (water vs. sediment) potentially correlated with changes in salinity and oxygen concentrations. Overall, the present results revealed for the first time unanticipated novel microbial groups and changes in the ammonia-oxidizing archaea in response to environmental gradients near the active seepages of a cold seep.

  8. Microbial community changes along the active seepage site of one cold seep in the Red Sea

    PubMed Central

    Cao, Huiluo; Zhang, Weipeng; Wang, Yong; Qian, Pei-Yuan

    2015-01-01

    The active seepage of the marine cold seeps could be a critical process for the exchange of energy between the submerged geosphere and the sea floor environment through organic-rich fluids, potentially even affecting surrounding microbial habitats. However, few studies have investigated the associated microbial community changes. In the present study, 16S rRNA genes were pyrosequenced to decipher changes in the microbial communities from the Thuwal seepage point in the Red Sea to nearby marine sediments in the brine pool, normal marine sediments and water, and benthic microbial mats. An unexpected number of reads from unclassified groups were detected in these habitats; however, the ecological functions of these groups remain unresolved. Furthermore, ammonia-oxidizing archaeal community structures were investigated using the ammonia monooxygenase subunit A (amoA) gene. Analysis of amoA showed that planktonic marine habitats, including seeps and marine water, hosted archaeal ammonia oxidizers that differed from those in microbial mats and marine sediments, suggesting modifications of the ammonia oxidizing archaeal (AOA) communities along the environmental gradient from active seepage sites to peripheral areas. Changes in the microbial community structure of AOA in different habitats (water vs. sediment) potentially correlated with changes in salinity and oxygen concentrations. Overall, the present results revealed for the first time unanticipated novel microbial groups and changes in the ammonia-oxidizing archaea in response to environmental gradients near the active seepages of a cold seep. PMID:26284035

  9. Assessment of electrical resistivity method to map groundwater seepage zones in heterogeneous sediments

    USGS Publications Warehouse

    Gagliano, Michael P.; Nyquist, Jonathan E.; Toran, Laura; Rosenberry, Donald O.

    2009-01-01

    Underwater electrical‐resistivity data were collected along the southwest shore of Mirror Lake, NH, as part of a multi‐year assessment of the utility of geophysics for mapping groundwater seepage beneath lakes. We found that resistivity could locate shoreline sections where water is seeping out of the lake. A resistivity line along the lake bottom starting 27‐m off shore and continuing 27‐m on shore (1‐m electrode spacing) showed the water table dipping away from the lake, the gradient indicative of lake discharge in this area. Resistivity could also broadly delineate high‐seepage zones. An 80‐m line run parallel to shore using a 0.5‐m electrode spacing was compared with measurements collected the previous year using 1‐m electrode spacing. Both data sets showed the transition from high‐seepage glacial outwash, to low‐seepage glacial till, demonstrating reproducibility. However, even the finer 0.5‐m electrode spacing was insufficient to resolve the heterogeneity well enough to predict seepage variability within each zone. For example, over a 12.5‐m stretch where seepage varied from 1–38 cm/day, resistivity varied horizontally from 700–3900 ohm‐m and vertically in the top 2‐m from 900–4000 ohm‐m without apparent correlation with seepage. In two sections along this 80‐m line, one over glacial outwash, the other over till, we collected 14 parallel lines of resistivity, 13.5 m long spaced 1 m apart to form a 13.5 × 13 m data grid. These lines were inverted individually using a 2‐D inversion program and then interpolated to create a 3‐D volume. Examination of resistivity slices through this volume highlights the heterogeneity of both these materials, suggesting groundwater flow takes sinuous flow paths. In such heterogeneous materials the goal of predicting the precise location of high‐seepage points remains elusive.

  10. H-Area Seepage Basins. Third quarter 1990 groundwater quality assessment report

    SciTech Connect

    Stejskal, G.

    1990-12-01

    During the third quarter of 1990 the wells which make up the H-Area Seepage Basins (H-HWMF) monitoring network were sampled. Laboratory analyses were performed to measure levels of hazardous constituents, indicator parameters, tritium, nonvolatile beta, and gross alpha. A Gas Chromatograph Mass Spectrometer (GCMS) scan was performed on all wells sampled to determine any hazardous organic constituents present in the groundwater. The primary contaminants observed at wells monitoring the H-Area Seepage Basins are tritium, nitrate, mercury, gross alpha, nonvolatile beta, trichloroethylene (TCE), tetrachloroethylene, lead, cadmium, arsenic, and total radium.

  11. H-Area Seepage Basin (H-HWMF): Fourth quarterly 1989, groundwater quality assessment report

    SciTech Connect

    Not Available

    1990-03-01

    During the fourth quarter of 1989 the wells which make up the H-Area Seepage Basins (H-HWMF){sup 1} monitoring network were sampled. Laboratory analyses were performed to measure levels of hazardous constituents, indicator parameters, tritium, and gross alpha. A Gas Chromatograph Mass Spectrometer (GCMS) scan was performed on all wells sampled to determine any hazardous organic constituents present in the groundwater. The primary contaminants observed at wells monitoring the H-Area Seepage Basins are tritium, nitrate, mercury, gross alpha, and total radium.

  12. H-Area Seepage Basin (H-HWMF): Fourth quarterly 1989, groundwater quality assessment report

    SciTech Connect

    Not Available

    1990-03-01

    During the fourth quarter of 1989 the wells which make up the H-Area Seepage Basins (H-HWMF){sup 1} monitoring network were sampled. Laboratory analyses were performed to measure levels of hazardous constituents, indicator parameters, tritium, and gross alpha. A Gas Chromatograph Mass Spectrometer (GCMS) scan was performed on all wells sampled to determine any hazardous organic constituents present in the groundwater. The primary contaminants observed at wells monitoring the H-Area Seepage Basins are tritium, nitrate, mercury, gross alpha, and total radium.

  13. Methane seepage effects on biodiversity and biological traits of macrofauna inhabiting authigenic carbonates

    NASA Astrophysics Data System (ADS)

    Levin, Lisa A.; Mendoza, Guillermo F.; Grupe, Benjamin M.

    2017-03-01

    Authigenic carbonate rocks at methane seeps are recognized as hosting diverse and abundant invertebrate assemblages, with potential forcing from fluid seepage and hydrography. Mensurative studies of carbonate macrofauna (>0.3 mm) at Hydrate Ridge, OR revealed little effect of water depth and overlying oxygenation (at 600 m and 800 m) but a large influence of seepage activity on density, taxonomic composition, diversity, and biological traits (feeding, lifestyle, motility, size and calcification). Rocks exposed to active seepage had 3-4× higher total macrofaunal densities than under inactive conditions. Assemblages exhibited higher species richness and reduced evenness (greater dominance) under active seepage than inactive conditions, but no difference in H‧ or rarefaction diversity. Actively seeping sites were characterized by errant (motile), bacterial grazing, small- and medium-sized, heavily calcified species, whereas inactive sites exhibited a greater diversity of feeding modes and more burrowers, sessile, large and lightly calcified species. Active rocks supported more exogonid (Syllidae), ampharetid, and cirratulid polychaetes, provannid snails, pyropeltid limpets, nemerteans, and sponges; whereas inactive rocks supported higher densities of ophiuroids, isopods, gammarid amphipods, hydroids, Typosyllis (Syllidae) and tanaids. Transplant experiments, in which rocks were transferred between active and inactive sites at Hydrate Ridge North (600 m), revealed that assemblages respond within 13 months to increase or cessation of seepage, taking on the feeding, size and calcification characteristics of the background fauna at the new site. Lifestyles and motility patterns shifted more slowly as the sessile, attached species did not track seepage as quickly. Provannid snails and pyropeltid limpets rapidly colonized rocks transplanted to active sites and disappeared when transplanted to inactive sites. Given the known variability of fluid fluxes and rapid community

  14. Seismic stability of subsea tunnels subjected to seepage.

    PubMed

    Cheng, Xuansheng; Ren, Yi; Du, Xiuli; Zhang, Yida

    2014-01-01

    Strength reduction method and ADINA software are adopted to study the stability of submarine tunnel structures subjected to seepage and earthquake under different seawater depths and overlying rock strata thicknesses. First, the excess pore water pressure in the rock mass is eliminated through consolidation calculation. Second, dynamic time-history analysis is performed by inputting the seismic wave to obtain the maximum horizontal displacement at the model top. Finally, static analysis is conducted by inputting the gravity and the lateral border node horizontal displacement when the horizontal displacement is the largest on the top border. The safety factor of a subsea tunnel structure subjected to seepage and earthquake is obtained by continuously reducing the shear strength parameters until the calculation is not convergent. The results show that the plastic zone initially appears at a small scope on the arch feet close to the lining structure and at both sides of the vault. Moreover, the safety factor decreases with increasing seawater depth and overlying rock strata thickness. With increasing seawater depth and overlying rock strata thickness, maximum main stress, effective stress, and maximum displacement increase, whereas displacement amplitude slightly decreases.

  15. Seismic Stability of Subsea Tunnels Subjected to Seepage

    PubMed Central

    Cheng, Xuansheng; Ren, Yi; Du, Xiuli

    2014-01-01

    Strength reduction method and ADINA software are adopted to study the stability of submarine tunnel structures subjected to seepage and earthquake under different seawater depths and overlying rock strata thicknesses. First, the excess pore water pressure in the rock mass is eliminated through consolidation calculation. Second, dynamic time-history analysis is performed by inputting the seismic wave to obtain the maximum horizontal displacement at the model top. Finally, static analysis is conducted by inputting the gravity and the lateral border node horizontal displacement when the horizontal displacement is the largest on the top border. The safety factor of a subsea tunnel structure subjected to seepage and earthquake is obtained by continuously reducing the shear strength parameters until the calculation is not convergent. The results show that the plastic zone initially appears at a small scope on the arch feet close to the lining structure and at both sides of the vault. Moreover, the safety factor decreases with increasing seawater depth and overlying rock strata thickness. With increasing seawater depth and overlying rock strata thickness, maximum main stress, effective stress, and maximum displacement increase, whereas displacement amplitude slightly decreases. PMID:24778591

  16. Quantitative determination of engine water ingestion

    NASA Technical Reports Server (NTRS)

    Parikh, P.; Hernan, M.; Sarohia, V.

    1986-01-01

    A nonintrusive optical technique is described for determination of liquid mass flux in a droplet laden airstream. The techniques were developed for quantitative determination of engine water ingestion resulting from heavy rain or wheel spray. Independent measurements of the liquid water content (LWC) of the droplet laden airstream and of the droplet velocities were made at the stimulated nacelle inlet plane for the liquid mass flux determination. The LWC was measured by illuminating and photographing the droplets contained within a thin slice of the flow field by means of a sheet of light from a pulsed laser. A fluorescent dye introduced in the water enchanced the droplet image definition. The droplet velocities were determined from double exposed photographs of the moving droplet field. The technique was initially applied to a steady spray generated in a wind tunnel. It was found that although the spray was initially steady, the aerodynamic breakup process was inherently unsteady. This resulted in a wide variation of the instantaneous LWC of the droplet laden airstream. The standard deviation of ten separate LWC measurements was 31% of the average. However, the liquid mass flux calculated from the average LWC and droplet velocities came within 10% of the known water ingestion rate.

  17. Seepage Bifurcation as a Critical Process

    NASA Astrophysics Data System (ADS)

    Yi, R.; Rothman, D.

    2015-12-01

    Channel networks form beautiful and surprisingly intricate geometries, yet diligently evade comprehensive mathematical understanding. Work in recent years has shed light on this problem. Networks driven by seepage flow, in particular, have been shown to grow in a field that can be described by the Laplace equation, providing us with an understanding of valley growth and shape. However, the process by which such networks branch to form these ramified shapes is yet a mystery. We focus our attention on a highly ramified seepage valley network in Bristol, Florida. We study the behavior of flux to valley heads as a function of valley length, and use this result to motivate our discussion of branch formation. We then hypothesize that a critical groundwater flux demarcates a transition point where topographic diffusion is overcome by branching processes, and we present network-wide flux calculations, cosmogenic data, and simulation to support our claim. Our results ultimately suggest a mechanism for seepage bifurcation, and inform our understanding of pattern formation in river networks.

  18. Inertial (non-Darcian) channeled seepage flow

    NASA Astrophysics Data System (ADS)

    Foda, Mostafa A.

    1994-10-01

    A slow wave solution is identified for an infinite elastic medium intersected by a two-dimensional fluid channel. Because the wave speed is much slower than the medium's elastic shear wave, the response in the elastic medium is governed by elastostatics. The inertia of the wave is essentially focused in the fluid channel. Furthermore, wave damping is caused by fluid viscous friction on the channel in an elastic solid. It is proposed that these solutions may also be used in the case of a granular porous medium. The seepage channels would then represent a network of preferential flow paths. Therefore we would allow, in this case, the channel porosity to be different from the average granular porosity. For a strongly channel seepage flow or for a low channel porosity the solution is shown to approach that of a single-channel solution, giving rise to a slow propagating wave mode. On the other hand, for weak channeling or nearly `homogeneous' seepage flow the solution is shown to reproduce Biot's (1956) critically damped wave of the second kind. It is proposed that the resonance observed by Foda and Tzang (1994) are in the form of these strongly channeled wave modes.

  19. The impact of oil seepages and municipal wastewaters on Tembi River sediments, Masjedsoleyman (SW Iran)

    NASA Astrophysics Data System (ADS)

    Bavarsad, Zeynab; Moore, Farid; Modaberi, Soroush; Hessam, Alireza

    2010-05-01

    Oil seepage in Masjedsoleyman oil-producing region and urban and industrial effluents discharge into the main stream of Masjedsoleyman and eventually into Tembi River has polluted this river. The water of Masjedsoleyman main stream is used for livestock drinking and Tembi River is famous as a tourist site and camping. In this study, ten sampling stations were chosen along the main stream of Masjed¬soleyman and Tembi River. Heavy metal concentrations (Zn, Ni, Cu, Cd, Co, Cr, Pb, Fe), carbonate content, texture, pH, total petroleum hydrocarbon (TPH), total organic carbon (TOC) and free hydrocarbon(S1) in sediments samples were analyzed using ICP-MS, GC-MS and Rockeval 6. In order to determine the most important transporting phase in the sediment, Tessier sequential extraction is used. Correlation between metals and petroleum hydrocarbon and physical properties of sediment, probable source and spread of pollution are discussed. The concentration of contaminants is compared with threshold effect concentration (TEC) and probable effect concentration (PEC). Contamination factor (CF) has been calculated to assess the degree of pollution in sediments. Enrichment factors illustrate maximum enrichment of metals in sediments of Dare Khersan of Masjedsoleyman stream. Sequential extraction analysis shows iron, chrome, copper and zinc accumulate mainly in residual phase. In the majority of sediment Pb occurs in the organic fraction. Cd in sediments appears mainly in the exchangeable fraction, followed by the Fe-Mn oxides and residual fractions. The bioavailability of heavy metals decrease as Cd> Ni> Co> Pb> Cr> Zn> Cu> Fe. This study shows that the major source of heavy metals is the discharge of municipal sewage but the source of Ni is the oil seepages. Comparing the heavy metal concentrations with the consensus-based TEC and PEC values revealed that some metals such as Cd, Cr, Ni and Zn in some sediment samples are higher than both TEC and PEC, values

  20. The origin of elevated water levels in emplacement boreholes, Pahute Mesa, Nevada Test Site: A numerical study

    SciTech Connect

    Gardner, G.G.; Brikowski, T.H.

    1993-12-01

    The origin of elevated water levels in emplacement boreholes at Pahute Mesa, Nevada Test Site, is uncertain. If the water is from naturally perched aquifers, then presumed ``above water table`` weapons tests may directly impact the groundwater quality. The purpose of this study is to determine the probable source of the elevated water in boreholes by comparing modeled seepage of infiltrated drilling fluids, and the seepage from a simulated naturally perched aquifer with the observed water level history. In the model, large volumes of water are infiltrated, yet return flow of fluids back into the hole stops within three days after the end of drilling and is insufficient to produce observed standing water. Return flow is limited for two reasons: (1) the volume of the saturated rock next to the borehole is small; (2) pressure head gradient direct unsaturated flow away from the borehole. Simulation of seepage from a naturally perched aquifer readily reproduces the observed water levels.

  1. Evaluation of seepage and discharge uncertainty in the middle Snake River, southwestern Idaho

    USGS Publications Warehouse

    Wood, Molly S.; Williams, Marshall L.; Evetts, David M.; Vidmar, Peter J.

    2014-01-01

    The U.S. Geological Survey, in cooperation with the State of Idaho, Idaho Power Company, and the Idaho Department of Water Resources, evaluated seasonal seepage gains and losses in selected reaches of the middle Snake River, Idaho, during November 2012 and July 2013, and uncertainty in measured and computed discharge at four Idaho Power Company streamgages. Results from this investigation will be used by resource managers in developing a protocol to calculate and report Adjusted Average Daily Flow at the Idaho Power Company streamgage on the Snake River below Swan Falls Dam, near Murphy, Idaho, which is the measurement point for distributing water to owners of hydropower and minimum flow water rights in the middle Snake River. The evaluated reaches of the Snake River were from King Hill to Murphy, Idaho, for the seepage studies and downstream of Lower Salmon Falls Dam to Murphy, Idaho, for evaluations of discharge uncertainty. Computed seepage was greater than cumulative measurement uncertainty for subreaches along the middle Snake River during November 2012, the non-irrigation season, but not during July 2013, the irrigation season. During the November 2012 seepage study, the subreach between King Hill and C J Strike Dam had a meaningful (greater than cumulative measurement uncertainty) seepage gain of 415 cubic feet per second (ft3/s), and the subreach between Loveridge Bridge and C J Strike Dam had a meaningful seepage gain of 217 ft3/s. The meaningful seepage gain measured in the November 2012 seepage study was expected on the basis of several small seeps and springs present along the subreach, regional groundwater table contour maps, and results of regional groundwater flow model simulations. Computed seepage along the subreach from C J Strike Dam to Murphy was less than cumulative measurement uncertainty during November 2012 and July 2013; therefore, seepage cannot be quantified with certainty along this subreach. For the uncertainty evaluation, average

  2. Assessing the impact of animal waste lagoon seepage on the geochemistry of an underlying shallow aquifer.

    PubMed

    McNab, Walt W; Singleton, Michael J; Moran, Jean E; Esser, Brad K

    2007-02-01

    Evidence of seepage from animal waste holding lagoons at a dairy facility in the San Joaquin Valley of California is assessed in the context of a process geochemical model that addresses reactions associated with the formation of the lagoon water as well as reactions occurring upon the mixture of lagoon water with underlying aquifer material. Comparison of model results with observed concentrations of NH4+, K+, PO4(3-), dissolved inorganic carbon, pH, Ca2+, Mg2+, SO4(2-), Cl-, and dissolved Ar in lagoon water samples and groundwater samples suggests three key geochemical processes: (i) off-gassing of significant quantities of CO2 and CH4 during mineralization of manure in the lagoon water, (ii) ion exchange reactions that remove K+ and NH4+ from seepage water as it migrates into the underlying anaerobic aquifer material, and (iii) mineral precipitation reactions involving phosphate and carbonate minerals in the lagoon water in response to an increase in pH as well as in the underlying aquifer from elevated Ca2+ and Mg2+ levels generated by ion exchange. Substantial off-gassing from the lagoons is further indicated by dissolved argon concentrations in lagoon water samples that are below atmospheric equilibrium. As such, Ar may serve as a unique tracer for lagoon water seepage since under-saturated Ar concentrations in groundwater are unlikely to be influenced by any processes other than mechanical mixing.

  3. Catchment-scale fluorescence water quality determination.

    PubMed

    Baker, A; Inverarity, R; Ward, D

    2005-01-01

    Chemical water quality determinants and river water fluorescence were determined on the River Tyne, northeast England. Statistically significant relationships between nitrate (r = 0.87), phosphate (r = 0.80), ammonia (r = 0.70), biochemical oxygen demand (BOD) (r = 0.85) and dissolved oxygen (r = -0.65) and tryptophan-like fluorescence intensity were observed. The strongest correlations are between tryptophan-like intensity and nitrate and phosphate, which in the Tyne catchment derive predominantly from point and diffuse source sewage inputs. The correlation between BOD and the tryptophan-like fluorescence intensity suggests that this fluorescence centre is related to the bioavailable or fluorescence intensity and ammonia concentration and dissolved oxygen. The weaker correlation with ammonia is due to good ammonia treatment within the wastewater treatment plants within the catchment, and that with dissolved oxygen due to the natural aeration of the river such that this is not a good indicator of water quality. Mean annual tryptophan-like fluorescence intensity, measured by both bench and portable spectrometers, agrees well with the General Water Quality Assessment as determined by the England and Wales environmental regulators, the Environment Agency.

  4. Shallow gas hydrate within the areas of subaquatic seepage

    SciTech Connect

    Ginsburg, G.; Soloviev, V. )

    1993-09-01

    Sedimentary framework of worldwide hydrate-bearing areas and structures of sediments containing hydrates suggest that fluid filtration is the major process responsible for its generation. A study of seepage-associated hydrate accumulations that are accessible without drilling is useful for gaining an understanding of subaquatic gas hydrate formation general. Localities of shallow hydrate are indicative of oil and gas content. They also may be hazardous for oil and gas field development. The paper presents the results of exploration of gas hydrate accumulations that associate with diapirs, mud volcanoes, faults, subaquatic canyons, and pockmarks in the Caspian, Black, Okhotsk, and Barents seas. Data acquisition included echo sounding, seismic survey, ground sampling geothermic measurements, chemical and isotopic analyses of gas and water, definition of water content, and measurement of equilibrium pressures and temperatures. Hydrate content in sediments of discovered accumulations was up to 30-40% by volume. Somewhere, hydrate rests immediately on the bottom. Hydrate accumulation requires not only gas but also water input. It may be filtering either water bringing dissolved gas or pore/sea water migrating to meet gas diffusing bottomward. The models of gas hydrate formation have been developed for both gas-saturated water and free gas. Isotopic composition of water oxygen mainly results from exchange with carbonate inclusions rather than from the effect of hydrate fractionation. It is possible to evaluate hydrate content in sediments from the amount and composition of water.

  5. Testing and modeling of seepage into underground openings in aheterogeneous fracture system at Yucca Mountain, Nevada

    SciTech Connect

    Ahlers, C.F.; Trautz, R.C.; Cook, P.J.; Finsterle, S.

    2002-03-25

    We discuss field activities designed to characterize seepage into an underground opening at the potential site for geologic storage of high-level radioactive waste (HLRW) at Yucca Mountain, Nevada, and the use of these data for development and calibration of a model for predicting seepage into planned HLRW emplacement drifts. Air-injection tests were conducted to characterize the permeability of the fractured rock, and liquid-release tests (LRTs) were conducted and seepage monitored to characterize the seepage-relevant properties of the fractured rock. Both air-injection and liquid-release tests were performed in the same borehole intervals, located above the underground openings. For modeling, three-dimensional, heterogeneous permeability fields were generated, conditioned on the air-permeability data. The initial seepage data collected were used to calibrate the model and test the appropriateness of the modeling approach. A capillary-strength parameter and porosity were the model parameters selected for estimation by data inversion. However, due to the short-term nature of the initial data, the inversion process was unable to independently determine the capillary strength and porosity of the fractured rock. Subsequent seepage data collection focused on longer-term tests, a representative selection of which was used for data inversion. Field observations also played a key role by identifying factors such as evaporation and ceiling geometry that can enhance or reduce seepage. These observations help guide future test and model development by ensuring that relevant processes that influence seepage are identified, characterized, and incorporated into the model, thus increasing confidence in the parameter estimates. It is this iterative and collaborative approach to field testing and modeling, and the feedback mechanisms of field-test-methodology and model review and revision, that has been employed to continuously improve the scientific quality of the study

  6. Quantifying seepage using heat as a tracer in selected irrigation canals, Walker River Basin, Nevada, 2012 and 2013

    USGS Publications Warehouse

    Naranjo, Ramon C.; Smith, David W.

    2016-11-16

    The Walker River is an important source of water for western Nevada. The river provides water for agriculture and recharge to local aquifers used by several communities. Farmers began diverting water from the Walker River in the 1860s to support growing agricultural development. Over time, the reduced inflows into Walker Lake from upstream reservoirs and diversions have resulted in 170 feet of lake level decline and increased dissolved-solids concentrations to levels that threaten aquatic ecosystems, including survival of Lahonton cutthroat trout, a native species listed in the Endangered Species Act. Investigations of the water-budget components in the Walker River Basin have revealed uncertainty in the recharge to aquifers from irrigation canals. To address this need, the U.S. Geological Survey conducted an extensive field study from March 2012 through October 2013 to quantify seepage losses in selected canals in the Smith Valley, Mason Valley, and Walker Lake Valley irrigation areas.The seepage rates estimated for the 2012 and 2013 irrigation seasons in the Smith Valley transect sites (Saroni and Plymouth canals) ranged between 0.01 to 2.5 feet per day (ft/d) (0.01 to 0.68 cubic feet per second per mile [ft3/s-mi]). From 2012 to 2013, the average number of days the canals had flowing water decreased from 190 to 125 due to drier climate and lack of water available for diversion from the Walker River. The nearly 50-percent reductions in volumetric loss rates between 2012 and 2013 were associated with less than average diversions into canals from the Walker River and reductions in infiltration rates following routine canal maintenance.Models developed for the Saroni canal in 2012 were recalibrated in 2013 to evaluate changes in seepage as a result of siltation. Just prior to the 2012 irrigation season, nearly the entire length of the canal was cleared of vegetation and debris to improve flow conveyance. In 2013, following the first year of maintenance, a 90-percent

  7. An analytical solution for predicting the transient seepage from a subsurface drainage system

    NASA Astrophysics Data System (ADS)

    Xin, Pei; Dan, Han-Cheng; Zhou, Tingzhang; Lu, Chunhui; Kong, Jun; Li, Ling

    2016-05-01

    Subsurface drainage systems have been widely used to deal with soil salinization and waterlogging problems around the world. In this paper, a mathematical model was introduced to quantify the transient behavior of the groundwater table and the seepage from a subsurface drainage system. Based on the assumption of a hydrostatic pressure distribution, the model considered the pore-water flow in both the phreatic and vadose soil zones. An approximate analytical solution for the model was derived to quantify the drainage of soils which were initially water-saturated. The analytical solution was validated against laboratory experiments and a 2-D Richards equation-based model, and found to predict well the transient water seepage from the subsurface drainage system. A saturated flow-based model was also tested and found to over-predict the time required for drainage and the total water seepage by nearly one order of magnitude, in comparison with the experimental results and the present analytical solution. During drainage, a vadose zone with a significant water storage capacity developed above the phreatic surface. A considerable amount of water still remained in the vadose zone at the steady state with the water table situated at the drain bottom. Sensitivity analyses demonstrated that effects of the vadose zone were intensified with an increased thickness of capillary fringe, capillary rise and/or burying depth of drains, in terms of the required drainage time and total water seepage. The analytical solution provides guidance for assessing the capillary effects on the effectiveness and efficiency of subsurface drainage systems for combating soil salinization and waterlogging problems.

  8. A method for estimating spatially variable seepage and hydrualic conductivity in channels with very mild slopes

    USGS Publications Warehouse

    Shanafield, Margaret; Niswonger, Richard G.; Prudic, David E.; Pohll, Greg; Susfalk, Richard; Panday, Sorab

    2014-01-01

    Infiltration along ephemeral channels plays an important role in groundwater recharge in arid regions. A model is presented for estimating spatial variability of seepage due to streambed heterogeneity along channels based on measurements of streamflow-front velocities in initially dry channels. The diffusion-wave approximation to the Saint-Venant equations, coupled with Philip's equation for infiltration, is connected to the groundwater model MODFLOW and is calibrated by adjusting the saturated hydraulic conductivity of the channel bed. The model is applied to portions of two large water delivery canals, which serve as proxies for natural ephemeral streams. Estimated seepage rates compare well with previously published values. Possible sources of error stem from uncertainty in Manning's roughness coefficients, soil hydraulic properties and channel geometry. Model performance would be most improved through more frequent longitudinal estimates of channel geometry and thalweg elevation, and with measurements of stream stage over time to constrain wave timing and shape. This model is a potentially valuable tool for estimating spatial variability in longitudinal seepage along intermittent and ephemeral channels over a wide range of bed slopes and the influence of seepage rates on groundwater levels.

  9. Ground-based thermal imaging of groundwater flow processes at the seepage face

    NASA Astrophysics Data System (ADS)

    Deitchman, Richard S.; Loheide, Steven P.

    2009-07-01

    There is no existing method to quantitatively image groundwater processes along a seepage face. Thus, it is often difficult to quantify the magnitude and spatial variability of groundwater flux. The objective of this work is to assess the use of ground-based thermal remote sensing for fine-scale mapping of groundwater discharge and for locating the water table position along a stream bank seepage face. Seepage faces are poorly understood and often neglected in regional hydrologic studies though they likely exert significant influence on hydrologic and ecologic processes in riparian zones. Although the importance of riparian areas is broadly recognized, our ability to quantify hydrologic, ecologic and biogeochemical processes and ecosystem services is hampered by our inability to characterize spatially variable processes such as groundwater discharge. This work employs a new, transferable, non-invasive method that uses heat as a natural tracer to image spatially-variable groundwater flow processes and distinguish between focused and diffuse groundwater discharge to the surface. We report, for the first time, that thermal remote sensing of groundwater at the seepage face provides indirect imaging of both the saturated zone-unsaturated zone transition and groundwater flux at the centimeter scale, offering insight into flow heterogeneity.

  10. Combined use of thermal methods and seepage meters to efficiently locate, quantify, and monitor focused groundwater discharge to a sand-bed stream

    USGS Publications Warehouse

    Rosenberry, Donald O.; Briggs, Martin; Delin, Geoffrey N.; Hare, Danielle K.

    2016-01-01

    Quantifying flow of groundwater through streambeds often is difficult due to the complexity of aquifer-scale heterogeneity combined with local-scale hyporheic exchange. We used fiber-optic distributed temperature sensing (FO-DTS), seepage meters, and vertical temperature profiling to locate, quantify, and monitor areas of focused groundwater discharge in a geomorphically simple sand-bed stream. This combined approach allowed us to rapidly focus efforts at locations where prodigious amounts of groundwater discharged to the Quashnet River on Cape Cod, Massachusetts, northeastern USA. FO-DTS detected numerous anomalously cold reaches one to several m long that persisted over two summers. Seepage meters positioned upstream, within, and downstream of 7 anomalously cold reaches indicated that rapid groundwater discharge occurred precisely where the bed was cold; median upward seepage was nearly 5 times faster than seepage measured in streambed areas not identified as cold. Vertical temperature profilers deployed next to 8 seepage meters provided diurnal-signal-based seepage estimates that compared remarkably well with seepage-meter values. Regression slope and R2 values both were near 1 for seepage ranging from 0.05 to 3.0 m d−1. Temperature-based seepage model accuracy was improved with thermal diffusivity determined locally from diurnal signals. Similar calculations provided values for streambed sediment scour and deposition at subdaily resolution. Seepage was strongly heterogeneous even along a sand-bed river that flows over a relatively uniform sand and fine-gravel aquifer. FO-DTS was an efficient method for detecting areas of rapid groundwater discharge, even in a strongly gaining river, that can then be quantified over time with inexpensive streambed thermal methods.

  11. Combined use of thermal methods and seepage meters to efficiently locate, quantify, and monitor focused groundwater discharge to a sand-bed stream

    NASA Astrophysics Data System (ADS)

    Rosenberry, Donald O.; Briggs, Martin A.; Delin, Geoffrey; Hare, Danielle K.

    2016-06-01

    Quantifying flow of groundwater through streambeds often is difficult due to the complexity of aquifer-scale heterogeneity combined with local-scale hyporheic exchange. We used fiber-optic distributed temperature sensing (FO-DTS), seepage meters, and vertical temperature profiling to locate, quantify, and monitor areas of focused groundwater discharge in a geomorphically simple sand-bed stream. This combined approach allowed us to rapidly focus efforts at locations where prodigious amounts of groundwater discharged to the Quashnet River on Cape Cod, Massachusetts, northeastern USA. FO-DTS detected numerous anomalously cold reaches one to several m long that persisted over two summers. Seepage meters positioned upstream, within, and downstream of 7 anomalously cold reaches indicated that rapid groundwater discharge occurred precisely where the bed was cold; median upward seepage was nearly 5 times faster than seepage measured in streambed areas not identified as cold. Vertical temperature profilers deployed next to 8 seepage meters provided diurnal-signal-based seepage estimates that compared remarkably well with seepage-meter values. Regression slope and R2 values both were near 1 for seepage ranging from 0.05 to 3.0 m d-1. Temperature-based seepage model accuracy was improved with thermal diffusivity determined locally from diurnal signals. Similar calculations provided values for streambed sediment scour and deposition at subdaily resolution. Seepage was strongly heterogeneous even along a sand-bed river that flows over a relatively uniform sand and fine-gravel aquifer. FO-DTS was an efficient method for detecting areas of rapid groundwater discharge, even in a strongly gaining river, that can then be quantified over time with inexpensive streambed thermal methods.

  12. Drift-Scale Coupled Processes (DST and THC Seepage) Models

    SciTech Connect

    E. Gonnenthal; N. Spyoher

    2001-02-05

    The purpose of this Analysis/Model Report (AMR) is to document the Near-Field Environment (NFE) and Unsaturated Zone (UZ) models used to evaluate the potential effects of coupled thermal-hydrologic-chemical (THC) processes on unsaturated zone flow and transport. This is in accordance with the ''Technical Work Plan (TWP) for Unsaturated Zone Flow and Transport Process Model Report'', Addendum D, Attachment D-4 (Civilian Radioactive Waste Management System (CRWMS) Management and Operating Contractor (M and O) 2000 [153447]) and ''Technical Work Plan for Nearfield Environment Thermal Analyses and Testing'' (CRWMS M and O 2000 [153309]). These models include the Drift Scale Test (DST) THC Model and several THC seepage models. These models provide the framework to evaluate THC coupled processes at the drift scale, predict flow and transport behavior for specified thermal loading conditions, and predict the chemistry of waters and gases entering potential waste-emplacement drifts. The intended use of this AMR is to provide input for the following: (1) Performance Assessment (PA); (2) Abstraction of Drift-Scale Coupled Processes AMR (ANL-NBS-HS-000029); (3) UZ Flow and Transport Process Model Report (PMR); and (4) Near-Field Environment (NFE) PMR. The work scope for this activity is presented in the TWPs cited above, and summarized as follows: continue development of the repository drift-scale THC seepage model used in support of the TSPA in-drift geochemical model; incorporate heterogeneous fracture property realizations; study sensitivity of results to changes in input data and mineral assemblage; validate the DST model by comparison with field data; perform simulations to predict mineral dissolution and precipitation and their effects on fracture properties and chemistry of water (but not flow rates) that may seep into drifts; submit modeling results to the TDMS and document the models. The model development, input data, sensitivity and validation studies described in

  13. Drift-Scale Coupled Processes (DST and THC Seepage) Models

    SciTech Connect

    E. Sonnenthale

    2001-04-16

    The purpose of this Analysis/Model Report (AMR) is to document the Near-Field Environment (NFE) and Unsaturated Zone (UZ) models used to evaluate the potential effects of coupled thermal-hydrologic-chemical (THC) processes on unsaturated zone flow and transport. This is in accordance with the ''Technical Work Plan (TWP) for Unsaturated Zone Flow and Transport Process Model Report'', Addendum D, Attachment D-4 (Civilian Radioactive Waste Management System (CRWMS) Management and Operating Contractor (M&O) 2000 [1534471]) and ''Technical Work Plan for Nearfield Environment Thermal Analyses and Testing'' (CRWMS M&O 2000 [153309]). These models include the Drift Scale Test (DST) THC Model and several THC seepage models. These models provide the framework to evaluate THC coupled processes at the drift scale, predict flow and transport behavior for specified thermal loading conditions, and predict the chemistry of waters and gases entering potential waste-emplacement drifts. The intended use of this AMR is to provide input for the following: Performance Assessment (PA); Near-Field Environment (NFE) PMR; Abstraction of Drift-Scale Coupled Processes AMR (ANL-NBS-HS-000029); and UZ Flow and Transport Process Model Report (PMR). The work scope for this activity is presented in the TWPs cited above, and summarized as follows: Continue development of the repository drift-scale THC seepage model used in support of the TSPA in-drift geochemical model; incorporate heterogeneous fracture property realizations; study sensitivity of results to changes in input data and mineral assemblage; validate the DST model by comparison with field data; perform simulations to predict mineral dissolution and precipitation and their effects on fracture properties and chemistry of water (but not flow rates) that may seep into drifts; submit modeling results to the TDMS and document the models. The model development, input data, sensitivity and validation studies described in this AMR are required

  14. Empirical sediment transport function predicting seepage erosion undercutting for cohesive bank failure prediction

    USDA-ARS?s Scientific Manuscript database

    Seepage erosion is an important factor in hillslope instability and failure. However, predicting erosion by subsurface flow or seepage and incorporating its effects into stability models remains a challenge. Limitations exist with all existing seepage erosion sediment transport functions, including ...

  15. Sources, extent and history of methane seepage on the continental shelf off northern Norway

    NASA Astrophysics Data System (ADS)

    Sauer, Simone; Lepland, Aivo; Chand, Shyam; Schubert, Carsten J.; Eichinger, Florian; Knies, Jochen

    2014-05-01

    Active natural hydrocarbon gas seepage was recently discovered in the Hola area on the continental shelf off Vesterålen, northern Norway. We conducted acoustic and geochemical investigations to assess the modern and past extent, source and pathways of the gas seepage . Water column echosounder surveys showed bubble plumes up to several tens of metres above the seafloor. Analyses of dissolved methane in the water column indicated slightly elevated concentrations (50 nM) close to the seafloor. To identify fluxes and origin of methane in the sediments we analysed sediment pore water chemistry, the isotopic composition of methane and of dissolved inorganic carbon (d13CCH4, d2HCH4, d13CDIC) in three closely spaced (

  16. Determination of beta activity in water

    USGS Publications Warehouse

    Barker, F.B.; Robinson, B.P.

    1963-01-01

    Many elements have one or more naturally radioactive isotopes, and several hundred other radionuclides have been produced artificially. Radioactive substances may be present in natural water as a result of geochemical processes or the release of radioactive waste and other nuclear debris to the environment. The Geological Survey has developed methods for measuring certain of these .radioactive substances in water. Radioactive substances often are present in water samples in microgram quantities or less. Therefore, precautions must be taken to prevent loss of material and to assure that the sample truly represents its source at the time of collection. Addition of acids, complexing agents, or stable isotopes often aids in preventing loss of radioactivity on container walls, on sediment, or on other solid materials in contact with the sample. The disintegration of radioactive atoms is a random process subject to established methods of statistical analysis. Because many water samples contain small amounts of radioactivity, low-level counting techniques must be used. The usual assumption that counting data follow a Gaussian distribution is invalid under these conditions, and statistical analyses must be based on the Poisson distribution. The gross beta activity in water samples is determined from the residue left after evaporation of the sample to dryness. Evaporation is accomplished first in a teflon dish, then the residue is transferred with distilled water to a counting planchet and again is reduced to dryness. The radioactivity on the planchet is measured with an anticoincidence-shielded, low-background, beta counter and is compared with measurements of a strontium-90-yttrium-90 standard prepared and measured in the same manner. Control charts are used to assure consistent operation of the counting instrument.

