A numerical study of the plume in Cape Fear River Estuary and adjacent coastal ocean

NASA Astrophysics Data System (ADS)

Xia, M.; Xia, L.; Pietrafesa, L. J.

2006-12-01

Cape Fear River Estuary (CFRE), located in southeast North Carolina, is the only river estuary system in the state which is directly connected to the Atlantic Ocean. It is also an important nursery for economically and ecologically important juvenile fish, crabs, shrimp, and other species because of the tidal influence and saline waters. In this study, Environmental Fluid Dynamic Code (EFDC) is used to simulate the salinity plume and trajectory distribution at the mouth of the CFRE and adjacent coastal ocean. Prescribed with the climatological freshwater discharge rates in the rivers, the modeling system was used to simulate the salinity plume and trajectory distribution distribution in the mouth of the CFRE under the influence of climatological wind conditions and tidal effect. We analyzed the plume formation processes and the strong relationship between the various plume distributions with respect to the wind and river discharge in the region. The simulations also indicate that strong winds tend to reduce the surface CFRE plume size and distorting the bulge region near the estuary mouth due to enhanced wind induced surface mixing. Even moderate wind speeds could fully reverse the buoyancy-driven plume structure in CFRE under normal river discharge conditions. Tide and the river discharge also are important factors to influence the plume structure. The comparions between the distribution of salinity plume and trajectory also are discussed in the study.

Shortnose sturgeon use small coastal rivers: The importance of habitat connectivity

USGS Publications Warehouse

Zydlewski, Gayle B.; Kinnison, M.T.; Dionne, P.E.; Zydlewski, Joseph D.; Wippelhauser, Gail S.

2011-01-01

Contrary to conventional wisdom for shortnose sturgeon (Acipenser brevirostrum), we document shortnose sturgeon use of habitats beyond large rivers. Telemetry data from 2008 to 2010 in the Gulf of Maine demonstrates that adult shortnose sturgeon (up to 70%) frequently move between Maine’s two largest rivers, the Kennebec and Penobscot Rivers. Even more interesting, small rivers located between these watersheds were used by 52% of the coastal migrants. Small river use was not trivial, 80% of observed movements extended more than 10 km upstream. However, visits were short in duration. This pattern indicates one of several possibilities: directed use of resources, searching behaviors related to reproduction (i.e. straying) or undirected wandering. Data suggest a relationship between residence time in small rivers and distance to the lowermost barrier. Restoring connectivity to upstream habitats in these rivers could allow opportunities for metapopulation expansion. Regional management of shortnose sturgeon in the Gulf of Maine should incorporate a habitat framework that considers small coastal rivers.

Simulation of river plume behaviors in a tropical region: Case study of the Upper Gulf of Thailand

NASA Astrophysics Data System (ADS)

Yu, Xiaojie; Guo, Xinyu; Morimoto, Akihiko; Buranapratheprat, Anukul

2018-02-01

River plumes are a general phenomenon in coastal regions. Most previous studies focus on river plumes in middle and high latitudes with few studies examining those in low latitude regions. Here, we apply a numerical model to the Upper Gulf of Thailand (UGoT) to examine a river plume in low latitudes. Consistent with observational data, the modeled plume has seasonal variation dependent on monsoon conditions. During southwesterly monsoons, the plume extends northeastward to the head of the gulf; during northeasterly monsoons, it extends southwestward to the mouth of the gulf. To examine the effects of latitude, wind and river discharge on the river plume, we designed several numerical experiments. Using a middle latitude for the UGoT, the bulge close to the river mouth becomes smaller, the downstream current flows closer to the coast, and the salinity in the northern UGoT becomes lower. The reduction in the size of the bulge is consistent with the relationship between the offshore distance of a bulge and the Coriolis parameter. Momentum balance of the coastal current is maintained by advection, the Coriolis force, pressure gradient and internal stresses in both low and middle latitudes, with the Coriolis force and pressure gradient enlarged in the middle latitude. The larger pressure gradient in the middle latitude is induced by more offshore freshwater flowing with the coastal current, which induces lower salinity. The influence of wind on the river plume not only has the advection effects of changing the surface current direction and increasing the surface current speed, but also decreases the current speed due to enhanced vertical mixing. Changes in river discharge influence stratification in the UGoT but have little effect on the behavior of the river plume.

Impact of river basin management on coastal water quality and ecosystem services: A southern Baltic estuary

NASA Astrophysics Data System (ADS)

Schernewski, Gerald; Hürdler, Jens; Neumann, Thomas; Stybel, Nardine; Venohr, Markus

2010-05-01

Eutrophication management is still a major challenge in the Baltic Sea region. Estuaries or coastal waters linked to large rivers cannot be managed independently. Nutrient loads into these coastal ecosystems depend on processes, utilisation, structure and management in the river basin. In practise this means that we need a large scale approach and integrated models and tools to analyse, assess and evaluate the effects of nutrient loads on coastal water quality as well as the efficiency of river basin management measures on surface waters and especially lagoons and estuaries. The Odra river basin, the Szczecin Lagoon and its coastal waters cover an area of about 150,000 km² and are an eutrophication hot-spot in the Baltic region. To be able to carry out large scale, spatially integrative analyses, we linked the river basin nutrient flux model MONERIS to the coastal 3D-hydrodynamic and ecosystem model ERGOM. Objectives were a) to analyse the eutrophication history in the river basin and the resulting functional changes in the coastal waters between early 1960's and today and b) to analyse the effects of an optimal nitrogen and phosphorus management scenario in the Oder/Odra river basin on coastal water quality. The models show that an optimal river basin management with reduced nutrient loads (e.g. N-load reduction of 35 %) would have positive effects on coastal water quality and algae biomass. The availability of nutrients, N/P ratios and processes like denitrification and nitrogen-fixation would show spatial and temporal changes. It would have positive consequences for ecosystems functions, like the nutrient retention capacity, as well. However, this optimal scenario is by far not sufficient to ensure a good coastal water quality according to the European Water Framework Directive. A "good" water quality in the river will not be sufficient to ensure a "good" water quality in the coastal waters. Further, nitrogen load reductions bear the risk of increased

The effects of precipitation, river discharge, land use and coastal circulation on water quality in coastal Maine

PubMed Central

Tilburg, Charles E.; Jordan, Linda M.; Carlson, Amy E.; Zeeman, Stephan I.; Yund, Philip O.

2015-01-01

Faecal pollution in stormwater, wastewater and direct run-off can carry zoonotic pathogens to streams, rivers and the ocean, reduce water quality, and affect both recreational and commercial fishing areas of the coastal ocean. Typically, the closure of beaches and commercial fishing areas is governed by the testing for the presence of faecal bacteria, which requires an 18–24 h period for sample incubation. As water quality can change during this testing period, the need for accurate and timely predictions of coastal water quality has become acute. In this study, we: (i) examine the relationship between water quality, precipitation and river discharge at several locations within the Gulf of Maine, and (ii) use multiple linear regression models based on readily obtainable hydrometeorological measurements to predict water quality events at five coastal locations. Analysis of a 12 year dataset revealed that high river discharge and/or precipitation events can lead to reduced water quality; however, the use of only these two parameters to predict water quality can result in a number of errors. Analysis of a higher frequency, 2 year study using multiple linear regression models revealed that precipitation, salinity, river discharge, winds, seasonality and coastal circulation correlate with variations in water quality. Although there has been extensive development of regression models for freshwater, this is one of the first attempts to create a mechanistic model to predict water quality in coastal marine waters. Model performance is similar to that of efforts in other regions, which have incorporated models into water resource managers' decisions, indicating that the use of a mechanistic model in coastal Maine is feasible. PMID:26587258

Wastewater influences nitrogen dynamics in a coastal catchment during a prolonged drought

PubMed Central

Hoellein, Timothy J.; Mooney, Rae F.; Gardner, Wayne S.; Buskey, Edward J.

2017-01-01

Abstract Ecosystem function measurements can enhance our understanding of nitrogen (N) delivery in coastal catchments across river and estuary ecosystems. Here, we contrast patterns of N cycling and export in two rivers, one heavily influenced by wastewater treatment plants (WWTP), in a coastal catchment of south Texas. We measured N export from both rivers to the estuary over 2 yr that encompass a severe drought, along with detailed mechanisms of N cycling in river, tidal river, and two estuary sites during prolonged drought. WWTP nutrient inputs stimulated uptake of N, but denitrification resulting in permanent N removal accounted for only a small proportion of total uptake. During drought periods, WWTP N was the primary source of exported N to the estuary, minimizing the influence of episodic storm‐derived nutrients from the WWTP‐influenced river to the estuary. In the site without WWTP influence, the river exported very little N during drought, so storm‐derived nutrient pulses were important for delivering N loads to the estuary. Overall, N is processed from river to estuary, but sustained WWTP‐N loads and periodic floods alter the timing of N delivery and N processing. Research that incorporates empirical measurements of N fluxes from river to estuary can inform management needs in the face of multiple anthropogenic stressors such as demand for freshwater and eutrophication. PMID:29263559

Methane emissions from a human-dominated lowland coastal river network (Shanghai, China)

NASA Astrophysics Data System (ADS)

Wang, D.; Yu, Z.

2017-12-01

Evasion of methane (CH4) in streams and rivers play a critical role in global carbon (C) cycle, offsetting the C uptake by terrestrial ecosystems. However, little is known about CH4 emissions from lowland coastal rivers profoundly modified by anthropogenic perturbations. Here, we report results from a long-term, large-scale study of CH4 partial pressures (pCH4) and evasion rates in the Shanghai river network. The spatiotemporal variability of pCH4 was examined along a land-use gradient and the annual CH4 evasion were estimated to assess its role in regional C budget. During the study period, the median pCH4 from 87 surveyed rivers was 241 μatm. CH4 was oversaturated throughout the river network, CH4 hotpots were concentrated in the small urban rivers and highly discharge-dependent. The annual median fCH4 for each site ranged from 3.1 mg C•m-2•d-1 to 296.6 mg C•m-2•d-1. The annual CH4 evasion were 105 Gg CO2-eq•yr-1 and 96 Gg CO2-eq•yr-1 for the entire river network and the mainland rivers, respectively. Given the rapid urbanization in global coastal areas, more research is needed to quantify the role of lowland coastal rivers as a major landscape C source in global C budget.

U.S. Geological Survey (USGS), Western Region: Coastal ecosystem responses to influences from land and sea, Coastal and Ocean Science

USGS Publications Warehouse

Bodkin, James L.

2010-01-01

Sea otters and the nearshore ecosystems they inhabit-from highly urbanized California to relatively pristine Alaska-are the focus of a new multidisciplinary study by scientists with the U.S. Geological Survey (USGS) and a suite of international, academic and government collaborators. The Coastal Ecosystem Responses to Influences from Land and Sea project will investigate the many interacting variables that influence the health of coastal ecosystems along the Northeast Pacific shore. These ecosystems face unprecedented challenges, with threats arising from the adjacent oceans and lands. From the ocean, challenges include acidification, sea level rise, and warming. From the land, challenges include elevated biological, geological and chemical pollutants associated with burgeoning human populations along coastlines. The implications of these challenges for biological systems are only beginning to be explored. Comparing sea otter population status indicators from around the northeastern Pacific Rim, will begin the process of defining factors of coastal ecosystem health in this broad region.

Regional Risk Assessment for climate change impacts on coastal aquifers.

PubMed

Iyalomhe, F; Rizzi, J; Pasini, S; Torresan, S; Critto, A; Marcomini, A

2015-12-15

Coastal aquifers have been identified as particularly vulnerable to impacts on water quantity and quality due to the high density of socio-economic activities and human assets in coastal regions and to the projected rising sea levels, contributing to the process of saltwater intrusion. This paper proposes a Regional Risk Assessment (RRA) methodology integrated with a chain of numerical models to evaluate potential climate change-related impacts on coastal aquifers and linked natural and human systems (i.e., wells, river, agricultural areas, lakes, forests and semi-natural environments). The RRA methodology employs Multi Criteria Decision Analysis methods and Geographic Information Systems functionalities to integrate heterogeneous spatial data on hazard, susceptibility and risk for saltwater intrusion and groundwater level variation. The proposed approach was applied on the Esino River basin (Italy) using future climate hazard scenarios based on a chain of climate, hydrological, hydraulic and groundwater system models running at different spatial scales. Models were forced with the IPCC SRES A1B emission scenario for the period 2071-2100 over four seasons (i.e., winter, spring, summer and autumn). Results indicate that in future seasons, climate change will cause few impacts on the lower Esino River valley. Groundwater level decrease will have limited effects: agricultural areas, forests and semi-natural environments will be at risk only in a region close to the coastline which covers less than 5% of the total surface of the considered receptors; less than 3.5% of the wells will be exposed in the worst scenario. Saltwater intrusion impact in future scenarios will be restricted to a narrow region close to the coastline (only few hundred meters), and thus it is expected to have very limited effects on the Esino coastal aquifer with no consequences on the considered natural and human systems. Copyright © 2015 Elsevier B.V. All rights reserved.

Spawning and movement behavior of migratory coastal cutthroat trout on the western Copper River delta, Alaska.

Treesearch

D.A. Saiget; M.R. Sloat; Reeves. G.H.

2007-01-01

We studied the movement patterns of migratory coastal cutthroat trout Oncorhynchus clarkii clarkii in the western Copper River delta, Alaska, near the northern extent of the subspecies' distribution. Life history information for coastal cutthroat trout is scarce within this region. Movement of coastal cutthroat trout was monitored from 1994 to...

Phytosociology and succession on earthquake-uplifted coastal wetlands, Copper River Delta, Alaska.

Treesearch

T.F. Thilenius

1995-01-01

The delta formed by the Copper River stretches more than 75 kilometers along the south-central coastline of Alaska. It is the terminus of the outwash deposits from a large part of the most heavily glaciated region of North American, and all major rivers that flow into the delta carry extremely high levels of suspended sediments. Coastal wetlands extend inland for as...

Nutrient dynamics in tropical rivers, lagoons, and coastal ecosystems of eastern Hainan Island, South China Sea

NASA Astrophysics Data System (ADS)

Li, R. H.; Liu, S. M.; Li, Y. W.; Zhang, G. L.; Ren, J. L.; Zhang, J.

2014-01-01

Nutrient dynamics based on field observations made along the eastern Hainan Island during the period 2006-2009 were investigated to understand nutrient biogeochemical processes, and to provide an overview of human perturbations of coastal ecosystems in this tropical region. The rivers showed seasonal variations in nutrient concentrations, with enrichment of dissolved inorganic nitrogen and dissolved silicate, and depletion of PO43-. High riverine concentrations of nitrate mainly originated from agricultural fertilizer inputs. The DIN : PO43- ratios ranged from 37 to 1063, suggesting preferential depletion of PO43- relative to nitrogen in rivers. Chemical weathering in the drainage area might explain the high levels of dissolved silicate. Aquaculture ponds contained high concentrations of NH4+ and dissolved organic nitrogen. The particulate phosphorus concentrations in the study area were lower than those reported for estuaries worldwide. The particulate silicate levels in rivers and lagoons were lower than the global average level. Nutrient biogeochemistry in coastal areas was affected by human activities (e.g., aquaculture, agriculture), and by natural phenomena including typhoons. The nutrient concentrations in coastal waters were low because of dispersion of land-derived nutrients in the sea. Nutrient budgets were built based on a steady-state box model, which showed that riverine fluxes are magnified by estuarine processes (e.g., regeneration, desorption) in estuaries and Laoyehai Lagoon, but not in Xiaohai Lagoon. Riverine and groundwater inputs were the major sources of nutrients to Xiaohai and Laoyehai lagoons, respectively, and riverine inputs and aquaculture effluents were the major sources for the eastern coast of Hainan Island. Nutrient inputs to the coastal ecosystem increased with typhoon-induced runoff of rainwater, elucidating the important influence of typhoons on small tropical rivers.

Influence of sea-land breezes on the tempospatial distribution of atmospheric aerosols over coastal region.

PubMed

Tsai, Hsieh-Hung; Yuan, Chung-Shin; Hung, Chung-Hsuang; Lin, Chitsan; Lin, Yuan-Chung

2011-04-01

The influence of sea-land breezes (SLBs) on the spatial distribution and temporal variation of particulate matter (PM) in the atmosphere was investigated over coastal Taiwan. PM was simultaneously sampled at inland and offshore locations during three intensive sampling periods. The intensive PM sampling protocol was continuously conducted over a 48-hr period. During this time, PM2.5 and PM(2.5-10) (PM with aerodynamic diameters < 2.5 microm and between 2.5 and 10 microm, respectively) were simultaneously measured with dichotomous samplers at four sites (two inland and two offshore sites) and PM10 (PM with aerodynamic diameters < or =10 microm) was measured with beta-ray monitors at these same 4 sites and at 10 sites of the Taiwan Air Quality Monitoring Network. PM sampling on a mobile air quality monitoring boat was further conducted along the coastline to collect offshore PM using a beta-ray monitor and a dichotomous sampler. Data obtained from the inland sites (n=12) and offshore sites (n=2) were applied to plot the PM10 concentration contour using Surfer software. This study also used a three-dimensional meteorological model (Pennsylvania State University/National Center for Atmospheric Research Meteorological Model 5) and the Comprehensive Air Quality Model with Extensions to simulate surface wind fields and spatial distribution of PM10 over the coastal region during the intensive sampling periods. Spatial distribution of PM10 concentration was further used in investigating the influence of SLBs on the transport of PM10 over the coastal region. Field measurement and model simulation results showed that PM10 was transported back and forth across the coastline. In particular, a high PM10 concentration was observed at the inland sites during the day because of sea breezes, whereas a high PM10 concentration was detected offshore at night because of land breezes. This study revealed that the accumulation of PM in the near-ocean region because of SLBs influenced the

Carbon dioxide and methane dynamics in a human-dominated lowland coastal river network (Shanghai, China)

NASA Astrophysics Data System (ADS)

Yu, Zhongjie; Wang, Dongqi; Li, Yangjie; Deng, Huanguang; Hu, Beibei; Ye, Mingwu; Zhou, Xuhui; Da, Liangjun; Chen, Zhenlou; Xu, Shiyuan

2017-07-01

Evasion of carbon dioxide (CO2) and methane (CH4) in streams and rivers play a critical role in global carbon (C) cycle, offsetting the C uptake by terrestrial ecosystems. However, little is known about CO2 and CH4 dynamics in lowland coastal rivers profoundly modified by anthropogenic perturbations. Here we report results from a long-term, large-scale study of CO2 and CH4 partial pressures (pCO2 and pCH4) and evasion rates in the Shanghai river network. The spatiotemporal variabilities of pCO2 and pCH4 were examined along a land use gradient, and the annual CO2 and CH4 evasion were estimated to assess its role in regional C budget. During the study period (August 2009 to October 2011), the overall mean pCO2 and median pCH4 from 87 surveyed rivers were 5846 ± 2773 μatm and 241 μatm, respectively. Internal metabolic CO2 production and dissolved inorganic carbon input via upstream runoff were the major sources sustaining the widespread CO2 supersaturation, coupling pCO2 to biogeochemical and hydrological controls, respectively. While CH4 was oversaturated throughout the river network, CH4 hot spots were concentrated in the small urban rivers and highly discharge-dependent. The Shanghai river network played a disproportionately important role in regional C budget, offsetting up to 40% of the regional terrestrial net ecosystem production and 10% of net C uptake in the river-dominated East China Sea fueled by anthropogenic nutrient input. Given the rapid urbanization in global coastal areas, more research is needed to quantify the role of lowland coastal rivers as a major landscape C source in global C budget.

Tracing Mississippi River influences in estuarine food webs of coastal Louisiana.

PubMed

Wissel, Björn; Fry, Brian

2005-08-01

The Breton Sound estuary in southern Louisiana receives large amounts of Mississippi River water via a controlled diversion structure at the upstream end of the estuary. We used stable isotopes to trace spatial and seasonal responses of the downstream food web to winter and spring introductions of river water. Analysis of delta13C, delta15N, and delta34S in the common local consumers such as grass shrimp (Palaemonetes sp.), barnacles (Balanus sp.), and small plankton-feeding fish (bay anchovies, Anchoa mitchilli) showed that the diversion was associated with two of the five major source regimes that were supporting food webs: a river regime near the diversion and a river-influenced productive marsh regime farther away from the diversion. Mixing models identified a third river-influenced source regime at the marine end of the estuary where major natural discharge from the Bird's Foot Delta wraps around into estuarine waters. The remaining two source regimes represented typical estuarine conditions: local freshwater sources especially from precipitation and a brackish source regime representing higher salinity marine influences. Overall, the Mississippi River diversion accounted for 75% of food web support in the upper estuary and 25% in the middle estuary, with influence strongest along known flow pathways and closest to the diversion. Isotopes also traced seasonal changes in river contributions, and indicated increased plant community productivity along the major flow path of diversion water. In the Breton Sound estuary, bottom-up forcing of food webs is strongly linked to river introductions and discharge, occurring in spatial and temporal patterns predictable from known river input regimes and known hydrologic circulation patterns.

Impact of Ibrahim River on the spatial variation of coastal marine sediment characteristics

NASA Astrophysics Data System (ADS)

Ghsoub, Myriam; Fakhri, Milad; Courp, Thierry; Khalaf, Gaby; Buscail, Roselyne; Ludwig, Wolfgang

2017-04-01

governed by a high hydrodynamism. On the other hand, low abundance characterizes these coastal areas subjected to unstable environmental conditions, coupled with a low availability of food resources preventing the establishment of stable benthic communities. The obtained results highlight the influence of the Ibrahim River flow on its coastal marine area subjected to high hydrodynamics conditions. According to this preliminary study, Ibrahim River coastal marine area was found to be less subjected to sources of contamination when comparing its sediment's chemical and biochemical contents to those from other coastal marine regions.

Nomenclature of regional hydrogeologic units of the Southeastern Coastal Plain aquifer system

USGS Publications Warehouse

Miller, J.A.; Renken, R.A.

1988-01-01

Clastic sediments of the Southeastern Coastal Plain aquifer system can be divided into four regional aquifers separated by three regional confining units. The four regional aquifers have been named for major rivers that cut across their outcrop areas and expose the aquifer materials. From youngest to oldest, the aquifers are called the Chickasawhay River, Pearl River, Chattahoochee River, and Black Warrior River aquifers, and the regional confining units separating them are given the same name as the aquifer they overlie. Most of the regional hydrogeologic units are subdivided within each of the four States that comprise the study area. Correlation of regional units is good with hydrogeologic units delineated by a similar regional study to the west and southwest. Because of complexity created by a major geologic structure to the northeast of the study area and dramatic facies change from clastic to carbonate strata to the southeast, correlation of regional hydrogeologic units is poor in these directions. (Author 's abstract)

Mapping CDOM Concentration in Waters Influenced by the Mississippi River Plume

NASA Technical Reports Server (NTRS)

Miller, Richard L.; DelCastillo, Carlos E.; Powell, Rodney T.; DSa, Eurico; Spiering, Bruce

2002-01-01

Colored dissolved organic matter (CDOM) is often an important component of the organic carbon pool in river-dominated coastal margins. CDOM directly influences remote sensing applications through its strong absorption in the UV and blue regions of the spectrum. This effect can complicate the use of chlorophyll a retrieval algorithms and phytoplankton production models that are based on remotely sensed ocean color. As freshwater input is the principle source of CDOM in coastal margins, CDOM distribution can often be described by conservative mixing with open ocean waters and may serve as an optical tracer of riverine water. Hence, there is considerable interest in the ability to accurately measure and map CDOM concentrations as well as understand the processes that govern the optical properties and distribution of CDOM in coastal environments. We are examining CDOM dynamics in the waters influenced by the Mississippi River plume. Our program incorporates discrete samples, flow-through measurements, and remote sensing. CDOM absorption spectra of discrete samples are measured at sea using a portable, multiple pathlength waveguide system. A SAFire multi-spectral fluorescence meter provides spectral characterization of CDOM (fluorescence and absorption) using a ship flow-through system for continuous surface mapping. In situ reflectance spectra are obtained by a hand held spectroradiometer. Remotely sensed images are obtained from the SeaWiFS and CRIS (Coastal Research Imaging Spectrometer) instruments. We describe here the instruments used, sampling protocols employed, and the relationships derived between in situ measurements and remotely sensed data for this optically complex environment.

Apparent Optical Properties in Waters Influenced by the Mississippi River

NASA Technical Reports Server (NTRS)

D'Sa, E.; Miller, R. L.; McKee, B. A.; Trzaska, R.

2002-01-01

In-water downwelling irradiance (E(sub d)) and upwelling radiance (L(sub u)) were measured in coastal waters influenced by the Mississippi River at wavelengths corresponding to SeaWiFS spectral bands in April of 2000. Results of derived apparent optical properties (AOP's) such as spectral diffise attenuation coefficient for downwelling irradiance (K(sub d)) suggest that they are mainly influenced by phytoplankton chlorophyll. Large variations in chlorophyll concentrations (0.2 to greater than 10 mg per cubic meters) correspond to variations in K(sub d) at 443 nm ranging from about 0.1 to greater than 1.5 per meter. Attenuation values at 443 nm generally peaked (or were minimal at 555 nm) at depths where chlorophyll concentrations were high. Above water remote sensing reflectance R(sub rs) (443) derived from E(sub d) and L(sub u) shows good agreement to surface chlorophyll. Ratios of remote sensing reflectance, R(sub rs)(443/R(sub rs)(555)versus chlorophyll suggests a potential for obtaining a suitable bio-optical algorithm for the region influenced by the Mississippi River.

Influence of multiple dam passage on survival of juvenile Chinook salmon in the Columbia River estuary and coastal ocean

PubMed Central

Rechisky, Erin L.; Welch, David W.; Porter, Aswea D.; Jacobs-Scott, Melinda C.; Winchell, Paul M.

2013-01-01

Multiple dam passage during seaward migration is thought to reduce the subsequent survival of Snake River Chinook salmon. This hypothesis developed because juvenile Chinook salmon from the Snake River, the Columbia River’s largest tributary, migrate >700 km through eight hydropower dams and have lower adult return rates than downstream populations that migrate through only 3 or 4 dams. Using a large-scale telemetry array, we tested whether survival of hatchery-reared juvenile Snake River spring Chinook salmon is reduced in the estuary and coastal ocean relative to a downstream, hatchery-reared population from the Yakima River. During the initial 750-km, 1-mo-long migration through the estuary and coastal ocean, we found no evidence of differential survival; therefore, poorer adult returns of Snake River Chinook may develop far from the Columbia River. Thus, hydrosystem mitigation efforts may be ineffective if differential mortality rates develop in the North Pacific Ocean for reasons unrelated to dam passage. PMID:23576733

Large-scale dam removal on the Elwha River, Washington, USA: coastal geomorphic change

USGS Publications Warehouse

Gelfenbaum, Guy R.; Stevens, Andrew W.; Miller, Ian M.; Warrick, Jonathan A.; Ogston, Andrea S.; Eidam, Emily

2015-01-01

Two dams on the Elwha River, Washington State, USA trapped over 20 million m3 of mud, sand, and gravel since 1927, reducing downstream sediment fluxes and contributing to erosion of the river's coastal delta. The removal of the Elwha and Glines Canyon dams, initiated in September 2011, induced massive increases in river sediment supply and provided an unprecedented opportunity to examine the geomorphic response of a coastal delta to these increases. Detailed measurements of beach topography and nearshore bathymetry show that ~ 2.5 million m3 of sediment was deposited during the first two years of dam removal, which is ~ 100 times greater than deposition rates measured prior to dam removal. The majority of the deposit was located in the intertidal and shallow subtidal region immediately offshore of the river mouth and was composed of sand and gravel. Additional areas of deposition include a secondary sandy deposit to the east of the river mouth and a muddy deposit west of the mouth. A comparison with fluvial sediment fluxes suggests that ~ 70% of the sand and gravel and ~ 6% of the mud supplied by the river was found in the survey area (within about 2 km of the mouth). A hydrodynamic and sediment transport model, validated with in-situ measurements, shows that tidal currents interacting with the larger relict submarine delta help disperse fine sediment large distances east and west of the river mouth. The model also suggests that waves and currents erode the primary deposit located near the river mouth and transport sandy sediment eastward to form the secondary deposit. Though most of the substrate of the larger relict submarine delta was unchanged during the first two years of dam removal, portions of the seafloor close to the river mouth became finer, modifying habitats for biological communities. These results show that river restoration, like natural changes in river sediment supply, can result in rapid and substantial coastal geomorphological

Hydrological Controls on Dissolved Organic Matter Quality and Export in a Coastal River System in Southeastern USA

NASA Astrophysics Data System (ADS)

Bhattacharya, R.; Osburn, C. L.

2017-12-01

Dissolved organic matter (DOM) exported from river catchments can influence the biogeochemical processes in coastal environments with implications for water quality and carbon budget. High flow conditions are responsible for most DOM export ("pulses") from watersheds, and these events reduce DOM transformation and production by "shunting" DOM from river networks into coastal waters: the Pulse-Shunt Concept (PSC). Subsequently, the source and quality of DOM is also expected to change as a function of river flow. Here, we used stream dissolved organic carbon concentrations ([DOC]) along with DOM optical properties, such as absorbance at 350 nm (a350) and fluorescence excitation and emission matrices modeled by parallel factor analysis (PARAFAC), to characterize DOM source, quality and fluxes under variable flow conditions for the Neuse River, a coastal river system in the southeastern US. Observations were made at a flow gauged station above head of tide periodically between Aug 2011 and Feb 2013, which captured low flow periods in summer and several high flow events including Hurricane Irene. [DOC] and a350 were correlated and varied positively with river flow, implying that a large portion of the DOM was colored, humic and flow-mobilized. During high flow conditions, PARAFAC results demonstrated the higher influx of terrestrial humic DOM, and lower in-stream phytoplankton production or microbial degradation. However, during low flow, DOM transformation and production increased in response to higher residence times and elevated productivity. Further, 70% of the DOC was exported by above average flows, where 3-4 fold increases in DOC fluxes were observed during episodic events, consistent with PSC. These results imply that storms dramatically affects DOM export to coastal waters, whereby high river flow caused by episodic events primarily shunt terrestrial DOM to coastal waters, whereas low flow promotes in-stream DOM transformation and amendment with microbial DOM.

Geomorphic and human influence on large-scale coastal change

USGS Publications Warehouse

Hapke, Cheryl J.; Kratzmann, Meredith G.; Himmelstoss, Emily A.

2013-01-01

An increasing need exists for regional-scale measurements of shoreline change to aid in management and planning decisions over a broad portion of the coast and to inform assessments of coastal vulnerabilities and hazards. A recent dataset of regional shoreline change, covering a large portion of the U.S. East coast (New England and Mid-Atlantic), provides rates of shoreline change over historical (~ 150 years) and recent (25–30 years) time periods making it ideal for a broad assessment of the regional variation of shoreline change, and the natural and human-induced influences on coastal behavior. The variable coastal landforms of the region provide an opportunity to investigate how specific geomorphic landforms relate to the spatial variability of shoreline change. In addition to natural influences on the rates of change, we examine the effects that development and human modifications to the coastline have on the measurements of regional shoreline change.Regional variation in the rates of shoreline change is a function of the dominant type and distribution of coastal landform as well as the relative amount of human development. Our results indicate that geomorphology has measurable influence on shoreline change rates. Anthropogenic impacts are found to be greater along the more densely developed and modified portion of the coast where jetties at engineered inlets impound large volumes of sediment resulting in extreme but discrete progradation updrift of jetties. This produces a shift in averaged values of rates that may mask the natural long-term record. Additionally, a strong correlation is found to exist between rates of shoreline change and relative level of human development. Using a geomorphic characterization of the types of coastal landform as a guide for expected relative rates of change, we found that the shoreline appears to be changing naturally only along sparsely developed coasts. Even modest amounts of development influence the rates of change

PAHs and PCBs deposited in surficial sediments along a rural to urban transect in a mid-Atlantic coastal river basin (USA).

PubMed

Foster, Gregory D; Cui, Vickie

2008-10-01

PAHs and PCBs were measured in river sediments along a 226 km longitudinal transect that spanned rural to urban land use settings through Valley and Ridge, Piedmont Plateau and Coastal Plain physiographic provinces in the Potomac River basin (mid-Atlantic USA). A gradient in PAH concentrations was found in river bed sediments along the upstream transect in the Potomac and Shenandoah Rivers that correlated with population densities in the nearby sub-basins. Sediment PAH concentrations halved per each approximately 40 km of transect distance upstream (i.e., the half-concentration distance) from the urban center (Washington, DC) of the Potomac River basin in direct proportion to population density. The PAH molecular composition was consistent across all geologic provinces, revealing a dominant pyrogenic source. Fluoranthene to perylene ratios served as useful markers for urban inputs, with a ratio > 2.4 observed in sediments near urban structures such as roadways, bridges and sewer outfalls. PCBs in sediments were not well correlated with population densities along the river basin transect, but the highest concentrations were found in the urban Coastal Plain region near Washington, DC and in the Shenandoah River near a known industrial Superfund site. PAHs were moderately correlated with sediment total organic carbon (TOC) in the Shenandoah River and Coastal Plain Potomac River regions, but TOC was poorly correlated with PCB concentrations throughout the entire basin. Although both PAHs and PCBs are widely recognized as urban-derived contaminants, their concentration profiles and geochemistry in river sediments were uniquely different throughout the upper Potomac River basin.

Factors influencing the spreading of a low-discharge river plume

NASA Astrophysics Data System (ADS)

Mestres, M.; Sierra, J. P.; Sánchez-Arcilla, A.

2007-09-01

Coastal plumes resulting from the continuous discharge of brackish or fresh river water are common features of continental and shelf seas. They are important for several aspects of the coastal environment, and can influence the local socio-economy to some degree. It is known from many studies that the evolution of plumes depends on various factors, such as the local bathymetry, hydrodynamics and meteorological conditions; most of these works; however, have focused on medium to large-scale rivers, while the smaller-scale discharges commonly found in the microtidal environments of the Mediterranean Sea have been less studied. This paper is centred on the behaviour of a freshwater plume arising from one of such outflows, in terms of both the physical configuration of the waterbody and the characteristics of the main driving mechanisms (discharge rate and wind stress). The modelled cases correspond to an open shallow bay, limited at one end by a large headland, and into which a typical Mediterranean waterway discharges. This particular setup is representative of a number of different bays existing on the Eastern Spanish coast. The numerical results highlight the large influence of the bay's topography on the river plume's extension and inner structure.

Seasonal and inter-annual dynamics of suspended sediment at the mouth of the Amazon river: The role of continental and oceanic forcing, and implications for coastal geomorphology and mud bank formation

NASA Astrophysics Data System (ADS)

Gensac, Erwan; Martinez, Jean-Michel; Vantrepotte, Vincent; Anthony, Edward J.

2016-04-01

Fine-grained sediments supplied to the Ocean by the Amazon River and their transport under the influence of continental and oceanic forcing drives the geomorphic change along the 1500 km-long coast northward to the Orinoco River delta. The aim of this study is to give an encompassing view of the sediment dynamics in the shallow coastal waters from the Amazon River mouth to the Capes region (northern part of the Amapa region of Brazil and eastern part of French Guiana), where large mud banks are formed. Mud banks are the overarching features in the dynamics of the Amazon-Orinoco coast. They start migrating northward in the Capes region. Suspended Particulate Matter (SPM) concentrations were calculated from satellite products (MODIS Aqua and Terra) acquired over the period 2000-2013. The Census-X11 decomposition method used to discriminate short-term, seasonal and long-term time components of the SPM variability has rendered possible a robust analysis of the impact of continental and oceanic forcing. Continental forcing agents considered are the Amazon River water discharge, SPM concentration and sediment discharge. Oceanic forcing comprises modelled data of wind speed and direction, wave height and direction, and currents. A 150 km-long area of accretion is detected at Cabo Norte that may be linked with a reported increase in the river's sediment discharge concurrent with the satellite data study period. We also assess the rate of mud bank migration north of Cabo Norte, and highlight its variability. Although we confirm a 2 km y-1 migration rate, in agreement with other authors, we show that this velocity may be up to 5 km y-1 along the Cabo Orange region, and we highlight the effect of water discharge by major rivers debouching on this coastal mud belt in modulating such rates. Finally, we propose a refined sediment transport pattern map of the region based on our results and of previous studies in the area such as the AMASSEDS programme, and discuss the

Fluvial terraces of the Little River Valley, Atlantic Coastal Plain, North Carolina

Treesearch

Bradley Suther; David Leigh; George Brook

2011-01-01

An optically-stimulated luminescence (OSL) and radiocarbon chronology is presented for fluvial terraces of the Little River, a tributary to the Cape Fear River that drains 880 km2 of the Sandhills Province of the upper Coastal Plain of North Carolina. This study differs from previous work in the southeastern Atlantic Coastal Plain in that numerical age estimates are...

Research on vulnerability assessments of the Huanghe (Yellow River) delta

NASA Astrophysics Data System (ADS)

qiao, shuqing; shi, xuefa

2014-05-01

Coastal zone located at the juncture of the sea, river and land, and under the influence of both land and ocean (including atmosphere), especially the sea-level rise and human activities, are vulnerable to environment and ecology. At highest risk are coastal zone of South, Southeast and East Asia with dense populations, low elevations and inadequate adaptive capacity. In China, more than 40% of the population live on the 15% of the land in coastal area and more than 70% cities located around the coastal area. The Chinese coastal region, especially river delta area has been experienced erosion, seawater intrusion and decrease in biodiversity under the combined influence of sea-level rise, tectonic subsidence and flooding. Furthermore, some kinds of human activity, such as land use, building, dam construction, reclamation from the sea and waste dumping strengthen the vulnerability of environment and ecosystem in coastal region. The coastal hazards (e.g. coastal erosion, seawater intrusion, land subsidence) and vulnerability of the Huanghe (Yelllow River) delta area are studied during the past several years. A systematic coastal assessment index is built and an evaluation model is developed using the development platform of Visual studio.Net 2005. The assessment index system includes two parts, inherent (sea level rise rate, elevation, morphology, water and sediment discharge, mean tidal range, mean wave height etc) and specific vulnerability index (population density, GDP, land utilization, protection structures etc). The assessment index are determined the weight using Analytic hierarchy process (AHP) method. Based on the research results, we better understand the current status and future change of coastal vulnerability and hazards, discuss the impact of the natural possess and human activities. Furthermore, we provide defending strategies for coastal zone vulnerability and typical coastal hazards.

Bio-Optical Properties and Ocean Color Algorithms for Coastal Waters Influenced by the Mississippi River During a Cold Front Passage

NASA Technical Reports Server (NTRS)

D'Sa Eurico J.; Miller, Richard L.; DelCastillo, Carlos

2006-01-01

During the passage of a cold front in March 2002, bio-optical properties examined in coastal waters impacted by the Mississippi River indicated westward advective flows and increasing river discharge containing a larger nonalgal particle content contributed significantly to surface optical variability. A comparison of seasonal data from three cruises indicated spectral models of absorption and scattering to be generally consistent with other coastal environments, while their parameterization in terms of chlorophyll a concentration (Chl) showed seasonal variability. The exponential slope of the colored dissolved organic matter (CDOM) averaged 0.0161 plus or minus 0.00054 per nanometer, and for nonalgal absorption it averaged 0.011 per nanometer with deviations from general trends observed due to anomalous water properties. Although the phytoplankton specific absorption coefficients varied over a wide range (0.02 to 0.1 square meters (mg Chl) sup -1)) being higher in offshore surface waters, values of phytoplankton absorption spectra at the SeaWiFS wavebands were highly correlated to modeled values. The normalized scattering spectral shapes and the mean spectrum were in agreement to observations in other coastal waters, while the backscattering ratios were on average lower in phytoplankton dominated surface waters (0.0101 plus or minus 0.002) and higher in near-bottom waters (0.0191 plus or minus 0.0045) with low Chl. Average percent differences in remote sensing reflectance R (sub rs) derived form modeled and in-eater radiometric measurements were highest in the blue wavebands (52%) and at sampling stations with a ore stratified water column. Estimates of Chl and CDOM absorption derived from SeaWiFS images generated using regional empirical algorithms were highly correlated to in situ data.

Coastal environmental monitoring using remotely sensed data and GIS techniques in the Modern Yellow River delta, China.

PubMed

Zhang, Yang

2011-08-01

On the basis of remote sensing and GIS techniques, the Landsat data obtained in 1987, 1996, and 2008 were used to examine coastline changes in the Modern Yellow River (MYR) delta in China. The coastal land lost and gained illustrations were derived, the rates of coastal change were estimated, and the coastal parts that experienced severe changes were identified. The results revealed that the accretion rates in the MYR delta coast has been decelerating while the accretion effect remained. Taken the artificial coast from the south of ShenXianGou (SXG) to Gudong Oil Field (GOF) as the landmark, the coast in the south of the landmark showed an accretion pattern, while the coast in the west of the landmark showed an erosion pattern. Wherein, the coast from Chao River Estuary (CRE) to Zhuang 106 (Z106) showed an erosion pattern with the transition from erosion to accretion and the accelerated rates from east to west. The coast from Z106 to the south border of GOF also showed erosion pattern but significant differences existed among the internal coastal parts. The coast from the south border of GOF to XiaoDao River Estuary (XDRE) showed a pattern from rapid accretion to dynamic balance of accretion/erosion, and the trend towards erosion. The coast from XDRE to XiaoQing River Estuary (XQRE) showed slow accretion pattern. Human activities have heavily influenced the natural evolution of the MYR delta coast.

Organic Biomarkers Along the River-Coastal Ocean Continuum: Human Activities and their Influence on Carbon Delivery (Invited)

NASA Astrophysics Data System (ADS)

Canuel, E. A.; Pondell, C. R.

2010-12-01

Human-induced changes in land-use and water diversion have modified the connectivity between upstream sources of organic carbon (OC) and their delivery to the coastal ocean. This connectivity will likely be further modified by climate variability. Biomarkers provide useful tools for tracing the delivery of terrigeous OC from the watershed to downstream environments. In this study, we used the Sacramento-San Joaquin River Delta CA and its watershed as a model system for understanding how human activities influenced delivery and composition of organic carbon (OC) over the past 50-60 years. Biomarker records, stable isotopes, and radiocarbon ages of bulk carbon signatures preserved in sediment cores were used to examine human impacts on carbon sources, amounts, and ages. Our presentation will discuss: 1) alterations in the sources of carbon preserved in the historical sedimentary record; and 2) environmental implications of such changes.

Study on water quality around mangrove ecosystem for coastal rehabilitation

NASA Astrophysics Data System (ADS)

Guntur, G.; Sambah, A. B.; Arisandi, D. M.; Jauhari, A.; Jaziri, A. A.

2018-01-01

Coastal ecosystems are vulnerable to environmental degradation including the declining water quality in the coastal environment due to the influence of human activities where the river becomes one of the input channels. Some areas in the coastal regions of East Java directly facing the Madura Strait indicate having experienced the environmental degradation, especially regarding the water quality. This research was conducted in the coastal area of Probolinggo Regency, East Java, aiming to analyze the water quality as the basis for coastal rehabilitation planning. This study was carried out using survey and observation methods. Water quality measurement results were analyzed conforming to predetermined quality standards. The coastal area rehabilitation planning as a means to restore the degraded water quality parameters is presumably implemented through mangrove planting. Thus, the mangrove mapping was also devised in this research. Based on 40 sampling points, the results illustrate that according to the quality standard, the water quality in the study area is likely to be deteriorated. On account of the mapping analysis of mangrove distribution in the study area, the rehabilitation of the coastal zone can be done through planning the mangrove forest plantation. The recommended coastal area maintenance is a periodic water quality observation planning in the river region which is divided into three zones to monitor the impact of fluctuating changes in land use or human activities on the coastal water quality.

Progress and limitations on quantifying nutrient and carbon loading to coastal waters

NASA Astrophysics Data System (ADS)

Stets, E.; Oelsner, G. P.; Stackpoole, S. M.

2017-12-01

Riverine export of nutrients and carbon to estuarine and coastal waters are important determinants of coastal ecosystem health and provide necessary insight into global biogeochemical cycles. Quantification of coastal solute loads typically relies upon modeling based on observations of concentration and discharge from selected rivers draining to the coast. Most large-scale river export models require unidirectional flow and thus are referenced to monitoring locations at the head of tide, which can be located far inland. As a result, the contributions of the coastal plain, tidal wetlands, and concentrated coastal development are often poorly represented in regional and continental-scale estimates of solute delivery to coastal waters. However, site-specific studies have found that these areas are disproportionately active in terms of nutrient and carbon export. Modeling efforts to upscale fluxes from these areas, while not common, also suggest an outsized importance to coastal flux estimates. This presentation will focus on illustrating how the problem of under-representation of near-shore environments impacts large-scale coastal flux estimates in the context of recent regional and continental-scale assessments. Alternate approaches to capturing the influence of the near-coastal terrestrial inputs including recent data aggregation efforts and modeling approaches will be discussed.

Groundwater Modeling in Coastal Arid Regions Under the Influence of Marine Saltwater Intrusion

NASA Astrophysics Data System (ADS)

Walther, Marc; Kolditz, Olaf; Grundmann, Jens; Liedl, Rudolf

2010-05-01

The optimization of an aquifer's "safe yield", especially within agriculturally used regions, is one of the fundamental tasks for nowaday's groundwater management. Due to the limited water ressources in arid regions, conflict of interests arise that need to be evaluated using scenario analysis and multicriterial optimization approaches. In the context of the government-financed research project "International Water Research Alliance Saxony" (IWAS), the groundwater quality for near-coastal, agriculturally used areas is investigated under the influence of marine saltwater intrusion. Within the near-coastal areas of the study region, i.e. the Batinah plains of Northern Oman, an increasing agricultural development could be observed during the recent decades. Simultaneously, a constant lowering of the groundwater table was registered, which is primarily due to the uncontrolled and unsupervised mining of the aquifers for the local agricultural irrigation. Intensively decreased groundwater levels, however, cause an inversion of the hydraulic gradient which is naturally aligned towards the coast. This, in turn,leads to an intrusion of marine saltwater flowing inland, endangering the productivity of farms near the coast. Utilizing the modeling software package OpenGeoSys, which has been developed and constantly enhanced by the Department of Environmental Informatics at the Helmholtz Centre for Environmental Research Leipzig (UFZ; Kolditz et al., 2008), a three-dimensional, density-dependent model including groundwater flow and mass transport is currently being built up. The model, comprehending three selected coastal wadis of interest, shall be used to investigate different management scenarios. The main focus of the groundwater modelling are the optimization of well positions and pumping schemes as well as the coupling with a surface runoff model, which is also used for the determination of the groundwater recharge due to wadi runoff downstream of retention dams. Based on

Critical coastal issues of Sagar Island, east coast of India.

PubMed

Gopinath, Girish

2010-01-01

Sagar Island, situated in the east coast of India and one of the biggest deltas in Sundarban group, faces coastal erosion and degradation of coastal vegetation and various natural hazards. Erosion is mainly due to clay mining, wave activities, and the impact of river and tidal currents of Muri Ganga and Hugly Rivers. Further, the coastal zone of Sagar Island faces increasingly severe problems of rapidly growing human population, deteriorating environmental quality, and loss of critical habitats. Sagar Island has been victimized several times by tropical cyclones and influenced daily by tidal fluctuations. The island needs immediate attention on the coastal zone in order to protect the shoreline and ecosystem. The capability of satellite remote sensing to provide synoptic, repetitive, and multispectral data has proved to be very useful in the inventory and monitoring of critical coastal issues. Sagar Island and its environs are subjected to both natural and anthropogenic activities that continuously modify the region.

The role of extreme floods in estuary-coastal behaviour: contrasts between river- and tide-dominated microtidal estuaries

NASA Astrophysics Data System (ADS)

Cooper, J. A. G.

2002-06-01

Contrasting modes of sedimentation and facies arrangement in tide- and river-dominated microtidal estuaries arise from the degree to which river or tidal discharge and sediment supply influences an estuary. A distinct facies gradation exists in tide-dominated systems from sandy, barrier/tidal delta-associated environments at the coast through deep mud-dominated middle reaches to fluvial sediment in the upper reaches. In river-dominated systems, fluvial sediment extends to the barrier and flood-tidal deltas are poorly developed or absent from the estuary. A number of independent observations during extreme floods on the South African coast indicate that these types of estuary respond differently to extreme river floods and that the mode of response corresponds to estuary type. Tide-dominated systems exhibit preferential erosion of noncohesive barrier and tidal delta sediments during river floods while the middle reaches remain little modified. River-dominated systems experience consistent erosion throughout their channel length during extreme floods. The increased cohesion of riverine sediments and stabilisation of bars by vegetation in river-dominated channels means that higher magnitude floods are necessary to effect significant morphological change. Barrier erosion, including the tidal delta, results in deposition of an ephemeral delta composed almost entirely of sands from these deposits in tide-dominated estuaries. In river-dominated systems, eroded channel sediments and material from the river catchment may augment barrier sediments in the ephemeral delta deposit. Post-flood, wave-reworking of ephemeral delta sediments acts to restore barriers to pre-flood morphology within a few years; however, in river-dominated systems, the additional sediment volume may produce significant coastal progradation that requires several years or decades to redistribute. These different modes of flood response mediated by the nature of the estuary have implications for coastal

Agrochemical loading in drains and rivers and its connection with pollution in coastal lagoons of the Mexican Pacific.

PubMed

Arellano-Aguilar, Omar; Betancourt-Lozano, Miguel; Aguilar-Zárate, Gabriela; Ponce de Leon-Hill, Claudia

2017-06-01

The state of Sinaloa in Mexico is an industrialized agricultural region with a documented pesticide usage of 700 t year -1 ; which at least 17 of the pesticides are classified as moderately to highly toxic. Pollutants in the water column of rivers and drains are of great concern because the water flows into coastal lagoons and nearshore waters and thereby affects aquatic organisms. This study was done in four municipalities in the state of Sinaloa that produce food intensively. To investigate the link between pollution in the lagoons and their proximity to agricultural sites, water was sampled in three coastal lagoons and in the rivers and drains that flow into them. Seawater from the Gulf of California, 10 km from the coast, was also analyzed. Concentrations of nutrients, organochlorines, and organophosphorus pesticides were determined. Nutrient determination showed an unhealthy environment with N/P ratios of <16, thus favoring nitrogen-fixing cyanobacteria. The organochlorine pesticides showed a clear accumulation in the coastal lagoons from the drains and rivers, with ΣHCH showing the highest concentrations. In the southern part of the region studied, pollution of the coastal lagoon of Pabellones could be traced mainly to the drains from the agricultural sites. Accumulation of OC pesticides was also observed in the Gulf of California. Tests for 22 organophosphates revealed only five (diazinon, disulfoton, methyl parathion, chlorpyrifos, and mevinphos); diazinon was detected at all the sites, although methyl parathion was present at some sites at concentrations one order of magnitude higher than diazinon.