  17. Application of unsaturated zone hydrology at waste rock facilities: Design of soil covers and prediction of seepage

    SciTech Connect

    Swanson, D.A.; O'Kane, M.

    1999-07-01

    The design of soil covers and the prediction of seepage for waste rock facilities are important components of permitting and closure at mines situated in arid climates. This design and prediction require an understanding and application of unsaturated zone hydrology, which, in many respects in counter-intuitive compared to the saturated conditions that are predominant in groundwater hydrology. For example, water under saturated conditions prefers to flow through course textured materials, whereas, under unsaturated conditions, water may prefer to flow through finer textured materials. To ensure accurate and defensible soil cover design and seepage prediction for waste rock facilities, methods must be employed using conceptual models based on unsaturated zone hydrology.

  18. Attention turns to naturally occurring methane seepage

    NASA Astrophysics Data System (ADS)

    Kvenvolden, Keith A.; Lorenson, Thomas D.; Reeburgh, William S.

    Methane is the most abundant organic compound in the Earth's atmosphere. As a powerful greenhouse gas, it has implications for global climate change. Sources of methane to the atmosphere are varied. Depending on the source, methane can contain either modern or ancient carbon. Methane exiting from swamps and wetlands contains modern carbon, whereas methane leaking from petroleum reservoirs contains ancient carbon. The total annual source of methane to the atmosphere has been constrained to about 540 teragrams (Tg) per year “Cicerone and Oremland, 1988”. Notably absent from any identified sources is the contribution of geologically sourced methane from naturally occurring seepage.

  19. Determination of uranium in natural waters

    USGS Publications Warehouse

    Barker, Franklin Butt; Johnson, J.O.; Edwards, K.W.; Robinson, B.P.

    1965-01-01

    A method is described for the determination of very low concentrations of uranium in water. The method is based on the fluorescence of uranium in a pad prepared by fusion of the dried solids from the water sample with a flux of 10 percent NaF 45.5 percent Na2CO3 , and 45.5 percent K2CO3 . This flux permits use of a low fusion temperature and yields pads which are easily removed from the platinum fusion dishes for fluorescence measurements. Uranium concentrations of less than 1 microgram per liter can be determined on a sample of 10 milliliters, or less. The sensitivity and accuracy of the method are dependent primarily on the purity of reagents used, the stability and linearity of the fluorimeter, and the concentration of quenching elements in the water residue. A purification step is recommended when the fluorescence is quenched by more than 30 percent. Equations are given for the calculation of standard deviations of analyses by this method. Graphs of error functions and representative data are also included.

  20. Chromatographic determination of solubilities in superheated water.

    PubMed

    Jones, Neil; Clifford, Anthony A; Bartle, Keith D; Myers, Peter

    2010-10-01

    Superheated water (SHW) is an effective solvent for the extraction of a variety of environmental pollutants, but knowledge of the solubilities in water at elevated temperatures necessary to maximise the efficiency of the process is often lacking. Ambient temperature aqueous solubilities have been measured by reverse-phase HPLC from correlations with retention factors, k, but for poorly soluble organics the eluent must contain a proportion of organic modifier followed by extrapolation to pure water. The use of SHW as mobile phase allows direct determination of aqueous solubility from measurement of k on a modified HPLC system in which the eluent is cooled before detection to improve baseline stability. Alumina-bonded octadecylsilane columns were found to be more stable in SHW chromatography than their silica-bonded counterparts. To validate the procedure, measurements of k were made between 100 and 200°C for toluene and correlated with literature solubilities; the solubilities at 170°C of a number of related aromatics were then determined from their k-values.

  1. Study of a Seepage Channel Formation Using the Combination of Microseismic Monitoring Technique and Numerical Method in Zhangmatun Iron Mine

    NASA Astrophysics Data System (ADS)

    Zhang, Penghai; Yang, Tianhong; Yu, Qinglei; Xu, Tao; Shi, Wenhao; Li, Shucai

    2016-09-01

    In 1996, a grout curtain was constructed in the Zhangmatun Iron Mine near Jinan City, China, which is subject to large groundwater inflows, to decrease the water volume rushing into the mine workings. However, water inflow has recently been increasing in the southwestern area through a seepage channel, which has resulted from the failure of the grout curtain. To understand how the seepage channel formed, the microseismic (MS) activities located in this area were studied and a numerical model was supplementarily used to analyze the damage zone. It is found that the seepage channel formation process is significantly affected by the distance between mining activities and the grout curtain. Mining activities periodically approached and retreated from the southwest grout curtain, causing periodically active and inactive microseismicity, and eventually the grout curtain failure. The damage zone in the grout curtain obtained from the numerical analysis coincides with the seepage channel, especially in the area where the distance between the grout curtain and excavation is less than 35 m. Therefore, the combination of MS monitoring and numerical analysis of damage zones can provide us with an overall understanding of the formation process and causes of the seepage channel.

  2. Calibration and use of continuous heat-type automated seepage meters for submarine groundwater discharge measurements

    USGS Publications Warehouse

    Mwashote, B.M.; Burnett, W.C.; Chanton, J.; Santos, I.R.; Dimova, N.; Swarzenski, P.W.

    2010-01-01

    Submarine groundwater discharge (SGD) assessments were conducted both in the laboratory and at a field site in the northeastern Gulf of Mexico, using a continuous heat-type automated seepage meter (seepmeter). The functioning of the seepmeter is based on measurements of a temperature gradient in the water between downstream and upstream positions in its flow pipe. The device has the potential of providing long-term, high-resolution measurements of SGD. Using a simple inexpensive laboratory set-up, we have shown that connecting an extension cable to the seepmeter has a negligible effect on its measuring capability. Similarly, the observed influence of very low temperature (???3 ??C) on seepmeter measurements can be accounted for by conducting calibrations at such temperatures prior to field deployments. Compared to manual volumetric measurements, calibration experiments showed that at higher water flow rates (>28 cm day-1 or cm3 cm-2 day-1) an analog flowmeter overestimated flow rates by ???7%. This was apparently due to flow resistance, turbulence and formation of air bubbles in the seepmeter water flow tubes. Salinity had no significant effect on the performance of the seepmeter. Calibration results from fresh water and sea water showed close agreement at a 95% confidence level significance between the data sets from the two media (R2 = 0.98). Comparatively, the seepmeter SGD measurements provided data that are comparable to manually-operated seepage meters, the radon geochemical tracer approach, and an electromagnetic (EM) seepage meter. ?? 2009 Elsevier Ltd.

  3. Catalytic determination of vanadium in water

    USGS Publications Warehouse

    Fishman, M. J.; Skougstad, M.W.

    1964-01-01

    A rapid, accurate, and sensitive spectrophotometric method for the quantitative determination of trace amounts of vanadium in water is based on the catalytic effect of vanadium on the rate of oxidation of gallic acid by persulfate in acid solution. Under given conditions of concentrations of reactants, temperature, and reaction time, the extent of oxidation of gallic acid is proportional to the concentration of vanadium present. Vanadium is determined by measuring the absorbance of the sample at 415 m?? and comparison with standard solutions treated in an identical manner. Concentrations in the range of from 0.1 to 8.0 ??g. per liter may be determined with a standard deviation of 0.2 or less. By reducing the reaction time, the method may be extended to cover the range from 1 to 100 ??g. with a standard deviation of 0.8 or less. Several substances interfere, including chloride above 100 p.p.m., and bromide and iodide in much lower concentrations. Interference from the halides is eliminated or minimized by the addition of mercuric nitrate solution. Most other substances do not interfere at the concentration levels at which they commonly occur in natural waters.

  4. Model Experiments and Elasto-Plastic Finite Element Analysis about Seepage Failure of Sand Behind Fixed Sheet Pile

    NASA Astrophysics Data System (ADS)

    Okajima, Kenji; Tanaka, Tadatsugu; Zhang, Shanji; Komatsu, Takahiro

    Constructing civil engineering structures, temporaly or permanent water proofing sheet piles often are used. The stability of seepage failure are carefully applied to those sheet piles, although many troubles of seepage failure were reported. On this problem the predictive method of the deformation and critical water head is required. In this study we carried out the model experiments which were designed for studying the seepage failure of soil behind fixed sheet piles and our elasto-plastic finite element method was applied to verify the effectiveness. Terzaghi method is very famous method for this problem and Terzaghi method was investigated by experiments data. As a result, it was confirmed that elasto-plastic finite element method was effectiveness and Terzaghi method was useful for this problem.

  5. Seepage study of Mapleton Lateral Canal near Mapleton, Utah, 2003

    USGS Publications Warehouse

    Wilkowske, Chris D.; Phillips, Jeff V.

    2004-01-01

    A study was conducted during the summer of 2003 on Mapleton Lateral Canal near Mapleton, Utah, to determine gain or loss of flow in the canal from seepage. Measurements were made in May, June, July, and September of 2003. The uppermost reach of the canal had an apparent average loss of 2.6 cubic feet per second. The next reach downstream showed an apparent average gain of 1.4 cubic feet per second. The next three downstream reaches had apparent average losses of 2.4, 2.5, and 2.7 cubic feet per second. The apparent average net loss from the canal was 8.8 cubic feet per second, or a loss of 30 percent of the total discharge measured at the head of the canal.

  6. Experimental Investigation of Seepage Properties of Fractured Rocks Under Different Confining Pressures

    NASA Astrophysics Data System (ADS)

    Ma, D.; Miao, X. X.; Chen, Z. Q.; Mao, X. B.

    2013-09-01

    The effectiveness of transmitting underground water in rock fractures is strongly influenced by the widths of the fractures and their interconnections. However, the geometries needed for water flow in fractured rock are also heavily controlled by the confining pressure conditions. This paper is intended to study the seepage properties of fractured rocks under different confining pressures. In order to do this, we designed and manufactured a water flow apparatus that can be connected to the electro-hydraulic servo-controlled test system MTS815.02, which provides loading and exhibits external pressures in the test. Using this apparatus, we tested fractured mudstone, limestone and sandstone specimens and obtained the relationship between seepage properties and variations in confining pressure. The calculation of the seepage properties based on the collection of water flow and confining pressure differences is specifically influenced by non-Darcy flow. The results show that: (1) The seepage properties of fractured rocks are related to confining pressure, i.e. with the increase of confining pressure, the permeability decreases and the absolute value of non-Darcy flow coefficient increases. (2) The sandstone coefficients and range from to m2 and to m-1, respectively, and exhibit a greater change compared to coefficients of mudstone and limestone. (3) From the regression analysis of experimental data, it is concluded that the polynomial function is a better fit than the power and logarithmic functions. The results obtained can provide an important reference for understanding the stability of rock surrounding roadways toward prevention of underground water gushing-out, and for developing underground resources (e.g. coal).

  7. Analysis of influence of seepage on stability of foundation pit

    NASA Astrophysics Data System (ADS)

    Li, Yongfu; Chai, Junrui; Xu, Zengguang

    2017-06-01

    Numerical analysis is executed to deep foundation pit by using the finite element software. In combination with the site data, the consequences with the consideration of groundwater seepage are contrasted to the consequences without the consideration of groundwater seepage including the stability of the foundation pit. The analysis indicates that the result with the consideration of seepage is relatively close to the site data. Compared with the result without consideration of groundwater seepage, the maximum horizontal offset of the pile increases approximate 5mm and the location of the maximum horizontal displacement moves 2m down. So seepage is harmful to the retaining structure of foundation pit and should be considered in the design of foundation pit.

  8. Ecohydrology of seepage springs in an urban National Park

    NASA Astrophysics Data System (ADS)

    Knee, K.; Melone, J.; Friedel, B.; Fong, D.

    2014-12-01

    Shallow groundwater-fed seepage springs, also known as hypotelminorheic habitats, are found around the Washington, DC area, including in the George Washington Parkway, a National Park unit in northern Virginia. These springs differ from better-known vernal pools both in their hydrology and their ecology: because they are groundwater-fed, they are more resistant to drying out than vernal pools, and they harbor cave-adapted arthropod species including amphipods of the genus Stygobroumus. This project seeks to understand the ecohydrology of the hypotelminorheic habitats that support these species, some of which are endangered, and which comprise an important but underappreciated component of biodiversity in DC-area National Parks. Our study focuses on two hypotelminorheic habitats in the GW Parkway area and consists of three main components: (1) a weekly population census of Stygobroumus using multiple mark-recapture methodology, (2) weekly monitoring of dissolved radon, a tracer of groundwater discharge, as well as conductivity, dissolved oxygen, and pH, and (3) continuous logging of spring water temperature. This poster presents preliminary data from the Stygobroumus population census and explores how these animals may be affected by spring hydrology. Specifically, we use temperature, conductivity, radon activity and precipitation data from a nearby weather station to understand how the springs respond to episodic and seasonal variation in temperature, precipitation and groundwater seepage and how this affects Stygobromus populations. We also explore whether variations in Stygobromus counts reflect (1) active migration between the surficial spring and the larger subterranean habitat, or (2) passive flushing driven by groundwater discharge. Our results provide basic hydrologic data about a little-understood habitat type and will help managers protect Stygobromus in the urban park environment.

  9. Seepage investigation and selected hydrologic data for the Escalante River drainage basin, Garfield and Kane Counties, Utah, 1909-2002

    USGS Publications Warehouse

    Wilberg, Dale E.; Stolp, Bernard J.

    2005-01-01

    This report contains the results of an October 2001 seepage investigation conducted along a reach of the Escalante River in Utah extending from the U.S. Geological Survey streamflow-gaging station near Escalante to the mouth of Stevens Canyon. Discharge was measured at 16 individual sites along 15 consecutive reaches. Total reach length was about 86 miles. A reconnaissance-level sampling of water for tritium and chlorofluorcarbons was also done. In addition, hydrologic and water-quality data previously collected and published by the U.S. Geological Survey for the 2,020-square-mile Escalante River drainage basin was compiled and is presented in 12 tables. These data were collected from 64 surface-water sites and 28 springs from 1909 to 2002.None of the 15 consecutive reaches along the Escalante River had a measured loss or gain that exceeded the measurement error. All discharge measurements taken during the seepage investigation were assigned a qualitative rating of accuracy that ranged from 5 percent to greater than 8 percent of the actual flow. Summing the potential error for each measurement and dividing by the maximum of either the upstream discharge and any tributary inflow, or the downstream discharge, determined the normalized error for a reach. This was compared to the computed loss or gain that also was normalized to the maximum discharge. A loss or gain for a specified reach is considered significant when the loss or gain (normalized percentage difference) is greater than the measurement error (normalized percentage error). The percentage difference and percentage error were normalized to allow comparison between reaches with different amounts of discharge.The plate that accompanies the report is 36" by 40" and can be printed in 16 tiles, 8.5 by 11 inches. An index for the tiles is located on the lower left-hand side of the plate. Using Adobe Acrobat, the plate can be viewed independent of the report; all Acrobat functions are available.

  10. Long-term groundwater transport of radionuclides from seepage basins at the Savannah River Site

    NASA Astrophysics Data System (ADS)

    Wiedmer, A.; Hunt, J. R.; Spycher, N.; Denham, M. E.

    2009-12-01

    The Savannah River Site (SRS) in South Carolina produced tritium and plutonium between 1953 and the beginning of the 1990s. The site released process wastewater containing plutonium, tritium, uranium, and fission products into seepage basins with the intent that short half-life radionuclides would decay in the years required for the groundwater to transport the waste materials to surface waters and that activity levels in the surface waters would not exceed levels considered appropriate in the 1950s. Between 1955 and 1988, the process operations at the F-area lead to the discharge of more than 12×106 cubic meters of low-level liquid radioactive waste solutions into unlined seepage basins. The waste contained longer half life nuclides that did not significantly decay during groundwater transit such as 3H (t½ = 12.28 years), 90Sr (t½ = 28.6 years), 99Tc (t½ = 2.13×105 years) and 129I (t½ = 1.57×107 years). Remediation started with the capping of the basin in 1990 followed by active plume pumping between 1997 and 2003. In 2004 a groundwater barrier was installed and in situ pH neutralization started in 2005. Tritium monitoring detected migration to Four Mile Creek by the end of the 1950s. Other radionuclides such as 90Sr, 99Tc and 129I have also been detected in groundwater seeping into the creek, and tritium levels and conductivity were well correlated at the seepage line. The seepage basin contaminated groundwater plume surfaced at seepage faces near a creek with a pH of 3. This acidity combined with high ionic strengths associated with nitrate mobilized contaminants such as 90Sr. The high levels of tritium, low pH and high conductivity at the seepage line show the likely importance of density driven flow for the salts of the plume and the limited dilution by groundwater flow. The Savannah River Site requires remediation to minimize radionuclide migration off-site, and there has been an extensive monitoring program of process waste discharges, groundwater

  11. H-Area Seepage Basins groundwater monitoring report. First quarter 1992

    SciTech Connect

    Thompson, C.Y.

    1992-06-01

    During first quarter 1992, tritium, nitrate, nonvolatile beta, total alpha-emitting radium (radium-224 and radium-226), gross alpha, antimony, mercury, lead, tetrachloroethylene, arsenic, and cadmium exceeded the US Environmental Protection Agency Primary Drinking Water Standards (PDWS) in groundwater samples from monitoring wells at the H-Area Seepage Basins (HASB) at the Savannah River Site. This report presents and discusses the groundwater monitoring results in the H-Area for first quarter 1992.

  12. Utilizing geophysical methods for asessment and characterization of canal seepage in El Paso's lower valley irrigation delivery systems

    NASA Astrophysics Data System (ADS)

    Cegon, Amanda Brooke

    El Paso County Water Improvement District No. 1 (EPCWID No.1) delivers the Rio Grande water for agricultural production and urban uses through numerous networked irrigation canals. Of the nearly 86 billion gallons of water released annually for irrigation uses in Texas, billions are lost due to evaporation and seepage in unlined canals with 56 million gallons of the billions are lost in Franklin Canal annually due to improper lining and sediment variation of the canals. To characterize seepage patterns and identify areas of high seepage, Electrical Resistivity, Ground Truthing via soil sample analysis were used along three, half-mile long sectioned canals during irrigation and non-irrigation seasons. The data lines acquired were processed in EARTHIMAGER 2D to create 2D vertical resistivity inversion profiles to locate potential areas of high seepage/high resistivity. The research results will help El Paso County Water Improvement District No. 1 to develop management strategies to conserve water and improve the delivery efficiency systems which leads to economic growth in the Rio Grande Basin.

  13. Groundwater quality assessment/corrective action feasibility plan. Savannah River Laboratory Seepage Basins

    SciTech Connect

    Stejskal, G.F.

    1989-11-15

    The Savannah River Laboratory (SRL) Seepage Basins are located in the northeastern section of the 700 Area at the Savannah River Site. Currently the four basins are out of service and are awaiting closure in accordance with the Consent Decree settled under Civil Act No. 1:85-2583. Groundwater monitoring data from the detection monitoring network around the SRL Basins was recently analyzed using South Carolina Hazardous Waste Management Regulations R.61-79.264.92 methods to determine if groundwater in the immediate vicinity of the SRL Basins had been impacted. Results from the data analysis indicate that the groundwater has been impacted by both volatile organic constituents (VOCs) and inorganic constituents. The VOCs, specifically trichloroethylene and tetrachloroethylene, are currently being addressed under the auspices of the SRS Hazardous Waste Permit Application (Volume III, Section J.6.3). The impacts resulting from elevated levels of inorganic constituent, such as barium, calcium, and zinc in the water table, do not pose a threat to human health and the environment. In order to determine if vertical migration of the inorganic constituents has occurred three detection monitoring wells are proposed for installation in the upper portion of the Congaree Aquifer.

  14. River Seepage Conductance in Large-Scale Regional Studies.

    PubMed

    Morel-Seytoux, Hubert J; Miller, Calvin D; Miracapillo, Cinzia; Mehl, Steffen

    2016-12-20

    Flow exchange between surface and groundwater is of great importance be it for beneficial allocation and use of water resources or for the proper exercise of water rights. In large-scale regional studies, most numerical models use coarse grid sizes, which make it difficult to provide an accurate depiction of the phenomenon. In particular, a somewhat arbitrary leakance coefficient in a third type (i.e., Cauchy, General Head) boundary condition is used to calculate the seepage discharge as a function of the difference of head in the river and in the aquifer, whose value is often found by calibration. A different approach is presented to analytically estimate that leakance coefficient. It is shown that a simple equivalence can be deduced from the analytical solution for the empirical coefficient, so that it provides the accuracy of the analytical solution while the model maintains a very coarse grid, treating the water-table aquifer as a single calculation layer. Relating the empirical leakance coefficient to the exact conductance, derived from physical principles, provides a physical basis for the leakance coefficient. Factors such as normalized wetted perimeter, degree of penetration of the river, presence of a clogging layer, and anisotropy can be included with little computational demand. In addition the river coefficient in models such as MODFLOW, for example, can be easily modified when grid size is changed without need for recalibration.

  15. Infinite slope stability under steady unsaturated seepage conditions

    USGS Publications Warehouse

    Lu, N.; Godt, J.

    2008-01-01

    [1] We present a generalized framework for the stability of infinite slopes under steady unsaturated seepage conditions. The analytical framework allows the water table to be located at any depth below the ground surface and variation of soil suction and moisture content above the water table under steady infiltration conditions. The framework also explicitly considers the effect of weathering and porosity increase near the ground surface on changes in the friction angle of the soil. The factor of safety is conceptualized as a function of the depth within the vadose zone and can be reduced to the classical analytical solution for subaerial infinite slopes in the saturated zone. Slope stability analyses with hypothetical sandy and silty soils are conducted to illustrate the effectiveness of the framework. These analyses indicate that for hillslopes of both sandy and silty soils, failure can occur above the water table under steady infiltration conditions, which is consistent with some field observations that cannot be predicted by the classical infinite slope theory. A case study of shallow slope failures of sandy colluvium on steep coastal hillslopes near Seattle, Washington, is presented to examine the predictive utility of the proposed framework. Copyright 2008 by the American Geophysical Union.

  16. Infinite slope stability under steady unsaturated seepage conditions

    NASA Astrophysics Data System (ADS)

    Lu, Ning; Godt, Jonathan

    2008-11-01

    We present a generalized framework for the stability of infinite slopes under steady unsaturated seepage conditions. The analytical framework allows the water table to be located at any depth below the ground surface and variation of soil suction and moisture content above the water table under steady infiltration conditions. The framework also explicitly considers the effect of weathering and porosity increase near the ground surface on changes in the friction angle of the soil. The factor of safety is conceptualized as a function of the depth within the vadose zone and can be reduced to the classical analytical solution for subaerial infinite slopes in the saturated zone. Slope stability analyses with hypothetical sandy and silty soils are conducted to illustrate the effectiveness of the framework. These analyses indicate that for hillslopes of both sandy and silty soils, failure can occur above the water table under steady infiltration conditions, which is consistent with some field observations that cannot be predicted by the classical infinite slope theory. A case study of shallow slope failures of sandy colluvium on steep coastal hillslopes near Seattle, Washington, is presented to examine the predictive utility of the proposed framework.

  17. Prototype development of an apparatus to locate and map sea floor petroleum seepages. Final technical report

    SciTech Connect

    1996-10-01

    The objective of the grant was to design, build, and test two autonomous instruments to measure vertical profiles of electrical potential in sea floor sediments. The objectives were fully met when the instruments were successfully deployed in 1,800 feet of water at known petroleum seepage sites in the Gulf of Mexico. The instruments were proven to be able to measure and record signals known to be appropriate to sediments altered by seepage. Two known seepage sites were visited on September 18th and 20th, 1996. At the first, a small-scale instrument capable of measuring 60 cm into the sediment was repeatedly emplaced by the manipulator arm of a research submarine, along a sea floor traverse. Further, the large-scale instrument, having a probe 3.3 m in length, was deployed by steel cable from the ship and emplaced in the sediment under gravity. Both successfully recorded data from multiple electrodes, revealing the expected negative potentials (Eh values at low at {minus}230 mV) at, and close to, the sediment-water interface, instead of at the normal depths of 3 to 4 m.

  18. Prototype development of an apparatus to locate and map sea floor petroleum seepages. Final technical report

    SciTech Connect

    Thompson, K.F.

    1997-12-31

    The objective of the grant was to design, build, and test two autonomous instruments to measure vertical profiles of electrical potential in sea floor sediments. The objectives were fully met when the instruments were successfully deployed in 1,800 feet of water at known petroleum seepage sites in the Gulf of Mexico. The instruments were proven to be able to measure and record signals known to be appropriate to sediments altered by seepage. Two known seepage sites were visited on September 18th and 20th, 1996. At the first, a small-scale instrument capable of measuring 60 cm into the sediment was repeatedly emplaced by the manipulator arm of a research submarine, along a sea floor traverse. Further, the large-scale instrument, having a probe 3.3 m in length, was deployed by steel cable from the ship and emplaced in the sediment under gravity. Both successfully recorded data from multiple electrodes, revealing the expected negative potentials (Eh values as low as {minus}230 mV) at, and close to, the sediment-water interface, instead of at the normal depths of 3 to 4 m.

  19. Texture-depending performance of an in situ method assessing deep seepage

    NASA Astrophysics Data System (ADS)

    Hohenbrink, Tobias L.; Lischeid, Gunnar

    2014-04-01

    Deep seepage estimation is important for water balance investigations of groundwater and the vadose zone. A simplified Buckingham-Darcy method to assess time series of deep seepage fluxes was proposed by Schindler and Müller (1998). In the method dynamics of water fluxes are calculated by a soil hydraulic conductivity function. Measured soil moistures and matric heads are used as input data. Resulting time series of flux dynamics are scaled to realistic absolute levels by calibrating the method with the areal water balance. An assumption of the method is that water fluxes at different positions exhibit identical dynamics although their absolute values can differ. The aim of this study was to investigate uncertainties of that method depending on the particle size distribution and textural heterogeneity in non-layered soils. We performed a numerical experiment using the two-dimensional Richards Equation. A basic model of transient water fluxes beneath the root and capillary zone was setup and used to simulate time series of soil moisture, matric head, and seepage fluxes for 4221 different cases of particle size distribution and intensities of textural heterogeneity. Soil hydraulic parameters were predicted by the pedotransfer function Rosetta. Textural heterogeneity was modeled with Miller and Miller scaling factors arranged in spatial random fields. Seepage fluxes were calculated with the Buckingham-Darcy method from simulated soil moisture and matric head time series and compared with simulated reference fluxes. The median of Root Mean Square Error was about 0.026 cm d-1 and the median of maximum cross correlation was 0.96 when the method was calibrated adequately. The method's performance was mainly influenced by (i) the soil textural class and (ii) the time period used for flux calibration. It performed best in sandy loam while hotspots of errors occurred in sand and silty texture. Calibrating the method with time periods that exhibit high variance of seepage

  20. Determination of water content using mass spectrometry

    NASA Technical Reports Server (NTRS)

    Wood, G. M.; Upchurch, B. T.; Hughes, D. B.

    1975-01-01

    Mass spectrometer is used to measure small quantities of water present in different materials. System has been applied in measuring water and gases desorbed from microcircuitry insulation, can also be used with foods, polymeric materials, and organic solvents.

  1. Determination of dissolved aluminum in water samples

    USGS Publications Warehouse

    Afifi, A.A.

    1983-01-01

    A technique has been modified for determination of a wide range of concentrations of dissolved aluminum (Al) in water and has been tested. In this technique, aluminum is complexed with 8-hydroxyquinoline at pH 8.3 to minimize interferences, then extracted with methyl isobutyl ketone (MIBK). The extract is analyzed colorimetrically at 395 nm. This technique is used to analyze two forms of monomeric Al, nonlabile (organic complexes) and labile (free, Al, Al sulfate, fluoride and hydroxide complexes). A detection limit 2 ug/L is possible with 25-ml samples and 10-ml extracts. The detection limit can be decreased by increasing the volume of the sample and (or) decreasing the volume of the methyl isobutyl ketone extract. The analytical uncertainty of this method is approximately + or - 5 percent. The standard addition technique provides a recovery test for this technique and ensures precision in samples of low Al concentrations. The average percentage recovery of the added Al plus the amount originally present was 99 percent. Data obtained from analyses of filtered standard solutions indicated that Al is adsorbed on various types of filters. However, the relationship between Al concentrations and adsorption remains linear. A test on standard solutions also indicated that Al is not adsorbed on nitric acid-washed polyethylene and polypropylene bottle wells. (USGS)

  2. [Quantification study on the runoff and seepage distribution and N, P pollutants removal of the vegetated buffer strips].

    PubMed

    Wang, Min; Huang, Yu-Chi; Wu, Jian-Qiang

    2010-11-01

    By using the constructed buffer strips test base and the runoff hydrometric devices, a research on stagnant runoff and nitrogen (N), phosphorous (P) pollutants removal capacity of the vegetated buffer strips was conducted. The results show that the vegetated buffer strips might reduce the speed of runoff significantly and improve the hydraulic permeability of soil. The runoff water output time of 19 m buffer strips planted with Cynodon dactylon, Festuca arundinacea and Trifolium repens are 2.46, 1.72 and 2.03 times higher than the control (no vegetation) respectively; The seepage water quantity of three vegetation buffer strips are 3.01, 2.16 and 2.45 times higher than the control respectively as well. Total removal efficiency of the three buffer strips increase about 237%, 268% and 274% comparing with the control respectively. The N, P removal capacity of seepage is significantly higher than that of the runoff, the larger seepage water quantity will cause higher N, P total removal efficiency and removal loads of unit area. With different vegetated buffer strips, the TN, NH4(+) -N, TP removal ratio of seepage and runoff are 2.79, 2.02 and 2.83 respectively.

  3. On the physics of unstable infiltration, seepage, and gravity drainage in partially saturated tuffs

    SciTech Connect

    Faybishenko, B.; Bodvarsson, G.S.; Salve, R.

    2002-04-01

    To improve understanding of the physics of dynamic instabilities in unsaturated flow processes within the Paintbrush nonwelded unit (PTn) and the middle nonlithophysal portion of the Tonopah Spring welded tuff unit (TSw) of Yucca Mountain, we analyzed data from a series of infiltration tests carried out at two sites (Alcove 4 and Alcove 6) in the Exploratory Studies Facility, using analytical and empirical functions. The analysis of infiltration rates measured at both sites showed three temporal scales of infiltration rate: (1) a macro-scale trend of overall decreasing flow, (2) a meso-scale trend of fast and slow motion exhibiting three-stage variations of the flow rate (decreasing, increasing, and [again] decreasing flow rate, as observed in soils in the presence of entrapped air), and (3) micro-scale (high frequency) fluctuations. Infiltration tests in the nonwelded unit at Alcove 4 indicate that this unit may effectively dampen episodic fast infiltration events; however, well-known Kostyakov, Horton, and Philip equations do not satisfactorily describe the observed trends of the infiltration rate. Instead, a Weibull distribution model can most accurately describe experimentally determined time trends of the infiltration rate. Infiltration tests in highly permeable, fractured, welded tuff at Alcove 6 indicate that the infiltration rate exhibits pulsation, which may have been caused by multiple threshold effects and water-air redistribution between fractures and matrix. The empirical relationships between the extrinsic seepage from fractures, matrix imbibition, and gravity drainage versus the infiltration rate, as well as scaling and self-similarity for the leading edge of the water front are the hallmark of the nonlinear dynamic processes in water flow under episodic infiltration through fractured tuff. Based on the analysis of experimental data, we propose a conceptual model of a dynamic fracture flow and fracture-matrix interaction in fractured tuff

  4. H-Area Seepage Basins groundwater monitoring report

    SciTech Connect

    Not Available

    1993-03-01

    During fourth quarter 1992, the groundwater at the H-Area Seepage Basins (HASB) was monitored in compliance with South Carolina Hazardous Waste Management Regulations, R61-79.265, Subpart F. Samples were collected from 130 wells that monitor the three separate hydrostratigraphic units that make up the uppermost aquifer beneath the HASB. A detailed description of the uppermost aquifer is included in the Resource Conservation and Recovery Act Part B Post-Closure Care Permit Application for the H-Area Hazardous Waste Management Facility submitted to the South Carolina Department of Health and Environmental Control in December 1990. Historically, as well as currently, tritium, nitrate, total alpha-emitting radium, gross alpha, and mercury have been the primary constituents observed above final Primary Drinking Water Standards (PDWS) in groundwater at the HASB. Isoconcentration/isoactivity maps included in this report indicate both the concentration/activity and extent of the primary contaminants in each of the three hydrostratigraphic units during first and fourth quarter 1992. Water-level maps indicate that the groundwater flow rates and directions at the HASB have remained relatively constant since the basins ceased to be active in 1988.

  5. Vertical transport of mercury in a Wisconsin seepage lake

    SciTech Connect

    Hurley, J.P. ); Watras, C.J. )

    1990-01-09

    During summer stratification, dissolved and particulate mercury species reach maxima in oxygen-depleted, sulfide-rich bottom water of a Wisconsin seepage lake. Initially, it appeared that this hypolimnetic build-up was due to redox-controlled release from bottom sediments. However, Hg did not increase near the bottom sediments during winter anoxia, when lakes are sealed from atmospheric inputs and biological productivity is low. In contrast, Fe shows both a summer and winter build-up with depth. Reinterpretation of depth profiles using seston distributions and sediment trap collections suggests that hypolimnetic enrichment may result from the transport of epilimnetic Hg to deeper waters via biotic particles. Furthermore, a preliminary Hg mass balance for the ice-free season shows that atmospheric inputs are the dominant source of Hg to the lakes and that Hg inputs are removed by sedimentation. Mercury-rich biotic particles tend to accumulate in layers at depth through both settling and in situ growth. We hypothesize that recycling of Hg within these deep plankton layers has a strong influence on the distribution and speciation of Hg in these lakes.

  6. Seepage investigation of the Rio Grande from below Leasburg Dam, Leasburg, New Mexico, to above American Dam, El Paso, Texas, 2015

    USGS Publications Warehouse

    Briody, Alyse C.; Robertson, Andrew J.; Thomas, Nicole

    2016-03-22

    Net seepage gain or loss was computed for each subreach (the interval between two adjacent measurement locations along the river) by subtracting the discharge measured at the upstream location from the discharge measured at the closest downstream location along the river and then subtracting any inflow to the river within the subreach. An estimated gain or loss was determined to be meaningful when it exceeded the cumulative measurement uncertainty associated with the net seepage computation. The cumulative seepage loss in the 64-mile study reach in 2015 was 17.3 plus or minus 2.6 cubic feet per second. Gaining and losing reaches identified in this investigation generally correspond to seepage patterns observed in previous investigations conducted during dry years, with the gaining reaches occurring primarily at the southern (downstream) end of the basin.

  7. Modelling groundwater seepage zones in an unconfined aquifer with MODFLOW: different approaches

    NASA Astrophysics Data System (ADS)

    Leterme, Bertrand; Gedeon, Matej

    2014-05-01

    In areas where groundwater level occurs close to surface topography, the discharge of groundwater flow to the ground surface (or seepage) can be an important aspect of catchment hydrological cycle. It is also associated with valuable zones from an ecological point of view, often having a permanent shallow water table and constant lithotrophic water quality (Batelaan et al., 2003). In the present study, we try to implement a correct representation of this seepage process in a MODFLOW-HYDRUS coupled model for a small catchment (18.6 km²) of north-east Belgium. We started from an exisiting transient groundwater model of the unconfined aquifer in the study area (Gedeon and Mallants, 2009) discretized in 50x50 m cells. As the model did not account for seepage, hydraulic heads were simulated above the surface topography in certain zones. In the coupled MODFLOW-HYDRUS setup, transient boundary conditions (potential evapotranspiration and precipitation) are used to calculate the recharge with the HYDRUS package (Seo et al., 2007) for MODFLOW-2000 (Harbaugh et al., 2000). Coupling HYDRUS to MODFLOW involves the definition of a number of zones based on similarity in estimated groundwater depth, soil type and land cover. Concerning simulation of seepage, several existing packages are tested, including the DRAIN package (as in Reeve et al., 2006), the SPF package (from VSF Process; Thoms et al., 2006) and the PBC package (Post, 2011). Alternatively to the HYDRUS package for MODFLOW, the UZF package (Niswonger et al., 2006) for the simulation of recharge (and seepage) is also tested. When applicable, the parameterization of drain conductance in the top layer is critical and is investigated in relation to the soil hydraulic conductivity values used for the unsaturated zone (HYDRUS). Furthermore, stability issues are discussed, and where successful model runs are obtained, simulation results are compared with observed groundwater levels from a piezometric network. Spatial and

  8. Fault zone controlled seafloor methane seepage in the rupture area of the 2010 Maule earthquake, Central Chile

    NASA Astrophysics Data System (ADS)

    Geersen, Jacob; Scholz, Florian; Linke, Peter; Schmidt, Mark; Lange, Dietrich; Behrmann, Jan H.; Völker, David; Hensen, Christian

    2016-11-01

    Seafloor seepage of hydrocarbon-bearing fluids has been identified in a number of marine fore arcs. However, temporal variations in seep activity and the structural and tectonic parameters that control the seepage often remain poorly constrained. Subduction zone earthquakes, for example, are often discussed to trigger seafloor seepage but causal links that go beyond theoretical considerations have not yet been fully established. This is mainly due to the inaccessibility of offshore epicentral areas, the infrequent occurrence of large earthquakes, and challenges associated with offshore monitoring of seepage over large areas and sufficient time periods. Here we report visual, geochemical, geophysical, and modeling results and observations from the Concepción Methane Seep Area (offshore Central Chile) located in the rupture area of the 2010 Mw. 8.8 Maule earthquake. High methane concentrations in the oceanic water column and a shallow subbottom depth of sulfate penetration indicate active methane seepage. The stable carbon isotope signature of the methane and hydrocarbon composition of the released gas indicate a mixture of shallow-sourced biogenic gas and a deeper sourced thermogenic component. Pristine fissures and fractures observed at the seafloor together with seismically imaged large faults in the marine fore arc may represent effective pathways for methane migration. Upper plate fault activity with hydraulic fracturing and dilation is in line with increased normal Coulomb stress during large plate-boundary earthquakes, as exemplarily modeled for the 2010 earthquake. On a global perspective our results point out the possible role of recurring large subduction zone earthquakes in driving hydrocarbon seepage from marine fore arcs over long timescales.

  9. Statistical analysis of liquid seepage in partially saturated heterogeneous fracture systems

    SciTech Connect

    Liou, Tai -Sheng

    1999-12-01

    Field evidence suggests that water flow in unsaturated fracture systems may occur along fast preferential flow paths. However, conventional macroscale continuum approaches generally predict the downward migration of water as a spatially uniform wetting front subjected to strong inhibition into the partially saturated rock matrix. One possible cause of this discrepancy may be the spatially random geometry of the fracture surfaces, and hence, the irregular fracture aperture. Therefore, a numerical model was developed in this study to investigate the effects of geometric features of natural rock fractures on liquid seepage and solute transport in 2-D planar fractures under isothermal, partially saturated conditions. The fractures were conceptualized as 2-D heterogeneous porous media that are characterized by their spatially correlated permeability fields. A statistical simulator, which uses a simulated annealing (SA) algorithm, was employed to generate synthetic permeability fields. Hypothesized geometric features that are expected to be relevant for seepage behavior, such as spatially correlated asperity contacts, were considered in the SA algorithm. Most importantly, a new perturbation mechanism for SA was developed in order to consider specifically the spatial correlation near conditioning asperity contacts. Numerical simulations of fluid flow and solute transport were then performed in these synthetic fractures by the flow simulator TOUGH2, assuming that the effects of matrix permeability, gas phase pressure, capillary/permeability hysteresis, and molecular diffusion can be neglected. Results of flow simulation showed that liquid seepage in partially saturated fractures is characterized by localized preferential flow, along with bypassing, funneling, and localized ponding. Seepage pattern is dominated by the fraction of asperity contracts, and their shape, size, and spatial correlation. However, the correlation structure of permeability field is less important

  10. Stream seepage and groundwater levels, Wood River Valley, south-central Idaho, 2012-13

    USGS Publications Warehouse

    Bartolino, James R.

    2014-01-01

    Stream discharge and water levels in wells were measured at multiple sites in the Wood River Valley, south-central Idaho, in August 2012, October 2012, and March 2013, as a component of data collection for a groundwater-flow model of the Wood River Valley aquifer system. This model is a cooperative and collaborative effort between the U.S. Geological Survey and the Idaho Department of Water Resources. Stream-discharge measurements for determination of seepage were made during several days on three occasions: August 27–28, 2012, October 22–24, 2012, and March 27–28, 2013. Discharge measurements were made at 49 sites in August and October, and 51 sites in March, on the Big Wood River, Silver Creek, their tributaries, and nearby canals. The Big Wood River generally gains flow between the Big Wood River near Ketchum streamgage (13135500) and the Big Wood River at Hailey streamgage (13139510), and loses flow between the Hailey streamgage and the Big Wood River at Stanton Crossing near Bellevue streamgage (13140800). Shorter reaches within these segments may differ in the direction or magnitude of seepage or may be indeterminate because of measurement uncertainty. Additional reaches were measured on Silver Creek, the North Fork Big Wood River, Warm Springs Creek, Trail Creek, and the East Fork Big Wood River. Discharge measurements also were made on the Hiawatha, Cove, District 45, Glendale, and Bypass Canals, and smaller tributaries to the Big Wood River and Silver Creek. Water levels in 93 wells completed in the Wood River Valley aquifer system were measured during October 22–24, 2012; these wells are part of a network established by the U.S. Geological Survey in 2006. Maps of the October 2012 water-table altitude in the unconfined aquifer and the potentiometric-surface altitude of the confined aquifer have similar topology to those on maps of October 2006 conditions. Between October 2006 and October 2012, water-table altitude in the unconfined aquifer rose by

  11. F-Area seepage basins, groundwater quality assessment report, first quarter 1990

    SciTech Connect

    Not Available

    1990-06-01

    During the first quarter of 1990, wells which make up the F-Area Seepage Basins (F-HWMF) monitoring network were sampled. Laboratory analyses were performed to measure levels of hazardous constituents, indicator parameters, tritium, gross alpha, and nonvolatile beta. The primary contaminants observed at wells monitoring the F-Area Seepage Basins are tritium, nitrate, cadmium, lead, total radium, gross alpha, and nonvolatile beta. Concentrations of at least one of the following constituents: tritium, nitrate, total radium, gross alpha, cadmium, lead, tetrachloroethylene, nonvolatile beta, endrin, lindane, barium, fluoride, mercury, and trichlorethylene in excess of the primary drinking water standard (PDWS) were observed in at least one well monitoring the F-Area Seepage Basins. Tritium concentrations above the PDWS occur in forty-four of the fifty-nine (75%) groundwater monitoring wells. Nitrate concentrations above the PDWS occur in thirty-four of the fifty-nine (59%) groundwater wells. The radionuclides, total radium, gross alpha, and nonvolatile beta, exceed the PDWS is over twenty-five percent of the groundwater wells. Heavy metals, cadmium and lead in particular, exceed the PDWS in over twelve percent of the wells. Since 1987, tritium and nitrate concentrations have been steadily declining in a majority of the wells. However, tritium concentrations, from fourth quarter 1989 to first quarter 1990, have increased.

  12. F-Area seepage basins, groundwater quality assessment report, first quarter 1990

    SciTech Connect

    Not Available

    1990-06-01

    During the first quarter of 1990, wells which make up the F-Area Seepage Basins (F-HWMF) monitoring network were sampled. Laboratory analyses were performed to measure levels of hazardous constituents, indicator parameters, tritium, gross alpha, and nonvolatile beta. The primary contaminants observed at wells monitoring the F-Area Seepage Basins are tritium, nitrate, cadmium, lead, total radium, gross alpha, and nonvolatile beta. Concentrations of at least one of the following constituents: tritium, nitrate, total radium, gross alpha, cadmium, lead, tetrachloroethylene, nonvolatile beta, endrin, lindane, barium, fluoride, mercury, and trichlorethylene in excess of the primary drinking water standard (PDWS) were observed in at least one well monitoring the F-Area Seepage Basins. Tritium concentrations above the PDWS occur in forty-four of the fifty-nine (75%) groundwater monitoring wells. Nitrate concentrations above the PDWS occur in thirty-four of the fifty-nine (59%) groundwater wells. The radionuclides, total radium, gross alpha, and nonvolatile beta, exceed the PDWS is over twenty-five percent of the groundwater wells. Heavy metals, cadmium and lead in particular, exceed the PDWS in over twelve percent of the wells. Since 1987, tritium and nitrate concentrations have been steadily declining in a majority of the wells. However, tritium concentrations, from fourth quarter 1989 to first quarter 1990, have increased.

  13. Measurement of seepage losses and chemical export from waste lagoons at animal feeding operations

    NASA Astrophysics Data System (ADS)

    Ham, J. M.; DeSutter, T. M.

    2001-05-01

    Whole-lagoon seepage rates were measured from 20 lagoons in Kansas using water balance techniques. Study sites included cattle feedlots, swine facilities, and one dairy. Seepage rates ranged from 0.2 mm/day to 2.4 mm/day with and overall average of 1.2 mm/day. Analysis of lagoon effluent (58 samples from 38 sites) indicated large differences in lagoon chemistry between locations. Ammonium nitrogen (NH4-N), which accounted for over 99 percent of the soluble nitrogen, ranged from 10 ppm to 3500 ppm. On average, nitrogen concentrations in swine lagoons were about five times higher than those at cattle feedlots. The chemical flux density (flux boundary condition) was estimated from the seepage rate and the corresponding waste chemistry data from each lagoon. Results showed that ammonium-N export was between 0.02 and 1.06 kg NH4-N m-2 yr^{-1} with an overall average of about 0.3 kg NH4-N m^{-2} yr^{-1}$ . Similar data are available for other soluble compounds. Soil cores were collected beneath eight lagoons that had been operated from 12 to 25 years. Results showed that NH4-N was strongly adsorbed by the soil clay particles and that nitrogen concentrations often decreased to background levels at 3 m beneath the lagoon. Other ions, such as chloride, penetrated to much lower depths at all locations. The 'reservoir' of NH4-N that exists beneath older lagoons could convert to nitrate and move to lower depths after lagoon closure. Data suggest that the properties if the soil beneath lagoons, the concentration of the waste, the seepage rate, and the depth to groundwater are the crucial factors that affect the risk of groundwater contamination.

  14. Groundwater seepage landscapes from distant and local sources in experiments and on Mars

    NASA Astrophysics Data System (ADS)

    Marra, W. A.; McLelland, S. J.; Parsons, D. R.; Murphy, B. J.; Hauber, E.; Kleinhans, M. G.

    2015-08-01

    Valleys with theater-shaped heads can form due to the seepage of groundwater and as a result of knickpoint (waterfall) erosion generated by overland flow. This ambiguity in the mechanism of formation hampers the interpretation of such valleys on Mars, particularly since there is limited knowledge of material properties. Moreover, the hydrological implications of a groundwater or surface water origin are important for our understanding of the evolution of surface features on Mars, and a quantification of valley morphologies at the landscape scale may provide diagnostic insights on the formative hydrological conditions. However, flow patterns and the resulting landscapes produced by different sources of groundwater are poorly understood. We aim to improve the understanding of the formation of entire valley landscapes through seepage processes from different groundwater sources that will provide a framework of landscape metrics for the interpretation of such systems. We study groundwater seepage from a distant source of groundwater and from infiltration of local precipitation in a series of sandbox experiments and combine our results with previous experiments and observations of the Martian surface. Key results are that groundwater flow piracy acts on valleys fed by a distant groundwater source and results in a sparsely dissected landscape of many small and a few large valleys. In contrast, valleys fed by a local groundwater source, i.e., nearby infiltration, result in a densely dissected landscape. In addition, valleys fed by a distant groundwater source grow towards that source, while valleys with a local source grow in a broad range of directions and have a strong tendency to bifurcate, particularly on flatter surfaces. We consider these results with respect to two Martian cases: Louros Valles shows properties of seepage by a local source of groundwater and Nirgal Vallis shows evidence of a distant source, which we interpret as groundwater flow from Tharsis.

  15. Radar sensing of petroleum seepage gases

    NASA Astrophysics Data System (ADS)

    Hemenway, Donald F.; Hansen, James P.; George, Eugene G.

    1993-01-01

    Simple X-band radars have been used by a number of commercial exploration companies since 1972 in the search for gas and oil deposits. Uncertainty and controversy over the physical mechanism involved in the radar sensing of gas and oil led to the April/May 1992 radar investigation conducted by NRL. A low power X-band radar was used by NRL to acquire experimental data in Texas. The attributes of return signals observed over producing and prospective oil fields were found to have a unique set of characteristics which included the following: return signals were from weak, distributed targets: simultaneous amplitude and range variations were observed (10 dB or more in amplitude and +/- 60 ft in range) within time intervals of 1/3rd second and at ranges of from 500 to 2,000 ft, and at elevation angles of less than + 1 deg. The range and amplitude varying radar returns were suppressed by rain and/or a wet earth. Also during a single period of 24 hour observation, the varying signals disappeared during a period of high humidity (local night-time) and then re-appeared the next day when the relative humidity dropped below 50%. Radar returns from seepage gases heights greater than 25 feet as well as gas associated radar returns over cattle feed lots (methane and ammonia) were not confirmed.

  16. Geochemical record of methane seepage in authigenic carbonates and surrounding host sediments: A case study from the South China Sea

    NASA Astrophysics Data System (ADS)

    Hu, Yu; Chen, Linying; Feng, Dong; Liang, Qianyong; Xia, Zhen; Chen, Duofu

    2017-05-01

    Sediments at marine methane seep sites provide potential archives of past fluid flow that serve to explore seepage activities over time. Three gravity cores (D-8, D-F, and D-7) were collected from seep sites on the northern slope of the South China Sea where gas hydrates were drilled in the subsurface. Various carbon and sulfur contents, δ13C values of total inorganic carbon (δ13CTIC), δ34S values of chromium reducible sulfur (δ34SCRS), trace element contents, grain size, and AMS 14C dating of planktonic Foraminifera in the sediments were determined to explore the availability of related proxies at seeps and to trace past methane seepage activities. Evidence for the presence of methane seepage and consequently anaerobic oxidation of methane comes from the occurrence of 13C-depleted authigenic carbonate nodules (δ13C values as low as -49‰) discovered at an interval of 150-200 cm in core D-7. This finding is supported by high S/C ratios and molybdenum enrichment in the same interval. However, low contents of CRS and negative δ34SCRS values are present. It is suggested to reflect a transient methane seepage event, which continued for about 1 ka based on the 14C ages. Cores D-8 and D-F have δ13CTIC values close to zero, low S/C ratios and CRS contents, negative δ34SCRS values, and no trace element enrichment, suggesting a negligible impact of methane-seepage on the sediments. The negative δ34SCRS values of the studied seep-impacted and background sediments suggest that the application of δ34SCRS alone as a proxy to identify AOM-related process may be insufficient. Sediment carbon-sulfur-trace element systematics and 14C ages used here have the potential to be a promising tool to recognize transient methane seepages and constrain their timescales.

  17. F-Area Seepage Basins groundwater monitoring report

    SciTech Connect

    Not Available

    1993-03-01

    During fourth quarter 1992, the groundwater at the F-Area Seepage Basins (FASB) was monitored in compliance with South Carolina Hazardous Waste Management Regulations, R61-79.265, Subpart F. Eighty-five wells provided samples from the three hydrostratigraphic units that make up the uppermost aquifer beneath the FASB. A detailed description of the uppermost aquifer is included in the Resource Conservation and Recovery Act Part B Post-Closure Care Permit Application for the F-Area Hazardous Waste Management Facility submitted to the South Carolina Department of Health and Environmental Control in December 1990. Historically, as well as currently, tritium, nitrate, gross alpha, total alpha-emitting radium, cadmium, and lead are the primary constituents observed above final Primary Drinking Water Standards (PDWS) in groundwater at the FASB. Nonvolatile beta has consistently exceeded its drinking water screening level. Other radionuclides and hazardous constituents also have exceeded the final PDWS in the groundwater at the FASB. The elevated constituents are found primarily in Aquifer Zone IIB[sub 2] (Water Table) and Aquifer Zone IIB[sub 1], (Barnwell/McBean) wells. However, several Aquifer Unit IIA (Congaree) wells also contain elevated levels of constituents, primarily tritium. Isoconcentration/isoactivity maps included in this report indicate both the concentration/ activity and extent of the primary contaminants in each of the three hydrostratigraphic units for first and fourth quarters 1992. Water-level maps indicate that the groundwater flow rates and directions at the FASB have remained relatively constant since the basins ceased to be active in 1988.

  18. Quantifying spatial and temporal variability of groundwater-surface-water exchange in fluvial settings

    NASA Astrophysics Data System (ADS)

    Rosenberry, Donald

    2010-05-01

    Substantial spatial variability in flow across the sediment-water interface is now generally accepted as ubiquitous in hyporheic settings. A growing body of evidence indicates exchange also varies temporally, including frequent reversals in flow direction, on scales of minutes to hours to days. The extent of this dynamism, and the significance with regard to water chemistry and ecosystem viability and stability, have yet to be determined for many hyporheic settings. Anthropogenic influences create even greater variability through bed disturbance, and manipulation of stream and river flow, sediment supply, and surface-water and groundwater quality. In-situ measurements of seepage rate and direction were made along two river reaches, one located well downstream of any control structures and where bed mobility was common, and the other located several kilometers downstream of a dam where the bed was immobile nearly all of the time. Seepage meters modified for use in flowing water were used to measure rates of exchange between surface and sub-surface water in a sand-and-gravel-bed river in Colorado, USA (South Platte River, mean annual river discharge = 9.7 m3/s), and in a cobble-bed river in western Pennsylvania, USA (Allegheny River, mean annual river discharge = 188 m3/s). The median value of all seepage measurements at the South Platte River was 0.24 m/day, indicating a small to moderate rate of groundwater discharge to the river. However, substantial local-scale bed topography as well as mobile bedforms in the river resulted in spatial and temporal variability an order of magnitude larger than the median groundwater discharge rate. Both upward and downward seepage were recorded along every transect across the river with rates ranging from +2.37 (upward) to -3.40 (downward) m/day. At the Allegheny River site, moss and algae covered much of the bed and river grass was common, indicating greater bed stability than at the South Platte River site. Median seepage was +0

  19. Study of differential fiber Bragg grating seepage pressure sensor

    NASA Astrophysics Data System (ADS)

    Chen, Xiao; Zhang, Dongsheng; Wu, Mengqi

    2017-03-01

    In order to accurate measurement of seepage water pressure in soil, according to the pressure sensor characteristic of bellows, and the strain sensor characteristic of triangle cantilever beam and FBG, a differential fiber Bragg grating sensor is designed. The bellows generate axial displacement under the action of osmotic pressure, then the axial displacement passes to the triangle cantilever beam, and the triangle cantilever beam generates a deflection change. The deflection change makes the FBG generate axial displacement. The pressure is obtained by detecting the difference between the center wavelengths of the FBG. And the effects of environmental changes are also reduced by using a differential structure. In the process of booster, calibration experiments show that the pressure sensitivity of the sensor is 11.96pm/kPa, its linearity is about 1.3%, the repeatability is 2.9% FS; in the process of decompression, the pressure sensitivity of the sensor is 10.56pm/kPa, its linearity is about 4.6%, the repeatability is 1.9% FS. And the environmental temperature change influence on measurement results lower than 1%. The results show that, the osmotic pressure of fiber grating sensor to a small range within the scope of the osmotic pressure can be measured accurately. It also can generalize to the large range of measurement by changing the parameters of bellows and equal strength beam.

  20. Seepage investigations of the Rio Grande from below Leasburg Dam, Leasburg, New Mexico, to above American Dam, El Paso, Texas, 2006-13

    USGS Publications Warehouse

    Crilley, D.M.; Matherne, A.M.; Thomas, Nicole; Falk, S.E.

    2013-01-01

    Seepage investigations were conducted annually by the U.S. Geological Survey from 1988 to 1998 and from 2004 to 2013 along a 64-mile reach of the Rio Grande from below Leasburg Dam, Leasburg, New Mexico, to above American Dam, El Paso, Texas, as part of the Mesilla Basin monitoring program. Results of studies conducted from 2006 to 2013 are presented in this report. Seepage investigations were conducted over a period of 1–2 days in February of each year, during low-flow conditions in the non-irrigation season. During the seepage investigations, discharge was measured at as many as 24 sites along the Rio Grande and as many as 20 inflow sites within the study reach. Net seepage gain or loss was computed for each subreach by subtracting the discharge measured at the upstream location from the discharge measured at the closest downstream location along the river and then subtracting any inflow to the river within the subreach. An estimated gain or loss was determined to be significant when it exceeded the cumulative measurement uncertainty associated with the net seepage computation. Study reaches during 2006 to 2013 ranged from 20.2 to 64 miles in length, and seepage losses ranged from 8.2 ± 3.1 to 47.9 ± 8.2 cubic feet per second.

  1. D-area oil seepage basin bioventing optimization test plan

    SciTech Connect

    Berry, C.J.; Radway, J.C.; Alman, D.; Hazen, T.C.

    1998-12-31

    The D Area Oil Seepage Basin (DOSB) was used from 1952 to 1975 for disposal of petroleum-based products (waste oils), general office and cafeteria waste, and apparently some solvents [trichloroethylene (TCE)/tetrachloroethylene (PCE)]. Numerous analytical results have indicated the presence of TCE and its degradation product vinyl chloride in groundwater in and around the unit, and of petroleum hydrocarbons in soils within the unit. The DOSB is slated for additional assessment and perhaps for environmental remediation. In situ bioremediation represents a technology of demonstrated effectiveness in the reclamation of sites contaminated with petroleum hydrocarbons and chlorinated solvents, and has been retained as an alternative for the cleanup of the DOSB. The Savannah River Site is therefore proposing to conduct a field treatability study designed to demonstrate and optimize the effectiveness of in situ microbiological biodegradative processes at the DOSB. The introduction of air and gaseous nutrients via two horizontal injection wells (bioventing) is expected to enhance biodegradation rates of petroleum components and stimulate microbial degradation of chlorinated solvents. The data gathered in this test will allow a determination of the biodegradation rates of contaminants of concern in the soil and groundwater, allow an evaluation of the feasibility of in situ bioremediation of soil and groundwater at the DOSB, and provide data necessary for the functional design criteria for the final remediation system.

  2. Widespread methane seepage along the continental margin off Svalbard - from Bjørnøya to Kongsfjorden

    NASA Astrophysics Data System (ADS)

    Mau, S.; Römer, M.; Torres, M. E.; Bussmann, I.; Pape, T.; Damm, E.; Geprägs, P.; Wintersteller, P.; Hsu, C.-W.; Loher, M.; Bohrmann, G.

    2017-02-01

    Numerous articles have recently reported on gas seepage offshore Svalbard, because the gas emission from these Arctic sediments was thought to result from gas hydrate dissociation, possibly triggered by anthropogenic ocean warming. We report on findings of a much broader seepage area, extending from 74° to 79°, where more than a thousand gas discharge sites were imaged as acoustic flares. The gas discharge occurs in water depths at and shallower than the upper edge of the gas hydrate stability zone and generates a dissolved methane plume that is hundreds of kilometer in length. Data collected in the summer of 2015 revealed that 0.02-7.7% of the dissolved methane was aerobically oxidized by microbes and a minor fraction (0.07%) was transferred to the atmosphere during periods of low wind speeds. Most flares were detected in the vicinity of the Hornsund Fracture Zone, leading us to postulate that the gas ascends along this fracture zone. The methane discharges on bathymetric highs characterized by sonic hard grounds, whereas glaciomarine and Holocene sediments in the troughs apparently limit seepage. The large scale seepage reported here is not caused by anthropogenic warming.

  3. Widespread methane seepage along the continental margin off Svalbard - from Bjørnøya to Kongsfjorden

    PubMed Central

    Mau, S.; Römer, M.; Torres, M. E.; Bussmann, I.; Pape, T.; Damm, E.; Geprägs, P.; Wintersteller, P.; Hsu, C.-W.; Loher, M.; Bohrmann, G.

    2017-01-01

    Numerous articles have recently reported on gas seepage offshore Svalbard, because the gas emission from these Arctic sediments was thought to result from gas hydrate dissociation, possibly triggered by anthropogenic ocean warming. We report on findings of a much broader seepage area, extending from 74° to 79°, where more than a thousand gas discharge sites were imaged as acoustic flares. The gas discharge occurs in water depths at and shallower than the upper edge of the gas hydrate stability zone and generates a dissolved methane plume that is hundreds of kilometer in length. Data collected in the summer of 2015 revealed that 0.02–7.7% of the dissolved methane was aerobically oxidized by microbes and a minor fraction (0.07%) was transferred to the atmosphere during periods of low wind speeds. Most flares were detected in the vicinity of the Hornsund Fracture Zone, leading us to postulate that the gas ascends along this fracture zone. The methane discharges on bathymetric highs characterized by sonic hard grounds, whereas glaciomarine and Holocene sediments in the troughs apparently limit seepage. The large scale seepage reported here is not caused by anthropogenic warming. PMID:28230189

  4. Widespread methane seepage along the continental margin off Svalbard - from Bjørnøya to Kongsfjorden.

    PubMed

    Mau, S; Römer, M; Torres, M E; Bussmann, I; Pape, T; Damm, E; Geprägs, P; Wintersteller, P; Hsu, C-W; Loher, M; Bohrmann, G

    2017-02-23

    Numerous articles have recently reported on gas seepage offshore Svalbard, because the gas emission from these Arctic sediments was thought to result from gas hydrate dissociation, possibly triggered by anthropogenic ocean warming. We report on findings of a much broader seepage area, extending from 74° to 79°, where more than a thousand gas discharge sites were imaged as acoustic flares. The gas discharge occurs in water depths at and shallower than the upper edge of the gas hydrate stability zone and generates a dissolved methane plume that is hundreds of kilometer in length. Data collected in the summer of 2015 revealed that 0.02-7.7% of the dissolved methane was aerobically oxidized by microbes and a minor fraction (0.07%) was transferred to the atmosphere during periods of low wind speeds. Most flares were detected in the vicinity of the Hornsund Fracture Zone, leading us to postulate that the gas ascends along this fracture zone. The methane discharges on bathymetric highs characterized by sonic hard grounds, whereas glaciomarine and Holocene sediments in the troughs apparently limit seepage. The large scale seepage reported here is not caused by anthropogenic warming.

  5. Widespread methane seepage along the continental margin off Svalbard - from Bjørnøya to Kongsfjorden

    DOE PAGES

    Mau, S.; Romer, M.; Torres, M. E.; ...

    2017-02-23

    Numerous articles have recently reported on gas seepage offshore Svalbard, because the gas emission from these Arctic sediments was thought to result from gas hydrate dissociation, possibly triggered by anthropogenic ocean warming. We report on findings of a much broader seepage area, extending from 74° to 79°, where more than a thousand gas discharge sites were imaged as acoustic flares. The gas discharge occurs in water depths at and shallower than the upper edge of the gas hydrate stability zone and generates a dissolved methane plume that is hundreds of kilometer in length. Data collected in the summer of 2015more » revealed that 0.02–7.7% of the dissolved methane was aerobically oxidized by microbes and a minor fraction (0.07%) was transferred to the atmosphere during periods of low wind speeds. Most flares were detected in the vicinity of the Hornsund Fracture Zone, leading us to postulate that the gas ascends along this fracture zone. The methane discharges on bathymetric highs characterized by sonic hard grounds, whereas glaciomarine and Holocene sediments in the troughs apparently limit seepage. The large scale seepage reported here is not caused by anthropogenic warming.« less

  6. Modified determination of radium in water

    USGS Publications Warehouse

    Barker, F.B.; Thatcher, L.L.

    1957-01-01

    The proposed method embodies a barium sulfate carrier precipitation, filtration through molecular filter membranes, and collection of activity after prescribed aging period. The method is sufficiently accurate and precise to indicate the potability of water and for use in general studies of radium in chemical hydrology. Amounts of radium as low as 0.1 ????c. can be detected by using 1 -hour counting times. Radium-226 is used as the standard and the results indicate about 100 to 110 % of the activity of the alpha-emitting radium isotopes as radium-223, radium-224, and radium-226.

  7. Methods to quantify seepage beneath Levee 30, Miami-Dade County, Florida

    USGS Publications Warehouse

    Sonenshein, R.S.

    2001-01-01

    A two-dimensional, cross-sectional, finite-difference, ground-water flow model and a simple application of Darcy?s law were used to quantify ground-water flow (from a wetlands) beneath Levee 30 in Miami-Dade County, Florida. Geologic and geophysical data, vertical seepage data from the wetlands, canal discharge data, ground-water-level data, and surface-water-stage data collected during 1995 and 1996 were used as boundary conditions and calibration data for the ground-water flow model and as input for the analytical model. Vertical seepage data indicated that water from the wetlands infiltrated the subsurface, near Levee 30, at rates ranging from 0.033 to 0.266 foot per day when the gates at the control structures along Levee 30 canal were closed. During the same period, stage differences between the wetlands (Water Conservation Area 3B) and Levee 30 canal ranged from 0.11 to 1.27 feet. A layer of low-permeability limestone, located 7 to 10 feet below land surface, restricts vertical flow between the surface water in the wetlands and the ground water. Based on measured water-level data, ground-water flow appears to be generally horizontal, except in the direct vicinity of the canal. The increase in discharge rate along a 2-mile reach of the Levee 30 canal ranged from 9 to 30 cubic feet per second per mile and can be attributed primarily to ground-water inflow. Flow rates in Levee 30 canal were greatest when the gates at the control structures were open. The ground-water flow model data were compared with the measured ground-water heads and vertical seepage from the wetlands. Estimating the horizontal ground-water flow rate beneath Levee 30 was difficult owing to the uncertainty in the horizontal hydraulic conductivity of the main flow zone of the Biscayne aquifer. Measurements of ground-water flows into Levee 30 canal, a substantial component of the water budget, were also uncertain, which lessened the ability to validate the model results. Because of vertical

  8. Effect of vegetation type on throughfall deposition and seepage flux.

    PubMed

    De Schrijver, A; Staelens, J; Wuyts, K; Van Hoydonck, G; Janssen, N; Mertens, J; Gielis, L; Geudens, G; Augusto, L; Verheyen, K

    2008-05-01

    This paper compares different vegetation types (coniferous and deciduous forest, grassed and pure heathland) in terms of input (throughfall deposition) and output (seepage flux) in a region with intermediate nitrogen load (+/-20kg Nha(-1)y(-1) via bulk precipitation) in comparable conditions in north Belgium. Coniferous forest (two plots Pinus sylvestris and two plots Pinus nigra) received significantly higher nitrogen and sulphur throughfall deposition than deciduous forest and heathland. Grassed and pure heathland had significantly highest throughfall quantities of Ca(2+) and Mg(2+), respectively. The observed differences in throughfall deposition between the different vegetation types were not univocally reflected in the ion seepage flux. Considerable seepage fluxes of NO(3)(-), SO(4)(2-), Ca(2+) and Al(III) were only found under the P. nigra plots. We discuss our hypothesis that the P. nigra forests already evolved to a situation of N saturation, while the other vegetation types did not.

  9. H-Area Seepage Basins Groundwater Monitoring Report: Volume 1, Third and Fourth quarters 1994

    SciTech Connect

    Chase, J.A.

    1994-03-01

    Isoconcentration/isocactivity maps included in this report indicate both the concentration/activity and extent of the primary contaminants in each of the three hydrostratigraphic units during the second half of 1994. Geologic cross sections indicate both the extent and depth of contamination of the primary contaminants in all of the hydrostratigraphic units during the second half of 1994. Water-level maps indicate that the groundwater flow rates and directions at the H-Area Seepage Basins have remained relatively constant since the basins ceased to be active in 1988.

  10. F-Area Seepage Basins Groundwater Monitoring Report: Volume 1, Third and fourth quarters 1994

    SciTech Connect

    Chase, J.A.

    1994-03-01

    Isoconcentration/isoactivity maps included in this report indicate both the concentration/activity and extent of the primary contaminants in each of the three hydrostratigraphic units. Geologic cross sections indicate both the extent and depth of contamination of the primary contaminants in all of the hydrostratigraphic units during the second half of 1994. Water-level maps indicate that the groundwater flow rates and directions at the F-Area Seepage Basins have remained relatively constant since the basins ceased to be active in 1988.

  11. Hydrologic and geochemical approaches for determining ground-water flow components

    USGS Publications Warehouse

    Hjalmarson, H.W.; Robertson, F.N.

    1991-01-01

    Lyman Lake is an irrigation-storage reservoir on the Little Colorado River near St. Johns, Arizona. The main sources of water for the lake are streamflow in the Little Colorado River and ground-water inflow from the underlying Coconino aquifer. Two approaches, a hydrologic analysis and a geochemical analysis, were used to compute the quantity of ground-water flow to and from Lyman Lake. Hydrologic data used to calculate a water budget were precipitation on the lake, evaporation from the lake, transpiration from dense vegetation, seepage through the dam, streamflow in and out of the lake, and changes in lake storage. Geochemical data used to calculate the ground-water flow components were major ions, trace elements, and the stable isotopes of hydrogen and oxygen. During the study, the potentiometric level of the Coconino aquifer was above the lake level at the upstream end of the lake and below the lake level at the downstream end. Hydrologic and geochemical data indicate that about 10 percent and 8 percent, respectively, of the water in the lake is ground-water inflow and that about 35 percent of the water in the Little Colorado River 6 miles downgradient from the lake near Salado Springs is ground water. These independent estimates of ground-water flow derived from each approach are in agreement and support a conceptual model of the water budget.

  12. Snow water equivalent determination by microwave radiometry

    NASA Technical Reports Server (NTRS)

    Chang, A. T. C.; Foster, J. L.; Hall, D. K.; Rango, A.; Hartline, B. K.

    1981-01-01

    One of the most important parameters for accurate snowmelt runoff prediction is snow water equivalent (SWE) which is contentionally monitored using observations made at widely scattered points in or around specific watersheds. Remote sensors which provide data with better spatial and temporal coverage can be used to improve the SWE estimates. Microwave radiation, which can penetrate through a snowpack, may be used to infer the SWE. Calculations made from a microscopic scattering model were used to simulate the effect of varying SWE on the microwave brightness temperature. Data obtained from truck mounted, airborne and spaceborne systems from various test sites were studied. The simulated SWE compares favorable with the measured SWE. In addition, whether the underlying soil is frozen or thawed can be discriminated successfully on the basis of the polarization of the microwave radiation.

  13. Using complementarity framework to couple subsurface flow and seepage processes: a physically based basis to integrate hotspots reactivity at the hillslope scale

    NASA Astrophysics Data System (ADS)

    Marçais, J.; De Dreuzy, J. R.; Erhel, J.

    2016-12-01

    Landscape structure and geological heterogeneities are major controls on subsurface flow dynamic. Particularly it has strong impact on saturated areas (potential hotspots) emergence, promoting seepage production. This control leads to highly non linear flow response where, for each hillslope location, two possible states can be distinguished: with or without seepage. Different algorithmic solutions have been proposed to model this process. A solution is to solve subsurface flow for an assumed water table position and then iterate on the water table position until convergence is met. Seepage areas and seepage values are then deduced from the locations where water table intersects surface. A second way to proceed is to explicitly couple groundwater equations and surface water equations with an exchange flux. Here we developed a novel approach using the complementarity framework to reconcile in a single system the two states potentially encountered (with or without seepage). The complementarity framework manages the current state and the possible transition between states thanks to a specifically devoted equation. This framework is applied to the 1D hillslope storage Boussinesq equations (Troch et al. 2003). Reformulating this complementarity system differently enables to partition effectively the local flux balance between storage variation and seepage. This differential algebraic equations (DAEs) system has the major benefit to be directly solvable with built-in ode libraries. Finally the system is regularized to enhance fast and efficient solving. This model is stable with fast spatial convergence. It respects the mass balance locally beyond the tolerance limits and shows limited sensitivity to the value of the regularization parameter. The model appears to be robust, able to solve complex realistic case with presence of landscape heterogeneity and real hydrologic forcing. This model will then be used as a physical basis to implement biogeochemistry reactivity.

  14. Determination of halonitromethanes in treated water.

    PubMed

    Montesinos, I; Cardador, M J; Gallego, M

    2011-05-06

    As halonitromethanes (HNMs) have begun to play an increasingly important role as disinfection by-products, the development of a highly sensitive method for their analysis has become a priority. The mass spectrometric behavior of the 9 HNMs revealed that trihalonitromethanes are more unstable than di- or monohalonitromethanes under common chromatographic conditions. The absence of a comprehensive method for HNMs has given rise to the development of the first method for the whole array of these species, involving the selection of a solventless technique. Single drop microextraction in the headspace mode (HS-SDME) was selected as it is inexpensive and easy to operate. Comparative measurements through EPA liquid-liquid extraction (LLE) method for halogenated volatile compounds, show this approach to be superior to the manual LLE procedure (the average limits of detection (LODs) for the 9 HNMs were 0.5 and 1 μg/L for the HS-SDME and EPA methods, respectively), adequate precision (8.2 and 7.0% for HS-SDME and EPA methods, respectively) and does not consume excessive solvent since the total extract (∼2 μL) was injected completely into the GC-MS instrument. The method was used to measure HNMs in treated water and the results were compared to the EPA method in parallel. Copyright © 2011 Elsevier B.V. All rights reserved.

  15. Estimating Vadose Zone Drainage From a Capped Seepage Basin, F Area, Savannah River Site

    NASA Astrophysics Data System (ADS)

    Wan, J.; Tokunaga, T. K.; Denham, M.

    2011-12-01

    Large volumes of waste solutions were commonly discharged into unlined seepage basins at many different facilities in the past. Plutonium was extracted from depleted uranium from 1955 to 1988 at the F-Area within the Savannah River Site, with contaminated process waters disposed of in permeable seepage basins. The primarily acidic solutions contained radioactive components (including tritium, 129I, and multiple isotopes of U, Pu, Sr, and Cs), elevated nitrate, and some metals (Hg, Pb, Cd). Basin 3 was the largest F-Area seepage basin, covering 2.0 hectare, with the water table typically at about 20 m below the soil surface. The local groundwater flows at an average velocity of 200 m/y in the approximately 10 m thick shallow aquifer, and is underlain by the low permeability Tan Clay. We used nearly 20 years of groundwater quality data from a monitoring well immediately downstream of Basin 3 to estimate the post-closure drainage of waste solutions through its underlying vadose zone, into the shallow aquifer. The measurements of tritium, nitrate, and specific conductance, were used as plume tracers in our estimates of vadose zone drainage. These calculations indicate that early stages of post-closure waste drainage occurred with high fluxes (≈ 1 m/y), and quickly declined. However, even after 20 years, drainage continues at a low but significant rate of several cm/y. These estimated drainage fluxes can help constrain predictions on the waste plume behavior, especially with respect to its emerging trailing gradient and anticipated time scales suitable for monitored natural attenuation.

  16. Fiber Bragg grating-based performance monitoring of a slope model subjected to seepage

    NASA Astrophysics Data System (ADS)

    Zhu, Hong-Hu; Shi, Bin; Yan, Jun-Fan; Zhang, Jie; Zhang, Cheng-Cheng; Wang, Bao-Jun

    2014-09-01

    In the past few years, fiber optic sensing technologies have played an increasingly important role in the health monitoring of civil infrastructures. These innovative sensing technologies have recently been successfully applied to the performance monitoring of a series of geotechnical structures. Fiber optic sensors have shown many unique advantages in comparison with conventional sensors, including immunity to electrical noise, higher precision and improved durability and embedding capabilities; fiber optic sensors are also smaller in size and lighter in weight. In order to explore the mechanism of seepage-induced slope instability, a small-scale 1 g model test of the soil slope has been performed in the laboratory. During the model’s construction, specially fabricated sensing fibers containing nine fiber Bragg grating (FBG) strain sensors connected in a series were horizontally and vertically embedded into the soil mass. The surcharge load was applied on the slope crest, and the groundwater level inside of the slope was subsequently varied using two water chambers installed besides the slope model. The fiber optic sensing data of the vertical and horizontal strains within the slope model were automatically recorded by an FBG interrogator and a computer during the test. The test results are presented and interpreted in detail. It is found that the gradually accumulated deformation of the slope model subjected to seepage can be accurately captured by the quasi-distributed FBG strain sensors. The test results also demonstrate that the slope stability is significantly affected by ground water seepage, which fits well with the results that were calculated using finite element and limit equilibrium methods. The relationship between the strain measurements and the safety factors is further analyzed, together with a discussion on the residual strains. The performance evaluation of a soil slope using fiber optic strain sensors is proved to be a potentially effective

  17. Heterogeneous seepage at the Nopal I natural analogue site, Chihuahua, Mexico

    NASA Astrophysics Data System (ADS)

    Dobson, Patrick F.; Ghezzehei, Teamrat A.; Cook, Paul J.; Rodríguez-Pineda, J. Alfredo; Villalba, Lourdes; de La Garza, Rodrigo

    2012-02-01

    A study of seepage occurring in an adit at the Nopal I uranium mine in Chihuahua, Mexico, was conducted as part of an integrated natural analogue study to evaluate the effects of infiltration and seepage on the mobilization and transport of radionuclides. An instrumented seepage collection system and local automated weather station permit direct correlation between local precipitation events and seepage. Field observations recorded between April 2005 and December 2006 indicate that seepage is highly heterogeneous with respect to time, location, and quantity. Seepage, precipitation, and fracture data were used to test two hypotheses: (1) that fast flow seepage is triggered by large precipitation events, and (2) that an increased abundance of fractures and/or fracture intersections leads to higher seepage volumes. A few zones in the back adit recorded elevated seepage volumes immediately following large (>20 mm/day) precipitation events, with transit times of less than 4 h through the 8-m thick rock mass. In most locations, there is a 1-6 month time lag between the onset of the rainy season and seepage, with longer times observed for the front adit. There is a less clear-cut relation between fracture abundance and seepage volume; processes such as evaporation and surface flow along the ceiling may also influence seepage.