Flooding Mitigation of seawalls and river embankments to storm surges in the coastal areas of Guangdong Province, China

NASA Astrophysics Data System (ADS)

Wang, Xianwei; Wang, Xina

2017-04-01

The coastal areas of Guangdong Province, China are susceptible to the destructions of tropical cyclones and storm surges. The projected global warming, coastal subsidence and sea level rise together will bring about greater flooding risk to these areas. The seawall and river embankment have played a significant role in mitigating and preventing the coastal low-land areas from the impairment of storm surges flooding and wave runup. However, few risk assessment studies in this region consider the existence of seawall and river embankment and often overestimate the risk and potential economic loss and population affected due to storm surge flooding. This study utilizes a hydraulic model to simulate the overtop flooding and compare those without seawall and river embankment using several specific tropic storm events and extreme events of tropic storm surges in different return periods of 2, 10, 20, 50, 100, 200 and 500 years. Most seawalls are 4 or 5 meters plus another meter of wave levee above the local mean sea level. The river embankments are usually 4 or 5 meter higher than the local mean sea level as well and decrease from the outer estuary to the inner riverine. The modeling results considering seawall and river embankments and from real storm surges are in agreement with on-site survey and observations, while those without infusing seawall and river embankments overestimate the inundation condition and economic loss. Modeling results demonstrate that seawall and river embankment greatly reduce the flooding risk and prevent the low-land area from inundation for most tropic storm events, e.g., for extreme events less than 20 to 50 years, in the coastal areas of Guangdong Province, China. However, the seawall and river embankment may also cause catastrophic disasters once there is an engineering failure of seawalls and river embankment, especially once encountering with an extreme typhoon event, e.g., the 1969 super typhoon Viola in Shantou China and the 2005

A methodological approach to rapid assessment of a river flood in coastal waters. First test in the Po River delta

NASA Astrophysics Data System (ADS)

Campanelli, Alessandra; Bellafiore, Debora; Bensi, Manuel; Bignami, Francesco; Caccamo, Giuseppe; Celussi, Mauro; Del Negro, Paola; Ferrarin, Christian; Marini, Mauro; Paschini, Elio; Zaggia, Luca

2014-05-01

) and high CDOM (20-22 ppb) values. These parameters showed a strong gradient from coast to offshore and from surface to the bottom. The fluorescence values were more variable since the phytoplankton growth is not quickly correlated with the load of riverborne materials. The higher fluorescence values (1.8-2 µg l-1) were, in fact, detected offshore and at bottom. A good correlation between salinity versus CDOM (R2=0.84) and salinity versus Spectral slope (SCDOM275-295; R2=0.86) were found. These features reveal the role of CDOM as tracer of the freshwater inputs. Chemical analysis of waters affected by the river plume display high concentration of organic carbon (100-160 µmol l-1) and nutrients strenghtening this zone as one of the most eutrophic area of the Mediterranean Sea (Campanelli et al. 2011, Marini et al. 2008). The synergy of actions applied in the test has proved useful to better analyze the variability of coastal water characteristics after a river flood. However, a similar methodological approach could be reasonably applied to the rapid assessment of different events (i.e. harmful phytoplankton growth, chemical spills) which can occur in the area or in areas with similar features. The definition of methodologies for rapid assessment of marine processes can be a useful tool for the future integrated management of coastal zone. References Campanelli, A., F. Grilli, E. Paschini, M. Marini, 2011. The influence of an exceptional Po River flood on the physical and chemical oceanographic properties of the Adriatic Sea. Dynam. Atmos. Oceans, 52: 284-297. Marini, M., B.H. Jones, A. Campanelli, F. Grilli & C.M. Lee. 2008. Seasonal variability and Po River plume influence on biochemical properties along western Adriatic coast. J. Geophys. Res., 113: C05S90, doi:10.1029/2007JC004370.

Evolution of the Lian River coastal basin in response to Quaternary marine transgressions in Southeast China

NASA Astrophysics Data System (ADS)

Tang, Yongjie; Zheng, Zhuo; Chen, Cong; Wang, Mengyuan; Chen, Bishan

2018-04-01

The coastal basin deposit in the Lian River plain is among the thickest Quaternary sequences along the southeastern coast of China. The clastic sediment accumulated in a variety of environmental settings including fluvial, channel, estuary/coastal and marine conditions. Detailed investigation of lithofacies, grain-size distributions, magnetic susceptibility, microfossils and chronology of marine core CN01, compared with regional cores, and combined with offshore seismic reflection profiles, has allowed us to correlate the spatial stratigraphy in the inner and outer plain and the seismic units. Grain size distribution analysis of core CN-01 through compositional data analysis and multivariate statistics were applied to clastic sedimentary facies and sedimentary cycles. Results show that these methods are able to derive a robust proxy information for the depositional environment of the Lian River plain. We have also been able to reconstruct deltaic evolution in response to marine transgressions. On the basis of dating results and chronostratigraphy, the estimated age of the onset of deposition in the Lian River coastal plain was more than 260 kyr BP. Three transgressive sedimentary cycles revealed in many regional cores support this age model. Detailed lithological and microfossil studies confirm that three marine (M3, M2 and M1) and three terrestrial (T3, T2 and T1) units can be distinguished. Spatial correlation between the inner plain, outer plain (typical cores characterized by marine transgression cycles) and offshore seismic reflectors reveals coherent sedimentary sequences. Two major boundaries (unconformity and erosion surfaces) can be recognized in the seismic profiles, and these correspond to weathered reddish and/or variegated clay in the study core, suggesting that Quaternary sediment changes on the Lian River plain were largely controlled by sea-level variations and coastline shift during glacial/interglacial cycles.

Monitoring runoff and nutrient transport in the coastal zone of a Danish lowland river

NASA Astrophysics Data System (ADS)

Ovesen, N. B.; Windolf, J.; Kronvang, B.

2012-04-01

Denmark has a very long coastline compared to its total area, and therefore large parts of the lower river reaches are influenced by tidal and coastal backwater effects. In general the gradients of these lowland rivers are very low, and furthermore thousands of small watercourses are flowing directly to the sea along the coastline. This situation makes it impossible to gauge the runoff to many fjords and marine inland waters utilizing traditional monitoring techniques, and consequently, even though Denmark is covered with several hundreds of gauging stations, only 50 percent of the country is gauged. Models are today used to estimate the total runoff and loads of nutrients to coastal waters. One of the major problems in the calibration of the models is however, the lacking of data from the lower part of rivers influenced by tidal and coastal backwater. In order to investigate the possibilities of improving the Danish gauging network and to test the models used for runoff estimation in the ungauged areas, a new monitoring station was established in the summer of 2011 in the River Skjern very close to the outlet in Ringkobing Fjord at the west coast of Jutland. The hydraulic conditions are here affected by tidal and backwater effects and the nutrient transport may be influenced by stratified flow conditions. The catchment area to the new station is 2455 km2, and the width of the channel is 70-80meters. The velocity distribution is measured in the profile by both horizontal and vertical multi cell Doppler sensors. Conductivity (salinity), turbidity and water temperature are measured by sensors in 2 levels, near bottom and in the upper part of the depth profile. Time integrated water samples are collected also in 2 levels with a 2 hour interval and analyzed for total nitrogen, nitrate, ammonium, total phosphorous, and phosphate. The wind speed and direction is registered at the station. The preliminary results show a strong correlation between the water velocities and

Natural and Human Influences on Water Quality in a Shallow Regional Unconsolidated Aquifer, Northern Atlantic Coastal Plain

USGS Publications Warehouse

Ator, Scott W.

2008-01-01

Data collected from more than 400 wells in the surficial unconfined aquifer in the Northern Atlantic Coastal Plain (New York through North Carolina) were compiled and analyzed to improve understanding of multiple natural and human influences on water quality in such shallow regional aquifers. Geochemical patterns were identified and described through principal components analysis on major ions, and correlation and logistic regression were used to relate observed concentrations of nitrate and selected pesticide compounds (atrazine, metolachlor, simazine, and deethylatrazine, an atrazine degradate) and volatile organic compounds (chloroform, 1,1,1-trichloroethane, tetrachlorethene, and methyl tert-butyl ether) to likely influences, such as observed geochemical patterns, land use, hydrogeology, and soils. Variability in major-ion concentrations is primarily related to ionic strength and redox condition. Concentrations of nitrate, pesticides, and volatile organic compounds are related to natural conditions, as well as the distribution of likely sources reflected in land use. Nitrate is most common in aerobic ground water and in relatively well-drained areas, for example; concentrations greater than 0.4 milligrams per liter may result from a variety of human activities, although concentrations greater than 3 milligrams per liter are more likely in agricultural areas. Atrazine, deethylatrazine, and metolachlor also are related to geochemical patterns, likely because ground-water geochemistry reflects hydrogeologic and soil conditions affecting pesticide transport to the water table. Results demonstrate the value of geochemical information along with the distribution of sources and other influences to understanding the regional occurrence of selected compounds in ground water. Such influences are not unique to the Northern Atlantic Coastal Plain, and thus observations and interpretations are relevant to broader areas.

PHOTOCHEMICAL AND BIOLOGICAL DEGRADATION OF CDOM IN WATERS FROM SELECTED COASTAL REGIONS OF THE SOUTHEASTERN UNITED STATES

EPA Science Inventory

Biological and photochemical degradation of colored dissolved organic matter (CDOM) were investigated in controlled experiments using waters from southeastern U.S. estuaries, from the Mississippi River plume and Gulf of Mexico, and from the coastal shelf region in the Florida Key...

Influence of gravel mining and other factors on detection probabilities of Coastal Plain fishes in the Mobile River Basin, Alabama

USGS Publications Warehouse

Hayer, C.-A.; Irwin, E.R.

2008-01-01

We used an information-theoretic approach to examine the variation in detection probabilities for 87 Piedmont and Coastal Plain fishes in relation to instream gravel mining in four Alabama streams of the Mobile River drainage. Biotic and abiotic variables were also included in candidate models. Detection probabilities were heterogeneous across species and varied with habitat type, stream, season, and water quality. Instream gravel mining influenced the variation in detection probabilities for 38% of the species collected, probably because it led to habitat loss and increased sedimentation. Higher detection probabilities were apparent at unmined sites than at mined sites for 78% of the species for which gravel mining was shown to influence detection probabilities, indicating potential negative impacts to these species. Physical and chemical attributes also explained the variation in detection probabilities for many species. These results indicate that anthropogenic impacts can affect detection probabilities for fishes, and such variation should be considered when developing monitoring programs or routine sampling protocols. ?? Copyright by the American Fisheries Society 2008.

Coastal Upwelling Supplies Oxygen-Depleted Water to the Columbia River Estuary

PubMed Central

Roegner, G. Curtis; Needoba, Joseph A.; Baptista, António M.

2011-01-01

Low dissolved oxygen (DO) is a common feature of many estuarine and shallow-water environments, and is often attributed to anthropogenic nutrient enrichment from terrestrial-fluvial pathways. However, recent events in the U.S. Pacific Northwest have highlighted that wind-forced upwelling can cause naturally occurring low DO water to move onto the continental shelf, leading to mortalities of benthic fish and invertebrates. Coastal estuaries in the Pacific Northwest are strongly linked to ocean forcings, and here we report observations on the spatial and temporal patterns of oxygen concentration in the Columbia River estuary. Hydrographic measurements were made from transect (spatial survey) or anchor station (temporal survey) deployments over a variety of wind stresses and tidal states during the upwelling seasons of 2006 through 2008. During this period, biologically stressful levels of dissolved oxygen were observed to enter the Columbia River estuary from oceanic sources, with minimum values close to the hypoxic threshold of 2.0 mg L−1. Riverine water was consistently normoxic. Upwelling wind stress controlled the timing and magnitude of low DO events, while tidal-modulated estuarine circulation patterns influenced the spatial extent and duration of exposure to low DO water. Strong upwelling during neap tides produced the largest impact on the estuary. The observed oxygen concentrations likely had deleterious behavioral and physiological consequences for migrating juvenile salmon and benthic crabs. Based on a wind-forced supply mechanism, low DO events are probably common to the Columbia River and other regional estuaries and if conditions on the shelf deteriorate further, as observations and models predict, Pacific Northwest estuarine habitats could experience a decrease in environmental quality. PMID:21533083

Regional biomass stores and dynamics in forests of coastal Alaska

Treesearch

Mikhaill A. Yatskov; Mark E. Harmon; Olga N. Krankina; Tara M. Barrett; Kevin R. Dobelbower; Andrew N. Gray; Becky Fasth; Lori Trummer; Toni L. Hoyman; Chana M. Dudoit

2015-01-01

Coastal Alaska is a vast forested region (6.2 million ha) with the potential to store large amounts of carbon in live and dead biomass thus influencing continental and global carbon dynamics. The main objectives of this study were to assess regional biomass stores, examine the biomass partitioning between live and dead pools, and evaluate the effect of disturbance on...

Impact of river discharge on the California coastal ocean circulation and variability

NASA Astrophysics Data System (ADS)

Leiva, J.; Chao, Y.; Farrara, J. D.; Zhang, H.

2016-12-01

A real-time California coastal ocean nowcast and forecast system is used to quantify the impact of river discharge on the California coastal ocean circulation and variability. River discharge and freshwater runoff is monitored by an extensive network of stream gages maintained through the U.S. Geological Survey, that offers archived stream flow records as well as real-time datasets. Of all the rivers monitored by the USGS, 25 empty into the Pacific Ocean and contribute a potential source of runoff data. Monthly averages for the current water year yield discharge estimates as high as 6,000 cubic meters per second of additional freshwater input into our present model. Using Regional Ocean Modeling System (ROMS), we performed simulations from October 2015 to May 2016 with and without the river discharge. Results of these model simulations are compared with available observations including both in situ and satellite. Particular attention is paid to the salinity simulation. Validation is done with comparisons to sea glider data available through Oregon State University and UC San Diego, which provides depth profiles along the California coast during this time period. Additional validation is performed through comparisons with sea surface salinity measurements from the Soil Moisture and Ocean Salinity (SMOS) mission. Continued testing for previous years, e.g. between 2011 and 2015, is being made using the Aquarius sea surface salinity data. Discharge data collected by the USGS stream gages provides a necessary source of freshwater input that must be accounted for. Incorporating a new runoff source produces a more robust model that generates improved forecasts. Following validation with available sea glider and satellite data, the enhanced model can be adapted to real-time forecasting.

Predicting impact of SLR on coastal flooding in Banda Aceh coastal defences

NASA Astrophysics Data System (ADS)

Al'ala, Musa; Syamsidik, Kato, Shigeru

2017-10-01

Banda Aceh is a low-lying city located at the northern tip of Sumatra Island and situated at the conjuncture of Malacca Strait and the Andaman Sea. A Sea Level Rise (SLR) rate at 7 mm/year has been observed around this region. In the next 50 years, this city will face a serious challenge to encounter impacts of the sea level rise, such as frequent coastal floodings. This study is aimed at estimating impacts of the sea level rise induced coastal floodings on several types of coastal structures and city drainage system. Numerical simulations of Delft3D were applied to investigate the influence of the gradual sea level rise in 50 years. The hydrodynamic process of coastal flooding and sediment transport were simulated by Delft3D-Flow. Topography and bathymetry data were collected from GEBCO and updated with the available nautical chart (DISHIDROS, JICA, and field measurements). Hydrodynamic process gains the flow process revealing the level of the sea water intrusion also observed in the model. Main rivers (Krueng Aceh, Krueng Neng, and Alue Naga Flood Canal) and the drainage system were observed to see the tides effects on coastal structures and drainage system. The impact on coastal community focusing on affected area, shoreline retreat, the rate of sea intrusion was analyzed with spatial tools. New coastal line, coastal flooding vulnerable area, and the community susceptibility properties map influenced by 50 years sea level rise is produced. This research found that the city needs to address strategies to anticipate the exacerbating impacts of the sea level rise by managing its coastal spatial planning and modify its drainage system, especially at the drainage outlets.

Short-term variability in particle flux: Storms, blooms and river discharge in a coastal sea

NASA Astrophysics Data System (ADS)

Johannessen, Sophia C.; Macdonald, Robie W.; Wright, Cynthia A.; Spear, David J.

2017-07-01

's organic carbon during a single collection interval (12 days). As short-term climate variability increases in a warming climate , the importance of these sorts of events is likely to increase in the future, particularly in coastal waters that are strongly influenced by river discharge.

Nutrient dynamics in tropical rivers, estuarine-lagoons, and coastal ecosystems along the eastern Hainan Island

NASA Astrophysics Data System (ADS)

Li, R. H.; Liu, S. M.; Li, Y. W.; Zhang, G. L.; Ren, J. L.; Zhang, J.

2013-06-01

Nutrient dynamics were studied along the eastern Hainan Island based on field observations during 2006-2009, to understand nutrient biogeochemical processes and to have an overview of human perturbations on coastal ecosystems in this tropical region. The concentrations of nutrients in the rivers had seasonal variations enriched with dissolved inorganic nitrogen (DIN). High riverine concentrations of nitrate were mainly originated from agricultural fertilizer input. The ratios of DIN : PO43- ranged from 37 to 1063, suggesting preferential PO43- relative to nitrogen in the rivers. The areal yields of dissolved silicate (DSi) varied from 76 to 448 × 103 mol km-2 yr-1 due to erosion over the drainage area, inducing high levels of DSi among worldwide tropical systems. Aquaculture ponds contained high concentrations of NH4+ (up to 157 μM) and DON (up to 130 μM). Particulate phosphorus concentrations (0.5 ∼1.4 μM) were in lower level comparied with estuaries around the world. Particulate silicate levels in rivers and lagoons were lower than global average level. Nutrient biogeochemistry in coastal areas were affected by human activities (e.g. aquaculture, agriculture), as well as natural events such as typhoon. Nutrient concentrations were low because open sea water dispersed land-derived nutrients. Nutrient budgets were built based on a steady-state box model, which showed that riverine fluxes would be magnified by estuarine processes (e.g. regeneration, desorption) in the Wenchanghe/Wenjiaohe Estuary, Wanquan River estuary, and the Laoyehai Lagoon except in the Xiaohai Lagoon. Riverine and groundwater input were the major sources of nutrients to the Xiaohai Lagoon and the Laiyehai Lagoon, respectively. Riverine input and aquaculture effluent were the major sources of nutrients to the eastern coastal of Hainan Island. Nutrient inputs to the coastal ecosystem can be increased by typhoon-induced runoff of rainwater, and phytoplankton bloom in the sea would be

Influence of the Yukon River on the Bering Sea

NASA Technical Reports Server (NTRS)

Dean, K.; Mcroy, C. P.

1986-01-01

The relationships between the discharge of the Yukon River to the currents and biological productivity in the northern Bering Sea were studied. Specific objectives were: to develop thermal, sediment, and chlorophyll surface maps using Thematic Mapper (TM) data of the discharge of the Yukon River and the Alaskan Coastal Current during the ice free season; to develop a historical model of the distribution of the Yukon River discharge and the Alaskan Coastal Current using LANDSAT Multispectral band scanner (MSS) and NOAA satellite imagery; and to use high resolution TM data to define the surface dynamics of the front between the Alaskan Coastal Current and the Bering Shelf/Anadyr Current. LANDSAT MSS, TM, and Advanced Very High Resolution Radiometer (AVHRR) data were recorded during the 1985 ice free period. The data coincided with shipboard measurements acquired by Inner Shelf Transfer and Recycling (ISTAR) project scientists. An integrated model of the distribution of turbid water discharged from the Yukon River was compiled. A similar model is also being compiled for the Alaskan Coastal and Bering Shelf/Anadyr water masses based on their thermal expressions seen on AVHRR imagery.

A meta-analysis of plant facilitation in coastal dune systems: responses, regions, and research gaps.

PubMed

Castanho, Camila de Toledo; Lortie, Christopher J; Zaitchik, Benjamin; Prado, Paulo Inácio

2015-01-01

Empirical studies in salt marshes, arid, and alpine systems support the hypothesis that facilitation between plants is an important ecological process in severe or 'stressful' environments. Coastal dunes are both abiotically stressful and frequently disturbed systems. Facilitation has been documented, but the evidence to date has not been synthesized. We did a systematic review with meta-analysis to highlight general research gaps in the study of plant interactions in coastal dunes and examine if regional and local factors influence the magnitude of facilitation in these systems. The 32 studies included in the systematic review were done in coastal dunes located in 13 countries around the world but the majority was in the temperate zone (63%). Most of the studies adopt only an observational approach to make inferences about facilitative interactions, whereas only 28% of the studies used both observational and experimental approaches. Among the factors we tested, only geographic region mediates the occurrence of facilitation more broadly in coastal dune systems. The presence of a neighbor positively influenced growth and survival in the tropics, whereas in temperate and subartic regions the effect was neutral for both response variables. We found no evidence that climatic and local factors, such as life-form and life stage of interacting plants, affect the magnitude of facilitation in coastal dunes. Overall, conclusions about plant facilitation in coastal dunes depend on the response variable measured and, more broadly, on the geographic region examined. However, the high variability and the limited number of studies, especially in tropical region, indicate we need to be cautious in the generalization of the conclusions. Anyway, coastal dunes provide an important means to explore topical issues in facilitation research including context dependency, local versus regional drivers of community structure, and the importance of gradients in shaping the outcome of net

Anthropogenic Impacts on Coastal Processes at Guadiaro River Mouth (Cádiz, Spain)

NASA Astrophysics Data System (ADS)

Diez, J. Javier

2014-05-01

The mouth of Guadiaro river (Cadiz, south of Spain) opens to the Alboran basin of the Mediterranean Sea, between the Spanish and North African coasts, next to the Strait of Gibraltar, where the Spanish coastal orientation is NNE-SSW, so that the stretch is mainly affected by eastern ("Levantes") wind and wave action. The river sources are in Grazalema Sierra (Cádiz), western Penibetic ridge, and although the Spanish Mediterranean facade is climatically dry and supports a very irregular rainfall regime, rains in that "Sierra" are among the highest and homogeneous in Spain throughout the year, much more than in the rest of the ridge. Maybe that is why the Guadiaro estuary has remained functional until preset years while all other river mouths estuaries were filled to become deltas along the eighteenth century (Diez, 1996). As most of Spanish rivers, the Guadiaro had suffered a major regulatory process and an upstream transfer has been recently implemented from its basin to the Atlantic through Guadalete river basin, therefore the mouth flow is becoming reduced, especially in its peaks. The closure of its mouth, favoured by the reduced flow of the river in a low tide basin sea, has been studied several times in the last decades (Muñoz et al, 2010), mainly because the spit closing it grows in the NNE direction when alongshore transport occurs mainly, and almost permanently, in the opposite direction. This paper is mainly based on most of those documents, whose researches have used numerical models such as SMC and MIKE 21, obtaining relevant results on the refraction but not diffraction. Two successive main structural actions that can have modified coastal processes were introduced in the environment of the mouth: a couple of jetties (1973), one of which was soon removed (1975), and the marina and harbour of Sotogrande (whose breakwater was built in 1986 and extended 1n 1994)). The influence of these elements is not well reflected in the numerical models. In this

The Hudson River Plume: Exploring Human Impact on the Coastal Environment

ERIC Educational Resources Information Center

McDonnell, Janice; Duncan, Ravit; Lichtenwalner, C. Sage; Dunbar, Laura

2010-01-01

The Hudson River Watershed contains a variety of geologic, topographic, climatic, and hydrologic features and a diversity of land-use patterns--making it an ideal model for studying human impact on the coastal environment. In this article, the authors present the Hudson River Plume (HRP), a problem-based online module that explores nonpoint-source…

Dispersal scaling from the world's rivers

USGS Publications Warehouse

Warrick, J.A.; Fong, D.A.

2004-01-01

Although rivers provide important biogeochemical inputs to oceans, there are currently no descriptive or predictive relationships of the spatial scales of these river influences. Our combined satellite, laboratory, field and modeling results show that the coastal dispersal areas of small, mountainous rivers exhibit remarkable self-similar scaling relationships over many orders of magnitude. River plume areas scale with source drainage area to a power significantly less than one (average = 0.65), and this power relationship decreases significantly with distance offshore of the river mouth. Observations of plumes from large rivers reveal that this scaling continues over six orders of magnitude of river drainage basin areas. This suggests that the cumulative area of coastal influence for many of the smallest rivers of the world is greater than that of single rivers of equal watershed size. Copyright 2004 by the American Geophysical Union.

Distribution of carbon, nitrogen and phosphorus in coastal wetland soil related land use in the Modern Yellow River Delta

PubMed Central

Yu, Junbao; Zhan, Chao; Li, Yunzhao; Zhou, Di; Fu, Yuqin; Chu, Xiaojing; Xing, Qinghui; Han, Guangxuan; Wang, Guangmei; Guan, Bo; Wang, Qing

2016-01-01

The delivery and distribution of nutrients in coastal wetland ecosystems is much related to the land use. The spatial variations of TOC, TN, NH4+-N, NO3−-N and TP and associated soil salinity with depth in 9 kinds land uses in coastal zone of the modern Yellow River Delta (YRD) was evaluated based on monitoring data in field from 2009 to 2015. The results showed that the average contents of soil TOC, TN, NO3−-N, NH4+-N and TP were 4.21 ± 2.40 g kg−1, 375.91 ± 213.44, 5.36 ± 9.59 and 7.20 ± 5.58 and 591.27 ± 91.16 mg kg−1, respectively. The high N and C contents were found in cropland in southern part and low values in natural wetland, while TP was relatively stable both in profiles and in different land uses. The land use, land formation age and salinity were important factors influencing distributions of TOC and N. Higher contents of TOC and N were observed in older formation age lands in whole study region, while the opposite regulation were found in new-born natural wetland, indicating that the anthropogenic activities could greatly alter the original distribution regulations of nutrients in coastal natural wetlands by changing the regional land use. PMID:27892492

[Spatial variations of biogenic elements in coastal wetland sediments of the Jiulong River Estuary].

PubMed

Yu, Xiao-Qing; Yang, Jun; Liu, Le-Mian; Tian, Yuan; Yu, Zheng; Wang, Chang-Fu

2012-11-01

To reveal the spatial distribution of biogenic elements and their influencing factors in the typical subtropical coastal wetland, both surface and core sediment samples were collected from the Jiulong River Estuary, southeast China in summer 2009. The biogenic elements including carbon, nitrogen, phosphorus, sulfur (C, N, P, S) were determined by Element Analyzer and Flow Injection Analyzer. The concentrations of TC, TN, TP, and TS were (12.64 +/- 2.66) g x kg(-1), (1.57 +/- 0.29) g x kg(-1), (0.48 +/- 0.06) g x kg(-1), and (2.61 +/- 1.37) g x kg(-1), respectively. Further, these biogenic elements showed a distinct spatial pattern which closely related with the vegetation type and tide level. Values of TC, TN, TP in the surface sediment of mangrove vegetation zones were higher than those in the cord-grass and mudflat zones, while TC, TN, TP concentrations in the high tide level regions were higher than those in the middle and low tide level regions. The TS concentration was the highest in cord-grass vegetation and middle tidal level zones. The TC and TN values in sedimentary core decreased gradually with depth, and they were the highest in the mangrove sites, followed by cord-grass and mudflat sites at the same depth. In mudflat sedimentary core, the average content of TP was the lowest, whereas TS was the highest. Redundancy analysis revealed that vegetation type, pH and tide level were the main factors influencing the distribution of biogenic elements in surface sediments of the Jiulong River Estuary, by explaining 24.0%, 19.0% and 11.6% of total variation in the four biogenic elements (C, N, P and S), respectively.