  18. Model Assessment of Alternatives for Reducing Seepage from Buried Uranium Mill Talings at the Morton Ranch Site in Central Wyoming

    SciTech Connect

    Nelson, R. W.; Reisenauer, A. E.; Gee, G. W.

    1980-06-01

    The purpose of this study is to examine potential ground water contamination by seepage from buried tailings under four alternatives of clay liners and tailings placement, which have been proposed for possible use at the Morton Ranch Site. To accomplish this comparison of alternatives, laboratory work and numerous measurements were made on materials typical of the Morton Ranch Site. These measurements provide the soil characteristics necessary for input to the hydrologic flow and transport models.

  19. Geologic seepage of methane and light alkanes in Los Angeles

    NASA Astrophysics Data System (ADS)

    Doezema, L. A.; Chang, K.; Baril, R.; Nwachuku, I.; Contreras, P.; Marquez, A.; Howard, D.

    2013-12-01

    Natural geologic seepage of methane from underground oil and natural gas reservoirs has been suggested to be an underreported part of the global methane budget. Other light alkanes are also given off in combination with the methane seepage, making it possible that geologic seepage is also a potentially significant global source of these light alkanes. This study reports C1-C5 findings from geologic seepage made in the Los Angeles region. Microseepage, invisible escape of gases, was measured primarily at Kenneth Hahn Regional Park, while macroseepage, the visible release of gases, was measured at the La Brea Tar Pits. Samples were collected using stainless steel canisters and flux chambers and were analyzed using gas chromatography with flame ionization detectors (GC-FID). Average microseepage flux rates of 0.95 μg m-2 h-1 for ethane and 0.51 μg m-2 h-1 were found for propane, while average macroseepage rates for methane, ethane, and propane were 664, 19.8, and 18.1 mg m-2 h-1 respectively. Relationships between microseepage flux rate and location of underground oil and natural deposit and earthquake fault lines are presented. Additionally, the relative importance of findings in context with global budgets and local air quality is discussed.

  20. Summary of Seepage Investigations in the Yakima River Basin, Washington

    USGS Publications Warehouse

    Magirl, C.S.; Julich, R.J.; Welch, W.B.; Curran, C.R.; Mastin, M.C.; Vaccaro, J.J.

    2009-01-01

    Discharge data collected by the U.S. Geological Survey, Washington State Department of Ecology, and Yakama Nation for seepage investigations in the Yakima River basin are made available as downloadable Microsoft Excel files. These data were collected for more than a century at various times for several different studies and are now available in one location to facilitate future analysis by interested parties.

  1. Seepage investigations of Noyes Canal, Menard County, Texas

    USGS Publications Warehouse

    Yost, Ivan Dale

    1953-01-01

    At the request of the U.S. Department of Agriculture, Soil Conservation Service, and the Menard Irrigation Company, a seepage investigation was made on Noyes Canal (Menard Irrigation Company Canal) in Menard County, Texas, from the headgates of the canal to where the canal empties back into the San Saba River.

  2. Behavior of fiber reinforced sandy slopes under seepage

    USDA-ARS?s Scientific Manuscript database

    Seepage flow is a major contributor to instability of natural hill slopes, river banks and engineered embankments. In order to increase the factor of safety, an emerging technology involves the inclusion of synthetic fibers in the soil. The addition of tension resisting fibers has a favorable effec...

  3. Determinants of virtual water flows in the Mediterranean.

    PubMed

    Fracasso, Andrea; Sartori, Martina; Schiavo, Stefano

    2016-02-01

    The aim of the paper is to investigate the main determinants of the bilateral virtual water (water used in the production of a commodity or service) flows associated with international trade in agricultural goods across the Mediterranean basin. We consider the bilateral gross flows of virtual water in the area and study what export-specific and import-specific factors are significantly associated with virtual water flows. We follow a sequential approach. Through a gravity model of trade, we obtain a "refined" version of the variable we aim to explain, one that is free of the amount of flows due to pair-specific factors affecting bilateral trade flows and that fully reflects the impact of country-specific determinants of virtual water trade. A number of country-specific potential explanatory variables, ranging from water endowments to trade barriers, from per capita GDP to irrigation prices, is presented and tested. To identify the variables that help to explain the bilateral flows of virtual water, we adopt a model selection procedure based on model averaging. Our findings confirm one of the main controversial results in the literature: larger water endowments do not necessarily lead to a larger 'export' of virtual water, as one could expect. We also find some evidence that higher water irrigation prices reduce (increase) virtual water 'exports' ('imports'). Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Seepage investigation on the Rio Grande from below Caballo Reservoir, New Mexico, to El Paso, Texas, 2012

    USGS Publications Warehouse

    Gunn, Mark A.; Roark, D. Michael

    2014-01-01

    A seepage investigation was conducted by the U.S. Geological Survey, in cooperation with the New Mexico Interstate Stream Commission, along an approximately 106-mile reach of the Rio Grande from below Caballo Reservoir, New Mexico, to El Paso, Texas, during June 26–28, 2012, to determine gain or loss of streamflow due to seepage to or from the river channel. Discharge measurements were made during the irrigation season at high flow including 5 sites along the Rio Grande, 5 diversions, and 63 inflows. The net gain or loss of flow in the river channel was computed for four reaches within the 106-mile reach of the Rio Grande. The normalized percentage difference was computed for each reach to determine the difference between discharge measured at upstream and downstream sites, and the normalized percentage uncertainty was computed to determine if a computed gain or loss exceeded cumulative uncertainty associated with measurement of discharge.

  5. Analytical Modeling of Groundwater Seepages to St. Lucie Estuary

    NASA Astrophysics Data System (ADS)

    Lee, J.; Yeh, G.; Hu, G.

    2008-12-01

    In this paper, six analytical models describing hydraulic interaction of stream-aquifer systems were applied to St Lucie Estuary (SLE) River Estuaries. These are analytical solutions for: (1) flow from a finite aquifer to a canal, (2) flow from an infinite aquifer to a canal, (3) the linearized Laplace system in a seepage surface, (4) wave propagation in the aquifer, (5) potential flow through stratified unconfined aquifers, and (6) flow through stratified confined aquifers. Input data for analytical solutions were obtained from monitoring wells and river stages at seepage-meter sites. Four transects in the study area are available: Club Med, Harbour Ridge, Lutz/MacMillan, and Pendarvis Cove located in the St. Lucie River. The analytical models were first calibrated with seepage meter measurements and then used to estimate of groundwater discharges into St. Lucie River. From this process, analytical relationships between the seepage rate and river stages and/or groundwater tables were established to predict the seasonal and monthly variation in groundwater seepage into SLE. It was found the seepage rate estimations by analytical models agreed well with measured data for some cases but only fair for some other cases. This is not unexpected because analytical solutions have some inherently simplified assumptions, which may be more valid for some cases than the others. From analytical calculations, it is possible to predict approximate seepage rates in the study domain when the assumptions underlying these analytical models are valid. The finite and infinite aquifer models and the linearized Laplace method are good for sites Pendarvis Cove and Lutz/MacMillian, but fair for the other two sites. The wave propagation model gave very good agreement in phase but only fairly agreement in magnitude for all four sites. The stratified unconfined and confined aquifer models gave similarly good agreements with measurements at three sites but poorly at the Club Med site. None of

  6. Effects of outcropping groundwater from the F- and H-Area seepage basins on the distribution of fish in Four Mile Creek

    SciTech Connect

    Paller, M.H.; Storey, C.

    1990-10-01

    Four Mile Creek was electrofished during June 26--July 2, 1990 to assess the impacts of outcropping ground water form the F- and H-Area Seepage Basins on fish abundance and distribution. Number of fish species and total catch were comparable at sample stations upstream from and downstream from the outcropping zone in Four Mile Creek. Species number and composition downstream from the outcropping zone in Four Mile Creek were similar to species number and composition in unimpacted portions of Pen Branch, Steel Creek, and Meyers Branch. These findings indicate that seepage basin outcropping was not adversely affecting the Four Mile Creek fish community. 5 refs., 3 figs., 4 tabs.

  7. Quantity and quality of seepage from two earthen basins used to store livestock waste in southern Minnesota during the first year of operation, 1997-98

    USGS Publications Warehouse

    Ruhl, James F.

    1999-01-01

    Seepage from the site B basin (based on 10 samples each from the bottom and sidewall) had chloride concentrations of 11 to 100 mg/L; ammonium-N concentrations of 2.58 mg/L or less; nitrate-N concentrations of 25.7 mg/L or less (except for one concentration of 146 mg/L); and organic-N concentrations of 0.92 mg/L or less. Nitrate-N concentrations in the seepage exceeded the U.S. Environmental Protection Agency (1996). MCL (maximum contaminant level) of 10 mg/L in 17 of 22 samples. Background ground-water quality, however, indicated that nitrate-N concentrations were greater than the MCL prior to operation of the basin. Fecal Coliform bacteria, as at the site A basin, were abundant in the basin wastewater, but not in the seepage.

  8. Determination of total dissolved solids in water analysis

    USGS Publications Warehouse

    Howard, C.S.

    1933-01-01

    The figure for total dissolved solids, based on the weight of the residue on evaporation after heating for 1 hour at 180??C., is reasonably close to the sum of the determined constituents for most natural waters. Waters of the carbonate type that are high in magnesium may give residues that weigh less than the sum. Natural waters of the sulfate type usually give residues that are too high on account of incomplete drying.

  9. Re: Request for Correction: Drinking Water: Determination on Perchlorate

    EPA Pesticide Factsheets

    Request for correction (RFC) of information developed and relied upon by the Environmental Protection Agency (EPA or Agency) to support its determination to regulate perchlorate under the Safe Drinking Water Act (SDWA).

  10. Determining pomegranate water and nitrogen requirements with drip irrigation

    USDA-ARS?s Scientific Manuscript database

    Despite being an ancient crop there is limited knowledge on the water and nitrogen (N) requirements of pomegranate. We conducted research at the University of California, Kearney Agricultural Research and Extension Center (KARE) to determine the water and nitrogen requirements of a developing pomegr...

  11. Methane Seepage on Mars: Where to Look and Why.

    PubMed

    Oehler, Dorothy Z; Etiope, Giuseppe

    2017-08-03

    Methane on Mars is a topic of special interest because of its potential association with microbial life. The variable detections of methane by the Curiosity rover, orbiters, and terrestrial telescopes, coupled with methane's short lifetime in the martian atmosphere, may imply an active gas source in the planet's subsurface, with migration and surface emission processes similar to those known on Earth as "gas seepage." Here, we review the variety of subsurface processes that could result in methane seepage on Mars. Such methane could originate from abiotic chemical reactions, thermogenic alteration of abiotic or biotic organic matter, and ancient or extant microbial metabolism. These processes can occur over a wide range of temperatures, in both sedimentary and igneous rocks, and together they enhance the possibility that significant amounts of methane could have formed on early Mars. Methane seepage to the surface would occur preferentially along faults and fractures, through focused macro-seeps and/or diffuse microseepage exhalations. Our work highlights the types of features on Mars that could be associated with methane release, including mud-volcano-like mounds in Acidalia or Utopia; proposed ancient springs in Gusev Crater, Arabia Terra, and Valles Marineris; and rims of large impact craters. These could have been locations of past macro-seeps and may still emit methane today. Microseepage could occur through faults along the dichotomy or fractures such as those at Nili Fossae, Cerberus Fossae, the Argyre impact, and those produced in serpentinized rocks. Martian microseepage would be extremely difficult to detect remotely yet could constitute a significant gas source. We emphasize that the most definitive detection of methane seepage from different release candidates would be best provided by measurements performed in the ground or at the ground-atmosphere interface by landers or rovers and that the technology for such detection is currently available. Key

  12. Migration of acidic groundwater seepage from uranium-tailings impoundments, 1. Field study and conceptual hydrogeochemical model

    NASA Astrophysics Data System (ADS)

    Morin, Kevin A.; Cherry, John A.; Dave, Nand K.; Lim, Tjoe P.; Vivyurka, Al J.

    1988-08-01

    In this first paper of a series, the results of a study at a non-operational tailings site are presented and are used to construct a general conceptual model for seepage migration from uranium-tailings impoundments. Many parts of the model are applicable to other types of tailings and to acid drainage in general. At the field site, the impoundment lies over a portion of a glaciofluvial sand aquifer. Tailings seepage drains downward into the aquifer and then migrates laterally away. Results of the field study indicate the seepage can be divided into three geochemical zones: (1) the inner core, which is essentially unaltered, acidic seepage from the tailings; (2) the neutralization zone, in which inner-core water is neutralized and aqueous concentrations decrease significantly; and (3) the outer zone, which contains both neutralized water from the neutralization zone and pH-neutral process water from the uranium milling operation. Yearly comparisons from 1979 to 1984 indicate the neutralization zone and inner core are migrating downgradient at a rate of about 1 meter/year, which is about 1/440 of the groundwater velocity. The mechanisms that produce the retardation and the decreases in aqueous concentrations are part of the conceptual model. The main features of the conceptual model are solid-liquid interactions, particularly mineral precipitation-dissolution, and buffering effects of dominant aqueous species. The important minerals undergoing precipitation-dissolution are the calcite-siderite solid solution, gypsum, Al-OH minerals, and Fe-OH minerals. "Cell and streamtube" calculations are used to evaluate the general trends in aqueous concentrations and to assist in explaining observed migration rates. Co-precipitation with the above minerals apparently accounts for decreases in other major, minor, and metal solutes. Because of the large amount of mineral precipitation and co-precipitation, variations in 2H and 18O were observed over a flow distance of several

  13. Monitoring of Potential Seepage Through Surface Sediments in the Sleipner Carbon Capture and Storage Area

    NASA Astrophysics Data System (ADS)

    James, R. H.; Lichtschlag, A.; Cevatoglu, M.; Reigstad, L.; Connelly, D.; Bull, J. M.

    2013-12-01

    Subseafloor Carbon Capture and Storage (CCS) has been recognized as critical technology for reducing the release of anthropogenic CO2 emissions to the atmosphere. However, the potential pathways of CO2 movement in the sedimentary overburden as well as the impact of any CO2 seepage from a storage site on the marine environment are poorly understood. As part of the ECO2 project, we have conducted a multidisciplinary survey of the area around Sleipner, which is one of the longest operated subseafloor CCS sites. Our aims were to: (1) Search for tracers of leakage of formation fluids or any other potential precursors of CO2 seepage, in the vicinity of the subseafloor CO2 plume. (2) Assess the potential for mobilization of toxic metals by CO2. (3) Characterize the environment in the vicinity of the Sleipner storage site. Potential pathways of seepage from the storage site were determined by the AUV AUTOSUB, that was equipped with a variety of instrumentation including sidescan sonar and an EM2000 multibeam systems, as well as a CHIRP profiler capable of inspecting the architecture of the sedimentary overburden. To detect geochemical indicators of leakage and their potential impact on the seafloor environment, the composition of fluids and gases were determined in the upper part of the sediment overburden (up to 3.8 m below seafloor), which was recovered by vibrocoring. The microbial activity in these sediments was also determined, by measuring the RNA content of selected cores. In this presentation we will compare the results that we have obtained from the area above the CO2 plume with results from an area ~20 km the north of the Sleipner platform (Hugin fracture). The Hugin fracture is several km long, and pore fluids from sediments recovered from the fracture have a distinctively different composition, with depletion of sulphate and chloride and increase of sulphide, dissolved inorganic carbon and total alkalinity. Assessing the natural variation in the sedimentary

  14. Quantifying Seepage Flux using Sediment Temperatures

    EPA Science Inventory

    This report provides a demonstration of different modeling approaches that use sediment temperatures to estimate the magnitude and direction of water flux across the groundwater-surface water transition zone. Analytical models based on steady-state or transient temperature solut...

  15. Quantifying Seepage Flux using Sediment Temperatures

    EPA Science Inventory

    This report provides a demonstration of different modeling approaches that use sediment temperatures to estimate the magnitude and direction of water flux across the groundwater-surface water transition zone. Analytical models based on steady-state or transient temperature solut...

  16. Elemental chemistry of sand-boil discharge used to trace variable pathways of seepage beneath levees during the 2011 Mississippi River flood

    USDA-ARS?s Scientific Manuscript database

    Water samples were collected from the Mississippi River, from sand boils near the toe of the levee on the Mississippi side of the river, and from actively flowing relief wells shortly after peak stage of the 2011 Mississippi River flood. Two distinct pathways for seepage under the levee were identif...

  17. Methane Seepage at Hyperalkaline Springs in the Ronda Peridotite Massif (Spain)

    NASA Astrophysics Data System (ADS)

    Etiope, G.; Vadillo, I.; Whiticar, M. J.; Marques, J. M.; Carreira, P. M.; Tiago, I.; Benavente, J.; Jimenez, P.; Urresti, B.

    2014-12-01

    Methane-rich, hyperalkaline spring waters and bubbling pools have been sampled in the Ronda peridotite massif in southern Spain. Water chemistry (T: 17.1-21.5 ºC; pH: 10.7-11.7; DO: <2 mg/L; Ca-OH facies) is characteristic of present-day serpentinization. Dissolved CH4 concentrations range from 0.1 to 3.2 mg/L. CH4 stable C and H isotope ratios suggest a dominant abiotic origin in two natural spring sites (delta13C: -13 to -29 ‰ VPDB; delta2H: -309 to -333 ‰ VSMOW) and a mixed biotic-abiotic origin in springs with artificial water delivery systems (i.e., pipes or fountains; delta13C: -44 to -69 ‰; delta2H: -180 to -319 ‰). At the natural springs, gas is mainly released through bubbles close to the water outlet (CH4 flux ~1 kg/day by individual bubble trains), and subordinately by microseepage from the ground, even at distances of ~100 m from the bubble-spring site (flux of 10's, up to 97, mg CH4 m-2day-1). Gas seepage is strictly controlled by faults. Under-saturation of CH4 in water, bubbling and seepage location suggest that CH4 is not exclusively transported to the surface by hyperalkaline water, but it follows autonomous migration pathways along faults. Similar 'dry' seepage of abiotic gas was observed in the Philippines, New Zealand, Turkey and Italy. Like other land-based serpentinization systems, the Ronda peridotite massif is characterized by low heat flow (<40 mW/m2), with temperatures <60°C at depths of 1.5 km. At these low T and high pH conditions, CO32- is the only available carbon source dissolved in the water, and unlikely contributes to catalysed Fischer-Tropsch Type reactions. Methane production from CO2 hydrogenation in a gas phase system (unsaturated fractured rocks) cannot be excluded. The presence of ruthenium-enriched chromitites in the Ronda peridotites may support the hypothesis that CH4 is produced by CO2 hydrogenation catalyzed by Ru minerals, even at temperatures below 100°C, as demonstrated in recent laboratory experiments

  18. Trace water determination in gases by infrared spectroscopy

    SciTech Connect

    Stallard, B.R.; Espinoza, L.H.; Niemczyk, T.M.

    1995-05-01

    Water determination in semiconductor process gases is desirable in order to extend the life of gas delivery systems and improve wafer yields. The authors review their work in applying Fourier transform infrared spectroscopy to this problem, where a 10 ppb detection limit has been demonstrated for water in N{sub 2}, HCl, and HBr. The potential for optical determination of other contaminants in these gases is discussed. Also, alternative optical spectroscopic approaches are briefly described. Finally, they discuss methods for dealing with interference arising from water in the instrument beam path, yet outside the sample cell.

  19. Coupling Seepage and Radionuclide Transport in and Around Emplacement Drifts at Yucca Mountain

    NASA Astrophysics Data System (ADS)

    Zhang, G.; Spycher, N.; Sonnenthal, E.; Steefel, C.

    2007-12-01

    The proposed nuclear waste repository of the United States is located at Yucca Mountain, Nevada. Waste packages will be placed in deep (~350 m) underground drifts in volcanic tuff. Seepage may potentially occur at the repository drifts when the drifts get rewetted after a dryout period. The potential seepage water will be quickly evaporated or boiled to near dryness as long as it falls on the top of the hot waste package leading to formation of brine, precipitation of salts and volatilization of gases. These processes may potentially impact the long-term safety of waste packages in the drift. The objectives of this study are to: (1) develop a quantitative model of coupled thermal, hydrological, and chemical (THC) processes potentially leading to brine formation, salt precipitation and gas volatilization on top of waste packages and/or a drip shield and (2) dynamically integrate such a model into the larger-scale models of processes within and around waste emplacement drifts, as well as into the smaller-scale waste-package corrosion models. Process models were implemented into an existing reactive transport numerical simulator, TOUGHREACT, to allow modeling of (1) evaporative concentration to very high ionic strength (up to 40 molal), (2) boiling point elevation due to dissolved salts, (3) boiling/evaporation to dryness, and (4) salt deliquescence. An integrated near-field and in-drift THC simulation was run using a vertical 2-D grid extending from near the ground surface to the groundwater table, and covering a width equal to half the design drift spacing of 81 m. The integrated model was then used to simulate a discrete dripping event within the drift. The model considered the release of radionuclides into seepage water as this water contacts the waste package and flows through the invert. The precipitation of uranophane and Np-uranophane was also considered. These minerals form in the invert from the neutralization of mildly acidic seepage water by clay minerals

  20. Determination of malachite green and its leuco form in water

    USGS Publications Warehouse

    Allen, J.L.; Meinertz, J.R.; Gofus, J.E.

    1992-01-01

    Liquid chromatographic (lc) analysis can detect malachite green residues in water at less than 10 mu-g/l. Water samples were concentrated on disposable diol columns, eluted with 0.05m P-toluene-sulfonic acid in methanol, and determined by reversed-phase lc. When combined with a lead oxide postcolumn reactor, the lc method can simultaneously determine both leuco and chromatic forms of malachite green. Recoveries averaged 95.4% For the chromatic form and 57.3% For the leuco form of malachite green oxalate and leuco malachite green in spiked pond water samples. Recoveries of the carbinol form of malachite green (an equilibrium product of the dye in water) from spiked tap water samples averaged 98.6%. Recoveries of leuco malachite green were low and ph-dependent.

  1. Groundwater flow and heterogeneous discharge into a seepage lake: Combined use of physical methods and hydrochemical tracers

    NASA Astrophysics Data System (ADS)

    Kazmierczak, J.; Müller, S.; Nilsson, B.; Postma, D.; Czekaj, J.; Sebok, E.; Jessen, S.; Karan, S.; Stenvig Jensen, C.; Edelvang, K.; Engesgaard, P.

    2016-11-01

    Groundwater discharge into a seepage lake was investigated by combining flux measurements, hydrochemical tracers, geological information, and a telescopic modeling approach using first two-dimensional (2-D) regional then 2-D local flow and flow path models. Discharge measurements and hydrochemical tracers supplement each other. Discharge measurements yield flux estimates but rarely provide information about the origin and flow path of the water. Hydrochemical tracers may reveal the origin and flow path of the water but rarely provide any information about the flux. While aquifer interacting with the lake remained under seemingly steady state conditions across seasons, a high spatial and temporal heterogeneity in the discharge to the lake was observed. The results showed that part of the groundwater flowing from the west passes beneath the lake and discharges at the eastern shore, where groundwater springs and high discharge zones (HDZs) are observed at the lake bottom and at seepage faces adjacent to the lake. In the 2-D cross section, surface runoff from the seepage faces delivers 64% of the total groundwater inputs to the lake, and a 2 m wide offshore HDZ delivers 13%. Presence of HDZs may control nutrient fluxes to the lake.

  2. The Role of Optimality in Characterizing CO2 Seepage from Geological Carbon Sequestration Sites

    NASA Astrophysics Data System (ADS)

    Cortis, A.; Oldenburg, C. M.; Benson, S. M.

    2007-12-01

    Storage of large amounts of carbon dioxide (CO2) in deep geological formations for greenhouse-gas mitigation is gaining momentum and moving from its conceptual and testing stages towards widespread application. In this talk we explore various optimization strategies for characterizing surface leakage (seepage) using near-surface measurement approaches such as accumulation chambers and eddy covariance towers. Seepage characterization objectives and limitations need to be defined carefully from the outset especially in light of large natural background variations that can mask seepage. The cost and sensitivity of seepage detection are related to four critical length scales pertaining to the size of the: (1) region that needs to be monitored; (2) footprint of the measurement approach; (3) main seepage zone; and (4) region in which concentrations or fluxes are influenced by seepage. Seepage characterization objectives may include one or all of the tasks of detecting, locating, and quantifying seepage. Each of these tasks has its own optimal strategy. Detecting and locating seepage in a region in which there is no expected or preferred location for seepage nor existing evidence for seepage requires monitoring on a fixed grid, e.g., using eddy covariance towers. The fixed-grid approaches needed to detect seepage are expected to require large numbers of eddy covariance towers for large-scale geologic CO2 storage. Once seepage has been detected and roughly located, seepage zones and features can be optimally pinpointed through a dynamic search strategy, e.g., employing accumulation chambers and/or soil-gas sampling. Quantification of seepage rates can be done through measurements on a localized fixed grid once the seepage is pinpointed. Background measurements are essential for seepage detection in natural ecosystems. Artificial neural networks are considered as regression models useful for distinguishing natural system behavior from anomalous behavior suggestive of CO2

  3. The role of optimality in characterizing CO2 seepage from geological carbon sequestration sites

    SciTech Connect

    Cortis, Andrea; Oldenburg, Curtis M.; Benson, Sally M.

    2008-09-15

    Storage of large amounts of carbon dioxide (CO{sub 2}) in deep geological formations for greenhouse gas mitigation is gaining momentum and moving from its conceptual and testing stages towards widespread application. In this work we explore various optimization strategies for characterizing surface leakage (seepage) using near-surface measurement approaches such as accumulation chambers and eddy covariance towers. Seepage characterization objectives and limitations need to be defined carefully from the outset especially in light of large natural background variations that can mask seepage. The cost and sensitivity of seepage detection are related to four critical length scales pertaining to the size of the: (1) region that needs to be monitored; (2) footprint of the measurement approach, and (3) main seepage zone; and (4) region in which concentrations or fluxes are influenced by seepage. Seepage characterization objectives may include one or all of the tasks of detecting, locating, and quantifying seepage. Each of these tasks has its own optimal strategy. Detecting and locating seepage in a region in which there is no expected or preferred location for seepage nor existing evidence for seepage requires monitoring on a fixed grid, e.g., using eddy covariance towers. The fixed-grid approaches needed to detect seepage are expected to require large numbers of eddy covariance towers for large-scale geologic CO{sub 2} storage. Once seepage has been detected and roughly located, seepage zones and features can be optimally pinpointed through a dynamic search strategy, e.g., employing accumulation chambers and/or soil-gas sampling. Quantification of seepage rates can be done through measurements on a localized fixed grid once the seepage is pinpointed. Background measurements are essential for seepage detection in natural ecosystems. Artificial neural networks are considered as regression models useful for distinguishing natural system behavior from anomalous behavior

  4. ASSESSMENT OF HYDROCARBON SEEPAGE DETECTION METHODS ON THE FORT PECK RESERVATION, NORTHEAST MONTANA

    SciTech Connect

    Lawrence M. Monson

    2003-06-30

    Surface exploration techniques have been employed in separate study areas on the Fort Peck Reservation in northeastern Montana. Anomalies associated with hydrocarbon seepage are documented in all three areas and a variety of surface exploration techniques can be compared. In a small area with established production, Head Gas and Thermal Desorption methods best match production; other methods also map depletion. In a moderate-size area that has prospects defined by 3D seismic data, Head Gas along with Microbial, Iodine, and Eh soil anomalies are all associated with the best hydrocarbon prospect. In a large area that contains many curvilinear patterns observed on Landsat images, that could represent micro-seepage chimneys, results are inconclusive. Reconnaissance mapping using Magnetic Susceptibility has identified a potential prospect; subsequent Soil Gas and Head Gas surveys suggest hydrocarbon potential. In the final year of this project the principle contractor, the Fort Peck Tribes, completed a second survey in the Wicape 3D Seismic Prospect Area (also known as Area 6 in Phase I of the project) and sampled several Landsat image features contained in the Smoke Creek Aeromag Anomaly Area (also known as Area 1 in Phase II of the project). Methods determined to be most useful in Phases I and II, were employed in this final Phase III of the study. The Southwest Wicape seismic anomaly was only partially confirmed. The abundant curvilinears proposed to be possible hydrocarbon micro-seepage chimneys in the Smoke Creek Area were not conclusively verified as such. Insufficient sampling of background data precludes affirmative identification of these mostly topographic Landsat features as gas induced soil and vegetation anomalies. However relatively higher light gas concentrations were found associated with some of the curvilinears. Based on the findings of this work the Assiniboine & Sioux Tribes of the Fort Peck Reservation intend to utilize surface hydrocarbon

  5. 21 CFR 352.76 - Determination if a product is water resistant or very water resistant.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... making the claim of “water resistant,” the label SPF shall be the label SPF value determined after 40... claim of “very water resistant,” the label SPF shall be the label SPF value determined after 80...

  6. 21 CFR 352.76 - Determination if a product is water resistant or very water resistant.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... making the claim of “water resistant,” the label SPF shall be the label SPF value determined after 40... claim of “very water resistant,” the label SPF shall be the label SPF value determined after 80...

  7. Seepage phenomena on Mars at subzero temperature

    NASA Astrophysics Data System (ADS)

    Kereszturi, Akos; Möhlmann, Diedrich; Berczi, Szaniszlo; Ganti, Tibor; Horvath, Andras; Kuti, Adrienn; Pocs, Tamas; Sik, Andras; Szathmary, Eors

    At the southern hemisphere of Mars seasonal slope structures emanating from Dark Dune Spots are visible on MGS MOC, and MRO HiRISE images. Based on their analysis two groups of streaks could be identified: diffuse and fan shaped ones forming in an earlier phase of local spring, probably by CO2 gas jets, and confined streaks forming only on steep slopes during a later seasonal phase. The dark color of the streaks may arise from the dark color of the dune grains where surface frost disappeared above them, or caused by the phase change of the water ice to liquid-like water, or even it may be influenced by the solutes of salts in the undercooled interfacial water The second group's morphology (meandering style, ponds at their end), morphometry, and related theoretical modelling suggest they may form by undercooled water that remains in liquid phase in a thin layer around solid grains. We analyzed sequence of images, temperature and topographic data of Russel (54S 12E), Richardson (72S 180E) and an unnamed crater (68S 2E) during southern spring. The dark streaks here show slow motion, with an average speed of meter/day, when the maximal daytime temperature is between 190 and 220 K. Based on thermophysical considerations a thin layer of interfacial water is inevitable on mineral surfaces under the present conditions of Mars. With 10 precipitable micrometer of atmospheric water vapor, liquid phase can be present down about 190 K. Under such conditions dark streaks may form by the movement of grains lubricatred by interfacial water. This possibility have various consequences on chemical, mechanical or even possible astrobiological processes on Mars. Acknowledgment: This work was supported by the ESA ECS-project No. 98004 and the Pro Renovanda Cultura Hungariae Foundation.

  8. Methane seepage intensities traced by biomarker patterns in authigenic carbonates from the South China Sea

    NASA Astrophysics Data System (ADS)

    Guan, H.; Feng, D.

    2015-12-01

    Authigenic carbonate rocks from an active seep (Site F) at 1120 m water depth of the South China Sea (SCS) were studied using mineralogical and lipid biomarker analyses. Carbonate mineral compositions, in specific samples, were predominantly aragonite, high-Mg calcite (HMC), or a mixture of both. Abundant 13C-depleted lipid biomarkers (various isoprenoids) diagnostic for archaea provide evidence that anaerobic oxidation of methane (AOM) mediated by anaerobic methane oxidizing archaea (ANME) and their bacterial partners is the major process leading to formation of the carbonates. Nearly a pure suite of AOM biomarkers was preserved in aragonitic carbonate in which predominant consortia were most likely ANME-2/Desulfosarcina & Desulfococcus (DSS) assemblages and a mixture of ANME-2/DSS and ANME-1/DSS consortia in the mixed mineral sample, the predominant consortia are in good accordance with the point that the relative higher methane seepage intensity favors the precipitation of aragonite over HMC. In contrast, the completely different biomarker patterns in HMC sample were mainly composed terrestrial organic matter and marine Thaumarchaea, which most likely originally within sediments accompanied with high organic matter input and low methane supply. This environment is known to be favored for archaea of ANME-1 and precipitation of HMC. High concentrations of 13C-depleted hopanoids, including diplopterol, hopanoic acids and hopanols were observed in the aragonite sample that may be sourced by the intermittent presence of oxic conditions in an overall anoxic condition, which was possibly induced by changing seepage intensities.

  9. F-Area Seepage Basins groundwater monitoring report: First and second quarters 1993. Volume 1

    SciTech Connect

    Not Available

    1993-09-01

    During the first half of 1993, the groundwater at the F-Area Seepage Basins (FASB) was monitored in compliance with South Carolina Hazardous Waste Management Regulations, R61-79.265, Subpart F. Eighty-seven wells provided samples from the three hydrostratigraphic units that make up the uppermost aquifer beneath the FASB. A detailed description of the uppermost aquifer is included in the Resource Conservation and Recovery Act Part B Post-Closure Care Permit Application for the F-Area Hazardous Waste Management Facility submitted to the South Carolina Department of Health and Environmental Control (SCDHEC) in December 1990. Beginning in the first quarter of 1993, the standard for comparison is the SCDHEC Groundwater Protection Standard (GWPS) specified in the approved F-Area Seepage Basins Part B Permit (November 1992). Currently and historically, gross alpha, nitrate, nonvolatile beta, and tritium are among the primary constituents to exceed standards. Numerous other radionuclides and hazardous constituents also exceeded the GWPS in the groundwater at the FASB during the first half of 1993, notably aluminum, iodine-129, technetium-99, and zinc. The elevated constituents are found primarily in Aquifer Zone IIB{sub 2} (Water Table) and Aquifer Zone IIB{sub 1}, (Barnwell/McBean) wells. However, several Aquifer Unit IIA (Congaree) wells also contain elevated levels of constituents.

  10. Radionuclide inventories for the F- and H-area seepage basin groundwater plumes

    SciTech Connect

    Hiergesell, Robert A; Kubilius, Walter P.

    2016-05-01

    Within the General Separations Areas (GSA) at the Savannah River Site (SRS), significant inventories of radionuclides exist within two major groundwater contamination plumes that are emanating from the F- and H-Area seepage basins. These radionuclides are moving slowly with groundwater migration, albeit more slowly due to interaction with the soil and aquifer matrix material. The purpose of this investigation is to quantify the activity of radionuclides associated with the pore water component of the groundwater plumes. The scope of this effort included evaluation of all groundwater sample analyses obtained from the wells that have been established by the Environmental Compliance & Area Completion Projects (EC&ACP) Department at SRS to monitor groundwater contamination emanating from the F- and H-Area Seepage Basins. Using this data, generalized groundwater plume maps for the radionuclides that occur in elevated concentrations (Am-241, Cm-243/244, Cs-137, I-129, Ni-63, Ra-226/228, Sr-90, Tc-99, U-233/234, U-235 and U-238) were generated and utilized to calculate both the volume of contaminated groundwater and the representative concentration of each radionuclide associated with different plume concentration zones.

  11. Neutron radiography determination of water diffusivity in fired clay brick.

    PubMed

    El Abd, A; Czachor, A; Milczarek, J

    2009-04-01

    The real time neutron and gamma radiography station at Maria reactor, Institute of Atomic Energy, Swierk, Poland, was used to investigate the isothermal water absorption into fired clay brick samples. The investigated brick is different from the bricks reported in El Abd and Milczarek [2004. Neutron radiology study of water absorption in porous building materials: anomalous diffusing analysis. J. Phys. D: Appl. Phys. 37, 2305-2313] in density and chemical composition. Neutron radiography images were acquired regularly as the absorption time elapses. The water content, theta, along the flow direction, x, namely the water profiles theta(x,t) and the water front position as a function of the absorption time, t, were extracted from neutron radiography images. The results were discussed in terms of the macroscopic theory of water infiltration in unsaturated porous media. It was shown that the water front position followed the square root t-scaling (x(m)=phi(m) square root t) and the profiles (theta-phi) converged to a universal one master curve. The water diffusivity was analytically determined from the experimental results. It has the so-called hypo-diffusive character, namely its gradient with respect to the water content is positive. Neutron radiography is a powerful method to distinguish among the unsaturated flow in different porous construction materials.

  12. Community and household determinants of water quality in coastal Ghana.

    PubMed

    McGarvey, Stephen T; Buszin, Justin; Reed, Holly; Smith, David C; Rahman, Zarah; Andrzejewski, Catherine; Awusabo-Asare, Kofi; White, Michael J

    2008-09-01

    Associations between water sources, socio-demographic characteristics and household drinking water quality are described in a representative sample of six coastal districts of Ghana's Central Region. Thirty-six enumeration areas (EAs) were randomly chosen from a representative survey of 90 EAs in rural, semi-urban and urban residence strata. In each EA, 24 households were randomly chosen for water quality sampling and socio-demographic interview. Escherichia coli per 100 ml H2O was quantified using the IDEXX Colilert system and multi-stage regression models estimated cross-sectional associations between water sources, sanitation and socio-demographic factors. Almost three quarters, 74%, of the households have > 2 E. coli /100 ml H2O. Tap water has significantly lower E. coli levels compared with surface or rainwater and well water had the highest levels. Households with a water closet toilet have significantly lower E. coli compared with those using pit latrines or no toilets. Household size is positively associated, and a possessions index is negatively associated, with E. coli. Variations in community and household socio-demographic and behavioural factors are key determinants of drinking water quality. These factors should be included in planning health education associated with investments in water systems.

  13. Community and household determinants of water quality in coastal Ghana

    PubMed Central

    McGarvey, Stephen T.; Buszin, Justin; Reed, Holly; Smith, David C.; Rahman, Zarah; Andrzejewski, Catherine; Awusabo-Asare, Kofi; White, Michael J.