Influence of the Yukon River on the Bering Sea

NASA Technical Reports Server (NTRS)

Dean, Kenneson G.; Mcroy, C. Peter

1988-01-01

Physical and biological oceanography of the northern Bering Sea including the influence of the Yukon River were studied. Satellite data acquired by the Advanced Very High Resolution Radiometer (AVHRR), the LANDSAT Multispectral Scanner (MSS) and the Thematic Mapper (TM) sensor were used to detect sea surface temperatures and suspended sediments. Shipboard measurements of temperature, salinity and nutrients were acquired through the Inner Shelf Transfer and Recycling (ISHTAR) project and were compared to digitally enhanced and historical satellite images. The satellite data reveal north-flowing, warm water along the Alaskan coast that is highly turbid with complex patterns of surface circulation near the Yukon River delta. To the west near the Soviet Union, cold water, derived from an upwelling, mixes with shelf water and also flows north. The cold and warm water coincide with the Anadyr, Bering Shelf and Alaskan coastal water masses. Generally, warm Alaskan coastal water forms near the coast and extends offshore as the summer progresses. Turbid water discharged by the Yukon River progresses in the same fashion but extends northward across the entrance to Norton Sound, attaining its maximum surface extent in October. The Anadyr water flows northward and around St. Lawrence Island, but its extent is highly variable and depends upon mesoscale pressure fields in the Arctic Ocean and the Bering Sea.

Water and sediment dynamics in the Red River mouth and adjacent coastal zone

NASA Astrophysics Data System (ADS)

van Maren, D. S.

2007-02-01

The coastline of the Red River Delta is characterized by alternating patterns of rapid accretion and severe erosion. The main branch of the Red River, the Ba Lat, is presently expanding seaward with a main depositional area several km downstream and offshore the Ba Lat River mouth. Sediment deposition rates are approximately 6 m in the past 50 years. Field measurements were done to determine the processes that regulate marine dispersal and deposition of sediment supplied by the Ba Lat. These measurements reveal that the waters surrounding the Ba Lat delta are strongly stratified with a pronounced southward-flowing surface layer. This southward-flowing surface layer is a coastal current which is generated by river plumes that flow into the coastal zone north of the Ba Lat. However, outflow of turbid river water is not continuous and most sediment enters the coastal zone when the alongshore surface velocities are low. As a consequence, most sediment settles from suspension close to the river mouth. In addition to the southward surface flow, the southward near-bottom currents are also stronger than northward currents. Contrasting with the residual flow near-surface, this southward flow component near-bottom is caused by tidal asymmetry. Because most sediment is supplied by the Ba Lat when wave heights are low, sediment is able to consolidate and therefore the long-term deposition is southward of, but still close to, the Ba Lat mouth.

The inorganic carbon distribution in Irish coastal waters

NASA Astrophysics Data System (ADS)

McGrath, Triona; Cave, Rachel; McGovern, Evin; Kivimae, Caroline

2014-05-01

Despite their relatively small surface area, coastal and shelf waters play a crucial role in the global climate through their influence on major biogeochemical cycles. Due to growing concern about ocean acidification as a result of increasing atmospheric CO2 concentrations, measurements of inorganic carbon parameters (dissolved inorganic carbon (DIC), total alkalinity (TA), pH and pCO2) have been made with increasing regularity over the past two decades. While it is clear that open ocean surface waters are acidifying at a fairly uniform rate ( -0.02 pH units per decade), less is known about changes in coastal waters due to the high complexity and spatial variability in these regions. Large spatial and temporal variability in coastal CO2 parameters is mainly due to nutrient inputs, biological activity, upwelling and riverine inputs of alkalinity and inorganic and organic carbon. The inorganic carbon system in Irish coastal waters is presented here, gathered from 9 surveys around the Irish coastline between 2009 and 2013. There are striking contrasts in the CO2 system between different areas, largely attributed to the bedrock composition of the nearby rivers. Freshwater end-member concentrations of TA, calculated from TA-salinity relationships in outer estuarine and nearshore coastal water, were supported by riverine TA data from the Irish Environmental Protection Agency. A large portion of Ireland is covered with limestone bedrock and as a result, many of the rivers have extremely high TA (>5000μmol/kg) due to the carbonate mineral content of the underlying bedrock. While such high TA has resulted in elevated pH and calcium carbonate saturation states in some coastal waters, (e.g. Galway Bay and Dublin Bay), the high TA in other areas was accompanied by particularly high DIC (e.g. River Shannon on the west coast), resulting in lower pH and aragonite/calcite saturation states and even CO2 degassing in the Shannon estuary. Due to non-limestone lithology in many parts

Characteristics and environmental carrying capacities of coastal area in Yogyakarta Special Region for aquaculture

NASA Astrophysics Data System (ADS)

Triyatmo, B.; Rustadi; Priyono, S. B.

2018-03-01

The purpose of this study were to determine characteristics and environmental carrying capacities of coastal area in Yogyakarta Special Region for aquaculture. This study was conducted in 2015 by characterizing land and water dynamics, land use, and the suitability of coastal environments for aquaculture. Evaluation on the coastal environments suitability for aquaculture ponds was based on the landforms, soil properties, water quality and land. Selection of coastal locations for aquaculture development was based on the level of suitability of coastal environment. The results showed that the coastal in Kulon Progo and Bantul Regencies were characterized by sand dune and beach ridge with sandy soil texture, while in Gunungkidul Regency was characterized by limestone hill with rocky texture. Water sources of the coastal area were the sea, river, and ground water with the salinity of 31–37, 7–11, 7–31 ppt and pH of 7.4–8.4 7.0–8.2 and 7.4–9.9, respectively. The coastal lands were used for seasonal/annual planting, ponds, fish landing sites, tourism areas and conservation areas. The coastal carrying capacity was rather suitable for aquaculture, especially in the sandy soil area. Aquaculture in that area can be done intensively for shrimp (Litopenaeus vannamei), using biocrete (biological material) or plastic sheet.

Renewed soil erosion and remobilisation of radioactive sediment in Fukushima coastal rivers after the 2013 typhoons.

PubMed

Evrard, Olivier; Chartin, Caroline; Onda, Yuichi; Lepage, Hugo; Cerdan, Olivier; Lefèvre, Irène; Ayrault, Sophie

2014-04-03

Summer typhoons and spring snowmelt led to the riverine spread of continental Fukushima fallout to the coastal plains of Northeastern Japan and the Pacific Ocean. Four fieldwork campaigns based on measurement of radioactive dose rates in fine riverine sediment that has recently deposited on channel bed-sand were conducted between November 2011 and May 2013 to document the spread of fallout by rivers. After a progressive decrease in the fresh riverine sediment doses rates between 2011 and early spring in 2013, a fifth campaign conducted in November 2013 showed that they started to increase again after the occurrence of violent typhoons. We show that this increase in dose rates was mostly due to remobilization of contaminated material that was temporarily stored in river channels or, more importantly, in dam reservoirs of the region during the typhoons. In addition, supply of particles from freshly eroded soils in autumn 2013 was the most important in areas where decontamination works are under progress. Our results underline the need to monitor the impact of decontamination works and dam releases in the region, as they may provide a continuous source of radioactive contamination to the coastal plains and the Pacific Ocean during the coming years.

Evolution of radioactive dose rates in fresh sediment deposits along coastal rivers draining Fukushima contamination plume

PubMed Central

Evrard, Olivier; Chartin, Caroline; Onda, Yuichi; Patin, Jeremy; Lepage, Hugo; Lefèvre, Irène; Ayrault, Sophie; Ottlé, Catherine; Bonté, Philippe

2013-01-01

Measurement of radioactive dose rates in fine sediment that has recently deposited on channel bed-sand provides a solution to address the lack of continuous river monitoring in Fukushima Prefecture after Fukushima Dai-ichi nuclear power plant (FDNPP) accident. We show that coastal rivers of Eastern Fukushima Prefecture were rapidly supplied with sediment contaminated by radionuclides originating from inland mountain ranges, and that this contaminated material was partly exported by typhoons to the coastal plains as soon as by November 2011. This export was amplified during snowmelt and typhoons in 2012. In 2013, contamination levels measured in sediment found in the upper parts of the catchments were almost systematically lower than the ones measured in nearby soils, whereas their contamination was higher in the coastal plains. We thereby suggest that storage of contaminated sediment in reservoirs and in coastal sections of the river channels now represents the most crucial issue. PMID:24165695

River, delta and coastal morphological response accounting for biological dynamics

NASA Astrophysics Data System (ADS)

Goldsmith, W.; Bernardi, D.; Schippa, L.

2015-03-01

Management and construction can increase resilience in the face of climate change, and benefits can be enhanced through integration of biogenic materials including shells and vegetation. Rivers and coastal landforms are dynamic systems that respond to intentional and unintended manipulation of critical factors, often with unforeseen and/or undesirable resulting effects. River management strategies have impacts that include deltas and coastal areas which are increasingly vulnerable to climate change with reference to sea level rise and storm intensity. Whereas conventional assessment and analysis of rivers and coasts has relied on modelling of hydrology, hydraulics and sediment transport, incorporating additional biological factors can offer more comprehensive, beneficial and realistic alternatives. Suitable modelling tools can provide improved decision support. The question has been whether current models can effectively address biological responses with suitable reliability and efficiency. Since morphodynamic evolution exhibits its effects on a large timescale, the choice of mathematical model is not trivial and depends upon the availability of data, as well as the spatial extent, timelines and computation effort desired. The ultimate goal of the work is to set up a conveniently simplified river morphodynamic model, coupled with a biological dynamics plant population model able to predict the long-term evolution of large alluvial river systems managed through bioengineering. This paper presents the first step of the work related to the application of the model accounting for stationary vegetation condition. Sensitivity analysis has been performed on the main hydraulic, sedimentology, and biological parameters. The model has been applied to significant river training in Europe, Asia and North America, and comparative analysis has been used to validate analytical solutions. Data gaps and further areas for investigation are identified.

A drifter for measuring water turbidity in rivers and coastal oceans.

PubMed

Marchant, Ross; Reading, Dean; Ridd, James; Campbell, Sean; Ridd, Peter

2015-02-15

A disposable instrument for measuring water turbidity in rivers and coastal oceans is described. It transmits turbidity measurements and position data via a satellite uplink to a processing server. The primary purpose of the instrument is to help document changes in sediment runoff from river catchments in North Queensland, Australia. The 'river drifter' is released into a flooded river and drifts downstream to the ocean, measuring turbidity at regular intervals. Deployment in the Herbert River showed a downstream increase in turbidity, and thus suspended sediment concentration, while for the Johnstone River there was a rapid reduction in turbidity where the river entered the sea. Potential stranding along river banks is a limitation of the instrument. However, it has proved possible for drifters to routinely collect data along 80 km of the Herbert River. One drifter deployed in the Fly River, Papua New Guinea, travelled almost 200 km before stranding. Copyright © 2014 Elsevier Ltd. All rights reserved.

A Conceptual Framework and Classification for the Fluvial-Backwater-Marine Transition in Coastal Rivers Globally

NASA Astrophysics Data System (ADS)

Howes, N. C.; Georgiou, I. Y.; Hughes, Z. J.; Wolinsky, M. A.

2012-12-01

Channels in fluvio-deltaic and coastal plain settings undergo a progressive series of downstream transitions in hydrodynamics and sediment transport, which is consequently reflected in their morphology and stratigraphic architecture. Conditions progress from uniform fluvial flow to backwater conditions with non-uniform flow, and finally to bi-directional tidal flow or estuarine circulation at the ocean boundary. While significant attention has been given to geomorphic scaling relationships in purely fluvial settings, there have been far fewer studies on the backwater and tidal reaches, and no systematic comparisons. Our study addresses these gaps by analyzing geometric scaling relationships independently in each of the above hydrodynamic regimes and establishes a comparison. To accomplish this goal we have constructed a database of planform geometries including more than 150 channels. In terms of hydrodynamics studies, much of the work on backwater dynamics has concentrated on the Mississippi River, which has very limited tidal influence. We will extend this analysis to include systems with appreciable offshore tidal range, using a numerical hydrodynamic model to study the interaction between backwater dynamics and tides. The database is comprised of systems with a wide range of tectonic, climatic, and oceanic forcings. The scale of these systems, as measured by bankfull width, ranges over three orders of magnitude from the Amazon River in Brazil to the Palix River in Washington. Channel centerlines are extracted from processed imagery, enabling continuous planform measurements of bankfull width, meander wavelength, and sinuosity. Digital terrain and surface models are used to estimate floodplain slopes. Downstream tidal boundary conditions are obtained from the TOPEX 7.1 global tidal model, while upstream boundary conditions such as basin area, relief, and discharge are obtained by linking the databases of Milliman and Meade (2011) and Syvitski (2005). Backwater

Influence of land cover on riverine dissolved organic carbon concentrations and export in the Three Rivers Headwater Region of the Qinghai-Tibetan Plateau.

PubMed

Ma, Xiaoliang; Liu, Guimin; Wu, Xiaodong; Smoak, Joseph M; Ye, Linlin; Xu, Haiyan; Zhao, Lin; Ding, Yongjian

2018-07-15

The Qinghai-Tibetan plateau (QTP) stores a large amount of soil organic carbon and is the headwater region for several large rivers in Asia. Therefore, it is important to understand the influence of environmental factors on river water quality and the dissolved organic carbon (DOC) export in this region. We examined the water physico-chemical characteristics, DOC concentrations and export rates of 7 rivers under typical land cover types in the Three Rivers Headwater Region during August 2016. The results showed that the highest DOC concentrations were recorded in the rivers within the catchment of alpine wet meadow and meadow. These same rivers had the lowest total suspended solids (TSS) concentrations. The rivers within steppe and desert had the lowest DOC concentrations and highest TSS concentrations. The discharge rates and catchment areas were negatively correlated with DOC concentrations. The SUVA 254 values were significantly negatively correlated with DOC concentrations. The results suggest that the vegetation degradation, which may represent permafrost degradation, can lead to a decrease in DOC concentration, but increasing DOC export and soil erosion. In addition, some of the exported DOC will rapidly decompose in the river, and therefore affect the regional carbon cycle, as well as the water quality in the source water of many large Asian rivers. Copyright © 2018 Elsevier B.V. All rights reserved.

Characterization of geomorphic units in the alluvial valleys and channels of Gulf Coastal Plain rivers in Texas, with examples from the Brazos, Sabine, and Trinity Rivers, 2010

USGS Publications Warehouse

Coffman, David K.; Malstaff, Greg; Heitmuller, Franklin T.

2011-01-01

The U.S. Geological Survey, in cooperation with the Texas Water Development Board, described and characterized examples of geomorphic units within the channels and alluvial valleys of Texas Gulf Coastal Plain rivers using a geomorphic unit classification scale that differentiates geomorphic units on the basis of their location either outside or inside the river channel. The geomorphic properties of a river system determine the distribution and type of potential habitat both within and adjacent to the channel. This report characterizes the geomorphic units contained in the river channels and alluvial valleys of Texas Gulf Coastal Plain rivers in the context of the River Styles framework. This report is intended to help Texas Instream Flow Program practitioners, river managers, ecologists and biologists, and others interested in the geomorphology and the physical processes of the rivers of the Texas Gulf Coastal Plain (1) gain insights into how geomorphic units develop and adjust spatially and temporally, and (2) be able to recognize common geomorphic units from the examples cataloged in this report. Recent aerial imagery (high-resolution digital orthoimagery) collected in 2008 and 2009 were inspected by using geographic information system software to identify representative examples of the types of geomorphic units that occurred in the study area. Geomorphic units outside the channels of Texas Gulf Coastal Plain rivers are called \\"valley geomorphic units\\" in this report. Valley geomorphic units for the Texas Gulf Coastal Plain rivers described in this report are terraces, flood plains, crevasses and crevasse splays, flood-plain depressions, tie channels, tributaries, paleochannels, anabranches, distributaries, natural levees, neck cutoffs, oxbow lakes, and constructed channels. Channel geomorphic units occur in the river channel and are subject to frequent stresses associated with flowing water and sediment transport; they adjust (change) relatively quickly in

Multivariate analysis of the influences of oceanic and meteorological processes on suspended particulate matter distributions in Mississippi coastal waters

NASA Astrophysics Data System (ADS)

O'Brien, S. J.; Fitzpatrick, P. J.; Dzwonkowski, B.; Dykstra, S. L.; Wallace, D. J.; Church, I.; Wiggert, J. D.

2016-02-01

The Mississippi Sound is influenced by a high volume of sediment discharge from the Biloxi River, Mobile Bay via Pas aux Herons, Pascagoula River, Pearl River, Wolf River, and Lake Pontchartrain through the Rigolets. The river discharge, variable wind speed, wind direction and tides have a significant impact on the turbidity and transport of sediments in the Sound. Level 1 Moderate Resolution Imaging Spectroradiometer (MODIS) data is processed to extract the remote sensing reflectance at the wavelength of 645 nm and binned into an 8-day composite at a resolution of 500 m. The study uses a regional ocean color algorithm to compute suspended particulate matter (SPM) concentration based on these 8-day composite images. Multivariate analysis is applied between the SPM and time series of tides, wind, turbidity and river discharge measured at federal and academic institutions' stations and moorings. The multivariate analysis also includes in situ measurements of suspended sediment concentration and advective exchanges through the Mississippi Sound's tidal inlets between the coastal shelf and the nearshore estuarine waters. Mechanisms underlying the observed spatiotemporal distribution of SPM, including material exchange between the Sound and adjacent shelf waters, will be explored. The results of this study will contribute to current understanding of exchange mechanisms and pathways with the Mississippi Bight via the Mississippi Sound's tidal inlets.

Carbon Speciation and Anthropogenic Influences in Haitian Rivers and Inland Waters

NASA Astrophysics Data System (ADS)

Markowitz, M.; Paine, J.; McGillis, W. R.; Hsueh, D. Y.

2014-12-01

Climate, geography, and land use patterns all contribute to the social, economic, and environmental challenges in Haiti. Water quality remains a predominant issue, and the health of freshwater systems has been linked to the cycling and transformation of carbon. A speciation dominated by carbonates and bicarbonates is conducive to higher alkalinity waters, which is part of an environmental signature in which cholera and other bacteria thrive. Numerous human activities such as deforestation, biomass burning, and agricultural practices have radically changed the abundances of carbon on land and rivers in Haiti. In Haitian small mountainous rivers, carbon speciation is also influenced by the weathering of limestone and other carbonate rocks. Additionally, rain events and natural disturbances such as earthquakes have shown to drastically increase the amount of carbon in rivers and coastal waters. Since 2010, a network of both satellite and autonomous hydrometeorological stations has been deployed to monitor the climate in southwestern Haiti. Additionally, various hydrological parameters from river, reservoir, and coastal sites have been measured during field visits. Research will be continued into the wet season, providing temporal analysis needed for quantifying the abundances and transformations of carbon. Together, data from weather stations and field sites can be contextualized with local land use patterns and other human activities to offer unique insights on the carbon system. Findings may offer new perspectives on the relationships between hydrologic cycles, human health, and environmental sustainability in Haiti.

SAR Interferometry as a Tool for Monitoring Coastal Changes in the Nile River Delta of Egypt

NASA Technical Reports Server (NTRS)

Aly, Mohamed H.; Klein, Andrew G.; Giardino, John R.

2005-01-01

The Nile River Delta is experiencing rapid rates of coastal change. The rate of both coastal retreat and accretion in the Eastern Nile Delta requires regular, accurate detection and measurement. Current techniques used to monitor coastal changes in the delta are point measurements and, thus, they provide a spatially limited view of the ongoing coastal changes. SAR interferometry can provide measurements of subtle coastal change at a significantly improved spatial resolution and over large areas (100 sq km). Using data provided by the ERS-1&2 satellites, monitoring can be accomplished as frequently as every 35 days when needed. Radar interferometry is employed in this study to detect segments of erosion and accretion during the 1993-2000 period. The average rates of erosion and accretion in the Eastern Nile Delta are measured to be -11.64 m/yr and +5.12 m/yr, respectively. The results of this interferometric study can be used effectively for coastal zone management and integrated sustainable development for the Nile River Delta.

Metal discharges by Sinaloa Rivers to the coastal zone of NW Mexico.

PubMed

Frías-Espericueta, M G; Mejía-Cruz, R; Osuna López, I; Muy-Rangel, M D; Rubio-Carrasco, W; Aguilar-Juárez, M; Voltolina, D

2014-02-01

The aim of this work was to survey the discharges of dissolved and particulate Cd, Cu, Fe, Mn, Pb and Zn of the eight main rivers of Sinaloa State to the Mexican coastal environment. Zn was the most abundant dissolved metal and Fe was the most abundant particulate (8.02-16.90 and 51.8-1,140.3 μg/L, respectively). Only particulate Mn had significantly (p = 0.028) higher values in summer-fall (rainy season), whereas the significantly (p = 0.036) higher values of dissolved Zn were observed in winter and spring. The highest annual total discharges to Sinaloa coastal waters were those of the rivers San Lorenzo and Piaxtla (>2 × 10(3) m.t.) and the lowest those of rivers Baluarte and El Fuerte (349 and 119 m.t., respectively). Pb concentrations may become of concern, because they are higher than the value recommended for the welfare of aquatic communities of natural waters.

Atmospheric Rivers Induced Heavy Precipitation and Flooding in the Western U.S. Simulated by the WRF Regional Climate Model

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

Leung, Lai R.; Qian, Yun

2009-02-12

Twenty years of regional climate simulated by the Weather Research and Forecasting model for North America has been analyzed to study the influence of the atmospheric rivers and the role of the land surface on heavy precipitation and flooding in the western U.S. Compared to observations, the simulation realistically captured the 95th percentile extreme precipitation, mean precipitation intensity, as well as the mean precipitation and temperature anomalies of all the atmospheric river events between 1980-1999. Contrasting the 1986 President Day and 1997 New Year Day atmospheric river events, differences in atmospheric stability are found to have an influence on themore » spatial distribution of precipitation in the Coastal Range of northern California. Although both cases yield similar amounts of heavy precipitation, the 1997 case was found to produce more runoff compared to the 1986 case. Antecedent soil moisture, the ratio of snowfall to total precipitation (which depends on temperature), and existing snowpack all seem to play a role, leading to a higher runoff to precipitation ratio simulated for the 1997 case. This study underscores the importance of characterizing or simulating atmospheric rivers and the land surface conditions for predicting floods, and for assessing the potential impacts of climate change on heavy precipitation and flooding in the western U.S.« less

Relative importance of natural and anthropogenic influences on the fresh surface water chemistry of the Hawkesbury-Nepean River, south-eastern Australia.

PubMed

Markich, S J; Brown, P L

1998-07-03

Fresh surface waters from the Hawkesbury-Nepean River, the major river supplying water to the Sydney region in south-eastern Australia, were sampled monthly during 1991 and analysed for major ions (Na, K, Ca, Mg, Cl, SO4 and HCO3), nutrients (NO3 and PO4), organic carbon and trace metals (Al, Fe, Cu, Zn, Pb, Cd, Ni, Co and Mn). The chemical composition of the river during 1991 was consistent with other studies of the river from 1977 to 1996. The major ion composition in the river is predominantly influenced by sea-salt aerosols in rainwater (headwaters) and connate sea-salt in groundwater (mid-lower reaches), with a cationic dominance order of Na > Mg > Ca > K (equivalents) and an anionic order of Cl > HCO3 > SO4. This is typical of the headwaters of other permanent coastal rivers (freshwater) in south-eastern Australia with a similar catchment lithology. These results differ markedly from the most common natural major ion assemblages established for world rivers (i.e. Ca > Mg > Na > K and HCO3 > SO4 > Cl), which tend to be predominantly influenced by chemical weathering of rocks and minerals. The mean concentrations of major ions, nutrients, organic carbon and trace metals in the freshwater reaches of the Hawkesbury-Nepean River increased by factors of 2.5-4.4, 14-18, 2.2 and 1.6-11, respectively, with increasing distance from the headwaters. Increases in major ion concentrations are attributed mainly to the increasing influence of saline groundwater inflows from regions of Wianamatta shale. Conversely, concentrations of nutrients, organic carbon and trace metals (except Fe and Al) increased as a consequence of anthropogenic inputs, particularly point discharges from sewage treatment plants (i.e. showing distinct, but variable, concentration peaks), as well as diffuse urban and/or agricultural runoff during storm events. The temporal variability of the mean concentrations of all measured parameters in this study was related to variability in water discharge. The

Taxonomic and functional diversity of a coastal planktonic bacterial community in a river-influenced marine area.

PubMed

Thiele, Stefan; Richter, Michael; Balestra, Cecilia; Glöckner, Frank Oliver; Casotti, Raffaella

2017-04-01

The Gulf of Naples is a dynamical area with intense exchanges between offshore oligotrophic and coastal eutrophic waters with frequent freshwater inputs. The Sarno River, one of the most polluted rivers in Europe, strongly contributes to the pollution of the area, discharging high amounts of heavy metals and organic wastes from heavily cultivated and industrial areas. This paper reports on the diversity and community structure of the marine residential Bacteria and Archaea of the Gulf of Naples in an area close to the river Sarno plume and investigates their small-scale taxonomic diversity and expression patterns as a proxy of potential metabolic activity using metagenomics and metatranscriptomics. Bacteria and Archaea were mainly represented by marine clades, with only minor contributors from freshwater ones. The community was dominated by Alpha- and Gammaproteobacteria, of which Rhodospirillales, Pelagibacteriales, and Oceanospirilalles were most represented. However, Alteromonadales and Rhodobacterales were the most active, despite their relative lower abundance, suggesting that they are important for overall ecosystem functioning and nutrient cycling. Nitrification and a reversed form of dissimilatory sulfate reduction were the major metabolic processes found in the metatrascriptomes and were mainly associated to Nitrosopumilales and Pelagibacter, respectively. No clear indication of transcripts related to stress induced by heavy metals or organic pollutants was found. In general, despite the high loads of pollutants discharged continuously by the Sarno River, the microbial community did not show marks of stress-induced changes neither structural nor functional, thus suggesting that this river has little or no effect on the planktonic bacterial community of the Gulf of Naples. Copyright © 2016 Elsevier B.V. All rights reserved.