    2013-01-01

    Associations between water sources, socio-demographic characteristics and household drinking water quality are described in a representative sample of six coastal districts of Ghana’s Central Region. Thirty-six enumeration areas (EAs) were randomly chosen from a representative survey of 90 EAs in rural, semi-urban and urban residence strata. In each EA, 24 households were randomly chosen for water quality sampling and socio-demographic interview. Escherichia coli per 100 ml H2O was quantified using the IDEXX Colilert® system and multi-stage regression models estimated cross-sectional associations between water sources, sanitation and socio-demographic factors. Almost three quarters, 74%, of the households have > 2 E. coli /100 ml H2O. Tap water has significantly lower E. coli levels compared with surface or rainwater and well water had the highest levels. Households with a water closet toilet have significantly lower E. coli compared with those using pit latrines or no toilets. Household size is positively associated, and a possessions index is negatively associated, with E. coli. Variations in community and household socio-demographic and behavioural factors are key determinants of drinking water quality. These factors should be included in planning health education associated with investments in water systems. PMID:19108554

  14. Natural seepage of crude oil into the marine environment

    USGS Publications Warehouse

    Kvenvolden, K.A.; Cooper, C.K.

    2003-01-01

    Recent global estimates of crude-oil seepage rates suggest that about 47% of crude oil currently entering the marine environment is from natural seeps, whereas 53% results from leaks and spills during the extraction, transportation, refining, storage, and utilization of petroleum. The amount of natural crude-oil seepage is currently estimated to be 600,000 metric tons per year, with a range of uncertainty of 200,000 to 2,000,000 metric tons per year. Thus, natural oil seeps may be the single most important source of oil that enters the ocean, exceeding each of the various sources of crude oil that enters the ocean through its exploitation by humankind.

  15. Coulometric Karl Fischer determination of trace amounts of water

    SciTech Connect

    Nichugovskii, G.F.

    1986-06-01

    The authors maintain that it is convenient to determine small amounts of water by coulometric titration in spent Fischer reagent because this method is highly sensitive and provides an absolute measurement. The water content of the sample is calculated from the amount of electricity consumed in the electrochemical production of enough molecular iodine to bond completely with the water. This paper attempts to correct for the effect of various factors on the indicator current in the coulometric titration of trace quantities of water by the Karl Fischer reagent. The paper discusses the sources of error by biamperometric indication of the titration endpoint. When the water content is lower than 0.001%, it is absolutely necessary according to the authors, to correct for the effect of the analytical sample. Analytical and graphical methods of calculating the correction are suggested.

  16. Determination of the Water Content of Snow by Dielectric Measurements

    DTIC Science & Technology

    1992-07-01

    AD- A256 299 R*UIIUIUIIII• 0P Determination of the Water Content of Snow by Dielectric Measurements Paul R. Camp and David R. LaBrecque July 1992 a...kHz to deterrnlne wfether measurements made In this frequency range might prove useful in evaluating the water content of snow. Dielectric heating at...20 kHz proved a very useful means of modifying the water content from 0 to 30% by weight. Six different natural snows were used in these experiments

  17. Determination of phosphorus in natural waters: A historical review.

    PubMed

    Worsfold, Paul; McKelvie, Ian; Monbet, Phil

    2016-04-28

    The aim of this paper is to introduce a virtual special issue that reviews the development of analytical approaches to the determination of phosphorus species in natural waters. The focus is on sampling and sample treatment, analytical methods and quality assurance of the data. The export of phosphorus from anthropogenic activities (from diffuse and point sources) can result in increased primary production and eutrophication, and potentially the seasonal development of toxic algal blooms, which can significantly impact on water quality. Therefore the quantification of phosphorus species in natural waters provides important baseline data for studying aquatic phosphorus biogeochemistry, assessing ecosystem health and monitoring compliance with legislation.

  18. Trihalomethane concentrations in tap water as determinant of bottled water use in the city of Barcelona.

    PubMed

    Font-Ribera, Laia; Cotta, Jordi Colomer; Gómez-Gutiérrez, Anna; Villanueva, Cristina M

    2017-08-01

    Bottled water consumption is increasing worldwide, despite its huge economic and environmental cost. We aim to describe personal and tap water quality determinants of bottled water use in the city of Barcelona. This cross-sectional study used data from the Health Survey of Barcelona in 2006 (N=5417 adults). The use of bottled water to drink and to cook was evaluated in relation to age, gender, educational level, district and levels of trihalomethanes (THMs), free chlorine, conductivity, chloride, sodium, pH, nitrate and aluminium in municipal tap water using Robust Poisson Regression. The prevalence of bottled water use to drink and cook was 53.9% and 6.7%, respectively. Chemical parameters in water had a large variability (interquartile range of THMs concentrations: 83.2-200.8μg/L) and were correlated between them, except aluminium. Drinking bottled water increased with educational level, while cooking with bottled water was higher among men than among women and decreased with age. After adjusting by these personal determinants, a dose-response relationship was found between concentrations of all chemicals except aluminium in tap water and bottled water use. The highest association was found for THMs, with a Prevalence Ratio of 2.00 (95%CI=1.86, 2.15) for drinking bottled water and 2.80 (95%CI=1.72, 4.58) for cooking with bottled water, among those with >150μg/L vs. <100μg/L THMs in tap water. More than half of Barcelona residents regularly drank bottled water, and the main determinant was the chemical composition of tap water, particularly THM level. Copyright © 2017. Published by Elsevier B.V.

  19. Determination of the taste threshold of copper in water.

    PubMed

    Zacarías, I; Yáñez, C G; Araya, M; Oraka, C; Olivares, M; Uauy, R

    2001-01-01

    Copper effects on human health represent a relevant issue in modern nutrition. One of the difficulties in assessing the early, acute effects of copper ingested via drinking water is that the taste of copper may influence the response and the capacity to taste copper in different waters is unknown. The purpose of the study was to determine the taste threshold of copper in different types of water, using soluble and insoluble salts (copper sulfate and copper chloride). Copper-containing solutions (range 1.0-8.0 mg/l Cu) were prepared in tap water, distilled deionized water and uncarbonated mineral water. Sixty-one healthy volunteers (17-50 years of age), with no previous training for sensory evaluation, participated in the study. A modified triangle test was used to define the taste threshold value. The threshold was defined as the lowest copper concentration detected by 50% of the subjects assessed. To evaluate the olfactory input in the threshold value obtained, 15 of 61 subjects underwent a second set of triangle tests with the nose open and clamped, using distilled water with copper sulfate at a concentration corresponding to the individual's threshold. The taste threshold in tap water was 2.6 mg/l Cu for both copper sulfate and copper chloride. The corresponding values for distilled deionized water were 2.4 and 2.5 mg/l Cu for copper sulfate and copper chloride, respectively. In uncarbonated mineral water the threshold values were slightly higher, 3.5 and 3.8 mg/l Cu for copper sulfate and for copper chloride, respectively, which are significantly higher than those observed in tap and distilled waters (P < 0.01, Kruskal-Wallis test). The taste threshold did not change significantly when the nose was clamped. In conclusion, the median values for copper taste threshold were low, ranging between 2.4 and 3.8 mg/l Cu, depending on the type of water.

  20. Environmental hazards from natural hydrocarbons seepage: integrated classification of risk from sediment chemistry, bioavailability and biomarkers responses in sentinel species.

    PubMed

    Benedetti, Maura; Gorbi, Stefania; Fattorini, Daniele; D'Errico, Giuseppe; Piva, Francesco; Pacitti, Davide; Regoli, Francesco

    2014-02-01

    Potential effects of natural emissions of hydrocarbons in the marine environment have been poorly investigated. In this study, a multidisciplinary weight of evidence (WOE) study was carried out on a shallow seepage, integrating sediment chemistry with bioavailability and onset of subcellular responses (biomarkers) in caged eels and mussels. Results from different lines of evidence (LOEs) were elaborated within a quantitative WOE model which, based on logical flowcharts, provide synthetic indices of hazard for each LOE, before their integration in a quantitative risk assessment. Evaluations of different LOEs were not always in accordance and their overall elaboration summarized as Moderate the risk in the seepage area. This study provided first evidence of biological effects in organisms exposed to natural hydrocarbon emissions, confirming the limit of chemical characterization as stand-alone criteria for environmental quality assessment and the utility of multidisciplinary investigations to determine the good environmental status as required by Environmental Directives. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Design Guidance for Confined Disposal Facility Lateral Seepage Control

    DTIC Science & Technology

    2005-09-01

    polyethylene (HDPE) liner. The trencher operates by cutting through soil using a chain-saw type apparatus attached to the boom of a crawler-mounted vehicle...effluent during filling operations (USEPA 1994), (2) surface runoff during precipitation after closure (USEPA 1994), (3) seepage through perimeter...Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202

  2. Geological settings and seafloor morphodynamic evolution linked to methane seepage

    NASA Astrophysics Data System (ADS)

    Van Landeghem, Katrien J. J.; Niemann, Helge; Steinle, Lea I.; O'Reilly, Shane S.; Huws, Dei G.; Croker, Peter F.

    2015-08-01

    Methane seeps have been shown to be a powerful agent in modifying seabed morphology, amongst others by cementation processes such as the formation of methane-derived authigenic carbonates (MDACs). The cements stabilise mobile sediment particles and thereby promote the formation of edifices such as mounds on various scales. The release of methane from shallow subsurface sources, when concentrated in seeps, has proven hazardous to offshore construction activities. In this paper, methane cycling and MDAC precipitation is explored as a potential "finger on the pulse" for the recognition of shallow gas pockets and active gas seepage. This would provide a valuable planning tool for seabed engineering developments in areas of potential gas seepage. Measurements of methane concentrations in the Irish Sea are correlated with a unique record of longer-term morphological evolution (up to 11 years) of MDAC structures and subsurface geological settings which would favour the build-up of shallow gas. It was found that gas seepage activity associated with fault zones correlates with carbonate mound steepness. Cessation of gas seepage results in a relatively slow process of erosion and burial of the mounds, eventually producing a subdued carbonate mound morphology after several decades. The Quaternary glacial legacy equally seems to define the distribution and geometry of the MDAC structures. In this case, methane gas locally concentrated in sands and gravels capped by clayey glacial sediments may percolate upwards to the seafloor. A link between methane seeps and the formation of unusually large, trochoidally shaped sediment waves observed on continental shelves worldwide is deemed unlikely. However, the observations suggest that gas percolating through sediment waves may be capped by muddy sediments which have deposited on the sediment waves due to anoxic conditions or eroded from a neighbouring cliff. Other sediment waves in the Irish Sea were found to have a step

  3. Determining gold in water by anion-exchange batch extraction

    USGS Publications Warehouse

    McHugh, J.B.

    1986-01-01

    This paper describes a batch procedure for determining gold in natural waters. It is completely adaptable to field operations. The water samples are filtered and acidified before they are equilibrated with an anion-exchange resin by shaking. The gold is then eluted with acetone-nitric acid solution, and the eluate evaporated to dryness. The residue is taken up in hydrobromic acid-bromine solution and the gold is extracted with methyl isobutyl ketone. The extract is electrothermally atomized in an atomic-absorption spectrophotometer. The limit of determination is 1 ng 1. ?? 1986.

  4. Determination of fixed water in rocks by infrared absorption

    USGS Publications Warehouse

    Breger, I.A.; Chandler, J.C.

    1969-01-01

    An infrared absorption technique has been developed for the quantitative determination of "fixed water" (H2O+) in rocks. Potassium bromide disks containing 2-mg samples are scanned in the 3-??m spectral region and absorption at 2.96 ??m is determined. Although the exact nature of this peak is not known, other than that it is caused by an interaction between the potassium bromide and hydroxyl groups and water, it can be used for quantitative analysis. Rock samples, other than those containing significant percentages of clay minerals, can be analyzed with a standard deviation of 0.26%.

  5. New method for measuring water seepage through salmon spawning gravel.

    Treesearch

    Richard D. Orchard

    1988-01-01

    A new method, with heat as a tracer, was developed for measuring rate and direction of intragravel waterflow through salmon spawning gravel. A commercial flowmeter was calibrated in the laboratory under controlled environmental conditions. Flow measurements comparing the flowmeter with a dye-tracer method were made in an artificial stream channel at Young Bay and in...

  6. An empirical method to determine inadequacy of dietary water.

    PubMed

    Armstrong, Lawrence E; Johnson, Evan C; McKenzie, Amy L; Muñoz, Colleen X

    2016-01-01

    The physiological regulation of total body water and fluid concentrations is complex and dynamic. The human daily water requirement varies because of differences in body size, dietary solute load, exercise, and activities. Although chronically concentrated urine increases the risk of renal diseases, an empirical method to determine inadequate daily water consumption has not been described for any demographic group; instead, statistical analyses are applied to estimate nutritional guidelines (i.e., adequate intake). This investigation describes a novel empirical method to determine the 24-h total fluid intake (TFI; TFI = water + beverages + moisture in food) and 24-h urine volume, which correspond to inadequate 24-h water intake (defined as urine osmolality of 800 mOsm/kg; U800). Healthy young women (mean ± standard deviation; age, 20 ± 2 y, mass, 60.8 ± 11.7 kg; n = 28) were observed for 7 consecutive days. A 24-h urine sample was analyzed for volume and osmolality. Diet records were analyzed to determine 24-h TFI. For these 28 healthy young women, the U800 corresponded to a TFI ≥2.4 L/d (≥39 mL/kg/d) and a urine volume ≥1.3 L/d. The U800 method could be employed to empirically determine 24-h TFI and 24-h urine volumes that correspond to inadequate water intake in diverse demographic groups, residents of specific geographic regions, and individuals who consume specialized diets or experience large daily water turnover. Because laboratory expertise and instrumentation are required, this technique provides greatest value in research and clinical settings. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Determination of parathion, aldicarb, and thiobencarb in tap water and bottled mineral water in Mashhad, Iran.

    PubMed

    Rezaee, Ramin; Hassanzadeh-Khayyat, Mohammad; Mehri, Fereshteh; Khashyarmanesh, Zahra; Moallemzadeh, Hamideh; Karimi, Gholamreza

    2012-04-01

    Water is a necessity for life. Currently, because of different contaminations in tap water, most people prefer using bottled mineral waters. Pesticides (e.g., organophophorous, carbamates, etc.) are among the most dangerous chemicals that may be found in drinking waters, which can cause long- and short-term complications. Because all people consume at least 2 L of water per day, water-quality monitoring is vital. In this study, we determined the concentration of three pesticides (aldicarb, parathion, and thiobencarb) in 13 tap-water samples collected from 13 different urban areas and 10 samples of bottled mineral water in Mashhad, a major city in northeast Iran. Samples were analyzed by gas chromatography coupled with a pulsed flame photometric detector after solid-phase extraction. Results showed that 2 of 13 tap-water samples and 2 of 10 bottled mineral water trademarks were contaminated either by parathion or by thiobencarb or both, with concentrations ranging between 0.6 and 0.8 ppb. According to the defined guideline values, determined concentrations of pesticides are below the permissible World Health Organization level for these toxic agents, and it is considered that drinking these tap waters and bottled mineral waters are safe for human consumption.

  8. The influence of woody plants on the seepage of flood protection levees: Experiences from a test site

    NASA Astrophysics Data System (ADS)

    Lammeranner, W.; Meixner, H.; Florineth, F.

    2009-04-01

    The past flood events have once more drawn the attention to the stability and maintenance of flood protection levees. The attention has also been focused on the relationship between vegetation and the structural integrity of dikes. Current standards regard dense turf to be safest vegetation cover for dikes. Many guidelines ban woody vegetation from dikes and levees to provide structural integrity, visual inspection and unhindered flood-fight access. The refusal of woody plants is mainly based on the argument that root penetration of woody plants facilitates water movement along their path. Within the frame of a research project carried out by the Institute of Soil Bioengineering and Landscape Construction (University of Natural Resources and Applied Life Sciences, Vienna), focusing on woody plants on levees, the effects of small to medium growing woody (shrubby) plants on the seepage are tested. Data are drawn from two natural-scaled research levees. The homogenous levees consist of a mineral silt-sand-gravel and have a fill height of 2.7 m and a slope inclination of 2:3. The tests investigate the impact of woody plants (living brush mattress - transversal) in comparison to compact turf (jute netting mulch seeding). Measured plant parameters, characterising the vegetation structures were shoot lengths, shoot diameters, and above ground biomass. Root growth is investigated in an extra plot area allowing excavation of the plants. Percolation is monitored using seepage monitoring pipes, soil moisture sensors and soil temperature probes, which were build into the embankment during construction. The proposed contribution discusses the effects of woody plants (shrubs) on seepage of flood protection levees. Methodology of research and results after three initial seepage tests are presented.

  9. Brines in Seepage Channels as Eluants for Subsurface Relict Biomolecules on Mars?

    NASA Astrophysics Data System (ADS)

    Wynn-Williams, David D.; Cabrol, Nathalie A.; Grin, Edmond A.; Haberle, Robert M.; Stoker, Carol R.

    2001-06-01

    Water, vital for life, not only maintains the integrity of structural and metabolic biomolecules, it also transports them in solution or colloidal suspension. Any flow of water through a dormant or fossilized microbial community elutes molecules that are potentially recognizable as biomarkers. We hypothesize that the surface seepage channels emanating from crater walls and cliffs in Mars Orbiter Camera images result from fluvial erosion of the regolith as low-temperature hypersaline brines. We propose that, if such flows passed through extensive subsurface catchments containing buried and fossilized remains of microbial communities from the wet Hesperian period of early Mars (~3.5 Ga ago), they would have eluted and concentrated relict biomolecules and delive red them to the surface. Life-supporting low-temperature hypersaline brines in Antarctic desert habitats provide a terrestrial analog for such a scenario. As in the Antarctic, salts would likely have accumulated in water-filled depressions on Mars by seasonal influx and evaporation. Liquid water in the Antarctic cold desert analogs occurs at -80°C in the interstices of shallow hypersaline soils and at -50°C in salt-saturated ponds. Similarly, hypersaline brines on Mars could have freezing points depressed below -50°C. The presence of hypersaline brines on Mars would have extended the amount of time during which life might have evolved. Phototrophic communities are especially important for the search for life because the distinctive structures and longevity of their pigments make excellent biomarkers. The surface seepage channels are therefore not only of geomorphological significance, but also provide potential repositories for biomolecules that could be accessed by landers.

  10. Brines in seepage channels as eluants for subsurface relict biomolecules on Mars?

    PubMed

    Wynn-Williams, D D; Cabrol, N A; Grin, E A; Haberle, R M; Stoker, C R

    2001-01-01

    Water, vital for life, not only maintains the integrity of structural and metabolic biomolecules, it also transports them in solution or colloidal suspension. Any flow of water through a dormant or fossilized microbial community elutes molecules that are potentially recognizable as biomarkers. We hypothesize that the surface seepage channels emanating from crater walls and cliffs in Mars Orbiter Camera images results from fluvial erosion of the regolith as low-temperature hypersaline brines. We propose that, if such flows passed through extensive subsurface catchments containing buried and fossilized remains of microbial communities from the wet Hesperian period of early Mars (approximately 3.5 Ga ago), they would have eluted and concentrated relict biomolecules and delivered them to the surface. Life-supporting low-temperature hypersaline brines in Antarctic desert habitats provide a terrestrial analog for such a scenario. As in the Antarctic, salts would likely have accumulated in water-filled depressions on Mars by seasonal influx and evaporation. Liquid water in the Antarctic cold desert analogs occurs at -80 degrees C in the interstices of shallow hypersaline soils and at -50 degrees C in salt-saturated ponds. Similarly, hypersaline brines on Mars could have freezing points depressed below -50 degrees C. The presence of hypersaline brines on Mars would have extended the amount of time during which life might have evolved. Phototrophic communities are especially important for the search for life because the distinctive structures and longevity of their pigments make excellent biomarkers. The surface seepage channels are therefore not only of geomorphological significance, but also provide potential repositories for biomolecules that could be accessed by landers.

  11. Timing of fluid seepage on summits of Quaker and Conical serpentine mud volcanoes, Mariana forearc: Evidence from U/Th dating of carbonate chimneys

    NASA Astrophysics Data System (ADS)

    Tong, Hongpeng; Fryer, Patricia; Feng, Dong; Chen, Duofu

    2017-04-01

    Serpetinization of forearc mantle along deep faults in the Mariana convergent plate margin permits formation of large active serpentinite mud volcanoes on the overiding plate within 90 km of the trench. Fluid seepage on summits of the mud volcanoes lead to the formation of authigenic carbonate chimneys close to the seafloor. Such carbonate chimneys are unique archives of past fluid seepage and assciated envrionemtnal parameters. Here, we report U/Th dating and stable carbon and oxygen isotopes of the chimneys from Quaker and Conical serpentine mud volcanoes. The resulting U/Th ages of samples from Quaker Seamount show three time intervals of 11,081 to10,542 yBP, 5,857 to 5,583 yBP, and 781 to 164 yBP, respectively. By comparison, carbonates from Conical Seamount have U/Th ages between 3,070 yBP and 1,623 yBP. Our results suggest that fluid seepage on the summits of serpentine mud volcanoes are episodic and probably locally controlled. Samples from Quaker seamount show depletion of 13C (δ13C=-7.0-0.4‰ V-PDB), indicating contribution of carbon from anoxic oxidation of abiogenic methane. By contrast, samples from Conical seamount have positive δ18O values (0.6-6.3), suggesting enrichment of 18O in the seepage fluid. The data obtained provide time integrated variation of seepage fluids and seepage dynamics that are archived in authigenic carbonates. This finding adds to the ongoing multidisciplinary effort to better constrain the environment in the Mariana forearc region and to determine the locally dominant biogeochemical processes. Acknowlegment: This study was funded by the CAS (Grant No. XDB06030102).

  12. RAPID DETERMINATION OF {sup 210} PO IN WATER SAMPLES

    SciTech Connect

    Maxwell, S.

    2013-05-22

    A new rapid method for the determination of {sup 210}Po in water samples has been developed at the Savannah River National Laboratory (SRNL) that can be used for emergency response or routine water analyses. If a radiological dispersive device (RDD) event or a radiological attack associated with drinking water supplies occurs, there will be an urgent need for rapid analyses of water samples, including drinking water, ground water and other water effluents. Current analytical methods for the assay of {sup 210}Po in water samples have typically involved spontaneous auto-deposition of {sup 210}Po onto silver or other metal disks followed by counting by alpha spectrometry. The auto-deposition times range from 90 minutes to 24 hours or more, at times with yields that may be less than desirable. If sample interferences are present, decreased yields and degraded alpha spectrums can occur due to unpredictable thickening in the deposited layer. Separation methods have focused on the use of Sr Resin, often in combination with 210Pb analysis. A new rapid method for {sup 210}Po in water samples has been developed at the Savannah River National Laboratory (SRNL) that utilizes a rapid calcium phosphate co-precipitation method, separation using DGA Resin (N,N,N,N-tetraoctyldiglycolamide extractant-coated resin, Eichrom Technologies or Triskem-International), followed by rapid microprecipitation of {sup 210}Po using bismuth phosphate for counting by alpha spectrometry. This new method can be performed quickly with excellent removal of interferences, high chemical yields and very good alpha peak resolution, eliminating any potential problems with the alpha source preparation for emergency or routine samples. A rapid sequential separation method to separate {sup 210} Po and actinide isotopes was also developed. This new approach, rapid separation with DGA Resin plus microprecipitation for alpha source preparation, is a significant advance in radiochemistry for the rapid

  13. A model to determine the economic viability of water fluoridation.

    PubMed

    Kroon, Jeroen; van Wyk, Philippus Johannes

    2012-01-01

    In view of concerns expressed by South African local authorities the aim of this study was to develop a model to determine whether water fluoridation is economically viable to reduce dental caries in South Africa. Microsoft Excel software was used to develop a model to determine economic viability of water fluoridation for 17 water providers from all nine South African provinces. Input variables for this model relate to chemical cost, labor cost, maintenance cost of infrastructure, opportunity cost, and capital depreciation. The following output variables were calculated to evaluate the cost of water fluoridation: per capita cost per year, cost-effectiveness and cost-benefit. In this model it is assumed that the introduction of community water fluoridation can reduce caries prevalence by an additional 15 percent and that the savings in cost of treatment will be equal to the average fee for a two surface restoration. Water providers included in the study serve 53.5 percent of the total population of South Africa. For all providers combined chemical cost contributes 64.5 percent to the total cost, per capita cost per year was $0.36, cost-effectiveness was calculated as $11.41 and cost-benefit of the implementation of water fluoridation was 0.34. This model confirmed that water fluoridation is an economically viable option to prevent dental caries in South African communities, as well as conclusions over the last 10 years that water fluoridation leads to significant cost savings and remains a cost-effective measure for reducing dental caries, even when the caries-preventive effectiveness is modest. © 2012 American Association of Public Health Dentistry.

  14. Determination of the Electronics Charge--Electrolysis of Water Method.

    ERIC Educational Resources Information Center

    Venkatachar, Arun C.

    1985-01-01

    Presents an alternative method for measuring the electronic charge using data from the electrolysis of acidified distilled water. The process (carried out in a commercially available electrolytic cell) has the advantage of short completion time so that students can determine electron charge and mass in one laboratory period. (DH)

  15. Determination of the Electronics Charge--Electrolysis of Water Method.

    ERIC Educational Resources Information Center

    Venkatachar, Arun C.

    1985-01-01

    Presents an alternative method for measuring the electronic charge using data from the electrolysis of acidified distilled water. The process (carried out in a commercially available electrolytic cell) has the advantage of short completion time so that students can determine electron charge and mass in one laboratory period. (DH)

  16. Factors Affecting the Temporal and Spatial Variability and Characteristics of Marine Hydrocarbon Seepage, Coal Oil Point, CA

    NASA Astrophysics Data System (ADS)

    del Sontro, T. S.; Leifer, I.; Luyendyk, B.

    2004-12-01

    , typically spanning several vents. Rising bubbles generate an upwelling flow of water that spins a turbine with an optical encoder on its axis. The encoders are connected to a multi-channel datalogger. Measurements are recorded in revolutions per second and converted to gas volume flux based on laboratory calibration. Spectra of the seepage time series showed the effect of external forcings, including swell and tides. Responses to external forcing factors, such as a 1% swell variation, differ between multiple tents. Seeps with a higher flux exhibit a smaller response than seeps with a lower flux. Flux variations between tents demonstrate the complexity of the underlying processes of gas, oil, and tar migration through an inter-connected subsurface fracture network.

  17. Determinations by Seasat of atmospheric water and synoptic fronts

    NASA Technical Reports Server (NTRS)

    Taylor, P. K.; Katsaros, K. B.; Lipes, R. G.

    1981-01-01

    It is shown by means of radiosonde data from the Joint Air-Sea Interaction (JASIN) experiment that the Seasat Scanning Multichannel Microwave Radiometer (SMMR) atmospheric water vapor distributions, taken over 600-km wide swaths with a resolution of 54 km, can be used to detect the position of atmospheric fronts in the lower troposphere. In addition to the fact that, unlike visible and IR radiometry, the SMMR determinations are not hampered by extensive cirrus or by a lack of frontal clouds, they use more channels, allowing better discrimination between the effects of liquid water, water vapor and sea state, and show improved spatial resolution. Data analysis results show that the SMMR atmospheric water vapor distributions have an accuracy comparable to that of in situ radiosonde measurements.

  18. 21 CFR 352.76 - Determination if a product is water resistant or very water resistant.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 5 2010-04-01 2010-04-01 false Determination if a product is water resistant or very water resistant. 352.76 Section 352.76 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS FOR HUMAN USE SUNSCREEN DRUG PRODUCTS FOR OVER-THE-COUNTER...

  19. Radar Sensing of Petroleum Seepage Gases

    DTIC Science & Technology

    1993-01-17

    was difuse and changing from one antenna scan to the next. The ground-based system operators, in searching for candidate returns, settled on three... cultural scatterers. Fig. A-1 I and A-1 2 show two views of the terrain. In Fig. A-1 1 photograph shows a view, looking north, at the mrbile-lab/radar... Cultural scatterers were situated so as to enhance determinations of ranges and bearing, yet did not intrude into the areas of interest. The cultural

  20. Determination of minor elements in water by emission spectroscopy

    USGS Publications Warehouse

    Barnett, Paul R.; Mallory, E.C.

    1971-01-01

    With the emission spectrograph, the analyst is able to determine many minor elements simultaneously in water samples. Spectrographic methods differ chiefly in techniques of preconcentrating the elements. For waters with dissolved solids of less than 1,000 milligrams per liter, the method of evaporating to dryness and determining the elements in the dried residue is sensitive, precise, and reasonably accurate. The lower limits of detection vary with the quantity of dissolved solids. Twenty-four elements are determined by this method. For waters with more than 1,000 milligrams per liter of dissolved solids, it is necessary to separate the minor elements from the major constituents before spectrographically determining the former, in order to achieve adequate lower limits of detection. Such procedures generally require more time than the residue method. In the first of two such procedures given, 21 of the metallic elements are precipitated with thioacetamide prior to spectrographic determination. In an alternate procedure, 18 elements are precipitated quantitatively with complexing reagents 8-hydroxyquinoline, tannic acid, and thioanlide. This method is faster than the thioacetamide method, but at the sacrifice of some elements. A Fortran IV computer program for processing densitometric data is given in the section 'Computer Program.'

  1. Seepage of methane at Jaco Scar, a slide caused by seamount subduction offshore Costa Rica

    NASA Astrophysics Data System (ADS)

    Mau, Susan; Rehder, Gregor; Sahling, Heiko; Schleicher, Tina; Linke, Peter

    2014-10-01

    Methane (CH4) concentrations and CH4 stable carbon isotopic composition () were investigated in the water column within Jaco Scar. It is one of several scars formed by massive slides resulting from the subduction of seamounts offshore Costa Rica, a process that can open up structural and stratigraphical pathways for migrating CH4. The release of large amounts of CH4 into the adjacent water column was discovered at the outcropping lowermost sedimentary sequence of the hanging wall in the northwest corner of Jaco Scar, where concentrations reached up to 1,500 nmol L-1. There CH4-rich fluids seeping from the sedimentary sequence stimulate both growth and activity of a dense chemosynthetic community. Additional point sources supplying CH4 at lower concentrations were identified in density layers above and below the main plume from light carbon isotope ratios. The injected CH4 is most likely a mixture of microbial and thermogenic CH4 as suggested by values between -50 and -62 ‰ Vienna Pee Dee Belemnite. This CH4 spreads along isopycnal surfaces throughout the whole area of the scar, and the concentrations decrease due to mixing with ocean water and microbial oxidation. The supply of CH4 appears to be persistent as repeatedly high CH4 concentrations were found within the scar over 6 years. The maximum CH4 concentration and average excess CH4 concentration at Jaco Scar indicate that CH4 seepage from scars might be as significant as seepage from other tectonic structures in the marine realm. Hence, taking into account the global abundance of scars, such structures might constitute a substantial, hitherto unconsidered contribution to natural CH4 sources at the seafloor.

  2. Investigating landfill-impacted groundwater seepage into headwater streams using stable carbon isotopes

    NASA Astrophysics Data System (ADS)

    Atekwana, E. A.; Krishnamurthy, R. V.

    2004-07-01

    The impact of landfill contaminated groundwater along a reach of a small stream adjacent to a municipal landfill was investigated using stable carbon isotopes as a tracer. Groundwater below the stream channel, groundwater seeping into the stream, groundwater from the stream banks and stream water were sampled and analysed for dissolved inorganic carbon (DIC) and the isotope ratio of DIC (13CDIC). Representative samples of groundwater seeping into the stream were collected using a device (a seepage well) specifically designed for collecting samples of groundwater seeping into shallow streams with soft sediments. The DIC and 13CDIC of water samples ranged from 52 to 205 mg C/L and -16.9 to +5.7 relative to VPDB standard, respectively. Groundwater from the stream bank adjacent to the landfill and some samples of groundwater below the stream channel and seepage into the stream showed evidence of 13C enriched DIC (δ13CDIC = -2.3 to +5.7), which we attribute to landfill impact. Stream water and groundwater from the stream bank opposite the landfill did not show evidence of landfill carbon (δ13CDIC = -10.0 to -16.9). A simple mixing model using DIC and δ13CDIC showed that groundwater below the stream and groundwater seeping into the stream could be described as a mixture of groundwater with a landfill carbon signature and uncontaminated groundwater. This study suggests that the hyporheic zone at the stream-groundwater interface probably was impacted by landfill contaminated groundwater and may have significant ecological implications for this ecotone.

  3. Determining the Most Appropriate Classification Methods for Water Quality

    NASA Astrophysics Data System (ADS)

    Gürsoy, Önder

    2016-10-01

    Assessing water resources’ quality and also monitoring them have attracted lots of attention in the recent years. Remote sensing has been growing widely in the last decade and its resources are very usable when it comes to water resources management. In this study, by using remote sensing technology, satellite images that have 350 to 1050 nanometres wavelength band sensors are used to determine the quality of the Kizilirmak River's water. Through the river's resources, ground based spectral measurements are made to identify the quality differences of the water at the test spots that have been determined before. In this context at Imranli, where the river contacts civilization for the first time, which is located in Sivas city of Turkey, samples are gathered in order to do ground based spectroradiometer measurements. These samples are gathered simultaneously with the image acquiring time of CHRIS Proba satellite. Spectral signatures that are obtained from ground measurements are used as reference data in order to classify CHRIS Proba satellite's hyperspectral images over the study area. Satellite images are classified based on Chemical Oxygen Demand (COD), Turbidity and Electrical Conductivity (EC) attributes. As a result, interpretations obtained from classified CHRIS Proba satellite hyperspectral images of the study area are presented. Spectras are readied for Matched Filtering and Spectral Angle Mapper methods for determining the best classification method.

  4. Effect of downward seepage on turbulent flow characteristics and bed morphology around bridge piers

    NASA Astrophysics Data System (ADS)

    Chavan, Rutuja; Sharma, Anurag; Kumar, Bimlesh

    2017-03-01

    In this work, experimental investigations have been pursued to analyse the influence of downward seepage on the turbulent characteristics of flow and corresponding changes in vortex structure around circular bridge pier in alluvial channel. Experiments were conducted in sand bed channel with circular piers of different sizes for no seepage, 10% seepage and 20% seepage cases. The measurement of turbulent flow statistics such as velocity and Reynolds stresses is found to be negative within the scour hole at upstream of the pier whereas application of downward seepage retards the reversal of the flow causing a decrement in the velocity and Reynolds stresses. Higher Reynolds shear stress prevails at the downstream side because of the production of wake vortices. Contribution of all bursting events to the total Reynolds shear stress production has been observed to increase with downward seepage. The analysis of integral scale suggest that size of eddies increases with seepage, which is responsible for increase in particle mobility. Initially rate of scouring is more which abatements gradually with expanding time as well as with the increased of downward seepage. Presence of downward seepage reduces the depth and length of vortex and shifts towards downstream side of the pier.

  5. Experimental investigation on flow and scour characteristics around tandem piers in sandy channel with downward seepage

    NASA Astrophysics Data System (ADS)

    Chavan, Rutuja; Kumar, Bimlesh

    2017-09-01

    Experimental investigations have been carried out to study morpho-hydraulic characteristics such as scour geometry and turbulent flow properties around tandem piers in alluvial channels. Experiments were carried out in a plane sand bed with two circular piers of same diameter arranged in tandem manner under no seepage, 10% seepage and 20% seepage conditions. Downward seepage minimizes the scour depth around piers and restrains the development of scour depth with time. Strong reversal flow is found near the bed at upstream of piers and near free surface at downstream of piers where velocity and Reynolds shear stress are found to be negative which reduce in magnitude with downward seepage. The flow is more critical within the gap between two piers where velocity is lesser near free surface and gradually increasing towards bed. Quadrant analysis shows that contribution of each event to the total Reynolds shear stress increases with downward seepage. Sedimentation effect prevails within the scour hole whereas outside the scour hole erosive forces become more dominant. Reduced reversal flow at upstream of pier because of downward seepage results in decreasing higher order moments and turbulent kinetic energy. At downstream of piers, secondary currents are dominant due to wake vortices. Strouhal number decreases in case of seepage runs than no seepage condition.

  6. Effect of downward seepage on turbulent flow characteristics and bed morphology around bridge piers

    NASA Astrophysics Data System (ADS)

    Chavan, Rutuja; Sharma, Anurag; Kumar, Bimlesh

    2017-01-01

    In this work, experimental investigations have been pursued to analyse the influence of downward seepage on the turbulent characteristics of flow and corresponding changes in vortex structure around circular bridge pier in alluvial channel. Experiments were conducted in sand bed channel with circular piers of different sizes for no seepage, 10% seepage and 20% seepage cases. The measurement of turbulent flow statistics such as velocity and Reynolds stresses is found to be negative within the scour hole at upstream of the pier whereas application of downward seepage retards the reversal of the flow causing a decrement in the velocity and Reynolds stresses. Higher Reynolds shear stress prevails at the downstream side because of the production of wake vortices. Contribution of all bursting events to the total Reynolds shear stress production has been observed to increase with downward seepage. The analysis of integral scale suggest that size of eddies increases with seepage, which is responsible for increase in particle mobility. Initially rate of scouring is more which abatements gradually with expanding time as well as with the increased of downward seepage. Presence of downward seepage reduces the depth and length of vortex and shifts towards downstream side of the pier.

  7. Experimental determination of cavitation thresholds in liquid water and mercury

    SciTech Connect

    Taleyarkhan, R.P.; West, C.D.; Moraga, F.

    1998-11-01

    An overview is provided on cavitation threshold measurement experiments for water and mercury. Various aspects to be considered that affect onset determination are discussed along with design specifications developed for construction of appropriate apparatus types. Both static and transient-cavitation effects were studied using radically different apparatus designs. Preliminary data are presented for cavitation thresholds for water and mercury over a range of temperatures in static and high-frequency environments. Implications and issues related to spallation neutron source target designs and operation are discussed.

  8. Simultaneous extraction and determination of various pesticides in environmental waters.

    PubMed

    Zhang, Zulin; Lefebvre, Thibault; Kerr, Christine; Osprey, Mark

    2014-12-01

    A simple and rapid method was developed for the simultaneous analysis of nine different pesticides in water samples by gas chromatography with mass spectrometry. A number of parameters that may affect the recovery of pesticides, such as the type of solid-phase extraction cartridge, eluting solvent in single or combination and their volumes, and water pH value were investigated. It showed that three solid-phase extraction cartridges (Strata-X, Oasis HLB, and ENVI-18) produced the greatest recovery while ethyl acetate/dichloromethane/acetone (45:10:45, 12 mL) followed by dichloromethane (6 mL) was efficient in eluting target pesticides from solid-phase extraction cartridges. Different water pH values (4-9) did not show a significant effect on the pesticides recovery. The optimized method was verified by performing spiking experiments with a series of concentrations (0.002-10 μg/L) in waters, with good linearity, recovery, and reproducibility for most compounds. The limit of detection and limit of quantification of this optimized method were 0.01-2.01 and 0.02-6.71 ng/L, respectively, much lower than the European Union environmental quality standard for the pesticides (0.1 μg/L) in waters. The proposed method was further validated by participation in an interlaboratory trial. It was then subsequently applied to river waters from north-east Scotland, UK, for the determination of the target pesticides.

  9. Determination of selected anions in water by ion chromatography

    USGS Publications Warehouse

    Fishman, Marvin J.; Pyen, Grace

    1979-01-01

    Ion chromatography is a rapid, sensitive, precise, and accurate method for the determination of major anions in rainwater and surface waters. Simultaneous analyses of a single sample for bromide, chloride, fluoride, nitrate, nitrite, orthophosphate, and sulfate require approximately 20 minutes to obtain a chromatogram. Minimum detection limits range from 0.01 mg/L for fluoride to 0.20 mg/L for chloride and sulfate. Relative standard deviations were less than 9% for all anions except nitrite in Standard Reference Water Samples. Only one reference sample contained nitrite and its concentration was near the minimum level of detection. Similar precision was found for chloride, nitrate, and sulfate at concentrations less than 5 mg/L in rainfall samples. Precision for fluoride ranged from 12 to 22%, but is attributed to the low concentrations in these samples. The other anions were not detected. To determine accuracy of results, several samples were spiked with known concentrations of fluoride, chloride, nitrate, and sulfate; recoveries ranged from 96 to 103%. Known amounts of bromide and phosphate were added, separately, to several other waters, which contained bromide or phosphate. Recovery of added bromide and phosphate ranged from approximately 95 to 104%. No recovery data were obtained for nitrite. Chloride, nitrate, nitrite, orthophosphate, and sulfate, in several samples, were also determined independently by automated colorimetric procedures. An automated ion-selective electrode method was used to determine fluoride. Results are in agreement with results obtained by ion chromatography. (USGS).

  10. Occurrence, distribution and prey items of juvenile marbled sole Pseudopleuronectes yokohamae around a submarine groundwater seepage on a tidal flat in southwestern Japan

    NASA Astrophysics Data System (ADS)

    Hata, Masaki; Sugimoto, Ryo; Hori, Masakazu; Tomiyama, Takeshi; Shoji, Jun

    2016-05-01

    Occurrence, distribution and prey items of juvenile marbled sole Pseudopleuronectes yokohamae were investigated around a submarine groundwater seepage on a tidal flat in southwestern Japan. Spatial distribution of radon-222 (222Rn) concentration in water showed more submarine groundwater seepage in the offshore area. The lower salinities at offshore sampling stations corresponded with the highest 222Rn concentrations. Juvenile marbled sole were collected from March through June with seasonal peak in April in 2013 and 2014. Mean abundance of juvenile marbled sole was highest at the second most offshore station where high submarine groundwater seepage was indicated. Major prey items in the stomachs of the marbled sole at the post-settlement stage (10-40 mm) were small crustaceans such as cumaceans and gammarids, which were partially replaced with polychaetes in larger juveniles (40-50 mm). Abundance of these major prey items was also higher at offshore stations. A negative correlation between gammarid abundance and salinity indicated a higher concentration of gammarids around the area of high submarine groundwater seepage, a pattern not observed for the other major prey organisms. Stable isotope analysis showed greater dependence of post-settlement stage marbled sole on the small crustaceans with low δ13C indicating that nutrients of terrestrial origin contribute to production of the juvenile marbled sole on the tidal flat.

  11. Platform and Environmental Effects on Above- and In-Water Determinations of Water-Leaving Radiances

    NASA Technical Reports Server (NTRS)

    Hooker, Stanford B.; Morel, Andre; McClain, Charles R. (Technical Monitor)

    2001-01-01

    A comparison of above- and in-water spectral measurements in Case-1 conditions showed the uncertainty in above-water determinations of water-leaving radiances depended on the pointing angle of the above-water instruments with respect to the side of the ship. Two above-water methods were used to create a diagnostic variable to quantify the presence of superstructure reflections which degraded the above-water intracomparisons of water-leaving radiances by 10.9-33.4% (for far-to-near viewing distances, respectively). The primary conclusions of the above- and in-water intercomparison of water-leaving radiances were as follows: a) the SeaWiFS 5% radiometric objective was achieved with the above-water approach, but reliably with only one method and only for about half the data; b) a decrease in water-leaving radiance values was seen in the presence of swell, although, wave crests were radiometrically brighter than the troughs; and c) standard band ratios used in ocean color algorithms remained severely affected, because of the relatively low signal and, thus, proportionally significant contamination at the 555nm wavelength.

  12. Determination of water use in Rockford and Kankakee areas, Illinois

    USGS Publications Warehouse

    LaTour, John K.

    1991-01-01

    Amounts of water withdrawn, delivered, consumed, released, returned, and lost or gained during conveyance were determined for six communities--Rockford, Loves Park, North Park, Kankakee, Bourbonnais, and Bradley--served by the public-water systems in the Rockford and the Kankakee areas of Illinois. Water-use categories studied were commercial, industrial, domestic, and municipal uses; public supply; and sewage treatment. The availability and accuracy of water-use data are described, and water-use coefficients and methods of estimating water use are provided to improve the collection and the analysis of water-use information. Water-use data were obtained from all the water utilities and from 30 major water users in the Rockford and the Kankakee areas. Data were available for water withdrawals by water suppliers; deliveries by water suppliers to water users; returns by sewage-treatment plants and water users; releases by water users to sewers; and sewer-conveyance losses. Accuracy of the water-use data was determined from discharge measurements or reliability tests of water meters, or was estimated according to the completeness of the data. Accuracy of withdrawal and sewage-treatment-return data for the Rockford area and of withdrawal, delivery, industrial release, and sewage-treatment-return data for the Kankakee area was considered to be at least 90 percent. Where water-use data were inadequate or unavailable, various methods were used to estimate consumptive uses; releases; returns by commercial, domestic, and municipal users; and conveyance losses and gains. The methods focused on water budgeting to assure that water uses balanced. Consumptive uses were estimated by use of the consumption-budget method, the types-of-use method, consumptive-use ratios, the winter base-rate method, and the maximum lawn-watering method. The winter base-rate method provided the best domestic consumptive-use estimates, whose ratios (consumptive use from the winter base-rate method

  13. Qualitative and quantitative determination of water in airborne particulate matter

    NASA Astrophysics Data System (ADS)

    Canepari, S.; Farao, C.; Marconi, E.; Giovannelli, C.; Perrino, C.

    2012-10-01

    This paper describes the optimization and validation of a new simple method for the quantitative determination of water in atmospheric particulate matter (PM). The analyses are performed by using a coulometric Karl-Fisher system equipped with a controlled heating device; different water contributions are separated by the application of an optimized thermal ramp (three heating steps: 50-120 °C, 120-180 °C, 180-250 °C). The analytical performance of the method was verified by using standard materials containing 5.55% and 1% by weight of water. The recovery was greater than 95%; the detection limit was about 20 μg. The method was then applied to NIST reference materials (NIST1649a, urban particulate matter) and to real PM10 samples collected in different geographical areas. In all cases the repeatability was satisfactory (10-15%). When analyzing the reference material, the separation of four different types of water was obtained. In real PM10 samples the amount of water and its thermal profile differed as a function of the chemical composition of the dust. Mass percentages of 3-4% of water were obtained in most samples, but values up to about 15% were reached in areas where the chemical composition of PM is dominated by secondary inorganic ions and organic matter. High percentages of water were also observed in areas where PM is characterized by the presence of desert dust. A possible identification of the quality of water released from the samples was tried by applying the method to some hygroscopic compounds that are likely contained in PM (pure SiO2, Al2O3, ammonium salts, carbohydrates and dicarboxylic acids) and by comparing the results with those obtained from field samples.

  14. Qualitative and quantitative determination of water in airborne particulate matter

    NASA Astrophysics Data System (ADS)

    Canepari, S.; Farao, C.; Marconi, E.; Giovannelli, C.; Perrino, C.

    2013-02-01

    This paper describes the optimization and validation of a new simple method for the quantitative determination of water in atmospheric particulate matter (PM). The analyses are performed by using a coulometric Karl-Fisher system equipped with a controlled heating device; different water contributions are separated by the application of an optimized thermal ramp (three heating steps: 50-120 °C, 120-180 °C, 180-250 °C). The analytical performance of the method was verified by using standard materials containing 5.55% and 1% by weight of water. The recovery was greater than 95%; the detection limit was about 20 μg. The method was then applied to NIST Reference Materials (NIST1649a, urban particulate matter) and to real PM10 samples collected in different geographical areas. In all cases the repeatability was satisfactory (10-15%). When analyzing the Reference Material, the separation of four different types of water was obtained. In real PM10 samples the amount of water and its thermal profile differed as a function of the chemical composition of the dust. Mass percentages of 3-4% of water were obtained in most samples, but values up to about 15% were reached in areas where the chemical composition of PM is dominated by secondary inorganic ions and organic matter. High percentages of water were also observed in areas where PM is characterized by the presence of desert dust. A possible identification of the quality of water released from the samples was tried by applying the method to some hygroscopic compounds that are likely contained in PM (pure SiO2, Al2O3, ammonium salts, carbohydrates and dicarboxylic acids) and by comparing the results with those obtained from field samples.

  15. Seepage carbonate mounds in Cenozoic sedimentary sequences from the Las Minas Basin, SE Spain

    NASA Astrophysics Data System (ADS)

    Pozo, M.; Calvo, J. P.; Scopelliti, G.; González-Acebrón, L.

    2016-04-01

    A number of carbonate mounds composed of indurate, strongly folded and/or brecciated calcite and dolomite beds occur interstratified in Cenozoic sedimentary sequences from the Las Minas Basin. Part of the fabric of the rock forming the carbonate mounds is composed of laminated to banded dolostone similar to the host rock but showing contrasted lithification. Moreover, the carbonate deposits of the mounds display aggrading neomorphism of dolomite, partial replacement of dolomite by calcite, calcite cementation, and extensive silicification, locally resulting in box-work fabric. Eight main lithofacies were distinguished in the carbonate mound deposits. In some lithofacies, chert is present as both microcrystalline to fibro-radial quartz and opal, the latter occurring mainly as cement whereas the former replace the carbonate and infill voids. Yet one of the carbonate mounds shows distinctive petrography and geochemical features thus suggesting a distinctive growth pattern. The carbon isotope compositions of calcite from the mound samples range from - 11.56 to - 5.15 δ‰ whilst dolomite is depleted in 13C, with values of - 12.38 to 3.02 δ‰. Oxygen isotopic compositions vary from - 9.42 to - 4.64 δ‰ for calcite and between - 6.68 and 8.19 δ‰ for dolomite. Carbonate in the mounds shows significant enrichment in Co, Cr, Ni and Pb content, especially in the strongly deformed (F-2-2 lithofacies) and brecciated carbonate (F-4). The carbonate deposits show depletion in REE and Y in contrast to that determined in lutite. The formation of the carbonate mounds was related to local artesian seepage thermal water flows of moderate to relative high temperatures. Pressure differences between the low permeability host rock and the circulating fluids accounted for dilational fracturing and brecciation of the host sediment packages, which combined with precipitation of new carbonate and silica mineral phases. Locally, some carbonate mounds developed where groundwater

  16. Hydrogeology, groundwater seepage, nitrate distribution, and flux at the Raleigh hydrologic research station, Wake County, North Carolina, 2005-2007

    USGS Publications Warehouse

    McSwain, Kristen Bukowski; Bolich, Richard E.; Chapman, Melinda J.

    2013-01-01

    gradients in the groundwater discharge area near the Neuse River were complex and were affected by fluctuations in river stage, with the exception of a well completed in a diabase dike. Water-quality data from the wells and surface-water sites at the RHRS were collected continuously as well as during periodic sampling events. Surface-water samples collected from a tributary were most similar in chemical composition to groundwater found in the regolith and transition zone. Nitrate (measured as nitrite plus nitrate, as nitrogen) concentrations in the sampled wells and tributary ranged from about 5 to more than 120 milligrams per liter as nitrogen. Waterborne continuous resistivity profiling conducted on the Neuse River in the area of the RHRS measured areas of low apparent resistivity that likely represent groundwater contaminated by high concentrations of nitrate. These areas were located on either side of a diabase dike and at the outfall of two unnamed tributaries. The diabase dike preferentially directed the discharge of groundwater to the Neuse River and may isolate groundwater movement laterally. Discrete temperature measurements made within the pore water beneath the Neuse River revealed seeps of colder groundwater discharging into warmer surface water near a diabase dike. Water-quality samples collected from the pore water beneath the Neuse River indicated that nitrate was present at concentrations as high as 80 milligrams per liter as nitrogen on the RHRS side of the river. The highest concentrations of nitrate were located within pore water collected from an area near a diabase dike that was identified as a suspected seepage area. Hydraulic head was measured and pore water samples were collected from two 140-centimeter-deep (55.1-inch-deep) multiport piezometers that were installed in bed sediments on opposite sides of a diabase dike. The concentration of nitrate in pore water at a suspected seepage area ranged from 42 to 82 milligrams per liter as nitrogen with a

  17. Uranium geochemistry in soil and groundwater at the F and H seepage basins

    SciTech Connect

    Serkiz, S.M.; Johnson, W.H.

    1994-09-01

    For 33 years, low activity liquid wastes from the chemical separation areas at the U.S. Department of Energy`s Savannah River Site were disposed of in unlined seepage basins. Soil and associated pore water samples of widely varying groundwater chemistries and contaminant concentrations were collected from the region downgradient of these basins using cone penetrometer technology. Analysis of samples using inductively coupled plasma - mass spectrometry has allowed the investigation of uranium partitioning between the aqueous phase and soil surfaces at this site. The distribution of uranium was examined with respect to the solution and soil chemistry (e.g., pH, redox potential, cation and contaminant concentration) and aqueous-phase chemical speciation modeling. The uranium soil source term at the F- and H-Area Seepage Basins (FHSB) is much smaller than has been used in previous modeling efforts. This should result in a much shorter remediation time and a greater effectiveness of a pump-and-treat design than previously predicted. Distribution coefficients at the (FHSB) were found to vary between 1.2 to 34,000 1 kg{sup {minus}1} for uranium. Differences in sorption of these elements can be explained primarily by changes in aqueous pH and the associated change in soil surface charge. Sorption models were fit directly to sorption isotherms from field samples. All models underestimated the fraction of uranium bound at low aqueous uranium concentrations. Linear models overestimated bound uranium at locations where the aqueous concentration was greater than 500 ppb. Mechanistic models provided a much better estimate of the bound uranium concentrations, especially at high aqueous concentrations. Since a large fraction of the uranium at the site is associated with the low-pH portion of the plume, consideration should be given to pumping water from the lowest pH portions of the plume in the F-Area.

  18. Indirect spectrophotometric determination of traces of bromide in water

    USGS Publications Warehouse

    Fishman, M. J.; Skougstad, M.W.

    1963-01-01

    A rapid, accurate, and sensitive indirect spectrophotometric method for the determination of bromide in natural waters is based on the catalytic effect of bromide on the oxidation of iodine to iodate by potassium permanganate in sulfuric acid solution. The method is applicable to concentrations ranging from 1 to 100 ??g. of bromide per liter, but may be modified to extend the concentration range. Most ions commonly occurring in water do not interfere. The standard deviation is 2.9 at bromide concentrations of 100 ??g. per liter and less at lower concentrations. The determination of bromide in samples containing known added amounts gave values ranging from 99 to 105% of the concentration calculated to be present.

  19. Spectrophotometric determination of trace copper in water samples with thiomichlersketone

    NASA Astrophysics Data System (ADS)

    Fu, Dayou; Yuan, Dong

    2007-02-01

    A simple and sensitive spectrophotometric method for determination of trace copper in water samples is proposed. In the presence of pH 4.6 HAc-NaAc buffer solution and surfactant polyethylene octyl phenyl ether (OP) medium, copper reacts with thiomichlersketone (TMK) to form a stable 1:4 complex. The complex Cu(II)-TMK-OP shows maximum absorbance at 500 nm with a molar absorptivity value of 5.7 × 10 4 l mol -1 cm -1. Beer's law is obeyed for copper concentrations in the range of 0-15 μg/25 ml. The average recovery of copper is between 95.8 and 106%. The method has been applied for determination of trace copper in different water samples with satisfactory results.

  20. Xanthene dye chemiluminescence for determination of free chlorine in water

    SciTech Connect

    Yamada, M.; Hobo, T.; Suzuki, S.

    1988-10-01

    Preliminary investigations by a batch method are described for aiming at the flow determination of free chlorine in water with novel chemiluminescence (CL) detection. The CL originates from the reaction of xanthene dyes with free chlorine, Cl/sub 2/, HOCl, and OCl/sup -/. Through the measurements of CL decay curves, fundamental CL characteristics were explored from the analytical point of view. Among xanthene dyes tested, eosin Y, eosin B, pyronin B, and rhodamine 6G were found to be promising CL reagents with such sensitivity and selectivity that free chlorine can be readily determined in tap water. In particular, these CL systems have the special advantage of being insensitive to oxo acids of chlorine and chloramine. Recommended flow systems are proposed.

  1. Glass electrode determination of sodium in closed basin waters

    USGS Publications Warehouse

    Truesdell, A.H.; Jones, B.F.; Van Denburgh, A.S.

    1965-01-01

    Because of its direct relation to total dissolved solids content, sodium concentration is the most useful single hydrochemical parameter of closed basin waters in the western United States. Therefore, it is advantageous to have a rapid method for sodium determination which could be readily adapted to field use. Accordingly, thirty waters of highly variable concentration and anionic composition from the western Great Basin have been analyzed with a sodium-sensitive glass electrode. Na+ values ranged from 10 to 130,000 ppm in waters containing from 102 to 401,000 ppm total dissolved solids. The electrode values were compared with conventional sodium determinations; results differed by as much as 11 per cent, although over two-thirds were within 5 per cent. No significant relation was found between the glass electrode and conventional method differences and the total dissolved solids or sodium concentration. The comparative accuracy of electrode and conventional procedures was checked, employing solutions of known sodium concentration. It was concluded that for the analysis of sodium in natural waters the glass electrode method offers results comparable in accuracy to those obtained by conventional methods, but with increased simplicity, and therefore the possibility of rapid, accurate field measurements. ?? 1965.

  2. High Throughput Determination of VX in Drinking Water by ...

    EPA Pesticide Factsheets

    Methods Report This document provides the standard operating procedure for determination of the chemical warfare agent VX (O-Ethyl S-2-Diisopropylamino-Ethyl Methylphosphonothioate) in drinking water by isotope dilution liquid chromatography tandem mass spectrometer (LC/MS/MS). This method was adapted from one that was initially developed by the Centers for Disease Control and Prevention, in the National Center for Environmental Health for the determination and quantitation of VX in aqueous matrices. This method is designed to support site-specific cleanup goals of environmental remediation activities following a homeland security incident involving this analyte.

  3. Determination of metal ions in biological purification of waste waters

    SciTech Connect

    Tikhomirova, L.N.; Spiridonova, N.N.; Mandzhgaladze, I.D.

    1994-12-01

    Chromium, nickel, copper, zinc, and manganese were determined in active sludge extracted for utilization from sewage purification works in biological purification of waste waters. The measurements were carried out by the atomic absorption method and with Merck colorimetric kits for rapid determination of metal ions. The results obtained by the rapid colorimetric method agree fairly well with those obtained by the atomic absorption method, which makes it possible to recommend rapid colorimetric methods for routine analysis of biological objects for the content of ions of heavy metals.

  4. Sorption preconcentration of vanadium for its determination in sea water

    SciTech Connect

    Andreeva, I.Yu.; Lebedeva, L.I.; Izotova, Yu.A.; Danilova, E.Ya.

    1987-08-10

    This work is devoted to a study of the conditions of vanadium sorption by a fibrous sorbent with a view to evolving a procedure for its determination in sea water. The sorbent was the same as used by them earlier for molybdenum preconcentration. It is a fiber based on polyethylenepolyamine-modified polyacrylonitrile. The sorbent contained 80% tertiary and approx. = 20% primary and secondary amino groups. Static exchange capacity of the sorbent relative to HCl 2 mmole/g, swelling 34%, fiber diameter 0.016 mm. The vanadium content was determined photometrically using acidic chromium blue K.

  5. Recent Experimental Advances to Determine (noble) Gases in Waters

    NASA Astrophysics Data System (ADS)

    Kipfer, R.; Brennwald, M. S.; Huxol, S.; Mächler, L.; Maden, C.; Vogel, N.; Tomonaga, Y.

    2013-12-01

    In aquatic systems noble gases, radon, and bio-geochemically conservative transient trace gases (SF6, CFCs) are frequently applied to determine water residence times and to reconstruct past environmental and climatic conditions. Recent experimental breakthroughs now enable ● to apply the well-established concepts of terrestrial noble gas geochemistry in waters to the minute water amounts stored in sediment pore space and in fluid inclusions (A), ● to determine gas exchange processes on the bio-geochemical relevant time scales of minutes - hours (B), and ● to separate diffusive and advective gas transport in soil air (C). A. Noble-gas analysis in water samples (< 1 g) facilitates determining the solute transport in the pore space and identifying the origin of bio- and geogenic fluids in (un) consolidated sediments [1]. Advanced techniques that combine crushing and sieving speleothem samples in ultra-high-vacuum to a specific grain size allow to separate air and water-bearing fluid inclusions and thus enables noble-gas-based reconstruction of environmental conditions from water masses as small as 1mg [2]. B. The coupling of noble gas analysis with approaches of gas chromatography permits combined analysis of noble gases and other gases species (e.g., SF6, CFCs, O2, N2) from a single water sample. The new method substantially improves ground water dating by SF6 and CFCs as excess air is quantified from the same sample and hence can adequately be corrected for [3]. Portable membrane-inlet mass spectrometers enable the quasi-continuous and real-time analysis of noble gases and other dissolved gases directly in the field, allowing, for instance, quantification of O2 turnover rates on small time scales [4]. C. New technical developments perfect 222Rn analysis in water by the synchronous the determination of the short-lived 220Rn. The combined 220,222Rn analysis sheds light on the emanation behaviour of radon by identifying soil water content to be the crucial

  6. Experimentally determined water storage capacity in the Earth's upper mantle

    NASA Astrophysics Data System (ADS)

    Ferot, A.; Bolfan-Casanova, N.

    2010-12-01

    Trace amounts of hydrogen dissolved as defects in nominally anhydrous minerals (NAMs) in the mantle are believed to play a key role in physical and chemical processes in the Earth’s upper mantle. Hence, the estimation of water storage in mantle phases and solubility mechanisms are important in order to better understand the effect of water. Experimental data on water solubility in NAMs are available for upper mantle minerals such as olivine, pyroxenes and garnet. However, the majority of studies are based on the study of single phases, and at temperatures or pressures that are too low for the Earth’s upper mantle. The aim of this study is to constrain the combined effects of pressure, temperature and composition on water solubility in olivine and orthopyroxene under upper mantle conditions. The solubility of water in coexisting orthopyroxene and olivine was investigated by simultaneously synthesizing the two phases at high pressure and high temperature in a multi-anvil press. Experiments were performed under water-saturated conditions in the MSH systems with Fe and Al at 2.5, 5, 7.5 and 9 GPa and temperatures between 1175 and 1400°C. Integrated OH absorbances were determined using polarized infrared spectroscopy on doubly polished thin sections of randomly oriented crystals. Water solubility in olivine increases with pressure and decreases with temperature as has been described previously (Bali et al., 2008). The aluminum content strongly decreases in olivine with pressure from 0.09 wt% at 2.5 GPa and 1250°C to 0.04 wt% at 9 GPa and 1175°C. The incorporation of this trivalent cation in the system enhances water solubility in olivine even if present in trace amounts, however this behavior appears to reverse at high pressure. The effect of temperature on water solubility follows a bell-shaped curve with a maximum solubility in olivine and orthopyroxene at 1250°C. Aluminum is incorporated in orthopyroxene following the Tschermak substitution and strongly

  7. Seepage weathering impacts on erosivity of arid stream banks: A new conceptual model

    NASA Astrophysics Data System (ADS)

    Nachshon, Uri

    2016-05-01

    Field observations have indicated the formation of horizontal, pipe shape cavities, along gully and dry stream channel banks in the semi-arid region of the northern Negev Desert, Israel. Piping is a well-known phenomenon in humid regions due to subsurface water flow and seepage weathering. However, in dry environments where rain events are scarce and subsurface water flow is rare, it is proposed here that capillary flow of saline water in the vadose zone leads to similar processes. It is suggested that where saline and shallow ground water persists, capillary flow may result in salt accumulation and precipitation at the top of the capillary fringe, consequently rendering this zone to be more susceptible to erosion. A conceptual model is presented and field observations, laboratory experiments, and a physically-based model are used to prove the feasibility of the proposed conceptual model and to explain why salts accumulate at the top of the capillary fringe, even though evaporation acts all along the vertical stream channel or gully banks. It is suggested that the low evaporative flux, in comparison to the liquid water flux, disables salt accumulation along the profile to the top of the capillary fringe where the liquid water flux is minimal. The presented findings strengthen the conceptual model, but thorough field studies are needed to estimate the impact of the proposed mechanism on erosion processes on a field scale.

  8. Radiometric method for determining solubility of organic solvents in water

    SciTech Connect

    Lo, J.M.; Tseng, C.L.; Yang, J.Y.

    1986-06-01

    Cobalt-60 labeled cobalt(III) pyrrolidinecarbodithioate (/sup 60/Co(PDC)/sub 3/) has a peculiar stability during storage in organic solvent and when its organic solution is shaken with an aqueous solution containing different acids or ions. Using these characteristics, the authors have attempted to use /sup 60/Co(PDC)/sub 3/ as a radioagent for determining solubilities of various organic solvents in water. The radioagent was first dissolved in the organic solvent under investigation before pure water was added. The solution mixture was shaken vigorously in order to let the organic phase contact with water sufficiently. Some of the organic solvent would dissolve in water after shaking, resulting in volume reduction of the organic phase. However, the radioagent was found not to accompany the organic solvent molecules going into water; i.e., all the radioactivity of /sup 60/Co(PDC)/sub 3/ would be retained in the organic phase. Solubility of the organic solvent in water therefore can be calculated from the value of the volume change of the organic phase divided by the water volume. Direct measurement of a small change in volume of organic phase with high accuracy is generally very difficult; alternatively, the authors have measured the specific activities of /sup 60/Co(PDC)/sub 3/ (cpm/mL) in the original and the final organic solutions, and the counting results were used to estimate the decrease in volume of the organic phase. Several commonly used organic solvents were selected to test the applicability of the proposed radiometric method. The solubilities of the organic solvents selected for this study range from very small values (10/sup -4/) to relatively large values (10/sup -2/), 6 references, 1 table.

  9. Behavioral Determinants of Switching to Arsenic-Safe Water Wells.

    PubMed

    George, Christine Marie; Inauen, Jennifer; Perin, Jamie; Tighe, Jennifer; Hasan, Khaled; Zheng, Yan

    2017-02-01

    More than 100 million people globally are estimated to be exposed to arsenic in drinking water that exceeds the World Health Organization guideline of 10 µg/L. In an effort to develop and test a low-cost sustainable approach for water arsenic testing in Bangladesh, we conducted a randomized controlled trial which found arsenic educational interventions when combined with fee-based water arsenic testing programs led to nearly all households buying an arsenic test for their drinking water sources (93%) compared with only 53% when fee-based arsenic testing alone was offered. The aim of the present study was to build on the findings of this trial by investigating prospectively the psychological factors that were most strongly associated with switching to arsenic-safe wells in response to these interventions. Our theoretical framework was the RANAS (risk, attitude, norm, ability, and self-regulation) model of behavior change. In the multivariate logistic regression model of 285 baseline unsafe well users, switching to an arsenic-safe water source was significantly associated with increased instrumental attitude (odds ratio [OR] = 9.12; 95% confidence interval [CI] = [1.85, 45.00]), descriptive norm (OR = 34.02; 95% CI = [6.11, 189.45]), coping planning (OR = 11.59; 95% CI = [3.82, 35.19]), and commitment (OR = 10.78; 95% CI = [2.33, 49.99]). In addition, each additional minute from the nearest arsenic-safe drinking water source reduced the odds of switching to an arsenic-safe well by more than 10% (OR = 0.89; 95% CI = [0.87, 0.92]). Future arsenic mitigation programs should target these behavioral determinants of switching to arsenic-safe water sources.

  10. Determining water and nitrogen balances for beneficial management practices using lysimeters at Wagna test site (Austria).

    PubMed

    Klammler, Gernot; Fank, Johann

    2014-11-15

    The shallow Murtal aquifer south of Graz, Austria, provides easily withdrawable groundwater, which is supplied as drinking water without any chemical treatment. The aquifer is also used intensively by agriculture. Common agricultural management practices are the main source for diffuse nitrogen leaching and high groundwater nitrate concentrations. To safeguard the coexisting use of these two important resources, lysimeters are operated at the agricultural test site Wagna, Austria, and the influence of two beneficial management practices--low nitrogen input and organic farming--on nitrogen leaching towards groundwater is investigated. The technical lysimeter design as presented here consists of: (1) high-resolution weighing cells, (2) a suction controlled lower boundary condition for sucking off seepage water, thus emulating undisturbed field conditions, (3) comparative soil temperature, water content and matrix potential measurements inside and outside the lysimeter at different depths, (4) an installation of the lysimeters directly into test plots and (5) a removable upper lysimeter ring enabling machinery soil tillage. Our results indicate that oasis effects or fringe effects of the lysimeter cylinder on unsaturated water flow did not occur. Another lysimeter cultivated with lawn is operated for observing grass-reference evapotranspiration, which resulted in good agreement with calculated grass-reference evapotranspiration according to the FAO-Penman-Monteith method. We conclude that lysimeters installed at Wagna test site did not show any fringe effects and, thus, are appropriate tools for measuring water balance elements and nitrogen leaching of arable and grass land at point scale. Furthermore, our results for the period of 2005 to 2011 show that beneficial management practices reduced nitrate leaching and, hence, may allow for a sustainable coexistence of drinking water supply and agriculture in the Murtal aquifer. Copyright © 2014 Elsevier B.V. All rights

  11. Changing composition of microbial communities indicates seepage fluid difference of the Thuwal Seeps in the Red Sea.

    PubMed

    Yang, Bo; Zhang, Weipeng; Tian, Renmao; Wang, Yong; Qian, Pei-Yuan

    2015-08-01

    Cold seeps are unique ecosystems that are generally characterized by high salinity and reducing solutions. Seepage fluid, the major water influx of this system, contains hypersaline water, sediment pore water, and other components. The Thuwal cold seeps were recently discovered on the continental margin of the Red Sea. Using 16S rRNA gene pyro-sequencing technology, microbial communities were investigated by comparing samples collected in 2011 and 2013. The results revealed differences in the microbial communities between the two sampling times. In particular, a significantly higher abundance of Marine Group I (MGI) Thaumarchaeota was coupled with lower salinity in 2013. In the brine pool, the dominance of Desulfobacterales in 2011 was supplanted by MGI Thaumarchaeota in 2013, perhaps due to a reduced supply of hydrogen sulfide from the seepage fluid. Collectively, this study revealed a difference in water components in this ecosystem between two sampling times. The results indicated that the seawater in this cold seep displayed a greater number of characteristics of normal seawater in 2013 than in 2011, which might represent the dominant driving force for changes in microbial community structures. This is the first study to provide a temporal comparison of the microbial biodiversity of a cold seep ecosystem in the Red Sea.

  12. The water kefir grain inoculum determines the characteristics of the resulting water kefir fermentation process.

    PubMed

    Laureys, D; De Vuyst, L

    2017-03-01

    To investigate the influence of the water kefir grain inoculum on the characteristics of the water kefir fermentation process. Three water kefir fermentation processes were started with different water kefir grain inocula and followed as a function of time regarding microbial species diversity, community dynamics, substrate consumption profile and metabolite production course. The inoculum determined the water kefir grain growth, the viable counts on the grains, the time until total carbohydrate exhaustion, the final metabolite concentrations and the microbial species diversity. There were always 2-10 lactic acid bacterial cells for every yeast cell and the majority of these micro-organisms was always present on the grains. Lactobacillus paracasei, Lactobacillus hilgardii, Lactobacillus nagelii and Saccharomyces cerevisiae were always present and may be the key micro-organisms during water kefir fermentation. Low water kefir grain growth was associated with small grains with high viable counts of micro-organisms, fast fermentation and low pH values, and was not caused by the absence of exopolysaccharide-producing lactic acid bacteria. The water kefir grain inoculum influences the microbial species diversity and characteristics of the fermentation process. A select group of key micro-organisms was always present during fermentation. This study allows a rational selection of a water kefir grain inoculum. © 2016 The Society for Applied Microbiology.

  13. Determining evaporation in the model of water transfer in soil

    NASA Astrophysics Data System (ADS)

    Zasukhin, Sergey

    2016-10-01

    In considered model a process of vertical water transfer in soil is described by one-dimensional nonlinear parabolic equation. Evaporation is one of most hard-determined component of the model. Determination of evaporation is formulated as an optimal control problem. In this problem, the objective function is mean-square deviation of soil moisture obtained by the model at various depths from some prescribed values. The sensitivity of soil moisture to changes of evaporation is estimated. These estimates allowed to determine an effective subsurface soil layer where it is advisable to compare calculated values of soil moisture with prescribed ones and to compute the objective function. This region definition has accelerated the convergence of numeric optimization process and has reduced the time of its execution.

  14. LPMLE3: A New Analytical Approach to Determine Vertical Groundwater-Surface Water Exchange Flux under Uncertainty and Heterogeneity

    NASA Astrophysics Data System (ADS)

    Schneidewind, Uwe; van Berkel, Matthijs; Anibas, Christian; Vandersteen, Gerd; Joris, Ingeborg; Seuntjens, Piet; Batelaan, Okke

    2015-04-01

    and parameter uncertainties. However, by assuming finite domains, thermal parameters only need to be considered locally constant, which is a more realistic assumption for a dynamic streambed. Flux results from the Slootbeek obtained with the LPMLE3 were compared to results from seepage meter measurements and those obtained with the LPML method (Vandersteen et al., 2014). For the Slootbeek we can show that during a three-week period in November 2012 the vertical flux varies between -186 mm/d (gaining stream conditions) and -300 mm/d with varying uncertainty. Hatch CE, Fisher AT, Revenaugh JS, Constantz J, Ruehl C. 2006. Quantifying surface water-groundwater interactions using time series analysis of streambed thermal records: Method development. Water Resour. Res., 42. DOI: 10.1029/2005wr004787. Keery J, Binley A, Crook N, Smith JWN. 2007. Temporal and spatial variability of groundwater-surface water fluxes: Development and application of an analytical method using temperature time series. J. Hydrol., 336: 1-16. DOI: 10.1016/j.jhydrol.2006.12.003. Vandersteen G*, Schneidewind U*, Anibas C*, Schmidt C, Seuntjens P, Batelaan O. 2014. Determining groundwater-surface water exchange from temperature time series: Combining a local polynomial method with a maximum likelihood estimator. Water Resour. Res. (accepted manuscript) DOI: 10.1002/2014wr015994. Wörman A, Riml J, Schmadel N, Neilson BT, Bottacin-Busolin A, Heavilin JE. 2012. Spectral scaling of heat fluxes in streambed sediments. Geophysical Research Letters, 39. DOI: 10.1029/2012gl053922.

  15. Groundwater and surface-water interactions and impacts of human activities in the Hailiutu catchment, northwest China

    NASA Astrophysics Data System (ADS)

    Yang, Zhi; Zhou, Yangxiao; Wenninger, Jochen; Uhlenbrook, Stefan; Wang, Xusheng; Wan, Li

    2017-08-01

    The interactions between groundwater and surface water have been significantly affected by human activities in the semi-arid Hailiutu catchment, northwest China. Several methods were used to investigate the spatial and temporal interactions between groundwater and surface water. Isotopic and chemical analyses of water samples determined that groundwater discharges to the Hailiutu River, and mass balance equations were employed to estimate groundwater seepage rates along the river using chemical profiles. The hydrograph separation method was used to estimate temporal variations of groundwater discharges to the river. A numerical groundwater model was constructed to simulate groundwater discharges along the river and to analyze effects of water use in the catchment. The simulated seepage rates along the river compare reasonably well with the seepage estimates derived from a chemical profile in 2012. The impacts of human activities (river-water diversion and groundwater abstraction) on the river discharge were analyzed by calculating the differences between the simulated natural groundwater discharge and the measured river discharge. Water use associated with the Hailiutu River increased from 1986 to 1991, reached its highest level from 1992 to 2000, and decreased from 2001 onwards. The reduction of river discharge might have negative impacts on the riparian ecosystem and the water availability for downstream users. The interactions between groundwater and surface water as well as the consequences of human activities should be taken into account when implementing sustainable water resources management in the Hailiutu catchment.

  16. Groundwater and surface-water interactions and impacts of human activities in the Hailiutu catchment, northwest China

    NASA Astrophysics Data System (ADS)

    Yang, Zhi; Zhou, Yangxiao; Wenninger, Jochen; Uhlenbrook, Stefan; Wang, Xusheng; Wan, Li

    2017-02-01

    The interactions between groundwater and surface water have been significantly affected by human activities in the semi-arid Hailiutu catchment, northwest China. Several methods were used to investigate the spatial and temporal interactions between groundwater and surface water. Isotopic and chemical analyses of water samples determined that groundwater discharges to the Hailiutu River, and mass balance equations were employed to estimate groundwater seepage rates along the river using chemical profiles. The hydrograph separation method was used to estimate temporal variations of groundwater discharges to the river. A numerical groundwater model was constructed to simulate groundwater discharges along the river and to analyze effects of water use in the catchment. The simulated seepage rates along the river compare reasonably well with the seepage estimates derived from a chemical profile in 2012. The impacts of human activities (river-water diversion and groundwater abstraction) on the river discharge were analyzed by calculating the differences between the simulated natural groundwater discharge and the measured river discharge. Water use associated with the Hailiutu River increased from 1986 to 1991, reached its highest level from 1992 to 2000, and decreased from 2001 onwards. The reduction of river discharge might have negative impacts on the riparian ecosystem and the water availability for downstream users. The interactions between groundwater and surface water as well as the consequences of human activities should be taken into account when implementing sustainable water resources management in the Hailiutu catchment.

  17. F/H seepage basin groundwater influent, effluent, precipitated sludge characterization task technical plan

    SciTech Connect

    Siler, J.L.

    1993-10-29

    A treatability study to support the development of a remediation system which would reduce the contaminant levels in groundwater removed from the aquifers in the vicinity of the F/H seepage basins and southwest of the Mixed Waste Management Facility (MWMF) at the Savannah River facility was conducted. Proposed changes in the remediation system require an additional study to determine whether precipitated sludge generated from the proposed remediation system will be hazardous as defined by RCRA. Several contaminants, such as lead and mercury, are above the groundwater protection standards. The presence of radionuclides and other contaminants in the sludge does not present a problem provided that the sludge can pass the Toxicity Characteristic Leaching Procedure (TCLP) test. The study has been developed in such a manner as to cover the possible range of treatment options that may be used.

  18. Source to surface - a model of hydrocarbon migration/seepage

    SciTech Connect

    Matthews, M.D.