Influences of Relative Sea-Level Rise and Mississippi River Delta Plain Evolution on the Holocene Middle Amite River, Southeastern Louisiana

USGS Publications Warehouse

Autin, W.J.

1993-01-01

The Holocene geomorphic history of southeastern Louisiana's middle Amite River is recorded in the stratigraphy of three alloformations, identified in decreasing age as the Watson (WAT), Denham Springs (DS), and Magnolia Bridge (MAG). The WAT meander belt formed by at least 9000 yr B.P., when sea level was lower and the Amite River was tributary to a larger ancestral drainage basin. The DS became an active meander belt by at least 3000 yr B.P., in response to relative sea-level rise and eastward progradation of the Mississippi River delta plain. The MAG developed its meander belt, in part, during the European settlement of the drainage basin, and is now attempting to adjust to modern anthropogenic influences. Geomorphic influences on the middle Amite River floodplain have temporal and spatial components that induce regional- and local-scale effects. Regional extrinsic influences caused meander belt avulsion that produced alloformations. However, local influences produced intrinsic geomorphic thresholds that modified channel morphology within a meander belt but did not induce alloformation development. Base-level influences of the relative sea-level rise and the Mississippi River delta plain were so dominant that the effects of possible climate change were not recognized in the Holocene Amite River system.

SAR detected river mixing and coastal wave/current difusion

NASA Astrophysics Data System (ADS)

Diez, Margarita; Martinez-Benjamin, Juan Jose; Sekula, Emil

2014-05-01

distribution of eddies and oil spills also mark the topology of the mixing [5-9]. A series of experimental measurements of the Lagrangian characteristics of the surface currents near Barcelona and Vilanova were performed during several years for different wind and wave conditions. The seasonal influence on the water recirculation and the influence of local conditions is apparent when the formation of a local thermocline also forces strong Langmuir circulations. Understanding the dispersion of very large freshwater discharge from the Rhone and the Ebro into the Mediterranean Sea and its impact on the biology and biogeochemistry of western Mediterranean. Because of the lack of tides and prevalence of strong wind forcing by the Mistral and Tramontana winds, the discharge of the rivers forms a classical example of a wind powered ROFI. The Fractal analysis indicates a river induced anisotropy anomalous surface mixing [6,7] Emil Sekula acknowledges the grants (SGR99-00145). ESP2005-07551, RYC-2003-005700). Authors also acknowledge the (ENV4-CT96-0334) European Union Project and the ESA (AO-ID C1P.2240) [1] Carrillo, A.; Sanchez, M.A.; Platonov, A.; Redondo, J.M., (2001). Coastal and Interfacial Mixing. Laboratory Experiments and Satellite Observations. Physics and Chemistry of the Earth, B, 26/4.305-311. [2] Sekula E., Redondo J. M. (2008) The structure of turbulent jets, vortices and boundary layer: Laboratory and field observations, Il Nuovo Cimento, Vol. 31, N. 5-6, 2008, DOI 10.1393/ncc/i2009-10358-y, 893-907. [3] B. Shirasago, V. Palà Comellas, J. J. Martínez Benjamín, D. Sánchez, A. Martínez, J. Font, R. Arbiol, J. Vázquez, V. Moreno (1996) Revista de teledetección: Revista de la Asociación Española de Teledetección, ISSN 1133-0953, Nº. 6. [4] J. M. Redondo, M. A. Sanchez, J. J. Martinez-Benjamin, and G. S. Jolly (1998)Spectral study of the ocean surface with SAR Proc. SPIE 3496, 217. [5] J. J. Martinez-Benjamin, C. Medeiros, O. Chic, M. O. Bezerra, and J. M

Antibiotics in water and sediments of rivers and coastal area of Zhuhai City, Pearl River estuary, south China.

PubMed

Li, Si; Shi, Wanzi; Li, Huimin; Xu, Nan; Zhang, Ruijie; Chen, Xuejiao; Sun, Weiling; Wen, Donghui; He, Shanliang; Pan, Jianguo; He, Zhidong; Fan, Yingying

2018-09-15

The occurrence, spatiotemporal distribution and ecological risks of 27 antibiotics in water and sediments from rivers and coastal area of Zhuhai, Pearl River estuary, south China were investigated. Higher concentrations of antibiotics were found in river water in dry season than those in wet season (p < 0.01), especially for quinolones (QNs) (6.36-463 ng/L) and aminoglycosides (AGs) (94.9-458 ng/L). In coastal water samples, the concentrations of antibiotics were up to 419 ng/L and 357 ng/L in dry season and wet season, respectively. Higher concentrations of antibiotics in coastal sediment samples were observed in wet season compared with those in dry season (p < 0.01). This may be ascribed to the greater discharge of antibiotics from mariculture and surface sediment flushing in wet season, leading to the accumulation of polluted sediments in the estuary. Redundancy analysis showed that the concentrations of antibiotics in water were correlated with biological/chemical oxygen demand, ammonia nitrogen, and/or total nitrogen (TN). In addition, sediment organic matter (SOC) and TN strongly affected the distribution of antibiotics in sediments. Ecological risk assessment based on risk quotients (RQs) indicated that most antibiotics in water samples posed insignificant risk to fish and green algae, and insignificant to medium risk to daphnid. Copyright © 2018 Elsevier B.V. All rights reserved.

Dissolved Organic Matter (DOM) Export from Watersheds to Coastal Oceans

NASA Astrophysics Data System (ADS)

Chen, R. F.; Gardner, G. B.; Peri, F.

2016-02-01

Dissolved organic matter (DOM) from terrestrial plants and soils is transported by surface waters and groundwaters to coastal ocean waters. Along the way, photochemical and biological degradation can remove DOM, and in situ processes such as phytoplankton leaching and sediment sources can add to the DOM in the river water. Wetlands, especially coastal wetlands can add significant amounts of DOM that is carried by rivers and is exported through estuaries to coastal systems. We will present observational data from a variety of coastal systems (San Francisco Bay, Boston Harbor, Chesapeake Bay, Hudson River, the Mississippi River, and a small salt marsh in the Gulf of Mexico). High resolution measurements of chromophoric dissolved organic matter (CDOM) can be correlated with dissolved organic carbon (DOC) so can be used to estimate DOC in specific systems and seasons. Gradients in CDOM/DOC combined with water fluxes can be used to estimate DOC fluxes from a variety of coastal watersheds to coastal systems. Influences of land use, system size, residence time, DOM quality, and photochemical and biological degradation will be discussed. The significance of coastal wetlands in the land-to-ocean export of DOC will be emphasized.

Dependency of high coastal water level and river discharge at the global scale

NASA Astrophysics Data System (ADS)

Ward, P.; Couasnon, A.; Haigh, I. D.; Muis, S.; Veldkamp, T.; Winsemius, H.; Wahl, T.

2017-12-01

It is widely recognized that floods cause huge socioeconomic impacts. From 1980-2013, global flood losses exceeded $1 trillion, with 220,000 fatalities. These impacts are particularly hard felt in low-lying densely populated deltas and estuaries, whose location at the coast-land interface makes them naturally prone to flooding. When river and coastal floods coincide, their impacts in these deltas and estuaries are often worse than when they occur in isolation. Such floods are examples of so-called `compound events'. In this contribution, we present the first global scale analysis of the statistical dependency of high coastal water levels (and the storm surge component alone) and river discharge. We show that there is statistical dependency between these components at more than half of the stations examined. We also show time-lags in the highest correlation between peak discharges and coastal water levels. Finally, we assess the probability of the simultaneous occurrence of design discharge and design coastal water levels, assuming both independence and statistical dependence. For those stations where we identified statistical dependency, the probability is between 1 and 5 times greater, when the dependence structure is accounted for. This information is essential for understanding the likelihood of compound flood events occurring at locations around the world as well as for accurate flood risk assessments and effective flood risk management. The research was carried out by analysing the statistical dependency between observed coastal water levels (and the storm surge component) from GESLA-2 and river discharge using gauged data from GRDC stations all around the world. The dependence structure was examined using copula functions.

River delta network hydraulic residence time distributions and their role in coastal nutrient biogeochemistry

NASA Astrophysics Data System (ADS)

Hiatt, M. R.; Castaneda, E.; Twilley, R.; Hodges, B. R.; Passalacqua, P.

2015-12-01

River deltas have the potential to mitigate increased nutrient loading to coastal waters by acting as biofilters that reduce the impact of nutrient enrichment on downstream ecosystems. Hydraulic residence time (HRT) is known to be a major control on biogeochemical processes and deltaic floodplains are hypothesized to have relatively long HRTs. Hydrological connectivity and delta floodplain inundation induced by riverine forces, tides, and winds likely alter surface water flow patterns and HRTs. Since deltaic floodplains are important elements of delta networks and receive significant fluxes of water, sediment, and nutrients from distributary channels, biogeochemical transformations occurring within these zones could significantly reduce nutrient loading to coastal receiving waters. However, network-scale estimates of HRT in river deltas are lacking and little is known about the effects of tides, wind, and the riverine input on the HRT distribution. Subsequently, there lacks a benchmark for evaluating the impact of engineered river diversions on coastal nutrient ecology. In this study, we estimate the HRT of a coastal river delta by using hydrodynamic modeling supported by field data and relate the HRT to spatial and temporal patterns in nitrate levels measured at discrete stations inside a delta island at Wax Lake Delta. We highlight the control of the degree of hydrological connectivity between distributary channels and interdistributary islands on the network HRT distribution and address the roles of tides and wind on altering the shape of the distribution. We compare the observed nitrate concentrations to patterns of channel-floodplain hydrological connectivity and find this connectivity to play a significant role in the nutrient removal. Our results provide insight into the potential role of deltaic wetlands in reducing the nutrient loading to near-shore waters in response to large-scale river diversions.

An operational methodology for riparian land cover fine scale regional mapping for the study of landscape influence on river ecological status

NASA Astrophysics Data System (ADS)

Tormos, T.; Kosuth, P.; Souchon, Y.; Villeneuve, B.; Durrieu, S.; Chandesris, A.

2010-12-01

Preservation and restoration of river ecosystems require an improved understanding of the mechanisms through which they are influenced by landscape at multiple spatial scales and particularly at river corridor scale considering the role of riparian vegetation for regulating and protecting river ecological status and the relevance of this specific area for implementing efficient and realistic strategies. Assessing correctly this influence over large river networks involves accurate broad scale (i.e. at least regional) information on Land Cover within Riparian Areas (LCRA). As the structure of land cover along rivers is generally not accessible using moderate-scale satellite imagery, finer spatial resolution imagery and specific mapping techniques are needed. For this purpose we developed a generic multi-scale Object Based Image Analysis (OBIA) scheme able to produce LCRA maps in different geographic context by exploiting information available from very high spatial resolution imagery (satellite or airborne) and/or metric to decametric spatial thematic data on a given study zone thanks to fuzzy expert knowledge classification rules. A first experimentation was carried out on the Herault river watershed (southern of France), a 2650 square kilometers basin that presents a contrasted landscape (different ecoregions) and a total stream length of 1150 Km, using high and very high multispectral remotely-sensed images (10m Spot5 multispectral images and 0.5m aerial photography) and existing spatial thematic data. Application of the OBIA scheme produced a detailed (22 classes) LCRA map with an overall accuracy of 89% and a Kappa index of 83% according to a land cover pressures typology (six categories). A second experimentation (using the same data sources) was carried out on a larger test zone, a part of the Normandy river network (25 000 square kilometers basin; 6000 km long river network; 155 ecological stations). This second work aimed at elaborating a robust statistical

Increasing Mississippi river discharge throughout the twenty-first century influenced by changes in climate, land use and atmospheric CO2

NASA Astrophysics Data System (ADS)

Tao, B.; Tian, H.; Ren, W.; Yang, J.; Yang, Q.; He, R.; Cai, W. J.; Lohrenz, S. E.

2014-12-01

Previous studies have demonstrated that changes in temperature and precipitation (hereafter climate change) would influence river discharge, but the relative importance of climate change, land use, and elevated atmospheric CO2 have not yet been fully investigated. Here we examined how river discharge in the Mississippi River basin in the 21st century might be influenced by these factors using the Dynamic Land Ecosystem Model driven by atmospheric CO2, downscaled GCMs climate and land use scenarios. Our results suggest that river discharge would be substantially enhanced (10.7-59.8%) by the 2090s compared to the recent decade (2000s), though large discrepancies exist among different climate, atmospheric CO2, and land use change scenarios. Our factorial analyses further indicate that the combined effects of land use change and human-induced atmospheric CO2 elevation on river discharge would outweigh climate change effect under the high emission scenario (A2) of Intergovernmental Panel for Climate Change. Our study offers the first attempt to project potential changes in river discharge in response to multiple future environmental changes. It demonstrates the importance of land use change and atmospheric CO2 concentrations in projecting future changes in hydrologic processes. The projected increase river discharge implies that riverine fluxes of carbon, nutrients and pesticide from the MRB to the coastal regions would increase in the future, and thus may influence the states of ocean acidification and hypoxia and deteriorate ocean water quality. Further efforts will also be needed to account for additional environmental factors (such as nitrogen deposition, tropospheric ozone pollution, dam construction, etc.) in projecting changes in the hydrological cycle.

Interpretation of the coastal zone color scanner signature of the Orinoco River plume

NASA Technical Reports Server (NTRS)

Hochman, Herschel T.; Mueller-Karger, F. E.; Walsh, John J.

1994-01-01

The Caribbean Sea is an area that traditionally has been considered oligotrophic, even though the Orinoco River contributes large quantities of fresh water, nutrients, and other dissolved material to this region during the wet boreal (fall) season. Little is known about the impact of this seasonal river plume, which extends from Venezuela to Puetro Rico shortly after maximum discharge. Here, we present results from a study of the bio-optical characteristics of the Orinoco River plume during the rainy season. The objective was to determine whether the coastal zone color scanner (CZCS) and the follow-on sea-viewing wide-field-of-view sensor (SeaWiFS) satellite instrument can be used to assess the concentrations of substances in large river plumes. Recent in situ shipboard measurements were compared to values from representative historical CZCS images using established bio-optical models. Our goal was to deconvolve the signatures of colored dissolved organic carbon and phytoplankton pigments within satellite images of the Orinoco River plume. We conclude that the models may be used for case 2 waters and that as much as 50 percent of the remotely sensored chlorophyll biomass within the plume is an artifact due to the presence of dissolved organic carbon. Dissolved organic carbon originates from a number of sources, including decay of dead organisms, humic materials from the soil, and gelbstoff.

Zooplankton From a Reef System Under the Influence of the Amazon River Plume

PubMed Central

Neumann-Leitão, Sigrid; Melo, Pedro A. M. C.; Schwamborn, Ralf; Diaz, Xiomara F. G.; Figueiredo, Lucas G. P.; Silva, Andrea P.; Campelo, Renata P. S.; de Melo Júnior, Mauro; Melo, Nuno F. A. C.; Costa, Alejandro E. S. F.; Araújo, Moacyr; Veleda, Dóris R. A.; Moura, Rodrigo L.; Thompson, Fabiano

2018-01-01

At the mouth of the Amazon River, a widespread carbonate ecosystem exists below the river plume, generating a hard-bottom reef (∼9500 km2) that includes mainly large sponges but also rhodolith beds. The mesozooplankton associated with the pelagic realm over the reef formation was characterized, considering the estuarine plume and oceanic influence. Vertical hauls were carried out using a standard plankton net with 200 μm mesh size during September 2014. An indicator index was applied to express species importance as ecological indicators in community. Information on functional traits was gathered for the most abundant copepod species. Overall, 179 zooplankton taxa were recorded. Copepods were the richest (92 species), most diverse and most abundant group, whereas meroplankton were rare and less abundant. Species diversity (>3.0 bits.ind-1) and evenness (>0.6) were high, indicating a complex community. Small holoplanktonic species dominated the zooplankton, and the total density varied from 107.98 ind. m-3 over the reef area to 2,609.24 ind. m-3 in the estuarine plume, with a significant difference between coastal and oceanic areas. The most abundant copepods were the coastal species ithona plumifera and Clausocalanus furcatus and early stages copepodites of Paracalanidae. The holoplanktonic Oikopleura, an important producer of mucous houses, was very abundant on the reefs. The indicator species index revealed three groups: (1) indicative of coastal waters under the influence of the estuarine plume [Euterpina acutifrons, Parvocalanus crassirostris, Oikopleura (Vexillaria) dioica and Hydromedusae]; (2) characterized coastal and oceanic conditions (Clausocalanus); (3) characterized the reef system (O. plumifera). Two major copepods functional groups were identified and sorted according to their trophic strategy and coastal-oceanic distribution. The species that dominated the coastal area and the area over the rhodolith beds are indicators of the estuarine plume and

Zooplankton From a Reef System Under the Influence of the Amazon River Plume.

PubMed

Neumann-Leitão, Sigrid; Melo, Pedro A M C; Schwamborn, Ralf; Diaz, Xiomara F G; Figueiredo, Lucas G P; Silva, Andrea P; Campelo, Renata P S; de Melo Júnior, Mauro; Melo, Nuno F A C; Costa, Alejandro E S F; Araújo, Moacyr; Veleda, Dóris R A; Moura, Rodrigo L; Thompson, Fabiano

2018-01-01

At the mouth of the Amazon River, a widespread carbonate ecosystem exists below the river plume, generating a hard-bottom reef (∼9500 km 2 ) that includes mainly large sponges but also rhodolith beds. The mesozooplankton associated with the pelagic realm over the reef formation was characterized, considering the estuarine plume and oceanic influence. Vertical hauls were carried out using a standard plankton net with 200 μm mesh size during September 2014. An indicator index was applied to express species importance as ecological indicators in community. Information on functional traits was gathered for the most abundant copepod species. Overall, 179 zooplankton taxa were recorded. Copepods were the richest (92 species), most diverse and most abundant group, whereas meroplankton were rare and less abundant. Species diversity (>3.0 bits.ind -1 ) and evenness (>0.6) were high, indicating a complex community. Small holoplanktonic species dominated the zooplankton, and the total density varied from 107.98 ind. m -3 over the reef area to 2,609.24 ind. m -3 in the estuarine plume, with a significant difference between coastal and oceanic areas. The most abundant copepods were the coastal species ithona plumifera and Clausocalanus furcatus and early stages copepodites of Paracalanidae. The holoplanktonic Oikopleura , an important producer of mucous houses, was very abundant on the reefs. The indicator species index revealed three groups: (1) indicative of coastal waters under the influence of the estuarine plume [ Euterpina acutifrons, Parvocalanus crassirostris, Oikopleura (Vexillaria) dioica and Hydromedusae]; (2) characterized coastal and oceanic conditions ( Clausocalanus ); (3) characterized the reef system ( O. plumifera ). Two major copepods functional groups were identified and sorted according to their trophic strategy and coastal-oceanic distribution. The species that dominated the coastal area and the area over the rhodolith beds are indicators of the

Influence of the Yukon River on the Bering Sea

NASA Technical Reports Server (NTRS)

Dean, K.; Mcroy, C. P.

1986-01-01

The purpose is to use satellite data to study relationships between discharge of the Yukon River to currents and biologic productivity in the northern Bering Sea. Amended specific objectives are: to develop thermal, sediment and chlorophyll surface maps using thematic mapping (TM) data of the discharge of the Yukon River and the Alaska Coastal Current during the ice free season; to develop a historical model of the distribution of the Yukon River discharge and the Alaska Coastal Current using LANDSAT multispectral scanner (MMS) and NOAA satellite imagery; and to use high resolution TM data to define the surface dynamics of the front between the Alaska Coastal Current and the Bering Shelf/Anadyr Current. LANDSAT MSS and TM, and Advanced Very High Resolution Radiometer (AVHRR) data were recorded during the 1985 ice-free period. The satellite data coincided with shipboard measurements acquired by Inner Self Transfer and Recycling scientists. Circumstances were such, that on July 5 and July 22, all three sensors recorded data that has been registered to a common map projection and map base, then contrast stretched, color composited, and density sliced.

The Minor Rivers of Black Sea North-Western Coast

NASA Astrophysics Data System (ADS)

Alyukaeva, Alevtina

2017-04-01

The generalisations and conclusions have been done based on the expeditional monitoring of minor rivers of the Russian Federation Black Sea Coast for summer-autumn mean water in 2011-2015. The length of coastal line under monitoring was 300 km with 78 rivers with length no longer, then 50 km. The monitoring task was to establish the natural background of river effluent for the region under study. The observation parameters are physical measures (temperature, pH, Eh), solution (salts) and suspension forms of effluent (feculence, suspension chemical composition). 1. The tendency to decrease minor river water temperature at isthmus correspondent to movement from north-west to south-east along the coastal line. The causes are the growing length of the rivers and steepness of the relief along the Black Sea Caucasus. 2. The dependence between the size of coagulated suspension and water temperature is established. Moreover the intensive mix is not able to compensate the negative influence of the low temperature. 3. The value of hydrogen index, mineralization and specific electric conductivity for minor river are growing from north-west to south-east along the coastal line. 4. By the main ionic composition of the minor rivers of Black Sea north-eastern coast can be classified as hydrocarbonate. The main characteristic (marker) of colt composition for the region is the sensible concentrations of potassium and sodium. 5. The amount of suspension substance in the river water and its feculence changes between 50 mg/dm3 дo 280 mg/dm3. In particle size distribution composition of river suspensions the politic fractions (up to 70%) are prevailed, sand and silt fractions are presented less (25%). 6. Suspension form content of microelements depends on general amount of suspension in river water. The suspension form migration is significant for lead, cobalt, tin and silver. Other metals "prefer" the solution forms and can be arranged approximately in the following: vanadium

Food Webs without Borders? Watershed-coast Interactions Influence Diet Sources of Fish in the St. Louis River

EPA Science Inventory

Complex ecosystems form where coastal rivers enter the Laurentian Great Lakes. These ecosystems span a river-to-Great Lake transition zone encompassing a mosaic of river channel, drowned river mouth, littoral, wetland and coastal habitats. Our goals were to determine whether we c...

River mouth morphodynamics - Examples from small, mountainous rivers (Invited)

NASA Astrophysics Data System (ADS)

Warrick, J. A.

2013-12-01

Small, high-sediment yield rivers are known to discharge massive amounts of sediment to the world's oceans. Because of these high rates of sediment discharge, many of these small rivers provide important sources of sediment to littoral cells, such as those along the west coasts of North and South America. Sediment discharge from these small watersheds is commonly ephemeral and dominated by infrequent high flow. Thus, the morphodynamic states of these river mouths will vary with time, often being 'wave dominated' for the majority of the year and then changing to 'river dominated' during river sediment discharge events. Here I will provide a summary of recent observations of the morphodynamics of river mouths along California that reveal that sediment dispersal and deposition patterns vary owing to the sediment transport processes at the river mouths, which are influenced by the buoyancy of the river discharge. During low rates of sediment discharge and low river sediment concentrations, sediment dispersal will occur in hypopycnal (positively buoyant) plumes and sand deposition will be close to the river mouth. These conditions commonly result in transfer of sand from the river delta to the littoral cell during the first 1-2 years following the river discharge event. During high rates of sediment discharge and high river sediment concentrations, river discharge may form hyperpycnal (negatively buoyant) plumes and disperse sand to deeper portions of the continental shelf, where transfer back to the littoral cell may take decades or may not occur. High-resolution bathymetry from southern California provides several examples of sand dispersal by hyperpycnal plumes to regions of the inner and middle continental shelf. Thus, sediment dispersal from river mouths influences coastal morphodynamics, morphology, and the rates and timing of sediment supply to littoral cells.

Simulating coastal to offshore interactions around the South Florida coastal seas and implications on management issues

NASA Astrophysics Data System (ADS)

Kang, H.; Kourafalou, V. H.; Hogan, P. J.; Smedstad, O.

2008-12-01

The South Florida coastal seas include shelf areas and shallow water bodies around ecologically fragile environments and Marine Protected Areas, such as Florida Bay, the Florida Keys National Marine Sanctuary (around the largest coral reef system of the continental U.S.) and the Dry Tortugas Ecological Reserve. Man- made changes in the hydrology of the Everglades have caused dramatic degradation of the coastal ecosystem through discharge in Florida Bay. New management scenarios are under way to restore historical flows. The environmental impacts of the management propositions are examined with an inter-disciplinary, multi-nested modeling system. The HYbrid Coordinate Ocean Model (HYCOM) has been employed for the Regional Model for South Florida Coastal Seas (SoFLA-HYCOM, 1/25 degree resolution) and for the embedded, high resolution coastal Florida Keys model (FKEYS- HYCOM, 1/100 degree). Boundary conditions are extracted from GODAE products: the large scale North Atlantic model (ATL-HYCOM, 1/12 degree) and the intermediate scale Gulf of Mexico model (GOM-HYCOM, 1/25 degree). The study targets the impacts of large scale oceanic features on the coastal dynamics. Eddies that travel along the Loop Current/Florida Current front are known to be an important mechanism for the interaction of nearshore and offshore flows. The high resolution FKEYS simulations reveal both mescoscale and sub- mesoscale eddy passages during a targeted 2-year simulation period (2004-2005), forced with high resolution/high frequency atmospheric forcing. Eddies influence sea level changes in the vicinity of Florida Bay with possible implications on current and future flushing patterns. They also enable upwelling of cooler, nutrient-rich waters in the vicinity of the Reef Tract and they influence transport and recruitment pathways for coral fish larvae, as they carry waters of different properties (such as river-borne low-salinity/nutrient-rich waters from as far as the Mississippi River) and

Vegetation of the Elwha River estuary: Chapter 8 in Coastal habitats of the Elwha River, Washington--biological and physical patterns and processes prior to dam removal

USGS Publications Warehouse

Shafroth, Patrick B.; Fuentes, Tracy L.; Pritekel, Cynthia; Beirne, Matthew M.; Beauchamp, Vanessa B.; Duda, Jeffrey J.; Warrick, Jonathan A.; Magirl, Christopher S.