    1995-06-01

    The physical and chemical constraints on migration from source to reservoir are joined with the spatial and chemical information available from surface seepage to better understand the process of migration. The processes leading to hydrocarbon micro and macro seepage at the surface (tertiary migration) must obey the same physical laws followed by migration within the source rock (primary migration), from source to reservoir (secondary migration) and up the production string. Evidence indicates that the dispersed mechanisms are not effective in mass transport of hydrocarbon in the subsurface but are effective both in blurring or destroying hydrocarbon concentrations (source, reservoir, and along the route of migration). Evidence does, however support the importance of separate phase migration as a mechanism of migration. The focused migration of hydrocarbons is considered as a rate process. The rate of generation of mobile hydrocarbons in a source rock and their rate of transport along the migration route must be greater than the loss of these hydrocarbons by dispersive mechanisms. The effects of the migration pathway are examined, particularly the changing pressure and temperature effects and the lithologic hetrogeniety along the migration path.

  19. Physical and bio-chemical mass-balance model around seafloor cold seepages

    NASA Astrophysics Data System (ADS)

    Yamazaki, T.; Takeuchi, R.; Monoe, D.; Oomi, T.; Nakata, K.; Fukushima, T.

    2007-12-01

    Natural cold seepages are characterized as rapid upward transports of methane from deeper part of geological structures to the seafloors. Prior to reach the seafloors, when methane meets downwards diffusing seawater sulfate, it is oxidized anaerobically by a consortium of microorganisms that use sulfate as an oxidant, producing sulfide. The anaerobic oxidation of methane and anaerobic sulfate reduction are clarified as a coupled biological activity. A significant portion of the bicarbonate produced after the sulfate reduction as authigenic carbonate, mainly aragonite and high-Mg calcite, near the seafloor. Where the methane fluxes are much, these anaerobic reactions occur just beneath the seafloor. There, usually sulfur oxidizing microorganisms are visible on the seafloor just above the coupled consortium of microorganisms. They are called bacterial mats. When the fluxes too much, direct methane bubbling occurs and chemosynthesis-immobilization communities such as tubeworms and clams distribute around the bubbling locations with the bacterial mats. The physical and bio-chemical mass-balance model around cold seepages on seafloor and in water column has been studied by the authors and some preliminary results were reported (Yamazaki et al., 2005 and 2006; Takeuchi et al., 2007). The approach is to analyze the existing field observation and numerical modeling studies of cold seepages and to create a new physical and bio-chemical mass-balance model in the environment. The model is separated into three parts. They are methane supply, seafloor ecosystem, and water column units. The seafloor ecosystem unit has been improved to analyze the unsteady formation processes of the ecosystem. The time dependencies of formations of the consortium of microorganisms (AOM), the chemosynthetic community, and bicarbonates examined with the improved model are introduced. After the bubbling from seafloor, the methane bubble jet blows up in the water column due to the buoyancy. Then the

  20. Distributed optical fiber-based theoretical and empirical methods monitoring hydraulic engineering subjected to seepage velocity

    NASA Astrophysics Data System (ADS)

    Su, Huaizhi; Tian, Shiguang; Cui, Shusheng; Yang, Meng; Wen, Zhiping; Xie, Wei

    2016-09-01

    In order to systematically investigate the general principle and method of monitoring seepage velocity in the hydraulic engineering, the theoretical analysis and physical experiment were implemented based on distributed fiber-optic temperature sensing (DTS) technology. During the coupling influence analyses between seepage field and temperature field in the embankment dam or dike engineering, a simplified model was constructed to describe the coupling relationship of two fields. Different arrangement schemes of optical fiber and measuring approaches of temperature were applied on the model. The inversion analysis idea was further used. The theoretical method of monitoring seepage velocity in the hydraulic engineering was finally proposed. A new concept, namely the effective thermal conductivity, was proposed referring to the thermal conductivity coefficient in the transient hot-wire method. The influence of heat conduction and seepage could be well reflected by this new concept, which was proved to be a potential approach to develop an empirical method monitoring seepage velocity in the hydraulic engineering.

  1. F-area seepage basins groundwater monitoring report. Volume 1. First and second quarters 1995

    SciTech Connect

    1995-09-01

    Groundwater at the F-Area Seepage Basins (FASB) is monitored in compliance with Module 111, Section C, of South Carolina Hazardous Waste Permit SCl-890-008-989, effective November 2, 1992. The monitoring well network is composed of 86 FSB wells and well HSB 85A. These wells are screened in the three hydrostratigraphic Units that make up the uppermost aquifer beneath the FASB. A detailed description of the uppermost aquifer is included in the Resource Conservation and Recovery Act Part B post-closure care permit application for the F-Area Hazardous Waste Management Facility submitted to the South Carolina Department of Health and Environmental Control (SCDHEC) in December 1900. Data from 9 FSL wells are included in this report only to provide additional information for this area; the FSL wells are not part of Permit SCl-890-008-989. Monitoring results are compared to the SCDHEC Groundwater Protection Standard (GWPS), which is specified in the approved F-Area Seepage Basins Part B permit (November 1992). Historically and currently, gross alpha, nitrate, nonvolatile beta, and tritium are among the primary constituents to exceed standards. Numerous other radionuclides and hazardous constituents also exceeded the GWPS in the groundwater at the FASB during the first half of 1995, notably aluminum, iodine-129, pH, strontium-90, and zinc. The elevated constituents are found primarily in Aquifer Zone IIB{sub 2} (Water Table) and Aquifer Zone IIB{sub 1}, (Barnwell/McBean) wells. However, several Aquifer Unit IIA (Congaree) wells also contain elevated levels of constituents. Isoconcentration/isoactivity maps included in this report indicate both the concentration/activity and extent of the primary contaminants in each of the three hydrostratigraphic units. Geologic cross sections indicate both the extent and depth of contamination of the primary contaminants in all of the hydrostratigraphic units during the first half of 1995.

  2. F-Area Seepage Basins groundwater monitoring report -- third and fourth quarters 1993. Volume 1

    SciTech Connect

    Butler, C.T.

    1994-03-01

    During the second half of 1993, the groundwater at the F-Area Seepage Basins (FASB) was monitored in compliance with Module 3, Section C, of South Carolina Hazardous Waste Permit SC1-890-008-989, effective November 2, 1992. The monitoring well network is composed of 87 FSB wells screened in the three hydrostratigraphic units that make up the uppermost aquifer beneath the FASB. A detailed description of the uppermost aquifer is included in the Resource Conservation and Recovery Act Part B post-closure care permit application for the F-Area Hazardous Waste Management Facility submitted to the South Carolina Department of Health and Environmental Control (SCDHEC) in December 1990. Beginning in the first quarter of 1993, the standard for comparison became the SCDHEC Groundwater Protection Standard (GWPS) specified in the approved F-Area Seepage Basins Part B permit. Currently and historically, gross alpha, nitrate, nonvolatile beta, and tritium are among the primary constituents to exceed standards. Numerous other radionuclides and hazardous constituents also exceeded the GWPS in the groundwater at the FASB during the second half of 1993, notably aluminum, iodine-129, and zinc. The elevated constituents are found primarily in Aquifer Zone 2B{sub 2} and Aquifer Zone 2B{sub 1} wells. However, several Aquifer Unit 2A wells also contain elevated levels of constituents. Isoconcentration/isoactivity maps included in this report indicate both the concentration/activity and extent of the primary contaminants in each of the three hydrostratigraphic units. Water-level maps indicate that the groundwater flow rates and directions at the FASB have remained relatively constant since the basins ceased to be active in 1988.

  3. Rapid determination of the presence of enteric bacteria in water.

    PubMed

    Kenard, R P; Valentine, R S

    1974-03-01

    A rapid and sensitive method is described for the detection of bacteria in water and various other natural substrates by the isolation of specific bacteriophage. By the addition of large numbers of the organism in question to the sample, the presence of virulent bacteriophage can be demonstrated in as little as 6 to 8 h. Fecal coliform, total coliform, and total coliphage counts were determined for over 150 water samples from several geographical areas over a period of 2 years. Computer analysis of the data shows a high degree of correlation between fecal coliforms and the coliphage present in the samples. With a high correlation coefficient between fecal coliform and coliphage counts, predictions of the fecal coliforms may be made by enumeration of the phage.

  4. Stopped flow kinetic-spectrophotometric determination of Diquat in waters.

    PubMed

    Diaz, Teresa Galeano; Merás, Isabel Durán; Franco, María F Alexandre

    2002-02-01

    Using the measures of initial reaction rate, a kinetic-photometric method is developed that uses the reaction of Diquat with H2O2 in basic medium. The reaction rate is very high and therefore the stopped-flow mixing technique is required in order to make kinetic measurements. The reaction rate is obtained in 20 s after the reactants are mixed and it allows the simple application of the method proposed to the routine analyses. The sensitivity of the method is very high being the detection limit 0.44 microgmL(-1) and the application range between 1 and 16 microgmL(-1). The time of measure per sample is 90s. The proposed kinetic-photometric method has been applied to the direct determination of this compound in river water, in the water of laundry of the olives, and in a commercial product. The results are very acceptable.

  5. Determination of acetone and methyl ethyl ketone in water

    USGS Publications Warehouse

    Tai, D.Y.

    1978-01-01

    Analytical procedures for the determination of acetone and methyl ethyl ketone in water samples were developed. Concentrations in the milligram-per-liter range were determined by injecting an aqueous sample into the analysis system through an injection port, trapping the organics on Tenax-GC at room temperature, and thermally desorbing the organics into a gas chromatograph with a flame ionization detector for analysis. Concentrations in the microgram-per-liter range were determined by sweeping the headspace vapors over a water sample at 50C, trapping on Tenax-GC, and thermally desorbing the organics into the gas chromatograph. The precision for two operators of the milligram-per-liter concentration procedure, expressed as the coefficient of variation, was generally less than 2 percent for concentrations ranging from 16 to 160 milligrams per liter. The precision from two operators of the microgram-per-liter concentration procedure was between 2 and 4 percent for concentrations of 20 and 60 micrograms per liter. (Woodard-USGS)

  6. Modeling of coupled heat transfer and reactive transport processesin porous media: Application to seepage studies at Yucca Mountain, Nevada

    SciTech Connect

    Mukhopadhyay, Sumit; Sonnenthal, Eric L.; Spycher, Nicolas

    2007-01-15

    When hot radioactive waste is placed in subsurface tunnels, a series of complex changes occurs in the surrounding medium. The water in the pore space of the medium undergoes vaporization and boiling. Subsequently, vapor migrates out of the matrix pore space, moving away from the tunnel through the permeable fracture network. This migration is propelled by buoyancy, by the increased vapor pressure caused by heating and boiling, and through local convection. In cooler regions, the vapor condenses on fracture walls, where it drains through the fracture network. Slow imbibition of water thereafter leads to gradual rewetting of the rock matrix. These thermal and hydrological processes also bring about chemical changes in the medium. Amorphous silica precipitates from boiling and evaporation, and calcite from heating and CO2 volatilization. The precipitation of amorphous silica, and to a much lesser extent calcite, results in long-term permeability reduction. Evaporative concentration also results in the precipitation of gypsum (or anhydrite), halite, fluorite and other salts. These evaporative minerals eventually redissolve after the boiling period is over, however, their precipitation results in a significant temporary decrease in permeability. Reduction of permeability is also associated with changes in fracture capillary characteristics. In short, the coupled thermal-hydrological-chemical (THC) processes dynamically alter the hydrological properties of the rock. A model based on the TOUGHREACT reactive transport software is presented here to investigate the impact of THC processes on flow near an emplacement tunnel at Yucca Mountain, Nevada. We show how transient changes in hydrological properties caused by THC processes often lead to local flow channeling and saturation increases above the tunnel. For models that include only permeability changes to fractures, such local flow channeling may lead to seepage relative to models where THC effects are ignored. However

  7. Modeling of coupled heat transfer and reactive transport processesin porous media: Application to seepage studies at Yucca Mountain, Nevada

    SciTech Connect

    Mukhopadhyay, S.; Sonnenthal, E.L.; Spycher, N.

    2007-01-15

    When hot radioactive waste is placed in subsurface tunnels, a series of complex changes occurs in the surrounding medium. The water in the pore space of the medium undergoes vaporization and boiling. Subsequently, vapor migrates out of the matrix pore space, moving away from the tunnel through the permeable fracture network. This migration is propelled by buoyancy, by the increased vapor pressure caused by heating and boiling, and through local convection. In cooler regions, the vapor condenses on fracture walls, where it drains through the fracture network. Slow imbibition of water thereafter leads to gradual rewetting of the rock matrix. These thermal and hydrological processes also bring about chemical changes in the medium. Amorphous silica precipitates from boiling and evaporation, and calcite from heating and CO{sub 2} volatilization. The precipitation of amorphous silica, and to a much lesser extent calcite, results in long-term permeability reduction. Evaporative concentration also results in the precipitation of gypsum (or anhydrite), halite, fluorite and other salts. These evaporative minerals eventually redissolve after the boiling period is over, however, their precipitation results in a significant temporary decrease in permeability. Reduction of permeability is also associated with changes in fracture capillary characteristics. In short, the coupled thermal-hydrological-chemical (THC) processes dynamically alter the hydrological properties of the rock. A model based on the TOUGHREACT reactive transport software is presented here to investigate the impact of THC processes on flow near an emplacement tunnel at Yucca Mountain, Nevada. We show how transient changes in hydrological properties caused by THC processes often lead to local flow channeling and saturation increases above the tunnel. For models that include only permeability changes to fractures, such local flow channeling may lead to seepage relative to models where THC effects are ignored

  8. Spectrofluorimetric determination of some water-soluble vitamins.

    PubMed

    Mohamed, Abdel-Maaboud I; Mohamed, Horria A; Abdel-Latif, Niveen M; Mohamed, Marwa R

    2011-01-01

    Two simple and sensitive spectrofluorimetric methods were developed for determination of three water-soluble vitamins (B1, B2, and B6) in mixtures in the presence of cyanocobalamin. The first one was for thiamine determination, which depends on the oxidation of thiamine HCl to thiochrome by iodine in an alkaline medium. The method was applied accurately to determine thiamine in binary, ternary, and quaternary mixtures with pyridoxine HCl, riboflavin, and cyanocobalamin without interference. In the second method, riboflavin and pyridoxine HCl were determined fluorimetrically in acetate buffer, pH 6. The three water-soluble vitamins (B1, B2, and B6) were determined spectrofluorimetrically in binary, ternary, and quaternary mixtures in the presence of cyanocobalamin. All variables were studied in order to optimize the reaction conditions. Linear relationship was obeyed for all studied vitamins by the proposed methods at their corresponding lambda(exc) or lambda(em). The linear calibration curves were obtained from 10 to 500 ng/mL; the correlation ranged from 0.9991 to 0.9999. The suggested procedures were applied to the analysis of the investigated vitamins in their laboratory-prepared mixtures and pharmaceutical dosage forms from different manufacturers. The RSD range was 0.46-1.02%, which indicates good precision. No interference was observed from common pharmaceutical additives. Good recoveries (97.6 +/- 0.7-101.2 +/- 0.8%) were obtained. Statistical comparison of the results with reported methods shows excellent agreement and indicates no significant difference in accuracy and precision.

  9. The determination of specific forms of aluminum in natural water

    USGS Publications Warehouse

    Barnes, R.B.

    1975-01-01

    A procedure for analysis and pretreatment of natural-water samples to determine very low concentrations of Al is described which distinguishes the rapidly reacting equilibrium species from the metastable or slowly reacting macro ions and colloidal suspended material. Aluminum is complexed with 8-hydroxyquinoline (oxine), pH is adjusted to 8.3 to minimize interferences, and the aluminum oxinate is extracted with methyl isobutyl ketone (MIBK) prior to analysis by atomic absorption. To determine equilibrium species only, the contact time between sample and 8-hydroxyquinoline is minimized. The Al may be extracted at the sample site with a minimum of equipment and the MIBK extract stored for several weeks prior to atomic absorption analysis. Data obtained from analyses of 39 natural groundwater samples indicate that filtration through a 0.1-??m pore size filter is not an adequate means of removing all insoluble and metastable Al species present, and extraction of Al immediately after collection is necessary if only dissolved and readily reactive species are to be determined. An average of 63% of the Al present in natural waters that had been filtered through 0.1-??m pore size filters was in the form of monomeric ions. The total Al concentration, which includes all forms that passed through a 0.1-??m pore size filter, ranged 2-70 ??g/l. The concentration of Al in the form of monomeric ions ranged from below detection to 57 ??g/l. Most of the natural water samples used in this study were collected from thermal springs and oil wells. ?? 1975.

  10. Water Resources Data, New Mexico, Water Year 1992

    USGS Publications Warehouse

    Cruz, R.R.; DeWees, R.K.; Funderburg, D.E.; Lepp, R.L.; Ortiz, D.; Shaull, D.A.

    1993-01-01

    measurements. Also, 1 seepage investigation is published this year. These data represent that part of the National Water Data System collected by the U.S. Geological Survey and cooperating State and Federal agencies in New Mexico.

  11. High-resolution continuum source graphite furnace molecular absorption spectrometry compared with ion chromatography for quantitative determination of dissolved fluoride in river water samples.

    PubMed

    Ley, Philip; Sturm, Manfred; Ternes, Thomas A; Meermann, Björn

    2017-10-03

    In addition to beneficial health effects, fluoride can also have adverse effects on humans, animals, and plants if the daily intake is strongly elevated. One main source of fluoride uptake is water, and thus several ordinances exist in Germany that declare permissible concentrations of fluoride in, for example, drinking water, mineral water, and landfill seepage water. Controlling the fluoride concentrations in aqueous matrices necessitate valid and fast analytical methods. In this work an alternative method for the determination of fluoride in surface waters based on high-resolution continuum source graphite furnace molecular absorption spectrometry (HR-CS-GFMAS) was applied. Fluoride detection was made possible by the formation of a diatomic molecule, GaF, and detection of characteristic molecular absorption. On HR-CS-GFMAS parameter optimization, the method was adapted to surface water sample analysis. The influence of potential main matrix constituents such as Na(+), Ca(2+), Mg(2+), and Cl(-) as well as surface water sampling/storage conditions on the molecular absorption signal of GaF was investigated. Method validation demonstrated a low limit of detection (8.1 μg L(-1)) and a low limit of quantification (26.9 μg L(-1)), both sufficient for direct river water sample analysis after 0.45-μm filtration. The optimized HR-CS-GFMAS method was applied for the analysis of real water samples from the rivers Rhine and Moselle. For method validation, samples were also analyzed by an ion chromatography (IC) method. IC and HR-CS-GFMAS results both agreed well. In comparison with IC, HR-CS-GFMAS has higher sample throughput, a lower limit of detection and a lower limit of quantification, and higher selectivity, and is a very suitable method for the analysis of dissolved fluoride in river water. Graphical abstract High-resolution continuum source graphite furnace molecular absorption spectrometry (HR-CS-GFMAS) was applied for the quantitative analysis of dissolved

  12. Determination of tributyltin in whole water matrices under the European Water Framework Directive.

    PubMed

    Richter, Janine; Fettig, Ina; Philipp, Rosemarie; Jakubowski, Norbert; Panne, Ulrich; Fisicaro, Paola; Alasonati, Enrica

    2016-08-12

    Monitoring of water quality is important to control water pollution. Contamination of the aquatic system has a large effect on human health and the environment. Under the European Water Framework Directive (WFD) 2000/60/EC and the related directive on environmental quality standards (EQS) in the field of water policy 2008/105/EC, the need for sensitive reference methods was highlighted. Since tributyltin (TBT) is one of the WFD listed priority substances a method was developed which is capable to qualify and quantify the pollutant at the required low WFD EQS of 0.2ngL(-1) in whole water bodies, i.e. in non-filtered water samples with dissolved organic carbon and suspended particulate matter. Therefore special attention was paid on the interaction of TBT with the suspended particulate matter and humic substances to obtain a complete representation of the pollution in surface waters. Different water samples were investigated varying the content of organic dissolved and suspended matter. Quantification was performed using species-specific isotope dilution (SSID) and gas chromatography with inductively coupled plasma mass spectrometry (GC-ICP-MS). Different sample treatment strategies were evaluated and compared. The process of internal standard addition was investigated and optimized, hence the equilibrium between internal standards and matrix is of primary importance to perform accurate SSID. Samples spiked at EQS level were analyzed with a recovery between 95 and 105 %. Additionally real surface water samples were investigated and the TBT concentration for the whole water body was determined and compared with conventional routine analysis method.

  13. Rapid determination of total trihalomethanes index in drinking water.

    PubMed

    Serrano, A; Gallego, M

    2007-06-22

    A method for the rapid determination of total trihalomethanes (THMs) index in drinking water has been developed by using a headspace-mass spectrometry (HS-MS) system and partial least squares (PLS) multivariate regression approach. Due to the presence of residual amounts of chlorine and organic matter in the drinking water, the use of a quenching reagent in order to avoid THM generation during the sample manipulation is necessary. The optimization experiments revealed that ascorbic acid was the best quenching reagent compared with sodium thiosulfate and ammonium sulfate. The use of a classification chemometric technique as soft independent modeling of class analogy before the PLS regression improved the results obtained in the prediction of the total THMs index, lowering the relative standard error of prediction (RSEP) from 11.4% to lower than 6.0%. The results obtained by the proposed HS-MS method were compared with those provided by a conventional chromatographic method after analyzing 20 real drinking water samples. A good agreement in the results was observed and no systematic differences were found, which corroborates the good performance of the proposed method.

  14. Water budget determination for Northern groundwater dependent lakes using stable isotopes of water

    NASA Astrophysics Data System (ADS)

    Isokangas, Elina; Rossi, Pekka; Ronkanen, Anna-Kaisa; Kløve, Bjørn

    2013-04-01

    Understanding groundwater - surface water interaction is crucial in numerous water resources management problems. Stable isotopes of water can bring understanding of this interaction especially in catchment scale questions. In this study stable isotopes were used in a Finnish esker aquifer (Lat 64.58° , Lon 26.50° ) where groundwater dependent lakes have suffered from seasonal water level declines. Esker aquifers are the main groundwater reserves in Finland used in water abstraction. In order to determine how hydrology of the lakes is dependent on groundwater, the isotopic composition of oxygen and hydrogen was studied from 36 sampling points during years 2010 to 2012. Samples were taken from 13 groundwater pipes, 11 lakes and 11 streams during winter, spring, summer and autumn. Additionally local precipitation was sampled. The CRDS-method (Picarro L2120-i analyzer) was used to analyze δ18O- and δ2H-values. The data from the study was used to define the Local Meteoric Water Line of the site (δ2H = 7.60 δ18O + 6.70) and the groundwater line of the esker aquifer (δ2H = 7.59 δ18O + 4.79). The groundwater line of the esker aquifer differs from the groundwater line of Finnish groundwaters (δ2H = 8.51 δ18O + 16.65) based on previous studies. This emphasizes the importance of using local isotopic values when stable isotopes of water are used in hydrological studies. Furthermore, the isotopic compositions of the examined lakes differed enough from the isotopic composition of the local groundwater to separate groundwater component in the lake hydrology. The results also verified that evaporation from lakes in Northern Finland can be high enough to utilize isotopic method for determination of groundwater and surface water interactions.

  15. Determinants of water and sodium intake and output.

    PubMed

    Stanhewicz, Anna E; Kenney, W Larry

    2015-09-01

    Physiological regulation of sodium and water intake and output is required for the maintenance of homeostasis. The behavioral and neuroendocrine mechanisms that govern fluid and salt balance are highly interdependent, with acute and chronic alterations in renal output tightly balanced by appropriate changes in thirst and, to a lesser extent in humans, sodium appetite. In healthy individuals, these tightly coupled mechanisms maintain extracellular fluid volume and body tonicity within a narrow homeostatic range by initiating ingestive behaviors and the release of hormones necessary to conserve water and sodium within the body. In this review, the factors that determine output of sodium and fluid and those that determine "normal" input (i.e., matched to output) are addressed. For output, individual variability accompanied by dysregulation of homeostatic mechanisms may contribute to acute and/or chronic disease. To illustrate that point, the specific condition of salt-sensitive hypertension is discussed. For input, physical characteristics, physiological phenotypes, genetic and developmental influences, and cultural and environmental factors combine to result in a wide range of individual variability that, in humans, is compensated for by alterations in excretion. © The Author(s) 2015. Published by Oxford University Press on behalf of the International Life Sciences Institute. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  16. Optimal Parameter Determination for Tritiated Water Storage in Polyacrylic Networks

    SciTech Connect

    Postolache, C.; Matei, Lidia; Georgescu, Rodica; Ionita, Gh.

    2005-07-15

    Due to the remarkable capacity of water retaining, croslinked polyacrylic acids (PAA) represent an interesting alternative for tritiated water trapping. The study was developed on radiolytical processes in PAA:HTO systems derivated from irradiation of polymeric network by disintegration of tritium atoms from HTO. The aim of these studies is the identification of polymeric structures and optimal storage conditions.Sol and gel fractions were determinated by radiometrical methods using PAA labeled with 14-C at carboxylic groups and T at main chains of the polymer. Simulation of radiolytical processes was realized using {gamma} radiation field emitted by a irradiation source of 60-Co which ensures a maximum of absorbed dose rate of 3 kGy/h. Self-radiolytical effects were investigated using labeled PAA in HTO with great radioactive concentration (37-185 GBq/mL). The experiment suggests as optimum for HTO storage as tritium liquid wastes a 1:30 PAA:HTO swelling degree at 18.5-37 MBqL. HTO radioactive concentration.RES studies of radiolytical processes were also realized on dry polyacrylic acid (PAA) and polyacrylic based hydrogels irradiated and determined at 77 K. In the study we observed the effect of swelling capacity of hydrogel o the formation of free radicals.

  17. Water required, water used, and potential water sources for rice irrigation, north coast of Puerto Rico

    USGS Publications Warehouse

    Roman-Mas, A. J.

    1988-01-01

    A 3-yr investigation was conducted to determine the water required and used (both consumed and applied) for irrigation in the rice-growing areas of Vega Baja, Manati, and Arecibo along the north coast. In addition, the investigation evaluated the water resources of each area with regard to the full development of rice farming areas. Based on experiments conducted at selected test farms, water required ranged from 3.13 to 5.25 acre-ft/acre/crop. The amount of water required varies with the wet and dry seasons. Rainfall was capable of supplying from 31 to 70% of the water required for the measured crop cycles. Statistical analyses demonstrated that as much as 95% of rainfall is potentially usable for rice irrigation. The amount of water consumed differed from the quantity required at selected test farms. The difference between the amount of water consumed and that required was due to unaccounted losses or gains, seepage to and from the irrigation and drainage canals, and lateral leakage through levees. Due to poor water-management practices, the amount of water applied to the farms was considerably larger than the sum of the water requirement and the unaccounted losses or gains. Rivers within the rice growing areas constitute the major water supply for rice irrigation. Full development of these areas will require more water than the rivers can supply. Efficient use of rainfall can significantly reduce the water demand from streamflow. The resulting water demand, however, would still be in excess of the amount available from streamflow. Groundwater development in the area is limited because of seawater intrusion in the aquifers underlying the rice-growing areas. Capture of seepage to the aquifers using wells located near streams, artificial recharge, and development of the deep artesian system can provide additional water for rice irrigation. (Author 's abstract)

  18. The determinants of thermal comfort in cool water.

    PubMed

    Guéritée, J; House, J R; Redortier, B; Tipton, M J

    2015-10-01

    Water-based activities may result in the loss of thermal comfort (TC). We hypothesized that in cooling water, the hands and feet would be responsible. Supine immersions were conducted in up to five clothing conditions (exposing various regions), as well as investigations to determine if a "reference" skin temperature (Tsk) distribution in thermoneutral air would help interpret our findings. After 10 min in 34.5 °C water, the temperature was decreased to 19.5 °C over 20 min; eight resting or exercising volunteers reported when they no longer felt comfortable and which region was responsible. TC, rectal temperature, and Tsk were measured. Rather than the extremities, the lower back and chest caused the loss of overall TC. At this point, mean (SD) chest Tsk was 3.3 (1.7) °C lower than the reference temperature (P = 0.005), and 3.8 (1.5) °C lower for the back (P = 0.002). Finger Tsk was 3.1 (2.7) °C higher than the reference temperature (P = 0.037). In cool and cooling water, hands and feet, already adapted to colder air temperatures, will not cause discomfort. Contrarily, more discomfort may arise from the chest and lower back, as these regions cool by more than normal. Thus, Tsk distribution in thermoneutral air may help understand variations in TC responses across the body.

  19. Heat as a tracer to determine streambed water exchanges

    USGS Publications Warehouse

    Constantz, J.

    2010-01-01

    This work reviews the use of heat as a tracer of shallow groundwater movement and describes current temperature-based approaches for estimating streambed water exchanges. Four common hydrologic conditions in stream channels are graphically depicted with the expected underlying streambed thermal responses, and techniques are discussed for installing and monitoring temperature and stage equipment for a range of hydrological environments. These techniques are divided into direct-measurement techniques in streams and streambeds, groundwater techniques relying on traditional observation wells, and remote sensing and other large-scale advanced temperatureacquisition techniques. A review of relevant literature suggests researchers often graphically visualize temperature data to enhance conceptual models of heat and water flow in the near-stream environment and to determine site-specific approaches of data analysis. Common visualizations of stream and streambed temperature patterns include thermographs, temperature envelopes, and one-, two-, and three-dimensional temperature contour plots. Heat and water transport governing equations are presented for the case of transport in streambeds, followed by methods of streambed data analysis, including simple heat-pulse arrival time and heat-loss procedures, analytical and time series solutions, and heat and water transport simulation models. A series of applications of these methods are presented for a variety of stream settings ranging from arid to continental climates. Progressive successes to quantify both streambed fluxes and the spatial extent of streambeds indicate heat-tracing tools help define the streambed as a spatially distinct field (analogous to soil science), rather than simply the lower boundary in stream research or an amorphous zone beneath the stream channel.

  20. Landscape characteristics impacts on water quality of urban lowland catchments: monitoring the Amsterdam city area

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

    In Dutch lowland polder systems, groundwater quality significantly contributes to surface water quality. This process is influenced by landscape characteristics such as topography, geology, and land use types. In this study, 23 variables were selected for 144 polder catchments, including groundwater and surface water solute concentrations (TN, TP, NH4+, NO3-, HCO3-, SO42-, Ca2+, Cl-), seepage rate in mm per year, elevation, paved area percentage, surface water area percentage, and soil types (calcite, humus and lutum percentage). The spatial patters in groundwater and surface water quality can largely be explained by groundwater seepage rates in polders and partly by artificial redistribution of water via the regional surface water system. High correlations (R2 up to 0.66) between solutes in groundwater and surface water revealed their probable interaction. This was further supported by results from principal component analysis (PCA) and linear regression. The PCA distinguished four factors that were related to a fresh groundwater factor, seepage rate factor, brackish groundwater factor and clay soil factor. Nutrients (TP, TN, NH4+ and NO3-) and SO42- in surface water bodies are mainly determined by groundwater quality combined with seepage rate, which is negatively related to surface water area percentage and elevation of the catchment. This pattern is more obvious in deep urban lowland catchments. Relatively high NO3- loads more tend to appear in catchments with high humus, but low calcite percentage soil type on top, which was attributed to clay soil type that was expressed by calcite percentage in our regression. Different from nitrogen contained solutes, TP is more closely related to fresh groundwater quality than to seepage rate. Surface water Cl- concentration has a high relation with brackish groundwater. Due to the artificial regulation of flow direction, brackish inlet water from upstream highly influences the chloride load in surface water bodies

  1. Savannah River Laboratory Seepage Basins: Waste site assessment report

    SciTech Connect

    Haselow, J.S.; Looney, B.B.; Nichols, R.L.

    1989-09-05

    This Waste Site Assessment for the SRL Seepage Basins is the second in a series of documents being prepared to support development of an appropriate closure plan for these basins. The closure of these basins will be designed to provide protection to human health and the environment and to meet the provisions of the Consent Decree. A Technical Data Summary for these basins has already been submitted as part of the Consent Decree. This Site Assessment Report includes a waste site characterization, and a discussion of closure options for the basins. A closure option is recommended in this report, but details of the recommended closure are not provided in this report since they will be provided in a subsequent closure plan. The closure plan is the third document required under the Consent Decree. 18 refs., 16 figs., 10 tabs.

  2. Environmental information document: Savannah River Laboratory Seepage Basins

    SciTech Connect

    Fowler, B.F.; Looney, B.B.; Simmons, R.V.; Bledsoe, H.W.

    1987-03-01

    This document provides environmental information on postulated closure options for the Savannah River Laboratory Seepage Basins at the Savannah River Plant and was developed as background technical documentation for the Department of Energy`s proposed Environmental Impact Statement (EIS) on waste management activities for groundwater protection at the plant. The results of groundwater and atmospheric pathway analyses, accident analysis, and other environmental assessments discussed in this document are based upon a conservative analysis of all foreseeable scenarios as defined by the National Environmental Policy Act (CFR, 1986). The scenarios do not necessarily represent actual environmental conditions. This document is not meant to be used as a closure plan or other regulatory document to comply with required federal or state environmental regulations.

  3. [The determination of molecular sulphur in Matsesta mineral water and its analog Novonukutskaya mineral water].

    PubMed

    Khutorianskiĭ, V A; Smirnov, A I; Matveev, D A

    2014-01-01

    The method of microcolumn reversed phase high performance liquid chromatography (rp-HPLC) was employed to determine the content of elemental sulphur in mineral waters. The study envisaged the analysis of the samples of sulphide-containing mineral waters Novonukutskaya and Matsesta obtained by the solid phase extraction technique. Based on these data, the authors discuss the origin and the circulation of sulphur in the hydrogen sulphide sources. The elution conditions selected in this study ensured the high-resolution separation of the octasulphur peak from the peaks of allotropic components of the extract whereas the two-wave detection technique allowed to identify the peaks of molecular sulphur.

  4. Massive asphalt deposits, oil seepage, and gas venting support abundant chemosynthetic communities at the Campeche Knolls, southern Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Sahling, Heiko; Borowski, Christian; Escobar-Briones, Elva; Gaytán-Caballero, Adriana; Hsu, Chieh-Wei; Loher, Markus; MacDonald, Ian; Marcon, Yann; Pape, Thomas; Römer, Miriam; Rubin-Blum, Maxim; Schubotz, Florence; Smrzka, Daniel; Wegener, Gunter; Bohrmann, Gerhard

    2016-08-01

    Hydrocarbon seepage is a widespread process at the continental margins of the Gulf of Mexico. We used a multidisciplinary approach, including multibeam mapping and visual seafloor observations with different underwater vehicles to study the extent and character of complex hydrocarbon seepage in the Bay of Campeche, southern Gulf of Mexico. Our observations showed that seafloor asphalt deposits previously only known from the Chapopote Knoll also occur at numerous other knolls and ridges in water depths from 1230 to 3150 m. In particular the deeper sites (Chapopopte and Mictlan knolls) were characterized by asphalt deposits accompanied by extrusion of liquid oil in form of whips or sheets, and in some places (Tsanyao Yang, Mictlan, and Chapopote knolls) by gas emission and the presence of gas hydrates in addition. Molecular and stable carbon isotopic compositions of gaseous hydrocarbons suggest their primarily thermogenic origin. Relatively fresh asphalt structures were settled by chemosynthetic communities including bacterial mats and vestimentiferan tube worms, whereas older flows appeared largely inert and devoid of corals and anemones at the deep sites. The gas hydrates at Tsanyao Yang and Mictlan Knolls were covered by a 5-to-10 cm-thick reaction zone composed of authigenic carbonates, detritus, and microbial mats, and were densely colonized by 1-2 m-long tube worms, bivalves, snails, and shrimps. This study increased knowledge on the occurrences and dimensions of asphalt fields and associated gas hydrates at the Campeche Knolls. The extent of all discovered seepage structure areas indicates that emission of complex hydrocarbons is a widespread, thus important feature of the southern Gulf of Mexico.

  5. A new Arctic seepage site? Preliminary evidence from benthic community

    NASA Astrophysics Data System (ADS)

    Caridi, Francesca; Sabbatini, Anna; Morigi, Caterina; Giulia Lucchi, Renata

    2017-04-01

    The Kveithola Trough is an abrupt and narrow sedimentary system located in the NW Barents Sea. The hydrographic, bio-geochemical conditions and the possible existence of gas seepage activity of the area have been investigated during the Eurofleets 2- BURSTER cruise, conducted on board the German icebreaker RV Polarstern. The aim of our work is to characterize the benthic biota and more specifically the macrofaunal community structure coupled to the study of benthic foraminiferal meiofauna. Preliminary qualitative results revealed that in the inner Kveithola Trough, the macrofaunal community is composed by abundant black worm tubes (Chaetopteridae worms and Siboglinidae-like taxa) with presence of Thyasiridae bivalve species. The occurrence of these macrofaunal taxa is usually associated to oxygen-reduced environments, hydrothermal vents and cold seeps. The living benthic foraminiferal assemblage in the same stations is characterized by the presence of typically oxygen-depleted environmental taxa including the calcareous species Nonionellina labradorica and Globobulimina spp.. Conversely, in the outer Kveithola trough, both benthic macrofauna and foraminiferal meiofauna assemblages are characterized by less opportunistic taxa with a higher biodiversity suggesting very distinct oceanographic sea bottom conditions. The organic matter richness plays a large role in the Kveithola Trough environmental setting and may bring anoxic conditions that could affect the biota of the area. In fact, the benthic community structure of this area inhabits suboxic, anoxic and organic-enriched sediments and disturbed environments, forming assemblages with low diversity and high abundances of a few tolerant and/or specialized species. This preliminary finding could be consistent with other studies examining benthic community structure around Svalbard and in particular cold seep and vents habitats where faunal characteristics are patchy, suggesting small-scale heterogeneity in the

  6. Salt water and its relation to fresh ground water in Harris County, Texas

    USGS Publications Warehouse

    Winslow, Allen G.; Doyel, William Watson; Wood, L.A.

    1957-01-01

    Other less probable potential sources of salt-water contamination which are discussed include upward movement of salt water from below, vertical movement around salt domes or along faults, downward seepage from surface sources, and contamination through leaking wells.

  7. F-Area Seepage Basins groundwater monitoring report, Third quarter 1992

    SciTech Connect

    Thompson, C.Y.

    1992-12-01

    During third quarter 1992, the groundwater at the F-Area Seepage Basins (FASB) was monitored in compliance with South Carolina Hazardous Waste Management Regulations, R61-79.265, Subpart F. Eighty-five wells provided samples from the three separate hydrostratigraphic units that make up the uppermost aquifer beneath the FASB. A detailed description of the uppermost aquifer is included in the Resource Conservation and Recovery Act Part B Post-Closure Care Permit Application for the F-Area Hazardous Waste Management Facility submitted to the South Carolina Department of Health and Environmental Control in December 1990. Historically, as well as currently, tritium, nitrate, lead, cadmium, and gross alpha are the primary constituents observed above the US Environmental Protection Agency Primary Drinking Water Standards (PDWS) in groundwater at the FASB. Nonvolatile beta has consistently exceeded its drinking water screening level. Other radionuclides and hazardous constituents also have exceeded the PDWS in the groundwater at the FASB. Isoconcentration maps included in this report indicate both the concentration and extent of the primary contaminants in each of the three hydrostratigraphic units. Water-level maps indicate that the groundwater flow rates and directions at the FASB have remained relatively constant since the basins ceased to be active in 1988.