2011-01-01

The Elwha River estuary supports one of the most diverse coastal wetland complexes yet described in the Salish Sea region, in terms of vegetation types and plant species richness. Using a combination of aerial imagery and vegetation plot sampling, we identified 6 primary vegetation types and 121 plant species in a 39.7 ha area. Most of the estuary is dominated by woody vegetation types, with mixed riparian forest being the most abundant (20 ha), followed by riparian shrub (6.3 ha) and willow-alder forest (3.9 ha). The shrub-emergent marsh transition vegetation type was fourth most abundant (2.2 ha), followed by minor amounts of dunegrass (1.75 ha) and emergent marsh (0.2 ha). This chapter documents the abundance, distribution, and floristics of these six vegetation types, including plant species richness, life form, species origin (native or introduced), and species wetland indicator status. These data will serve as a baseline to which future changes can be compared, following the impending removal of Glines Canyon and Elwha Dams upstream on the Elwha River. Dam removals may alter many of the processes, materials, and biotic interactions that influence the estuary plant communities, including hydrology, salinity, sediment and wood transport, nutrients, and plant-microbe interactions.

Influence of a water regulation event on the age of Yellow River water in the Bohai

NASA Astrophysics Data System (ADS)

Li, Zhen; Wang, Haiyan; Guo, Xinyu; Liu, Zhe; Gao, Huiwang; Zhang, Guiling

2017-10-01

Abrupt changes in freshwater inputs from large rivers usually imply regime shifts in coastal water environments. The influence of a water regulation event on the age of the Yellow River water in the Bohai was modeled using constituent-oriented age and residence time theory to better understand the change in the environmental function of the hydrodynamic field owing to human activities. The water ages in Laizhou Bay, the central basin, and the Bohai strait are sensitive to water regulation. The surface ages in those areas can decrease by about 300 days, particularly in July, and the age stratification is also strengthened. A water regulation event can result in declines in the water age in early July ahead of declines in the water age under climatological conditions (without the regulation event) by about 1 and 5 months in the central basin and Laizhou Bay, respectively. The change in the coastal circulation due to the water regulation event is the primary reason for the change in the Yellow River water age. The high Yellow River flow rate can enhance the density flow and, therefore, reduce the age of the Yellow River water. The subsequent impact of a single water regulation event can last about 1.0 to 4.0 years in different subregions.

Trends in the suspended-sediment yields of coastal rivers of northern California, 1955–2010

USGS Publications Warehouse

Warrick, J.A.; Madej, Mary Ann; Goñi, M. A.; Wheatcroft, R.A.

2013-01-01

Time-dependencies of suspended-sediment discharge from six coastal watersheds of northern California – Smith River, Klamath River, Trinity River, Redwood Creek, Mad River, and Eel River – were evaluated using monitoring data from 1955 to 2010. Suspended-sediment concentrations revealed time-dependent hysteresis and multi-year trends. The multi-year trends had two primary patterns relative to river discharge: (i) increases in concentration resulting from both land clearing from logging and the flood of record during December 1964 (water year 1965), and (ii) continual decreases in concentration during the decades following this flood. Data from the Eel River revealed that changes in suspended-sediment concentrations occurred for all grain-size fractions, but were most pronounced for the sand fraction. Because of these changes, the use of bulk discharge-concentration relationships (i.e., “sediment rating curves”) without time-dependencies in these relationships resulted in substantial errors in sediment load estimates, including 2.5-fold over-prediction of Eel River sediment loads since 1979. We conclude that sediment discharge and sediment discharge relationships (such as sediment rating curves) from these coastal rivers have varied substantially with time in response to land use and climate. Thus, the use of historical river sediment data and sediment rating curves without considerations for time-dependent trends may result in significant errors in sediment yield estimates from the globally-important steep, small watersheds.

Spatio-temporal variation in bed-material load using dune topography collected during a severe flood on the coastal Trinity River, east TX, USA

NASA Astrophysics Data System (ADS)

Mason, J.; Mohrig, D. C.

2015-12-01

A series of six repeat surveys along 27 kilometers of the coastal Trinity River in east Texas, USA, reveal the temporal and spatial changes in bed material load during and following a historically large flood. The river event was above the National Weather Service flood stage for 55 days at the Liberty USGS station, and had a maximum discharge of about 80,000 cfs. As a community, we are beginning to understand how fluvial geomorphology is influenced by the backwater effect, but we still lack an understanding of how the bed-material transport adjusts to accommodate larger-scale changes in river bend pattern and kinematics. Survey data from this project includes sidescan sonar along the channel centerline, multibeam bathymetry, and channel bed sediment samples. In combination, this data set provides new insight into how and when bed material, primarily medium sand with some pebbles, moves through this region, and how this connects to previously observed changes in channel geometry (including downstream decreases in channel width to depth ratio, bar form volume and surface area, and lateral migration rates of river bends). Preliminary examination of sidescan sonar of two bends within the survey area, one upstream and one downstream, reveal a striking difference in bedform behavior in response to the changing hydrograph. Upstream, bedforms decrease 80% in height and 83% in length and increase in 3-dimensionality throughout the extended peak flow. During the falling limb of the flood these same bedforms increase in size as they become more laterally continuous and straight-crested. Downstream, 3-dimensional bedforms decrease 80% in height and 87% in length throughout the extended peak flow and then remain this size during the falling limb of the flood. This presentation will discuss these results with respect to backwater dynamics, sediment supply and transport, implications for coastal geomorphology as well as sediment delivery into deltaic systems.

North Atlantic Oscillation influence on the stramflows of the Iberian Rivers

NASA Astrophysics Data System (ADS)

Lorenzo-Lacruz, J.; González-Hidalgo, J. C.; Vicente-Serrano, S. M.; López-Moreno, J. I.

2010-09-01

"NORTH ATLANTIC OSCILLATION INFLUENCE ON THE STREAMFLOWS OF THE IBERIAN RIVERS" LORENZO-LACRUZ, J. ¹, GONZÁLEZ-HIDALGO, J.C.², VICENTE-SERRANO, S.M. ¹, LÓPEZ-MORENO, J.I.¹ ¹Instituto Pirenaico de Ecología, CSIC (Spanish Research Council), Campus de Aula Dei, P.O. Box 202, Zaragoza 50080, Spain ²Departamento de Geografía, Universidad de Zaragoza, Zaragoza, Spain. We analyzed the North Atlantic Oscillation (NAO) influence on the monthly river discharges of Iberian rivers from 1945 to 2005. The study covers most of the Iberian river basins, using 187 monthly discharge series. The aim of this study is to determine the role of the variability of the NAO on the Iberian river discharges. Using the winter NAO we calculated correlations with the monthly river discharge series. We identified the positive and negative phases of the winter NAO for the period 1945-2006, and related to river discharge anomalies. Significant differences in river discharge were found between the positive and negative NAO phases with negative anomalies (dry conditions) during positive NAO periods, and positive anomalies (wet conditions) during negative NAO periods The results show a consistent and strong control of the river discharges by the winter NAO, but some spatial differences are shown, as three different domains were defined: a region under the direct influence of the NAO (central and western part of the Iberian Peninsula), a transition zone (Ebro Valley) and region free from that influence (Eastern part of the Iberian Peninsula). The spatial differences are also identified in the annual pattern of discharge anomalies. The basin characteristics, the location of the gauging stations and the human management are the possible drivers of these differences.

Assessment of coastal vulnerability to climate change hazards at the regional scale: the case study of the North Adriatic Sea

NASA Astrophysics Data System (ADS)

Torresan, S.; Critto, A.; Rizzi, J.; Marcomini, A.

2012-07-01

Sea level rise, changes in storms and wave climate as a consequence of global climate change are expected to increase the size and magnitude of flooded and eroding coastal areas, thus having profound impacts on coastal communities and ecosystems. River deltas, beaches, estuaries and lagoons are considered particularly vulnerable to the adverse effects of climate change, which should be studied at the regional/local scale. This paper presents a regional vulnerability assessment (RVA) methodology developed to analyse site-specific spatial information on coastal vulnerability to the envisaged effects of global climate change, and assist coastal communities in operational coastal management and conservation. The main aim of the RVA is to identify key vulnerable receptors (i.e. natural and human ecosystems) in the considered region and localize vulnerable hot spot areas, which could be considered as homogeneous geographic sites for the definition of adaptation strategies. The application of the RVA methodology is based on a heterogeneous subset of bio-geophysical and socio-economic vulnerability indicators (e.g. coastal topography, geomorphology, presence and distribution of vegetation cover, location of artificial protection), which are a measure of the potential harm from a range of climate-related impacts (e.g. sea level rise inundation, storm surge flooding, coastal erosion). Based on a system of numerical weights and scores, the RVA provides relative vulnerability maps that allow to prioritize more vulnerable areas and targets of different climate-related impacts in the examined region and to support the identification of suitable areas for human settlements, infrastructures and economic activities, providing a basis for coastal zoning and land use planning. The implementation, performance and results of the methodology for the coastal area of the North Adriatic Sea (Italy) are fully described in the paper.

Bacterial Biogeography across the Amazon River-Ocean Continuum

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

Doherty, Mary; Yager, Patricia L.; Moran, Mary Ann

Spatial and temporal patterns in microbial biodiversity across the Amazon river-ocean continuum were investigated along ~675 km of the lower Amazon River mainstem, in the Tapajos River tributary, and in the plume and coastal ocean during low and high river discharge using amplicon sequencing of 16S rRNA genes in whole water and size-fractionated samples (0.2-2.0 μm and >2.0 μm). River communities varied among tributaries, but mainstem communities were spatially homogeneous and tracked seasonal changes in river discharge and co-varying factors. Co-occurrence network analysis identified strongly interconnected river assemblages during high (May) and low (December) discharge periods, and weakly interconnected transitionalmore » assemblages in September, suggesting that this system supports two seasonal microbial communities linked to river discharge. In contrast, plume communities showed little seasonal differences and instead varied spatially tracking salinity. However, salinity explained only a small fraction of community variability, and plume communities in blooms of diatom-diazotroph assemblages were strikingly different than those in other high salinity plume samples. This suggests that while salinity physically structures plumes through buoyancy and mixing, the composition of plume-specific communities is controlled by other factors including nutrients, phytoplankton community composition, and dissolved organic matter chemistry. Co-occurrence networks identified interconnected assemblages associated with the highly productive low salinity nearshore region, diatom-diazotroph blooms, and the plume edge region, and weakly interconnected assemblages in high salinity regions. This suggests that the plume supports a transitional community influenced by immigration of ocean bacteria from the plume edge, and by species sorting as these communities adapt to local environmental conditions. Few studies have explored patterns of microbial diversity in tropical rivers

Bacterial Biogeography across the Amazon River-Ocean Continuum.

PubMed

Doherty, Mary; Yager, Patricia L; Moran, Mary Ann; Coles, Victoria J; Fortunato, Caroline S; Krusche, Alex V; Medeiros, Patricia M; Payet, Jérôme P; Richey, Jeffrey E; Satinsky, Brandon M; Sawakuchi, Henrique O; Ward, Nicholas D; Crump, Byron C

2017-01-01

Spatial and temporal patterns in microbial biodiversity across the Amazon river-ocean continuum were investigated along ∼675 km of the lower Amazon River mainstem, in the Tapajós River tributary, and in the plume and coastal ocean during low and high river discharge using amplicon sequencing of 16S rRNA genes in whole water and size-fractionated samples (0.2-2.0 μm and >2.0 μm). River communities varied among tributaries, but mainstem communities were spatially homogeneous and tracked seasonal changes in river discharge and co-varying factors. Co-occurrence network analysis identified strongly interconnected river assemblages during high (May) and low (December) discharge periods, and weakly interconnected transitional assemblages in September, suggesting that this system supports two seasonal microbial communities linked to river discharge. In contrast, plume communities showed little seasonal differences and instead varied spatially tracking salinity. However, salinity explained only a small fraction of community variability, and plume communities in blooms of diatom-diazotroph assemblages were strikingly different than those in other high salinity plume samples. This suggests that while salinity physically structures plumes through buoyancy and mixing, the composition of plume-specific communities is controlled by other factors including nutrients, phytoplankton community composition, and dissolved organic matter chemistry. Co-occurrence networks identified interconnected assemblages associated with the highly productive low salinity near-shore region, diatom-diazotroph blooms, and the plume edge region, and weakly interconnected assemblages in high salinity regions. This suggests that the plume supports a transitional community influenced by immigration of ocean bacteria from the plume edge, and by species sorting as these communities adapt to local environmental conditions. Few studies have explored patterns of microbial diversity in tropical rivers and

Bacterial Biogeography across the Amazon River-Ocean Continuum

DOE PAGES

Doherty, Mary; Yager, Patricia L.; Moran, Mary Ann; ...

2017-05-23

Spatial and temporal patterns in microbial biodiversity across the Amazon river-ocean continuum were investigated along ~675 km of the lower Amazon River mainstem, in the Tapajos River tributary, and in the plume and coastal ocean during low and high river discharge using amplicon sequencing of 16S rRNA genes in whole water and size-fractionated samples (0.2-2.0 μm and >2.0 μm). River communities varied among tributaries, but mainstem communities were spatially homogeneous and tracked seasonal changes in river discharge and co-varying factors. Co-occurrence network analysis identified strongly interconnected river assemblages during high (May) and low (December) discharge periods, and weakly interconnected transitionalmore » assemblages in September, suggesting that this system supports two seasonal microbial communities linked to river discharge. In contrast, plume communities showed little seasonal differences and instead varied spatially tracking salinity. However, salinity explained only a small fraction of community variability, and plume communities in blooms of diatom-diazotroph assemblages were strikingly different than those in other high salinity plume samples. This suggests that while salinity physically structures plumes through buoyancy and mixing, the composition of plume-specific communities is controlled by other factors including nutrients, phytoplankton community composition, and dissolved organic matter chemistry. Co-occurrence networks identified interconnected assemblages associated with the highly productive low salinity nearshore region, diatom-diazotroph blooms, and the plume edge region, and weakly interconnected assemblages in high salinity regions. This suggests that the plume supports a transitional community influenced by immigration of ocean bacteria from the plume edge, and by species sorting as these communities adapt to local environmental conditions. Few studies have explored patterns of microbial diversity in tropical rivers

Bacterial Biogeography across the Amazon River-Ocean Continuum

PubMed Central

Doherty, Mary; Yager, Patricia L.; Moran, Mary Ann; Coles, Victoria J.; Fortunato, Caroline S.; Krusche, Alex V.; Medeiros, Patricia M.; Payet, Jérôme P.; Richey, Jeffrey E.; Satinsky, Brandon M.; Sawakuchi, Henrique O.; Ward, Nicholas D.; Crump, Byron C.

2017-01-01

Spatial and temporal patterns in microbial biodiversity across the Amazon river-ocean continuum were investigated along ∼675 km of the lower Amazon River mainstem, in the Tapajós River tributary, and in the plume and coastal ocean during low and high river discharge using amplicon sequencing of 16S rRNA genes in whole water and size-fractionated samples (0.2–2.0 μm and >2.0 μm). River communities varied among tributaries, but mainstem communities were spatially homogeneous and tracked seasonal changes in river discharge and co-varying factors. Co-occurrence network analysis identified strongly interconnected river assemblages during high (May) and low (December) discharge periods, and weakly interconnected transitional assemblages in September, suggesting that this system supports two seasonal microbial communities linked to river discharge. In contrast, plume communities showed little seasonal differences and instead varied spatially tracking salinity. However, salinity explained only a small fraction of community variability, and plume communities in blooms of diatom-diazotroph assemblages were strikingly different than those in other high salinity plume samples. This suggests that while salinity physically structures plumes through buoyancy and mixing, the composition of plume-specific communities is controlled by other factors including nutrients, phytoplankton community composition, and dissolved organic matter chemistry. Co-occurrence networks identified interconnected assemblages associated with the highly productive low salinity near-shore region, diatom-diazotroph blooms, and the plume edge region, and weakly interconnected assemblages in high salinity regions. This suggests that the plume supports a transitional community influenced by immigration of ocean bacteria from the plume edge, and by species sorting as these communities adapt to local environmental conditions. Few studies have explored patterns of microbial diversity in tropical rivers and

Challenges of Tsunami Disaster and Extreme climate Events Along Coastal Region in Asia-Pacific

NASA Astrophysics Data System (ADS)

Chaudhari, S.

2017-12-01

South Asia is more vulnerable to Geo disasters and impacts of climate changes in recent years. On 26 December 2004 massive waves triggered by an earthquake surged into coastal communities in Asia and East Africa with devastating force. Hitting Indonesia, Sri Lanka , Thailand and India hardest, the deadly waves swept more than 200 000 people to their deaths. Also in an another extreme climate change phenomenon during 2005 - 2006,causing heavy rains and flooding situation in the South Asia - Europe and Pacific region ,more than 100 million population in these regions are witnessing the social- economical and ecological risks and impacts due to climate changes and Geohazards. For mitigating geo-disasters, marine hazards and rehabilitation during post tsunami period, scientific knowledge is needed, requiring experienced research communities who can train the local population during tsunami rehabilitation. Several civil society institutions jointly started the initiatives on the problem identifications in management of risks in geo-disasters, tsunami rehabilitation ,Vulnerability and risk assessments for Geohazards etc., to investigate problems related to social-economic and ecological risks and management issues resulting from the December tsunami and Geo- disaster, to aid mitigation planning in affected areas and to educate scientists and local populations to form a basis for sustainable and economic solutions. The poster aims to assess the potential risk and hazard , technical issues, problems and damage arising from Tsunami in the Asia-pacific region in coastal geology, coastal ecosystems and coastal environmental systems . This poster deals with the status and issues of interactions between Human and Ocean Systems, Geo-risks, marine risks along coastal region of Asia- Pacific and also human influence on the earth system . The poster presentation focuses on capacity building of the local population, scientists and researchers for integration of human and ocean

Patterns of migration and residency in coastal cutthroat trout Oncorhynchus clarkii clarkii from two tributaries of the lower Columbia River

USGS Publications Warehouse

Zydlewski, G.B.; Zydlewski, Joseph D.; Johnson, J.

2009-01-01

Coastal cutthroat trout Onchorhynchus clarkii clarkii life-history variants, migration and freshwater residency were monitored using stationary passive integrated transponder (PIT) tag arrays in two tributaries of the Columbia River from 2001 to 2005 (Abernathy Creek, river kilometre, rkm 76) and from 2002 to 2005 (Chinook River, rkm 6). In 2001-2003 and 2002-2003 (Abernathy and Chinook, respectively), 300-500 coastal O. c. clarkii were captured in each tributary by electrofishing and implanted with 23 mm PIT tags. PIT arrays monitored movements from the initiation of tagging through the spring of 2005. Rotary screw traps were also operated on both tributaries. In Abernathy Creek, 28% of tagged individuals were observed through either active capture or passive interrogation. Of these, 32% were identified as migrants and 68% were identified as residents. In the Chinook River, 48% of tagged fish were observed subsequent to tagging; 92% of these fish were migrants and only 8% were resident. In both tributaries, a greater proportion of resident fish were in the upper reaches. The majority of migrants (78-93%) moved the spring following tagging. Migrants leaving at age 2+ years tended to grow faster than those that migrated at age 3+ years or residents. Patterns of growth or growth opportunities may influence both patterns of life-history expression and the timing of migration. ?? 2009 The Fisheries Society of the British Isles.

Hydrologic Conditions that Influence Streamflow Losses in a Karst Region of the Upper Peace River, Polk County, Florida

USGS Publications Warehouse

Metz, P.A.; Lewelling, B.R.

2009-01-01

The upper Peace River from Bartow to Fort Meade, Florida, is described as a groundwater recharge area, reflecting a reversal from historical groundwater discharge patterns that existed prior to the 1950s. The upper Peace River channel and floodplain are characterized by extensive karst development, with numerous fractures, crevasses, and sinks that have been eroded in the near-surface and underlying carbonate bedrock. With the reversal in groundwater head gradients, river water is lost to the underlying groundwater system through these karst features. An investigation was conducted to evaluate the hydrologic conditions that influence streamflow losses in the karst region of the upper Peace River. The upper Peace River is located in a basin that has been altered substantially by phosphate mining and increases in groundwater use. These alterations have changed groundwater flow patterns and caused streamflow declines through time. Hydrologic factors that have had the greatest influence on streamflow declines in the upper Peace River include the lowering of the potentiometric surfaces of the intermediate aquifer system and Upper Floridan aquifer beneath the riverbed elevation due to below-average rainfall (droughts), increases in groundwater use, and the presence of numerous karst features in the low-water channel and floodplain that enhance the loss of streamflow. Seepage runs conducted along the upper Peace River, from Bartow to Fort Meade, indicate that the greatest streamflow losses occurred along an approximate 2-mile section of the river beginning about 1 mile south of the Peace River at Bartow gaging station. Along the low-water and floodplain channel of this 2-mile section, there are about 10 prominent karst features that influence streamflow losses. Losses from the individual karst features ranged from 0.22 to 16 cubic feet per second based on measurements made between 2002 and 2007. The largest measured flow loss for all the karst features was about 50 cubic

Modeling the influence of river discharge on salt intrusion and residual circulation in Danshuei River estuary, Taiwan

USGS Publications Warehouse

Liu, W.-C.; Chen, W.-B.; Cheng, R.T.; Hsu, M.-H.; Kuo, A.Y.

2007-01-01

A 3-D, time-dependent, baroclinic, hydrodynamic and salinity model was implemented and applied to the Danshuei River estuarine system and the adjacent coastal sea in Taiwan. The model forcing functions consist of tidal elevations along the open boundaries and freshwater inflows from the main stream and major tributaries in the Danshuei River estuarine system. The bottom friction coefficient was adjusted to achieve model calibration and verification in model simulations of barotropic and baroclinic flows. The turbulent diffusivities were ascertained through comparison of simulated salinity time series with observations. The model simulation results are in qualitative agreement with the available field data. The validated model was then used to investigate the influence of freshwater discharge on residual current and salinity intrusion under different freshwater inflow condition in the Danshuei River estuarine system. The model results reveal that the characteristic two-layered estuarine circulation prevails most of the time at Kuan-Du station near the river mouth. Comparing the estuarine circulation under low- and mean flow conditions, the circulation strengthens during low-flow period and its strength decreases at moderate river discharge. The river discharge is a dominating factor affecting the salinity intrusion in the estuarine system. A correlation between the distance of salt intrusion and freshwater discharge has been established allowing prediction of salt intrusion for different inflow conditions. ?? 2007 Elsevier Ltd. All rights reserved.

Regional water quality patterns in an alluvial aquifer: direct and indirect influences of rivers.

PubMed

Baillieux, A; Campisi, D; Jammet, N; Bucher, S; Hunkeler, D

2014-11-15

The influence of rivers on the groundwater quality in alluvial aquifers can be twofold: direct and indirect. Rivers can have a direct influence via recharge and an indirect one by controlling the distribution of fine-grained, organic-carbon rich flood deposits that induce reducing conditions. These direct and indirect influences were quantified for a large alluvial aquifer on the Swiss Plateau (50km(2)) in interaction with an Alpine river using nitrate as an example. The hydrochemistry and stable isotope composition of water were characterized using a network of 115 piezometers and pumping stations covering the entire aquifer. Aquifer properties, land use and recharge zones were evaluated as well. This information provided detailed insight into the factors that control the spatial variability of groundwater quality. Three main factors were identified: (1) diffuse agricultural pollution sources; (2) dilution processes resulting from river water infiltrations, revealed by the δ(18)OH2O and δ(2)HH2O contents of groundwater; and (3) denitrification processes, controlled by the spatial variability of flood deposits governed by fluvial depositional processes. It was possible to quantify the dependence of the nitrate concentration on these three factors at any sampling point of the aquifer using an end-member mixing model, where the average nitrate concentration in recharge from the agricultural area was evaluated at 52mg/L, and the nitrate concentration of infiltrating river at approximately 6mg/L. The study shows the importance of considering the indirect and direct impacts of rivers on alluvial aquifers and provides a methodological framework to evaluate aquifer scale water quality patterns. Copyright © 2014 Elsevier B.V. All rights reserved.

Optimization and Modeling of Extreme Freshwater Discharge from Japanese First-Class River Basins to Coastal Oceans

NASA Astrophysics Data System (ADS)

Kuroki, R.; Yamashiki, Y. A.; Varlamov, S.; Miyazawa, Y.; Gupta, H. V.; Racault, M.; Troselj, J.

2017-12-01

We estimated the effects of extreme fluvial outflow events from river mouths on the salinity distribution in the Japanese coastal zones. Targeted extreme event was a typhoon from 06/09/2015 to 12/09/2015, and we generated a set of hourly simulated river outflow data of all Japanese first-class rivers from these basins to the Pacific Ocean and the Sea of Japan during the period by using our model "Cell Distributed Runoff Model Version 3.1.1 (CDRMV3.1.1)". The model simulated fresh water discharges for the case of the typhoon passage over Japan. We used these data with a coupled hydrological-oceanographic model JCOPE-T, developed by Japan Agency for Marine-earth Science and Technology (JAMSTEC), for estimation of the circulation and salinity distribution in Japanese coastal zones. By using the model, the coastal oceanic circulation was reproduced adequately, which was verified by satellite remote sensing. In addition to this, we have successfully optimized 5 parameters, soil roughness coefficient, river roughness coefficient, effective porosity, saturated hydraulic conductivity, and effective rainfall by using Shuffled Complex Evolution method developed by University of Arizona (SCE-UA method), that is one of the optimization method for hydrological model. Increasing accuracy of peak discharge prediction of extreme typhoon events on river mouths is essential for continental-oceanic mutual interaction.

A statistical model for water quality predictions from a river discharge using coastal observations

NASA Astrophysics Data System (ADS)

Kim, S.; Terrill, E. J.

2007-12-01

Understanding and predicting coastal ocean water quality has benefits for reducing human health risks, protecting the environment, and improving local economies which depend on clean beaches. Continuous observations of coastal physical oceanography increase the understanding of the processes which control the fate and transport of a riverine plume which potentially contains high levels of contaminants from the upstream watershed. A data-driven model of the fate and transport of river plume water from the Tijuana River has been developed using surface current observations provided by a network of HF radar operated as part of a local coastal observatory that has been in place since 2002. The model outputs are compared with water quality sampling of shoreline indicator bacteria, and the skill of an alarm for low water quality is evaluated using the receiver operating characteristic (ROC) curve. In addition, statistical analysis of beach closures in comparison with environmental variables is also discussed.

Flooding on California's Russian River: Role of atmospheric rivers

USGS Publications Warehouse

Ralph, F.M.; Neiman, P.J.; Wick, G.A.; Gutman, S.I.; Dettinger, M.D.; Cayan, D.R.; White, A.B.

2006-01-01

Experimental observations collected during meteorological field studies conducted by the National Oceanic and Atmospheric Administration near the Russian River of coastal northern California are combined with SSM/I satellite observations offshore to examine the role of landfalling atmospheric rivers in the creation of flooding. While recent studies have documented the characteristics and importance of narrow regions of strong meridional water vapor transport over the eastern Pacific Ocean (recently referred to as atmospheric rivers), this study describes their impact when they strike the U.S. West Coast. A detailed case study is presented, along with an assessment of all 7 floods on the Russian River since the experimental data were first available in October 1997. In all 7 floods, atmospheric river conditions were present and caused heavy rainfall through orographic precipitation. Not only do atmospheric rivers play a crucial role in the global water budget, they can also lead to heavy coastal rainfall and flooding, and thus represent a key phenomenon linkingweather and climate. Copyright 2006 by the American Geophysical Union.

Future riverine nitrogen export to US coastal regions ...

EPA Pesticide Factsheets

Excess nitrogen (N) in the environment degrades ecosystems and adversely affects human health. Here we examine predictions of contemporary (2000) and future (2030) coastal N loading in the continental US by the Nutrient Export from WaterSheds (NEWS) model. Future output is from storylines of the Millennium Ecosystem Assessment (MEA) and two additional scenarios that reflect “business as usual” and “ambitious” approaches to nutrient management. Modeled total nitrogen (TN) export by rivers to US coastal areas ranged between 2.5 Tg N y-1 in 2000 and 1.9 - 3.0 Tg N y-1 in 2030, depending on scenario. Differences among scenarios reflect the interactions of increased food and energy demands associated with population growth and efforts to reduce losses of N to the environment. Depending on year and scenario, agriculture supplies 25-43% of coastal TN, atmospheric N deposition 6-8%, human sewage 6-12%, and natural and particulate N sources account for the remainder. Our analysis suggests that achieving reductions in coastal N loading will require aggressive management actions. Coastal TN export could be reduced 22% between 2000 and 2030 to 1.9 Tg N y-1 if currently available best management practices and technologies are fully implemented to control N from agriculture, fossil fuel emissions, and wastewater effluent. If N management capabilities do not improve by 2030, coastal N loads could increase 20% to 3.0 Tg N y-1, due primarily to increases in N from agricu

Sedimentology of paleochannels on foreland coastal plain, Judith River Formation (upper Cretaceous), southeast Alberta

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

Koster, E.H.

1984-04-01

The upper 90 m (295 ft) of the sub-Bearpaw Judith River Formation, continuously exposed in the badlands along the Red Deer River 185 km (115 mi) east of Calgary, is famous for the unrivaled assemblage of dinosaur fossils. Dinosaur Provincial Park presents are a rare opportunity to view the architecture of a foreland coastal-plain sequence as well as to clarify the origin and distribution of subbituminous coal zones and gas reservoirs associated with this formation across southeast Alberta. The distal reaches of paleodrainage from the developing Cordillera to the Western Interior seaway are being examined by north-south traversed across themore » badlands. Sharp-based paleochannel units, enclosed by rooted, olive-gray mudstone sequences that are commonly 4-6 m (13-20 ft) thick, vary between 2 end members. The first contains laterally accreted sand-mud couplets with abundant macrofloral debris, and represents cyclical, low-energy growth of point bars, possible with an estuarine influence. The second, mainly comprising cosets of large trough cross-beds with mudstone intraclasts, was formed by episodic aggradation of high-energy systems. An intermediate composite type displays evidence for an energy increase as channel sinuosity decreased. This variation in paleochannel type is attributed to alternating alluviation/rejuvenation associated with an unstable base level. Coal zones and potential reservoirs appear to be associated with the transgressive and regressive phases, respectively, of the Bearpaw coast. Amalgamation of paleochannels - marked by laterally extensive horizons of bone fragments, lithic and intraclastic gravel - is more common seaward over the axial region of the Sweetgrass arch.« less

Geomorphology of the Elwha River and its Delta: Chapter 3 in Coastal habitats of the Elwha River, Washington--biological and physical patterns and processes prior to dam removal

USGS Publications Warehouse

Warrick, Jonathan A.; Draut, Amy E.; McHenry, Michael L.; Miller, Ian M.; Magirl, Christopher S.; Beirne, Matthew M.; Stevens, Andrew Stevens; Logan, Joshua B.; Duda, Jeffrey J.; Warrick, Jonathan A.; Magirl, Christopher S.

2011-01-01

The removal of two dams on the Elwha River will introduce massive volumes of sediment to the river, and this increase in sediment supply in the river will likely modify the shapes and forms of the river and coastal landscape downstream of the dams. This chapter provides the geologic and geomorphologic background of the Olympic Peninsula and the Elwha River with emphasis on the present river and shoreline. The Elwha River watershed was formed through the uplift of the Olympic Mountains, erosion and movement of sediment throughout the watershed from glaciers, and downslope movement of sediment from gravitational and hydrologic forces. Recent alterations to the river morphology and sediment movement through the river include the two large dams slated to be removed in 2011, but also include repeated bulldozing of channel boundaries, construction and maintenance of flood plain levees, a weir and diversion channel for water supply purposes, and engineered log jams to help enhance river habitat for salmon. The shoreline of the Elwha River delta has changed in location by several kilometers during the past 14,000 years, in response to variations in the local sea-level of approximately 150 meters. Erosion of the shoreline has accelerated during the past 80 years, resulting in landward movement of the beach by more than 200 meters near the river mouth, net reduction in the area of coastal wetlands, and the development of an armored low-tide terrace of the beach consisting primarily of cobble. Changes to the river and coastal morphology during and following dam removal may be substantial, and consistent, long-term monitoring of these systems will be needed to characterize the effects of the dam removal project.

Bank storage buffers rivers from saline regional groundwater: an example from the Avon River Australia

NASA Astrophysics Data System (ADS)

Gilfedder, Benjamin; Hofmann, Harald; Cartwrighta, Ian

2014-05-01

Groundwater-surface water interactions are often conceptually and numerically modeled as a two component system: a groundwater system connected to a stream, river or lake. However, transient storage zones such as hyporheic exchange, bank storage, parafluvial flow and flood plain storage complicate the two component model by delaying the release of flood water from the catchment. Bank storage occurs when high river levels associated with flood water reverses the hydraulic gradient between surface water and groundwater. River water flows into the riparian zone, where it is stored until the flood water recede. The water held in the banks then drains back into the river over time scales ranging from days to months as the hydraulic gradient returns to pre-flood levels. If the frequency and amplitude of flood events is high enough, water held in bank storage can potentially perpetually remain between the regional groundwater system and the river. In this work we focus on the role of bank storage in buffering river salinity levels against saline regional groundwater on lowland sections of the Avon River, Victoria, Australia. We hypothesize that the frequency and magnitude of floods will strongly influence the salinity of the stream water as banks fill and drain. A bore transect (5 bores) was installed perpendicular to the river and were instrumented with head and electrical conductivity loggers measuring for two years. We also installed a continuous 222Rn system in one bore. This data was augmented with long-term monthly EC from the river. During high rainfall events very fresh flood waters from the headwaters infiltrated into the gravel river banks leading to a dilution in EC and 222Rn in the bores. Following the events the fresh water drained back into the river as head gradients reversed. However the bank water salinities remained ~10x lower than regional groundwater levels during most of the time series, and only slightly above river water. During 2012 SE Australia

Restoring the Mississippi River Basin from the Catchment to the Coast Defines Science and Policy Issues of Ecosystem Services Associated with Alluvial and Coastal Deltaic Floodplains: Soil Conservation, Nutrient Reduction, Carbon Sequestration, and Flood Control

NASA Astrophysics Data System (ADS)

Twilley, R.

2014-12-01

Large river systems are major economic engines that provide national economic wealth in transporting commerce and providing extensive agriculture production, and their coastal deltas are sites of significant ports, energy resources and fisheries. These coupled natural and social systems from the catchment to the coast depend on how national policies manage the river basins that they depend. The fundamental principle of the Mississippi River Basin, as in all basins, is to capitalize on the ability of fertile soil that moves from erosional regions of a large watershed, through downstream regions of the catchment where sediment transport and storage builds extensive floodplains, to the coastal region of deposition where deltas capture sediment and nutrients before exported to the oceans. The fate of soil, and the ability of that soil to do work, supports the goods and services along its path from the catchment to the coast in all large river basin and delta systems. Sediment is the commodity of all large river basin systems that together with the seasonal pulse of floods across the interior of continents provide access to the sea forming the assets that civilization and economic engines have tapped to build national and global wealth. Coastal landscapes represent some of the most altered ecosystems worldwide and often integrate the effects of processes over their entire catchment, requiring systemic solutions to achieve restoration goals from alluvial floodplains upstream to coastal deltaic floodplains downstream. The urgent need for wetland rehabilitation at landscape scales has been initiated through major floodplain reclamation and hydrologic diversions to reconnect the river with wetland processes. But the constraints of sediment delivery and nutrient enrichment represent some critical conflicts in earth surface processes that limit the ability to design 'self sustaining' public work projects; particularly with the challenges of accelerated sea level rise. Only

Increasing Influence of Societal Response Variables in Coastal Evolution Projections (Invited)

NASA Astrophysics Data System (ADS)

Gayes, P. T.; McCoy, C. A.; Pietrafesa, L. J.

2010-12-01

programs are strongly cyclic and can act in or out of phase with natural cyclic (inlet migration, sea level variability) or stochastic (storms) drivers with significant effects on coastal response and predictions of coastal behavior. Economic cycles and events may similarly moderate timing and scale of coastal defense relative to natural drivers. Societal decisions to not, enhance and or even abandon and remove existing engineering structures as future forces and costs increase, can result in a disproportional response and potentially failure of a section of coast. Some communities have expressed confidence in the ability to maintain the oceanfront shoreline against most projections of sea level rise over the next 100 years. The long-term trend in sea level change may be less important than naturally occurring regional scale, seasonal to inter-annual to multi-decadal variability in sea level; and these are complex but deterministic. There is less confidence, however, in the ability to combat passive submergence and associated flooding issues behind the immediate oceanfront. To the extent that may influence commitment to defend the oceanfront could strongly influence coastal behavior and stability in the long term.

Fluoride occurrence in the groundwater in a coastal region of Andhra Pradesh, India

NASA Astrophysics Data System (ADS)

Rao, N. Subba; Rao, P. Surya; Dinakar, A.; Rao, P. V. Nageswara; Marghade, Deepali

2017-06-01

Fluoride (F-) content varies from 0.60 to 1.80 mg/L in the coastal region between Chirala and Ongole of Andhra Pradesh, India. It exceeds the threshold limit of 1.20 mg/L in 20 % of the total groundwater samples. The aim of the present study is to assess the controlling factors of F- content. The study area experiences a dry climate and is underlain by Charnockite Group of rocks over which the river and coastal alluvium occur. The results of the study identify the four factors that control the high F- content. First one is related to alkalinity, leading to active dissolution and leaching of F--bearing minerals, which supports the positive correlation of F- with pH and HCO3 -. A longer water residence time in the clays is the second factor, which activates not only solubility and dissolution of F--bearing minerals, but also anion exchange between F- and OH-. Third factor is a result of higher Na+ due to impact of saline water, ion exchange between Na+ and Ca2+, and precipitation of CaCO3. This reduces the Ca2+ content, causing dissolution of CaF2 to maintain the chemical equilibria, which is supported by positive correlation between Na2+ and F-. The influence of anthropogenic activities is the last factor, which acts as an additional source of F-. Thus, the shallow groundwater shows higher content of F- and the hydrogeochemical facies also support this hypothesis. The study suggests the remedial measures to reduce the F- content.

Nutrient Loads Flowing into Coastal Waters from the Main Rivers of China (2006-2012).

PubMed

Tong, Yindong; Zhao, Yue; Zhen, Gengchong; Chi, Jie; Liu, Xianhua; Lu, Yiren; Wang, Xuejun; Yao, Ruihua; Chen, Junyue; Zhang, Wei

2015-11-19

Based on monthly monitoring data of unfiltered water, the nutrient discharges of the eight main rivers flowing into the coastal waters of China were calculated from 2006 to 2012. In 2012, the total load of NH3-N (calculated in nitrogen), total nitrogen (TN, calculated in nitrogen) and total phosphorus (TP, calculated in phosphorus) was 5.1 × 10(5), 3.1 × 10(6) and 2.8 × 10(5) tons, respectively, while in 2006, the nutrient load was 7.4 × 10(5), 2.2 × 10(6) and 1.6 × 10(5) tons, respectively. The nutrient loading from the eight major rivers into the coastal waters peaked in summer and autumn, probably due to the large water discharge in the wet season. The Yangtze River was the largest riverine nutrient source for the coastal waters, contributing 48% of the NH3-N discharges, 66% of the TN discharges and 84% of the TP discharges of the eight major rivers in 2012. The East China Sea received the majority of the nutrient discharges, i.e. 50% of NH3-N (2.7 × 10(5) tons), 70% of TN (2.2 × 10(6) tons) and 87% of TP (2.5 × 10(5) tons) in 2012. The riverine discharge of TN into the Yellow Sea and Bohai Sea was lower than that from the direct atmospheric deposition, while for the East China Sea, the riverine TN input was larger.

Evidence of panmixia between sympatric life history forms of coastal cutthroat trout in two lower Columbia River tributaries

USGS Publications Warehouse

Johnson, Jeffrey R.; Baumsteiger, Jason; Zydlewski, Joseph D.; Hudson, J. Michael; Ardren, William R.

2010-01-01

Coastal cutthroat trout Oncorhynchus clarkii clarkii exhibit resident and migratory life history strategies that often occur sympatrically, but the relationship between these forms within a population is poorly characterized. Through use of passive integrated transponder technology, migratory and resident coastal cutthroat trout were identified in two lower Columbia River tributaries (Abernathy Creek and the Chinook River) separated by more than 80 km. Genetic data from 17 highly variable microsatellite loci were used to ascertain the genetic population structure of these life history forms within and between streams. No distinct genetic separation was observed between the life history forms within a stream, as assessed by four different statistical approaches: permutation tests based on the genetic differentiation index F ST, principal components analysis of individuals, analysis of molecular variance, and contingency tests of allele frequency heterogeneity. Genetic differences were an order of magnitude higher between stream samples (F ST > 0.03) than between life history forms within a stream (F ST < 0.003). The contingency test detected allele frequency differences between migratory and resident life history forms in Abernathy Creek (P = 0.001), but this result was influenced more by age-class structure than by reproductive isolation between life history forms. Results are consistent with a single, randomly mating population in each stream producing both migratory and resident life history forms. These data suggest that individual life history strategy in coastal cutthroat trout is predominantly determined by phenotypic plasticity rather than genotype.

Climate Drivers of Spatiotemporal Variability of Precipitation in the Source Region of Yangtze River

NASA Astrophysics Data System (ADS)

Du, Y.; Berndtsson, R.; An, D.; Yuan, F.

2017-12-01

Variability of precipitation regime has significant influence on the environment sustainability in the source region of Yangtze River, especially when the vegetation degradation and biodiversity reduction have already occurred. Understanding the linkage between variability of local precipitation and global teleconnection patterns is essential for water resources management. Based on physical reasoning, indices of the climate drivers can provide a practical way of predicting precipitation. Due to high seasonal variability of precipitation, climate drivers of the seasonal precipitation also varies. However, few reports have gone through the teleconnections between large scale patterns with seasonal precipitation in the source region of Yangtze River. The objectives of this study are therefore (1) assessment of temporal trend and spatial variability of precipitation in the source region of Yangtze River; (2) identification of climate indices with strong influence on seasonal precipitation anomalies; (3) prediction of seasonal precipitation based on revealed climate indices. Principal component analysis and Spearman rank correlation were used to detect significant relationships. A feed-forward artificial neural network(ANN) was developed to predict seasonal precipitation using significant correlated climate indices. Different influencing climate indices were revealed for precipitation in each season, with significant level and lag times. Significant influencing factors were selected to be the predictors for ANN model. With correlation coefficients between observed and simulated precipitation over 0.5, the results were eligible to predict the precipitation of spring, summer and winter using teleconnections, which can improve integrated water resources management in the source region of Yangtze River.

Flood risk trends in coastal watersheds in South Spain: direct and indirect impact of river regulation

NASA Astrophysics Data System (ADS)

Egüen, M.; Polo, M. J.; Gulliver, Z.; Contreras, E.; Aguilar, C.; Losada, M. A.

2015-06-01

Spain is one of the world's countries with a large number of reservoirs per inhabitant. This intense regulation of the fluvial network during the 20th century has resulted in a decrease in flood events, a higher availability of water resources, and a high development of the irrigated crop area, even in the drier regions. For decades, flood perception was reduced since the development of reservoirs protected the floodplains of river; this resulted in later occupation of soil by urban, agricultural and industrial uses. In recent years, an increasing perception of flood events is observed, associated to the higher damage associated to extreme events in the now occupied areas, especially in coastal watersheds. This work shows the change on flood risk in the coastal areas of three hydrographic basins in Andalusia (South Spain) during the reservoir expansion period: the Guadalete, Guadalquivir and Guadalhorce river basins. The results differentiate the impact of the regulation level on both the cumulative distribution functions of the fluvial discharge near the river mouth, for different time scales, and the associated damage related to the enhanced soil occupation during this period. The different impact on the final medium and long term flood risk is also assessed in terms of the storage capacity per unit area throughout the basins, the effective annual runoff/precipitation index, the frequency of sea storms, and the human factor (change in social perception of floods), for different intervals in the flood extreme regime. The implications for adaptation actions is also assessed.

Influence of river discharge on abundance and dissemination of heterotrophic, indicator and pathogenic bacteria along the East Coast of India.

PubMed

Prasad, V R; Srinivas, T N R; Sarma, V V S S

2015-06-15

In order to examine the influence of discharge from different rivers from peninsular India and urban sewage on intensity and dissemination of heterotrophic, indicator and pathogenic bacteria, a study was carried out during peak discharge period along coastal Bay of Bengal. The coastal Bay received freshwater inputs from the river Ganges while Godavari and Krishna contributed to the south. Contrasting difference in salinity, temperature, nutrients and organic matter was observed between north and south east coast of India. The highest heterotrophic, indicator and pathogenic bacterial abundance was observed in the central coastal Bay that received urban sewage from the major city. Intensity and dissemination of heterotrophic, indicator and pathogenic bacteria displayed linear relation with magnitude of discharge. The coliform load was observed up to 100km from the coast suggesting that marine waters were polluted during the monsoon season and its impact on the ecosystem needs further studies. Copyright © 2015 Elsevier Ltd. All rights reserved.

Mercury Enrichment in Sediments of the Coastal Area of Northern Latium, Italy.

PubMed

Scanu, Sergio; Piazzolla, Daniele; Frattarelli, Francesco Manfredi; Mancini, Emanuele; Tiralongo, Francesco; Brundo, Maria Violetta; Tibullo, Daniele; Pecoraro, Roberta; Copat, Chiara; Ferrante, Margherita; Marcelli, Marco

2016-05-01

The purpose of this study was to evaluate the extent of the Hg geochemical anomaly arising in the Amiata and Tolfa complex to the coastal area of northern Latium and to examine the possible influence on this area by the Mignone River, and by the small coastal basins, which are characterized by both previous mining activities and decades of past industrial impact. The results confirm the extension of the anomaly of concentrations of Hg in the coastal area of northern Latium, with the northern sector influenced by the contributions of the Fiora and Mignone Rivers and the southern sector influenced by the contributions of minor basins. The results show high values of the Adverse Effect Index throughout the considered area and highlight the need for further investigation in order to assess the impact of human activities on the present and past values of Hg in marine sediments.

The Morphologic Evolution of the Amazon Coastal Plain, Cabo Norte, Amapa, Brazil: The Need for Integrated Investigation on the Internal Continental Shelf.

NASA Astrophysics Data System (ADS)

Silveira, O.; Santos, V. F.; Takiyama, L. R.

2007-05-01

The north brazilian coastal region is submitted to the conjunction of three major forcing: 1) Atmospheric, related to the wind and precipitation regimen and controlling the climatic seasonality and the local rivers hydrology; 2) Oceanic, result of the general oceanic circulation (North Equatorial Current-NEC) and it modulation with the atmospheric forcing (North Brazilian Coastal Current reflection), and 3) Amazonic, which is a result of the sedimentary transport from Amazon river, being itself under the influence of the atmospheric and oceanic forcing. Their main characteristic are the proper periodicities and also variabilities expressed according multiples and differentiated scales of time and space, determining the structure and functioning of the coastal space, giving to the Amazon coast line a considerable environmental instability. The Amapa Coastal Plain shows important part of this environmental instability. Semidiurnal macro tides, strong currents and tidal bores acts over a low gradient coastal plain which evolutionary process are intrinsically related with tectonic and geological settings. Two main areas can be distinguished in this scenario. The first one is the Amapa Lakes Region, developed over meanders of ancient drainages building a mosaic of low relief forms, with varied shapes, linked throughout communication channels. Two lacustrine belts showing alignments with the main tectonic traces were recognized beginning at the internal limit of the coastal plain, flowing southeast through the Tabaco Creek until reach the Araguari River. In it way it conform the Occidental and Meridional Belts represented by shallow lakes, totally dependent of Tartarugal River discharge and surrounded by enormous areas of peat highly sensitive to fire during the regional low discharge. Light blue clays, peat and a package of tidal deposits with fluidization structures were recognized close to Araguari River, suggesting deposition during high sea level. The second area

Hydrochemistry, water quality and land use signatures in an ephemeral tidal river: implications in water management in the southwestern coastal region of Bangladesh

NASA Astrophysics Data System (ADS)

Roy, Kushal; Karim, Md. Rezaul; Akter, Farjana; Islam, Md. Safiqul; Ahmed, Kousik; Rahman, Masudur; Datta, Dilip Kumar; Khan, M. Shah Alam

2018-05-01

Despite its complexity and importance in managing water resources in populous deltas, especially in tidal areas, literatures on tidal rivers and their land use linkage in connection to water quality and pollution are rare. Such information is of prior need for Integrated Water Resource Management in water scarce and climate change vulnerable regions, such as the southwestern coast of Bangladesh. Using water quality indices and multivariate analysis, we present here the land use signatures of a dying tidal river due to anthropogenic perturbation. Correlation matrix, hierarchical cluster analysis, factor analysis, and bio-geo-chemical fingerprints were used to quantify the hydro-chemical and anthropogenic processes and identify factors influencing the ionic concentrations. The results show remarkable spatial and temporal variations ( p < 0.05) in water quality parameters. The lowest solute concentrations are observed at the mid reach of the stream where the agricultural and urban wastewater mix. Agricultural sites show higher concentration of DO, Na+ and K+ reflecting the effects of tidal spill-over and shrimp wastewater effluents nearby. Higher level of Salinity, EC, Cl-, HCO3 -, NO3 -, PO4 3- and TSS characterize the urban sites indicating a signature of land use dominated by direct discharge of household organic waste into the waters. The spatial variation in overall water quality suggests a periodic enhancement of quality especially for irrigation and non-drinking purposes during monsoon and post-monsoon, indicating significant influence of amount of rainfall in the basin. We recommend that, given the recent trend of increasing precipitation and ground water table decrease, such dying tidal river basins may serve as excellent surface water reservoir to supplement quality water supply to the region.

Understanding and Projecting Climate and Human Impacts on Terrestrial-Coastal Carbon and Nutrient Fluxes

NASA Astrophysics Data System (ADS)

Lohrenz, S. E.; Cai, W. J.; Tian, H.; He, R.; Fennel, K.

2017-12-01

Changing climate and land use practices have the potential to dramatically alter coupled hydrologic-biogeochemical processes and associated movement of water, carbon and nutrients through various terrestrial reservoirs into rivers, estuaries, and coastal ocean waters. Consequences of climate- and land use-related changes will be particularly evident in large river basins and their associated coastal outflow regions. Here, we describe a NASA Carbon Monitoring System project that employs an integrated suite of models in conjunction with remotely sensed as well as targeted in situ observations with the objectives of describing processes controlling fluxes on land and their coupling to riverine, estuarine and ocean ecosystems. The nature of our approach, coupling models of terrestrial and ocean ecosystem dynamics and associated carbon processes, allows for assessment of how societal and human-related land use, land use change and forestry and climate-related change affect terrestrial carbon transport as well as export of materials through watersheds to the coastal margins. Our objectives include the following: 1) Provide representation of carbon processes in the terrestrial ecosystem to understand how changes in land use and climatic conditions influence the export of materials to the coastal ocean, 2) Couple the terrestrial exports of carbon, nutrients and freshwater to a coastal biogeochemical model and examine how different climate and land use scenarios influence fluxes across the land-ocean interface, and 3) Project future changes under different scenarios of climate and human impact, and support user needs related to carbon management and other activities (e.g., water quality, hypoxia, ocean acidification). This research is providing information that will contribute to determining an overall carbon balance in North America as well as describing and predicting how human- and climate-related changes impact coastal water quality including possible effects of coastal

Coastal Ocean Variability Off the Coast of Taiwan in Response toTyphoon Morakot: River Forcing, Atmospheric Forcing, and Cold Dome Dynamics

DTIC Science & Technology

2014-09-01

very short time period and in this research, we model and study the effects of this rainfall on Taiwan?s coastal oceans as a result of river discharge...model and study the effects of this rainfall on Taiwan’s coastal oceans as a result of river discharge. We do this through the use of a river discharge... Effects of Footprint Shape on the Bulk Mixing Model . . . . . . . . . 57 4.2 Effects of the Horizontal Extent of the Bulk Mixing Model . . . . . . 59

Linking the historic 2011 Mississippi River flood to coastal wetland sedimentation

USGS Publications Warehouse

Falcini, Federico; Khan, Nicole S.; Macelloni, Leonardo; Horton, Benjamin P.; Lutken, Carol B.; McKee, Karen L.; Santoleri, Rosalia; Colella, Simone; Li, Chunyan; Volpe, Gianluca; D’Emidio, Marco; Salusti, Alessandro; Jerolmack, Douglas J.