  8. H-Area Seepage Basins groundwater monitoring report, third quarter 1992

    SciTech Connect

    Not Available

    1992-12-01

    During third quarter 1992, the groundwater at the H-Area Seepage Basins (HASB) was monitored in compliance with South Carolina Hazardous Waste Management Regulations, R61-79.265, Subpart F. One hundred thirty wells provided samples from the three separate hydrostratigraphic units that make up the uppermost aquifer beneath the HASB. A detailed description of the uppermost aquifer is included in the Resource Conservation and Recovery Act Part B Post-Closure Care Permit Application for the H-Area Hazardous Waste Management Facility submitted to the South Carolina Department of Health and Environmental Control in December 1990. Historically, as well as currently, tritium, nitrate, mercury, and gross alpha have been the primary constituents observed above the US Environmental Protection Agency Primary Drinking Water Standards (PDWS) in groundwater at the HASB. Nonvolatile beta has consistently exceeded its drinking water screening level. Other radionuclides and hazardous constituents also have exceeded the PDWS in the groundwater at the HASB. Isoconcentration maps included in this report indicate both the concentration and extent of the primary contaminants in each of the three hydrostratigraphic units. Water-level maps indicate that the groundwater flow rates and directions at the HASB have remained relatively constant since the basins ceased to be active in 1988.

  9. Probability distribution functions of turbulence in seepage-affected alluvial channel

    NASA Astrophysics Data System (ADS)

    Sharma, Anurag; Kumar, Bimlesh

    2017-02-01

    The present experimental study is carried out on the probability distribution functions (PDFs) of turbulent flow characteristics within near-bed-surface and away-from-bed surfaces for both no seepage and seepage flow. Laboratory experiments were conducted in the plane sand bed for no seepage (NS), 10% seepage (10%S) and 15% seepage (15%) cases. The experimental calculation of the PDFs of turbulent parameters such as Reynolds shear stress, velocity fluctuations, and bursting events is compared with theoretical expression obtained by Gram-Charlier (GC)-based exponential distribution. Experimental observations follow the computed PDF distributions for both no seepage and seepage cases. Jensen-Shannon divergence (JSD) method is used to measure the similarity between theoretical and experimental PDFs. The value of JSD for PDFs of velocity fluctuation lies between 0.0005 to 0.003 while the JSD value for PDFs of Reynolds shear stress varies between 0.001 to 0.006. Even with the application of seepage, the PDF distribution of bursting events, sweeps and ejections are well characterized by the exponential distribution of the GC series, except that a slight deflection of inward and outward interactions is observed which may be due to weaker events. The value of JSD for outward and inward interactions ranges from 0.0013 to 0.032, while the JSD value for sweep and ejection events varies between 0.0001 to 0.0025. The theoretical expression for the PDF of turbulent intensity is developed in the present study, which agrees well with the experimental observations and JSD lies between 0.007 and 0.015. The work presented is potentially applicable to the probability distribution of mobile-bed sediments in seepage-affected alluvial channels typically characterized by the various turbulent parameters. The purpose of PDF estimation from experimental data is that it provides a complete numerical description in the areas of turbulent flow either at a single or finite number of points.

  10. Results of a seepage investigation at Bear Creek Valley, Oak Ridge, Tennessee, January through September 1994

    USGS Publications Warehouse

    Robinson, J.A.; Johnson, G.C.

    1996-01-01

    A seepage investigation was conducted of 4,600 acres of Bear Creek Valley southwest of the Y-12 Plant, Oak Ridge, Tennessee, for the period of January through September 1994. The data were collected to help the Y-12 Environmental Restoration Program develop a better understanding of ground-water and surface-water interactions, recharge and discharge relations, and ground-water flow patterns. The project was divided into three phases: a reconnaissance and mapping of seeps, springs, and stream-measurment sites; a high base flow seepage investigation; and a low base flow seepage investigation. The reconnaissance was conducted from January 6 to March 1, 1994, to identify and map the locations of seeps, springs, and stream-measurement sites. A total of 701 sites were identified. They consisted of 382 stream- measurement sites, 265 seeps, 48 springs, and 6 wetlands. A global positioning system was used to locate 680 sites to within 3- to 5-meter accuracy. The high base flow seepage investigation was conducted from March 14 through March 19, 1994. Measurements were made at 579 of the 701 sites identified in the reconnaissance that still had flowing water. Flow rates ranged from less than 0.005 to 6.89 cubic feet per second for the streams, from less than 0.005 to 0.13 cubic foot per second for the seeps, and from less than 0.005 to 1 cubic foot per second for the springs. pH ranged from 5.0 to 8.4 for the streams, from 5.1 to 8.2 for the seeps, from 5.3 to 8.0 for the springs, and from 6.7 to 6.8 for the wetland sites. Specific conductance ranged from 16 to 1,670 microsiemens per centimeter for the streams, from 17 to 1,710 microsiemens per centimeter for the seeps, from 14 to 1,150 microsiemens per centimeter for the springs, and from 102 to 160 microsiemens per centimeter for the wetland sites. Temperature ranged from 4.5 to 16.0 degrees Celsius for the streams, from 5.0 to 21.0 degrees Celsius for the seeps, from 6.0 to 13.5 degrees Celsius for the springs, and from 13

  11. A microscale Kjeldahl nitrogen determination for environmental waters.

    PubMed

    Campins-Falco, P; Meseguer-Lloret, S; Climent-Santamaria, T; Molins-Legua, C

    2008-05-30

    A microscale Kjeldahl system has been designed which has been homemade reduced. The digestor unit of a macroKjeldahl system and a modified glassware microdistillation unit have been used. The optimal conditions for digestion and distillation have been established for ammonium and methylamine as model compound of organic amino nitrogen. The optimised procedure has been applied to the determination of Kjeldahl nitrogen in water samples. Recoveries near 100% and good precision have been achieved. This procedure combines nitrogen miniaturized system and the use of a selective ion electrode for ammonia detection. The analysis time was reduced 4.8 times and the analysis cost 6.6 times compared with classical procedure. The residues generated have been also markedly minimized. A preconcentration factor of 4 instead of 1.5 obtained by the macroscale design has been achieved.

  12. Azomethine H colorimetric method for determining dissolved boron in water

    USGS Publications Warehouse

    Spencer, R.R.; Erdmann, D.E.

    1979-01-01

    An automated colorimetric method for determining dissolved boron in water is described. The boron is complexed with azomethine H, which is readily available as the condensation product of H acid (8-amino-1-naphthol-3,6-disulfonic acid) and salicylaldehyde. The absorbance of the yellow complex formed is then measured colorimetrically at 410 nm. Interference effects from other dissolved species are minimized by the addition of diethylenetriaminepentaacetic acid (DTPA); however, iron, zinc, and bicarbonate interfere at concentrations above 400 ??g/L, 2000 ??g/L, and 200 mg/L, respectively. The bicarbonate interference can be eliminated by careful acidification of the sample with concentrated HCl to a pH between 5 and 6. Thirty samples per hour can be routinely analyzed over the range of from 10 to 400 ??g/L, boron.

  13. Voltammetric Determination of Ni and Co in Water Samples

    NASA Astrophysics Data System (ADS)

    Herrera-Melian, Jose Alberto; Dona-Rodriguez, Jose Miguel; Hernandez-Brito, Joaquin; Perez Pena, Jesus

    1997-12-01

    Stripping voltammetry has attracted considerable attention for the determination of trace and ultratrace metals. This is mainly due to its high sensitivity and low cost of instrumentation. In adsorptive stripping voltammetry an organometallic complex is formed by the addition of a suitable ligand to the sample. The complex is adsorbed onto the Hg-drop by the application of the proper adsorption potential (more positive than E1/2) and solution stirring. After an adsorption period a cathodic (negative going) potential scan is applied and the metal concentration is calculated by the standard addition method. Nickel is found in natural waters at nM levels and is closely related with phosphates and silicates. Cobalt is a component of vitamin B12 and occurs in natural waters at concentration about 0.1 nM. We propose the voltammetric analysis of these elements by adsorptive stripping voltammetry as an introductory laboratory experiment for advanced chemistry or for chemical or environmental engineering students. The experiment has been proven to be very suitable for the laboratory part of the instrumental analysis course at the University of Las Palmas de Gran Canaria (Spain). In general, about 70% of the students have obtained good agreement (less than 10% of difference) between their results and the expected ones. Two hours is enough for the overall instrumental performance and the preparation of Ni and Co standards.

  14. Micellar electrokinetic chromatographic determination of triazine herbicides in water samples.

    PubMed

    Li, Zhi; Zhang, Shuaihua; Yin, Xiaofang; Wang, Chun; Wang, Zhi

    2014-09-01

    Dispersive liquid-liquid microextraction combined with online sweeping preconcentration in micellar electrokinetic chromatography was developed for the simultaneous determination of five triazine herbicides (atrazine, simazine, propazine, prometon and simetryn) in water samples. Several experimental parameters affecting the extraction efficiencies such as the type and volume of both the extraction and dispersive solvents, the addition of salt to sample solution, the extraction time and the pH of the sample solution were investigated. Under optimum conditions, the linearity of the method was good in the range from 0.33 to 20 ng mL(-1) for simazine, propazine, atrazine and simetryn, and from 0.17 to 20 ng mL(-1) for prometon, respectively. The sensitivity enrichment factors were in the range from 1750 to 2100, depending on the compound. The limit of detection (S/N = 3) ranged from 0.05 to 0.10 ng mL(-1). The developed method was successfully applied to the analysis of the five triazines in river, ground and well waters.

  15. Instream water use in the United States: water laws and methods for determining flow requirements

    USGS Publications Warehouse

    Lamb, Berton L.; Doerksen, Harvey R.

    1987-01-01

    the conterminous United States consists of about 12,000 miles of maintained waterways, over which about 500 million tons of cargo is carried each year (U.S. Army Corps of Engineers, 1988, p. 16). Although not so widely practiced in recent years, streams have been used to dispose of raw waste products from homes, communities, and factories. This use has been discouraged by law and public policy because of public health concerns and the damage it causes to the environment. Beginning in the mid-1960's, other instream uses gained new prominence in the water-resources arena-the assertion of a legal right to a free-flowing stream for biological, recreational, and esthetic purposes. These uses themselves, however, are not new. Riverine habitat always has produced fish, and the beauty of flowing water always has evoked a strong sense of esthetic appreciation. What is new is the emerging legitimacy and awareness of these noneconomic uses under State and Federal laws and regulations. In the past, environmental uses of flowing water were ignored, for the most part, under a long-standing legal tradition that favored offstream uses and certain instream uses that had a strong economic basis. The history of instream-flow policy debate really concerns those recently recognized types of interim uses. Although the more transitional water uses have been protected by law, the recognition of other in stream uses has resulted in substantial changes in State water laws. Although methods for determining the volume of water needed for most traditional water uses are relatively straight-forward and well-established, methods for determining water requirements for the in stream uses have been developed only recently and are continuing to evolve. Water laws that have favored the more traditional water uses, the inherent nature of conflict between instream and offstream water uses, and the special kinds of technological and philosophical problems posed by the "newer" types of instream uses are

  16. Electromembrane extraction for the determination of parabens in water samples.

    PubMed

    Villar-Navarro, Mercedes; Moreno-Carballo, María Del Carmen; Fernández-Torres, Rut; Callejón-Mochón, Manuel; Bello-López, Miguel Ángel

    2016-02-01

    To our knowledge, for the first time an electromembrane extraction combined with a high-performance liquid chromatography procedure using diode-array detection has been developed for the determination of five of the most widely used parabens: ethyl 4-hydroxybenzoate, propyl 4-hydroxybenzoate, butyl 4-hydroxybenzoate, isobutyl 4-hydroxybenzoate, and benzyl 4-hydroxybenzoate. Parabens were extracted from pH 4 aqueous sample solutions with use of an Accurel® S6/2 polypropylene hollow fiber that supports a liquid membrane of 1-octanol to a pH 12 aqueous acceptor solution placed inside the lumen of the hollow fiber. An electric current of 30 V was applied over the supported liquid membrane by means of platinum wires placed in the donor and acceptor phases. Parabens were extracted in 40 min with enrichment factors in the 30-49 range. The procedure has detection limits between 0.98 and 1.43 μg L(-1). The method was applied to the determination of parabens in surface environmental waters with excellent results.

  17. Rapid screening of triazines and quantitative determination in drinking water.

    PubMed

    Hamada, Mazen; Wintersteiger, Reinhold

    2002-01-01

    A sensitive, rapid and inexpensive analysis method has been developed for the triazines most frequently used in Palestine; the method includes fluorodensitometric screening and densitometric determination of the individual substances. Terbutryn as a model substance was derivatized with dansyl chloride in sodium hydrogen-carbonate or phosphate buffer solution to yield a green-blue fluorescent compound. Derivatization occurred at 120 degrees C within maximum of 10-min reaction time. The fluorescent compound formed was separated from excess reagent and other by-products on silica gel TLC plates and was then determined fluorodensitometrically. A linearity range between 20 and 1200 pg/spot was achieved. The method was also applied to other triazine herbicides such as ametryn, atrazine, propazine, terbuthylazine and simazine. Drinking water samples spiked with triazines were extracted using RP-C18 polar plus cartridges, and the extract could be then dansylated as a total. Recoveries were between 88% and 95%; the detection limit was 10 pg/spot and could be further improved to 2 pg/spot by a dipping solution. For quantification, each of the six triazines can be separated on one of three different stationary phases after solid phase extraction and measured densitometrically. The LOD for each individual triazine was 100 ng/l.

  18. Electrical resistivity investigation of fluvial geomorphology to evaluate potential seepage conduits to agricultural lands along the San Joaquin River, Merced County, California, 2012–13

    USGS Publications Warehouse

    Groover, Krishangi D.; Burgess, Matthew K.; Howle, James F.; Phillips, Steven P.

    2017-02-08

    Increased flows in the San Joaquin River, part of the San Joaquin River Restoration Program, are designed to help restore fish populations. However, increased seepage losses could result from these higher restoration flows, which could exacerbate existing drainage problems in neighboring agricultural lands and potentially damage crops. Channel deposits of abandoned river meanders that are hydraulically connected to the river could act as seepage conduits, allowing rapid and widespread water-table rise during restoration flows. There is a need to identify the geometry and properties of these channel deposits to assess their role in potential increased seepage effects and to evaluate management alternatives for reducing seepage. Electrical and electromagnetic surface geophysical methods have provided a reliable proxy for lithology in studies of fluvial and hyporheic systems where a sufficient electrical contrast exists between deposits of differing grain size. In this study, direct-current (DC) resistivity was used to measure subsurface resistivity to identify channel deposits and to map their subsurface geometry. The efficacy of this method was assessed by using DC resistivity surveys collected along a reach of the San Joaquin River in Merced County, California, during the summers of 2012 and 2013, in conjunction with borings and associated measurements from a hydraulic profiling tool. Modeled DC resistivity data corresponded with data from cores, hand-auger samples, a hydraulic profiling tool, and aerial photographs, confirming that DC resistivity is effective for differentiating between silt and sand deposits in this setting. Modeled DC resistivity data provided detailed two-dimensional cross-sectional resistivity profiles to a depth of about 20 meters. The distribution of high-resistivity units in these profiles was used as a proxy for identifying areas of high hydraulic conductivity. These data were used subsequently to guide the location and depth of wells

  19. Ecology and equity: key determinants of sustainable water security.

    PubMed

    Swaminathan, M S

    2001-01-01

    Trends in water consumption indicate that demand for water for household and industrial uses in developing countries could double as a proportion of total water demand in the next 25 years. Scope for expansion of water supply will, at the same time, be limited because development of irrigation and urban water supplies is becoming increasingly expensive, and often involves high costs in terms of environmental degradation and human resettlement. Without fundamental reform of water management, the rapid growth in urban water demand will require large transfers of water from irrigated agriculture, thereby threatening food security. Hence, water supply and demand should be managed in an integrated fashion, simultaneously considering all uses and sources. This will call for the establishment of community centred food and water security systems and national water trusts. Once such systems and Trusts are established there could be a legally binding Global Water Convention on the model of the Global Convention on Climate and Biodiversity. The details of such a Global Water Conventions can be finalized at one of the future Stockholm Water Symposia. There are uncommon opportunities today for a water-secure world through synergy between technology, public policy and peoples' participation.

  20. 43 CFR 418.10 - Determining the amount of water duty to be delivered.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 1 2013-10-01 2013-10-01 false Determining the amount of water duty to be..., NEVADA Conditions of Water Delivery § 418.10 Determining the amount of water duty to be delivered. (a) Eligible land may receive no more than the amount of water in acre-feet per year established as...

  1. 43 CFR 418.10 - Determining the amount of water duty to be delivered.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 1 2012-10-01 2011-10-01 true Determining the amount of water duty to be..., NEVADA Conditions of Water Delivery § 418.10 Determining the amount of water duty to be delivered. (a) Eligible land may receive no more than the amount of water in acre-feet per year established as...

  2. 43 CFR 418.10 - Determining the amount of water duty to be delivered.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 1 2011-10-01 2011-10-01 false Determining the amount of water duty to be..., NEVADA Conditions of Water Delivery § 418.10 Determining the amount of water duty to be delivered. (a) Eligible land may receive no more than the amount of water in acre-feet per year established as...

  3. 18 CFR 430.7 - Determination of protected areas and restriction on water use.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... Determination of protected areas and restriction on water use. In consideration of the foregoing facts and for... 18 Conservation of Power and Water Resources 2 2014-04-01 2014-04-01 false Determination of protected areas and restriction on water use. 430.7 Section 430.7 Conservation of Power and Water...

  4. 18 CFR 430.7 - Determination of protected areas and restriction on water use.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 18 Conservation of Power and Water Resources 2 2013-04-01 2012-04-01 true Determination of protected areas and restriction on water use. 430.7 Section 430.7 Conservation of Power and Water Resources DELAWARE RIVER BASIN COMMISSION SPECIAL REGULATIONS GROUND WATER PROTECTION AREA: PENNSYLVANIA § 430.7 Determination of protected areas...

  5. 18 CFR 430.7 - Determination of protected areas and restriction on water use.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 18 Conservation of Power and Water Resources 2 2012-04-01 2012-04-01 false Determination of protected areas and restriction on water use. 430.7 Section 430.7 Conservation of Power and Water Resources DELAWARE RIVER BASIN COMMISSION SPECIAL REGULATIONS GROUND WATER PROTECTION AREA: PENNSYLVANIA § 430.7 Determination of protected areas...

  6. H-Area Seepage Basins groundwater monitoring report. Fourth quarter 1992 and 1992 summary

    SciTech Connect

    Not Available

    1993-03-01

    During fourth quarter 1992, the groundwater at the H-Area Seepage Basins (HASB) was monitored in compliance with South Carolina Hazardous Waste Management Regulations, R61-79.265, Subpart F. Samples were collected from 130 wells that monitor the three separate hydrostratigraphic units that make up the uppermost aquifer beneath the HASB. A detailed description of the uppermost aquifer is included in the Resource Conservation and Recovery Act Part B Post-Closure Care Permit Application for the H-Area Hazardous Waste Management Facility submitted to the South Carolina Department of Health and Environmental Control in December 1990. Historically, as well as currently, tritium, nitrate, total alpha-emitting radium, gross alpha, and mercury have been the primary constituents observed above final Primary Drinking Water Standards (PDWS) in groundwater at the HASB. Isoconcentration/isoactivity maps included in this report indicate both the concentration/activity and extent of the primary contaminants in each of the three hydrostratigraphic units during first and fourth quarter 1992. Water-level maps indicate that the groundwater flow rates and directions at the HASB have remained relatively constant since the basins ceased to be active in 1988.

  7. Ra-224 and Ra-226: A New Method for Measuring Groundwater Seepage in Lake Michigan

    NASA Astrophysics Data System (ADS)

    Stevens, K. R.; Buyan, A. C.; Waples, J. T.

    2008-12-01

    Radium isotopes have been used to estimate groundwater discharge (GWD) in coastal marine waters for decades, but this technique has never before been used in the Laurentian Great Lakes. In this study, we used a RAD7 radon-in-air monitor to measure naturally-occurring radium isotopes Ra-224 (half-life= 3.64 d) and Ra-226 (half-life = 1600 a) in groundwater and three shallow water sites along Lake Michigan's Wisconsin coastline. Radium-224 activities in groundwater ranged from 1153 dpm m-3 in a deep aquifer (New Berlin well no.7) to 31 dpm m-3 in a shallow aquifer (Pryor well). Nearshore Lake Michigan measurements of Ra-224 were lowest at Red Arrow Beach (0.2 dpm m-3), higher in the Milwaukee harbor (GLWI slip, 1.1 dpm m-3) and highest at Harrington Beach (4.1 dpm m-3) and correspond well with groundwater seepage estimates made by Cherkauer et al. (1990) using alternate methods (i.e., where higher radium activity is indicative of higher GWD). These Ra-224 measurements are the first ever made in Lake Michigan (and presumably any of the Great Lakes) and we conclude that, by sampling offshore radium activity gradients, this RAD7 technique is a viable method for directly measuring GWD in Lake Michigan and other freshwater systems.

  8. Whole-lake burdens and spatial distribution of cadmium in sediments of Wisconsin seepage lakes, USA

    SciTech Connect

    Powell, D.E.; Rada, R.G.; Wiener, J.G.; Atchison, G.J.

    2000-06-01

    Cadmium was quantified in the surface sediments of six seepage lakes ranging from 8 to 70 ha in surface area, 6 to 20 m in maximum depth, 5.2 to 7.0 in mean epilimnetic pH, and 1.7 to 6.8 mg{sm_bullet}L{sup {minus}1} in dissolved organic carbon. Within each lake, dry-weight concentrations of cadmium were positively correlated with volatile matter content of the sediments, which increased with water depth. Volumetric concentrations were correlated with water depth in only one lake, and they more accurately represented the spatial distribution of sedimentary cadmium within the lakes. Analysis of sediment cores from two of the lakes indicated that surface sediments were enriched with cadmium. The source of cadmium and the within-lake processes controlling deposition to the sediments were presumably similar among the lakes, as demonstrated by the strong correlation between lake area and whole-lake burdens of cadmium in the surface sediments. Hence, cadmium in these lakes appears to be derived largely from atmospheric deposition. When normalized for lake area, cadmium burdens in the surface sediments ranged from 62 to 92 g{sm_bullet}ha{sup {minus}1} and were strongly correlated with dissolved organic carbon, but not with lake pH, which suggests a link between the transport of cadmium and organic matter to the sediments.

  9. Spatial distribution of methane seepage on the East Siberian Arctic Shelf

    NASA Astrophysics Data System (ADS)

    Stubbs, C.; Leifer, I.; Shakhova, N. E.; Semiletov, I. P.; Luyendyk, B. P.

    2010-12-01

    A 2009 multibeam sonar survey of the shallow water-column (mean depth 10 m), near-coastal region of the East Siberian Arctic Shelf (ESAS) adjacent to the Lena River Delta detected tens of thousands of widespread bubble plume seeps. The ESAS contains an estimated 1400 GT (109 tons = 1 GT) of carbon sequestered within and beneath a sub-sea permafrost unit that has become inundated due to sea-level transgression over the last ~15,000 years. This carbon pool includes methane (CH4) as free and dissolved gas, as well as potentially extensive methane hydrate deposits, yet its contribution to global carbon stocks has traditionally been ignored due to the assumed integrity of the sub-sea permafrost as an impermeable barrier to hydrocarbon migration. Recent results indicate that in some regions of the ESAS, methane is migrating through destabilized permafrost into the shallow water-column from which it efficiently vents to the atmosphere. This process represents an unknown but potentially significant contribution to the global greenhouse gas budget and is likely to accelerate under global warming scenarios. We hypothesize that the mapped seeps are fed by methane deposits within and beneath capping permafrost units that release gas into the thin overlying sediments through columns of thaw sediments and other permeable structures within the permafrost. Such sub-sea permafrost features have been previously identified in association with isolated bubble plumes in the ESAS as close as 25 km from the study area (Rekant et al., 2009). These proposed migration pathways suggest thermal destabilization within the subsea permafrost cap; however, the rates at which these processes are occurring remain unknown. The spatial distributions of the most numerous and intense areas of seepage correlate with the areas of greatest fluvial discharge from the Lena and Olenek Rivers and their tributaries. This thermal influence is also evident in seasonal time series of adjacent sea ice retreat over

  10. Contrasting extremes in water-related stresses determine species survival

    NASA Astrophysics Data System (ADS)

    Bartholomeus, R. P.; Witte, J. P. M.; van Bodegom, P. M.; van Dam, J. C.; Aerts, R.

    2012-04-01

    In temperate climates, soil moisture, in concert with nutrient availability and soil acidity, is the most important environmental filter in determining local plant species composition, as it determines the availability of both oxygen and water to plant roots. These resources are indispensable for meeting the physiological demands of plants. Especially the occurrence of both excessive dry and wet moisture conditions at a particular site has strong implications for the survival of species, because plants need traits that allow them to respond to such counteracting conditions. However, adapting to one stress may go at the cost of the other, i.e. there exists a trade-off in the tolerance for wet conditions and the tolerance for dry conditions. Until now, both large-scale (global) and plot-scale effects of soil moisture conditions on plant species composition have mostly been investigated through indirect environmental measures, which do not include the key soil physical and plant physiological processes in the soil-plant-atmosphere system. Moreover, researchers only determined effects of one of the water-related stresses, i.e. either oxygen or drought stress. In order to quantify both oxygen and drought stress with causal measures, we focused on interacting meteorological, soil physical, microbial, and plant physiological processes in the soil-plant-atmosphere system. We simulated these plant stresses with a novel, process-based approach, incorporating in detail the interacting processes in the soil-plant-atmosphere interface. High variability and extremes in resource availability can be highly detrimental to plant species ('you can only die once'). We show that co-occurrence of oxygen and drought stress reduces the percentage of specialists within a vegetation plot. The percentage of non-specialists within a vegetation plot, however, decreases significantly with increasing stress as long as only one of the stresses prevails, but increases significantly with an

  11. Freshwater seepages and ephemeral macroalgae proliferation in an intertidal bay: I Effect on benthic community structure and food web

    NASA Astrophysics Data System (ADS)

    Ouisse, Vincent; Riera, Pascal; Migné, Aline; Leroux, Cédric; Davoult, Dominique

    2011-01-01

    Freshwater seepages and ephemeral Enteromorpha spp. proliferation create heterogeneity at small spatial scale in intertidal sediment. Macrobenthic community diversity was compared between these two disturbances and their respective control points throughout the year 2007 at the Roscoff Aber Bay (Western English Channel, France). In March and September 2007, trophic community pathways of characteristic species were additionally studied using stable isotope ratios of carbon and nitrogen. The low salinity recorded at the freshwater seepage induced the exclusion of the main bioturbator and the presence of omnivores which modified the community composition by biotic pressure. Moreover, food web analyses clearly highlighted a separation at small spatial scale between the two trophic pathways of the impacted area and its control. On the contrary, little differences were observed owning to the ephemeral Enteromorpha spp. proliferation. This suggested a progressive and diffusive disturbance which was applied from the algal mat to the nearby area. However, seasonal changes were observed. First, the algal expansion phase increased the macrofauna diversity and foraminifers' abundance (meiofauna) and then acted as a physical barrier decreasing sediment and water column exchanges and decreasing the fauna diversity. This study highlights the need to take into account small spatial heterogeneity to avoid misinterpretations in intertidal ecology studies.

  12. First evidence of widespread active methane seepage in the Southern Ocean, off the sub-Antarctic island of South Georgia

    NASA Astrophysics Data System (ADS)

    Römer, M.; Torres, M.; Kasten, S.; Kuhn, G.; Graham, A. G. C.; Mau, S.; Little, C. T. S.; Linse, K.; Pape, T.; Geprägs, P.; Fischer, D.; Wintersteller, P.; Marcon, Y.; Rethemeyer, J.; Bohrmann, G.

    2014-10-01

    An extensive submarine cold-seep area was discovered on the northern shelf of South Georgia during R/V Polarstern cruise ANT-XXIX/4 in spring 2013. Hydroacoustic surveys documented the presence of 133 gas bubble emissions, which were restricted to glacially-formed fjords and troughs. Video-based sea floor observations confirmed the sea floor origin of the gas emissions and spatially related microbial mats. Effective methane transport from these emissions into the hydrosphere was proven by relative enrichments of dissolved methane in near-bottom waters. Stable carbon isotopic signatures pointed to a predominant microbial methane formation, presumably based on high organic matter sedimentation in this region. Although known from many continental margins in the world's oceans, this is the first report of an active area of methane seepage in the Southern Ocean. Our finding of substantial methane emission related to a trough and fjord system, a topographical setting that exists commonly in glacially-affected areas, opens up the possibility that methane seepage is a more widespread phenomenon in polar and sub-polar regions than previously thought.

  13. Laser based water equilibration method for d18O determination of water samples

    NASA Astrophysics Data System (ADS)

    Mandic, Magda; Smajgl, Danijela; Stoebener, Nils

    2017-04-01

    Determination of d18O with water equilibration method using mass spectrometers equipped with equilibration unit or Gas Bench is known already for many years. Now, with development of laser spectrometers this extends methods and possibilities to apply different technologies in laboratory but also in the field. The Thermo Scientific™ Delta Ray™ Isotope Ratio Infrared Spectrometer (IRIS) analyzer with the Universal Reference Interface (URI) Connect and Teledyne Cetac ASX-7100 offers high precision and throughput of samples. It employs optical spectroscopy for continuous measurement of isotope ratio values and concentration of carbon dioxide in ambient air, and also for analysis of discrete samples from vials, syringes, bags, or other user-provided sample containers. Test measurements and conformation of precision and accuracy of method determination d18O in water samples were done in Thermo Fisher application laboratory with three lab standards, namely ANST, Ocean II and HBW. All laboratory standards were previously calibrated with international reference material VSMOW2 and SLAP2 to assure accuracy of the isotopic values of the water. With method that we present in this work achieved repeatability and accuracy are 0.16‰ and 0.71‰, respectively, which fulfill requirements of regulatory method for wine and must after equilibration with CO2.

  14. Determination of oil/water and octanol/water distribution coefficients from aqueous solutions from four fossil fuels. [MS thesis; in oil-water and octanol-water

    SciTech Connect

    Thomas, B.L.

    1984-07-01

    Liquid fossil fuels, both petroleum and synthetically derived oils, are exceedingly complex mixtures of thousands of components. The effect of many of these energy-related components on the environment is largely unknown. Octanol/water distribution coefficients relate both to toxicity and to the bioaccumulation potential of chemical components. Use of these partition data in conjunction with component concentrations in the oils in environmental models provides important information on the fate of fossil fuel components when released to the environment. Octanol/water distribution data are not available for many energy-related organic compounds, and those data that are available have been determined for individual components in simple, one-component octanol/water equilibrium mixtures. In this study, methods for determining many octanol/water distribution coefficients from aqueous extracts of oil products were developed. Sample aqueous mixtures were made by equilibrating liquid fossil fuels with distilled water. This approach has the advantage of detecting interactions between components of interest and other sample components. Compound types studied included phenols, nitrogen bases, hydrocarbons, sulfur heterocyclic compounds, and carboxylic acids. Octanol/water distribution coefficients that were determined in this study ranged from 9.12 for aniline to 67,600 for 1,2-dimethylnaphthalene. Within a compound type, distribution coefficients increased logarithmically with increasing alkyl substitution and molecular weight. Additionally, oil/water distribution data were determined for oil components. These data are useful in predicting maximum environmental concentrations in water columns. 96 references, 26 figures, and 40 tables.

  15. Calcareous forest seepages acting as biodiversity hotspots and refugia for woodland snail faunas

    NASA Astrophysics Data System (ADS)

    Horsák, Michal; Tajovská, Eva; Horsáková, Veronika

    2017-07-01

    Land-snail species richness has repeatedly been found to increase with the increasing site calcium content and humidity. These two factors, reported as the main drivers of land-snail assemblage diversity, are also among the main habitat characteristics of calcareous seepages. Here we explore local species richness and compositional variation of forest spring-fed patches (i.e. seepages), to test the hypothesis that these habitats might act as biodiversity hotspots and refugia of regional snail faunas. In contrast to treeless spring fens, only little is known about land snail faunas inhabiting forest seepages. Studying 25 isolated calcareous forest seepages, evenly distributed across the White Carpathians Protected Landscape Area (SE Czech Republic), we found that these sites, albeit spatially very limited, can harbour up to 66% of the shelled land-snail species known to occur in this well-explored protected area (in total 83 species). By comparing land snail assemblages of the studied seepages with those occurring in the woodland surroundings of each site as well as those previously sampled in 28 preserved forest sites within the study area, we found the seepages to be among the most species rich sites. Although the numbers of species did not statistically differ among these three systems, we found highly significant differences in species composition. Seepage faunas were composed of many species significantly associated with spring sites, in contrast to the assemblages of both surrounding and preserved forest sites. Our results highly support the hypothesis that calcareous forest seepages might serve as refugia and biodiversity hotspots of regional land snail faunas. Protection of these unique habitats challenges both conservation plans and forest management guidelines as they might act as sources for the recolonization and restoration of forest snail assemblages particularly in areas impoverished by harvesting and clearcutting.

  16. Factors Affecting Atrazine Concentration and Quantitative Determination in Chlorinated Water

    EPA Science Inventory

    Although the herbicide atrazine has been reported to not react measurably with free chlorine during drinking water treatment, this work demonstrates that at contact times consistent with drinking water distribution system residence times, a transformation of atrazine can be obser...

  17. Factors Affecting Atrazine Concentration and Quantitative Determination in Chlorinated Water

    EPA Science Inventory

    Although the herbicide atrazine has been reported to not react measurably with free chlorine during drinking water treatment, this work demonstrates that at contact times consistent with drinking water distribution system residence times, a transformation of atrazine can be obser...

  18. Seepage investigation on selected reaches of Fish Creek, Teton County, Wyoming, 2004

    USGS Publications Warehouse

    Wheeler, Jerrod D.; Eddy-Miller, Cheryl A.

    2005-01-01

    A seepage investigation was conducted on Fish Creek, a tributary to the Snake River in Teton County in western Wyoming, near Wilson. Mainstem, return flow, tributary, spring, and diversion sites were selected and measured on six reaches along Fish Creek. Flow was measured under two flow regimes, high flow in August 2004 and base flow in November 2004. During August 17-19, 2004, 20 sites had quantifiable discharge with median values ranging from 0.93 to 384 ft3/s for the 14 mainstem sites on Fish Creek, and from 0.35 to 12.2 ft3/s for the 5 return, spring, and tributary sites (inflows). The discharge was 2.23 ft3/s for the single diversion site (outflow). Estimated gains or losses from ground water were calculated for all reaches using the median discharge values and the estimated measurement errors. Reach 1 had a calculated gain in discharge from ground water (23.8 ?3.3 ft3/s). Reaches 2-6 had no calculated gains in flow, greater than the estimated error, that could be attributed to ground water. A second set of measurements were made under base-flow conditions during November 3-4, 2004. Twelve of the 20 sites visited in August 2004 were flowing and were measured. All of the Reach 1 sites near Teton Village were dry. Median discharge values ranged from 10.3 to 70.0 ft3/s on the nine Fish Creek mainstem sites, and from 2.32 to 3.71 ft3/s on the three return, spring, and tributary sites (inflows). Reaches 2, 3 and 6 had a gain from ground water. Reaches 4 and 5 had no calculated gains in flow, greater than the estimated error, that could be attributed to ground water.

  19. Assessing the Impact of Animal Waste Lagoon Seepage on the Geochemistry of an Underlying Shallow Aquifer

    SciTech Connect

    McNab, W W; Singleton, M J; Moran, J E; Esser, B K

    2006-03-07

    Dairy facilities and similar confined animal operation settings pose a significant nitrate contamination threat via oxidation of animal wastes and subsequent transport to shallow groundwater. While nitrate contamination resulting from application of animal manure as fertilizer to fields is well recognized, the impact of manure lagoon leakage on groundwater quality is less well characterized. In this study, a dairy facility located in the southern San Joaquin Valley of California has been instrumented with monitoring wells as part of a two-year multidisciplinary study to evaluate nitrate loading and denitrification associated with facility operations. Among multiple types of data collected from the site, groundwater and surface water samples have been analyzed for major cations, anions, pH, oxidation-reduction potential, dissolved organic carbon, and selected dissolved gases (CO{sub 2}, CH{sub 4}, N{sub 2}, Ar, Ne). Modeling of putative geochemical processes occurring within the dairy site manure lagoons shows substantial off-gassing of CO{sub 2} and CH{sub 4} in response to mineralization of organic matter. The gas ebullition appears to strip dissolved gases, including Ar and Ne, from the lagoon water leaving concentrations that are undersaturated with respect to the atmosphere. The resulting fractionated dissolved gas signature serves as an effective tracer for the lagoon water in the underlying shallow groundwater and can be used to constrain inverse geochemical models that assess mixing fractions of lagoon water and local groundwater water. Together with ion exchange and mineral equilibria reactions, identification of lagoon seepage helps explain key attributes of the local groundwater chemistry, including input and cycling of nitrogen, across the site.

  20. Gas-Chromatographic Determination Of Water In Freon PCA

    NASA Technical Reports Server (NTRS)

    Melton, Donald M.

    1994-01-01

    Gas-chromatographic apparatus measures small concentrations of water in specimens of Freon PCA. Testing by use of apparatus faster and provides greater protection against accidental contamination of specimens by water in testing environment. Automated for unattended operation. Also used to measure water contents of materials, other than Freon PCA. Innovation extended to development of purgeable sampling accessory for gas chromatographs.

  1. Gas-Chromatographic Determination Of Water In Freon PCA

    NASA Technical Reports Server (NTRS)

    Melton, Donald M.

    1994-01-01

    Gas-chromatographic apparatus measures small concentrations of water in specimens of Freon PCA. Testing by use of apparatus faster and provides greater protection against accidental contamination of specimens by water in testing environment. Automated for unattended operation. Also used to measure water contents of materials, other than Freon PCA. Innovation extended to development of purgeable sampling accessory for gas chromatographs.

  2. Applications of spectroscopy to remote determination of water quality

    NASA Technical Reports Server (NTRS)

    Goldberg, M. C.; Weiner, E. R.

    1972-01-01

    The use of remote laser Raman and molecular spectroscopic techniques to measure water quality is examined. Measurements cover biological, chemical, and physical properties of the water. Experimental results show chemical properties are harder to obtain remotely than biological or physical properties and that molecular spectroscopy seems to be the best method for obtaining water quality data.

  3. Determinants of