2012-01-01

Wetlands in the Mississippi River deltaic plain are deteriorating in part because levees and control structures starve them of sediment. In Spring of 2011 a record-breaking flood brought discharge on the lower Mississippi River to dangerous levels, forcing managers to divert up to 3500 m3/s-1 of water to the Atchafalaya River Basin. Here we quantify differences between the Mississippi and Atchafalaya River inundation and sediment-plume patterns using field-calibrated satellite data, and assess the impact these outflows had on wetland sedimentation. We characterize hydrodynamics and suspended sediment patterns of the Mississippi River plume using in-situ data collected during the historic flood. We show that the focused, high-momentum jet from the leveed Mississippi delivered sediment far offshore. In contrast, the plume from the Atchafalaya was more diffuse; diverted water inundated a large area; and sediment was trapped within the coastal current. Maximum sedimentation (up to several centimetres) occurred in the Atchafalaya Basin despite the larger sediment load carried by the Mississippi. Minimum accumulation occurred along the shoreline between these river sources. Our findings provide a mechanistic link between river-mouth dynamics and wetland sedimentation patterns that is relevant for plans to restore deltaic wetlands using artificial diversions.

The geomorphic function and characteristics of large woody debris in low gradient rivers, coastal Maine, USA

NASA Astrophysics Data System (ADS)

Magilligan, F. J.; Nislow, K. H.; Fisher, G. B.; Wright, J.; Mackey, G.; Laser, M.

2008-05-01

The role, function, and importance of large woody debris (LWD) in rivers depend strongly on environmental context and land use history. The coastal watersheds of central and northern Maine, northeastern U.S., are characterized by low gradients, moderate topography, and minimal influence of mass wasting processes, along with a history of intensive commercial timber harvest. In spite of the ecological importance of these rivers, which contain the last wild populations of Atlantic salmon ( Salmo salar) in the U.S., we know little about LWD distribution, dynamics, and function in these systems. We conducted a cross-basin analysis in seven coastal Maine watersheds, documenting the size, frequency, volume, position, and orientation of LWD, as well as the association between LWD, pool formation, and sediment storage. In conjunction with these LWD surveys, we conducted extensive riparian vegetation surveys. We observed very low LWD frequencies and volumes across the 60 km of rivers surveyed. Frequency of LWD ≥ 20 cm diameter ranged from 15-50 pieces km - 1 and wood volumes were commonly < 10-20 m 3 km - 1 . Moreover, most of this wood was located in the immediate low-flow channel zone, was oriented parallel to flow, and failed to span the stream channel. As a result, pool formation associated with LWD is generally lacking and < 20% of the wood was associated with sediment storage. Low LWD volumes are consistent with the relatively young riparian stands we observed, with the large majority of trees < 20 cm DBH. These results strongly reflect the legacy of intensive timber harvest and land clearing and suggest that the frequency and distribution of LWD may be considerably less than presettlement and/or future desired conditions.

Coastal habitat and biological community response to dam removal on the Elwha River

USGS Publications Warehouse

Foley, Melissa M.; Warrick, Jonathan A.; Ritchie, Andrew C.; Stevens, Andrew; Shafroth, Patrick B.; Duda, Jeff; Beirne, Matthew M.; Paradis, Rebecca; Gelfenbaum, Guy R.; McCoy, Randall; Cubley, Erin S.

2017-01-01

Habitat diversity and heterogeneity play a fundamental role in structuring ecological communities. Dam emplacement and removal can fundamentally alter habitat characteristics, which in turn can affect associated biological communities. Beginning in the early 1900s, the Elwha and Glines Canyon dams in Washington, USA, withheld an estimated 30 million tonnes of sediment from river, coastal, and nearshore habitats. During the staged removal of these dams—the largest dam removal project in history—over 14 million tonnes of sediment were released from the former reservoirs. Our interdisciplinary study in coastal habitats—the first of its kind—shows how the physical changes to the river delta and estuary habitats during dam removal were linked to responses in biological communities. Sediment released during dam removal resulted in over a meter of sedimentation in the estuary and over 400 m of expansion of the river mouth delta landform. These changes increased the amount of supratidal and intertidal habitat, but also reduced the influx of seawater into the pre-removal estuary complex. The effects of these geomorphic and hydrologic changes cascaded to biological systems, reducing the abundance of macroinvertebrates and fish in the estuary and shifting community composition from brackish to freshwater-dominated species. Vegetation did not significantly change on the delta, but pioneer vegetation increased during dam removal, coinciding with the addition of newly available habitat. Understanding how coastal habitats respond to large-scale human stressors—and in some cases the removal of those stressors—is increasingly important as human uses and restoration activities increase in these habitats.

High salmon density and low discharge create periodic hypoxia in coastal rivers

Treesearch

Christopher J. Sergeant; J. Ryan Bellmore; Casey McConnell; Jonathan W. Moore

2017-01-01

Dissolved oxygen (DO) is essential to the survival of almost all aquatic organisms. Here, we examine the possibility that abundant Pacific salmon (Oncorhynchus spp.) and low streamflow combine to create hypoxic events in coastal rivers. Using high-frequency DO time series from two similar watersheds in southeastern Alaska, we summarize DO regimes...

Characterization of labile organic carbon in coastal wetland soils of the Mississippi River deltaic plain: relationships to carbon functionalities.

PubMed

Dodla, Syam K; Wang, Jim J; Delaune, Ronald D

2012-10-01

Adequate characterization of labile organic carbon (LOC) is essential to the understanding of C cycling in soil. There has been very little evaluation about the nature of LOC characterizations in coastal wetlands, where soils are constantly influenced by different redox fluctuations and salt water intrusions. In this study, we characterized and compared LOC fractions in coastal wetland soils of the Mississippi River deltaic plain using four different methods including 1) aerobically mineralizable C (AMC), 2) cold water extractable C (CWEC), 3) hot water extractable C (HWEC), and 4) salt extractable C (SEC), as well as acid hydrolysable C (AHC) which includes both labile and slowly degradable organic C. Molecular organic C functional groups of these wetland soils were characterized by (13)C solid-state nuclear magnetic resonance (NMR). The LOC and AHC increased with soil organic C (SOC) regardless of wetland soil type. The LOC estimates by four different methods were positively and significantly linearly related to each other (R(2)=0.62-0.84) and with AHC (R(2)=0.47-0.71). The various LOC fractions accounted for ≤4.3% of SOC whereas AHC fraction represented 16-49% of SOC. AMC was influenced positively by O/N-alkyl and carboxyl C but negatively by alkyl C, whereas CWEC and SEC fractions were influenced only positively by carboxyl C but negatively by alkyl C in SOC. On the other hand, HWEC fraction was found to be only influenced positively by carbonyl C, and AHC positively by O/N-alkyl and alkyl C but negatively by aromatic C groups in SOC. Overall these relations suggested different contributions of various molecular organic C moieties to LOC in these wetlands from those often found for upland soils. The presence of more than 50% non-acid hydrolysable C suggested the dominance of relatively stable SOC pool that would be sequestered in these Mississippi River deltaic plain coastal wetland soils. The results have important implications to the understanding of the

Spatio-temporal assessment and trend analysis of surface water salinity in the coastal region of Bangladesh.

PubMed

Shammi, Mashura; Rahman, Md Mostafizur; Islam, Md Atikul; Bodrud-Doza, Md; Zahid, Anwar; Akter, Yeasmin; Quaiyum, Samia; Kurasaki, Masaaki

2017-06-01

The study was designed to collect water samples over two seasons-wet-monsoon season (n = 96) (March-April) and dry-monsoon season (n = 44) (September-October)-to understand the seasonal variation in anion and cation hydrochemistry of the coastal rivers and estuaries contributing in the spatial trend in salinity. Hydrochemical examination of wet-monsoon season primarily revealed Ca-Mg-HCO 3 type (66%) and followed by Na-Cl type (17.70%) water. In the dry-monsoon season, the scenario reversed with primary water being Na-Cl type (52.27%) followed by Ca-Mg-HCO 3 type (31.81%). Analysis of Cl/Br molar ratio vs. Cl (mg/L) depicted sampling area affected by seawater intrusion (SWI). Spatial analysis by ordinary kriging method confirmed approximately 77% sample in the dry-monsoon, and 34% of the wet-monsoon season had shown SWI. The most saline-intruded areas in the wet-monsoon seasons were extreme south-west coastal zone of Bangladesh, lower Meghna River floodplain and Meghna estuarine floodplain and south-eastern part of Chittagong coastal plains containing the districts of Chittagong and Cox's Bazar adjacent to Bay of Bengal. In addition, mid-south zone is also affected slightly in the dry-monsoon season. From the analyses of data, this study could further help to comprehend seasonal trends in the hydrochemistry and water quality of the coastal and estuarine rivers. In addition, it can help policy makers to obligate some important implications for the future initiatives taken for the management of land, water, fishery, agriculture and environment of coastal rivers and estuaries of Bangladesh.

National Coastal Geology Program: a plan of geologic research on coastal erosion, coastal wetlands, polluted sediments, and coastal hard-mineral resources

USGS Publications Warehouse

,

1990-01-01

More than 50 percent of the U.S. population currently live within 50 miles of an ocean, Great Lake, or major estuary. According to forecasts, the concentration of people along our coastlines will continue to increase into the 21st century. In addition to residential and commercial buildings and facilities worth tens of billions of dollars, the coasts and associated wetlands are natural resources of tremendous value, with estimates in excess of $13 billion per year for commercial and recreational fisheries alone. Human activities and natural processes are stressing the coastal environment. * Each of the coastal states and island territories is suffering problems related to coastal erosion. * Deterioration of wetlands is widespread and of great public concern. * Pollutants carried by rivers or runoff are discharged directly into coastal waters and accumulate in the sediments on the sea floor, in some areas causing damage to living resources and presenting a threat to public health. * Onshore sources for hard-mineral resources, such as sand and gravel used for construction purposes, are becoming increasingly difficult to find. New sources are being sought in coastal waters. Coastal issues will become even more important into the next century if sea level is significantly influenced by climate change and other factors.

Nutrient Loads Flowing into Coastal Waters from the Main Rivers of China (2006–2012)

PubMed Central

Tong, Yindong; Zhao, Yue; Zhen, Gengchong; Chi, Jie; Liu, Xianhua; Lu, Yiren; Wang, Xuejun; Yao, Ruihua; Chen, Junyue; Zhang, Wei

2015-01-01

Based on monthly monitoring data of unfiltered water, the nutrient discharges of the eight main rivers flowing into the coastal waters of China were calculated from 2006 to 2012. In 2012, the total load of NH3-N (calculated in nitrogen), total nitrogen (TN, calculated in nitrogen) and total phosphorus (TP, calculated in phosphorus) was 5.1 × 105, 3.1 × 106 and 2.8 × 105 tons, respectively, while in 2006, the nutrient load was 7.4 × 105, 2.2 × 106 and 1.6 × 105 tons, respectively. The nutrient loading from the eight major rivers into the coastal waters peaked in summer and autumn, probably due to the large water discharge in the wet season. The Yangtze River was the largest riverine nutrient source for the coastal waters, contributing 48% of the NH3-N discharges, 66% of the TN discharges and 84% of the TP discharges of the eight major rivers in 2012. The East China Sea received the majority of the nutrient discharges, i.e. 50% of NH3-N (2.7 × 105 tons), 70% of TN (2.2 × 106 tons) and 87% of TP (2.5 × 105 tons) in 2012. The riverine discharge of TN into the Yellow Sea and Bohai Sea was lower than that from the direct atmospheric deposition, while for the East China Sea, the riverine TN input was larger. PMID:26582206

Issues in ecology: Nutrient pollution of coastal rivers, bays, and seas

USGS Publications Warehouse

Howarth, Robert W.; Anderson, D. B.; Cloern, James E.; Elfring, Chris; Hopkinson, Charles S.; Lapointe, Brian; Maloney, Thomas J.; Marcus, Nancy; McGlathery, Karen; Sharpley, A.N.; Walker, D.

2000-01-01

Over the past 40 years, antipollution laws have greatly reduced discharges of toxic substances into our coastal waters. This effort, however, has focused largely on point-source pollution of industrial and municipal effluent. No comparable effort has been made to restrict the input of nitrogen (N) from municipal effluent, nor to control the flows of N and phosphorus (P) that enter waterways from dispersed or nonpoint sources such as agricultural and urban runoff or as airborne pollutants. As a result, inputs of nonpoint pollutants, particularly N, have increased dramatically. Nonpoint pollution from N and P now represents the largest pollution problem facing the vital coastal waters of the United States. Nutrient pollution is the common thread that links an array of problems along the nation’s coastline, including eutrophication, harmful algal blooms, ”dead zones,” fish kills, some shellfish poisonings, loss of seagrass and kelp beds, some coral reef destruction, and even some marine mammal and seabird deaths. More than 60 percent of our coastal rivers and bays in every coastal state of the continental United States are moderately to severely degraded by nutrient pollution. This degradation is particularly severe in the mid Atlantic states, in the southeast, and in the Gulf of Mexico. A recent report from the National Research Council entitled “Clean Coastal Waters: Understanding and Reduc- ing the Effects of Nutrient Pollution” concludes that: Nutrient over-enrichment of coastal ecosystems generally triggers ecological changes that decrease the biologi- cal diversity of bays and estuaries. While moderate N enrichment of some coastal waters may increase fish production, over-enrichment generally degrades the marine food web that supports commercially valuable fish. The marked increase in nutrient pollution of coastal waters has been accompanied by an increase in harmful algal blooms, and in at least some cases, pollution has triggered these blooms. High

Hydrology, geomorphology, and vegetation of Coastal Plain rivers in the southeastern United States

Treesearch

Cliff R. Hupp

2000-01-01

Rivers of the Coastal Plain of the southeastern United States are characteristically low-gradient meandering systems that develop broad floodplains subjected to frequent and prolonged flooding. These floodplains support a relatively unique forested wetland (Bottomland Hardwoods), which have received considerable ecological study, but distinctly less hydrogeomorphic...

Tracking Cholera in Coastal Regions using Satellite Observations

PubMed Central

Jutla, Antarpreet S; Akanda, Ali S; Islam, Shafiqul

2010-01-01

Cholera remains a significant health threat across the globe. The pattern and magnitude of the seven global pandemics suggest that cholera outbreaks primarily originate in coastal regions and then spread inland through secondary means. Cholera bacteria show strong association with plankton abundance in coastal ecosystems. This review study investigates relationship(s) between cholera incidence and coastal processes and explores utility of using remote sensing data to track coastal plankton blooms, using chlorophyll as a surrogate variable for plankton abundance, and subsequent cholera outbreaks. Most studies over the last several decades have primarily focused on the microbiological and epidemiological understanding of cholera outbreaks. Accurate identification and mechanistic understanding of large scale climatic, geophysical and oceanic processes governing cholera-chlorophyll relationship is important for developing cholera prediction models. Development of a holistic understanding of these processes requires long and reliable chlorophyll dataset(s), which are beginning to be available through satellites. We have presented a schematic pathway and a modeling framework that relate cholera with various hydroclimatic and oceanic variables for understanding disease dynamics using latest advances in remote sensing. Satellite data, with its unprecedented spatial and temporal coverage, have potentials to monitor coastal processes and track cholera outbreaks in endemic regions. PMID:21072249

Perfluoroalkyl acids in the water cycle from a freshwater river basin to coastal waters in eastern China.

PubMed

Zhu, Xiaobin; Jin, Ling; Yang, Jingping; Wu, Jianfeng; Zhang, Beibei; Zhang, Xiaowei; Yu, Nanyang; Wei, Si; Wu, Jichun; Yu, Hongxia

2017-02-01

The distribution of perfluoroalkyl acids (PFAAs), one class of persistent organic pollutants, in groundwater, especially in confined aquifers remains poorly understood. In this study, we investigated the occurrence of 12 PFAAs through a water cycle from the Huai River Basin to the Yellow Sea, including confined aquifers, unconfined aquifers, rivers, and coastal waters. We found the ubiquity of PFAAs in all types of samples, including those from confined aquifers (2.7-6.8 ng/L). Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) were the major PFAAs in all samples, accounting for an average of 49.1% (0.8-84.8%) and 33.3% (6.3-92.2%) of total PFAAs, respectively. Comparing the concentration of PFOA with that of PFOS, we found a higher concentration of PFOA in rivers and a higher concentration of PFOS in confined aquifers. Short-chain perfluoropentanoic acid accounted for an average of 10.3% (1.9-24.6%) of total PFAAs in rivers and coastal waters. Branched isomers of both PFOA and PFOS were detected in most samples (36/42 and 39/42, respectively). One-way analysis of variance indicated a significant difference in the profiles of PFAAs among the different types of water samples. Principal component analysis suggested that rainwater and recent uses of PFAAs could be the major sources of PFAAs in confined aquifers, while recent and current uses of PFAAs could be the major source of PFAAs in unconfined aquifers, rivers and coastal waters. The risk quotients of PFOA and PFOS in groundwater and rivers were 2-3 orders of magnitude lower than unity, indicating no immediate risks via drinking water consumption. Copyright © 2016 Elsevier Ltd. All rights reserved.

Historical bathymetry and bathymetric change in the Mississippi-Alabama coastal region, 1847-2009

USGS Publications Warehouse

Buster, Noreen A.; Morton, Robert A.

2011-01-01

Land loss and seafloor change around the Mississippi and Alabama (MS-AL) barrier islands are of great concern to the public and to local, state, and federal agencies. The islands provide wildlife protected areas and recreational land, and they serve as a natural first line of defense for the mainland against storm activity (index map on poster). Principal physical conditions that drive morphological seafloor and coastal change in this area include decreased sediment supply, sea-level rise, storms, and human activities (Otvos, 1970; Byrnes and others, 1991; Morton and others, 2004; Morton, 2008). Seafloor responses to the same processes can also affect the entire coastal zone. Sediment eroded from the barrier islands is entrained in the littoral system, where it is redistributed by alongshore currents. Wave and current activity is partially controlled by the profile of the seafloor, and this interdependency along with natural and anthropogenic influences has significant effects on nearshore environments. When a coastal system is altered by human activity such as dredging, as is the case of the MS-AL coastal region, the natural state and processes are altered, and alongshore sediment transport can be disrupted. As a result of deeply dredged channels, adjacent island migration is blocked, nearshore environments downdrift in the littoral system become sediment starved, and sedimentation around the channels is modified. Sediment deposition and erosion are reflected through seafloor evolution. In a rapidly changing coastal environment, understanding historically where and why changes are occurring is essential. To better assess the comprehensive dynamics of the MS-AL coastal zone, a 160-year evaluation of the bathymetry and bathymetric change of the region was conducted.

Concentrations and annual fluxes of sediment-associated chemical constituents from conterminous US coastal rivers using bed sediment data

USGS Publications Warehouse

Horowitz, Arthur J.; Stephens, Verlin C.; Elrick, Kent A.; Smith, James J.

2012-01-01

Coastal rivers represent a significant pathway for the delivery of natural and anthropogenic sediment-associated chemical constituents to the Atlantic, Pacific and Gulf of Mexico coasts of the conterminous USA. This study entails an accounting segment using published average annual suspended sediment fluxes with published sediment-associated chemical constituent concentrations for (1) baseline, (2) land-use distributions, (3) population density, and (4) worldwide means to estimate concentrations/annual fluxes for trace/major elements and total phosphorus, total organic and inorganic carbon, total nitrogen, and sulphur, for 131 coastal river basins. In addition, it entails a sampling and subsequent chemical analysis segment that provides a level of ‘ground truth’ for the calculated values, as well as generating baselines for sediment-associated concentrations/fluxes against which future changes can be evaluated. Currently, between 260 and 270 Mt of suspended sediment are discharged annually from the conterminous USA; about 69% is discharged from Gulf rivers (n = 36), about 24% from Pacific rivers (n = 42), and about 7% from Atlantic rivers (n = 54). Elevated sediment-associated chemical concentrations relative to baseline levels occur in the reverse order of sediment discharges:Atlantic rivers (49%)>Pacific rivers (40%)>Gulf rivers (23%). Elevated trace element concentrations (e.g. Cu, Hg, Pb, Zn) frequently occur in association with present/former industrial areas and/or urban centres, particularly along the northeast Atlantic coast. Elevated carbon and nutrient concentrations occur along both the Atlantic and Gulf coasts but are dominated by rivers in the urban northeast and by southeastern and Gulf coast (Florida) ‘blackwater’ streams. Elevated Ca, Mg, K, and Na distributions tend to reflect local petrology, whereas elevated Ti, S, Fe, and Al concentrations are ubiquitous, possibly because they have substantial natural as well as anthropogenic sources

Water-balance and groundwater-flow estimation for an arid environment: San Diego region, California

NASA Astrophysics Data System (ADS)

Flint, L. E.; Flint, A. L.; Stolp, B. J.; Danskin, W. R.

2012-03-01

The coastal-plain aquifer that underlies the San Diego City metropolitan area in southern California is a groundwater resource. The understanding of the region-wide water balance and the recharge of water from the high elevation mountains to the east needs to be improved to quantify the subsurface inflows to the coastal plain in order to develop the groundwater as a long term resource. This study is intended to enhance the conceptual understanding of the water balance and related recharge processes in this arid environment by developing a regional model of the San Diego region and all watersheds adjacent or draining to the coastal plain, including the Tijuana River basin. This model was used to quantify the various components of the water balance, including semi-quantitative estimates of subsurface groundwater flow to the coastal plain. Other approaches relying on independent data were used to test or constrain the scoping estimates of recharge and runoff, including a reconnaissance-level groundwater model of the San Diego River basin, one of three main rivers draining to the coastal plain. Estimates of subsurface flow delivered to the coastal plain from the river basins ranged from 12.3 to 28.8 million m3 yr-1 from the San Diego River basin for the calibration period (1982-2009) to 48.8 million m3 yr-1 from all major river basins for the entire coastal plain for the long-term period 1940-2009. This range of scoping estimates represents the impact of climatic variability and realistically bounds the likely groundwater availability, while falling well within the variable estimates of regional recharge. However, the scarcity of physical and hydrologic data in this region hinders the exercise to narrow the range and reduce the uncertainty.

Coastal flooding hazard assessment on potentially vulnerable coastal sectors at Varna regional coast

NASA Astrophysics Data System (ADS)

Eftimova, Petya; Valchev, Nikolay; Andreeva, Nataliya

2017-04-01

Storm induced flooding is one of the most significant threats that the coastal communities face. In the light of the climate change it is expected to gain even more importance. Therefore, the adequate assessment of this hazard could increase the capability of mitigation of environmental, social, and economic impacts. The study was accomplished in the frames of the Coastal Risk Assessment Framework (CRAF) developed within the FP7 RISC-KIT Project (Resilience-Increasing Strategies for Coasts - toolkit). The hazard assessment was applied on three potentially vulnerable coastal sectors located at the regional coast of Varna, Bulgarian Black Sea coast. The potential "hotspot" candidates were selected during the initial phase of CRAF which evaluated the coastal risks at regional level. The area of interest comprises different coastal types - from natural beaches and rocky cliffs to man modified environments presented by coastal and port defense structures such as the Varna Port breakwater, groynes, jetties and beaches formed by the presence of coastal structures. The assessment of coastal flooding was done using combination of models -XBeach model and LISFLOOD inundation model applied consecutively. The XBeach model was employed to calculate the hazard intensities at the coast up to the berm crest, while LISFLOOD model was used to calculate the intensity and extent of flooding in the hinterland. At the first stage, 75 extreme storm events were simulated using XBeach model run in "non-hydrostatic" mode to obtain series of flood depth, depth-velocity and overtopping discharges at the predefined coastal cross-shore transects. Extreme value analysis was applied to the calculated hazard parameters series in order to determine their probability distribution functions. This is so called response approach, which is focused on the onshore impact rather than on the deep water boundary conditions. It allows calculation of the hazard extremes probability distribution induced by a

18 CFR 725.7 - Regional or river basin planning.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 18 Conservation of Power and Water Resources 2 2013-04-01 2012-04-01 true Regional or river basin... Responsibilities § 725.7 Regional or river basin planning. (a) In agreements between river basin commissions or other regional planning sponsors and the Council for the preparation and revision of regional and river...

18 CFR 725.7 - Regional or river basin planning.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 18 Conservation of Power and Water Resources 2 2014-04-01 2014-04-01 false Regional or river basin... Responsibilities § 725.7 Regional or river basin planning. (a) In agreements between river basin commissions or other regional planning sponsors and the Council for the preparation and revision of regional and river...

Meteorological Influences on Nitrogen Dynamics of a Coastal Onsite Wastewater Treatment System

PubMed Central

O’Driscoll, M.A.; Humphrey, C. P.; Deal, N.E.; Lindbo, D.L.; Zarate-Bermudez, M.A.

2016-01-01

Onsite wastewater treatment systems (OWTS) can contribute nitrogen (N) to coastal waters. In coastal areas with shallow groundwater, OWTS are likely affected by meteorological events. However, the meteorological influences on temporal variability of N exports from OWTS are not well documented. Hydrogeological characterization and seasonal monitoring of wastewater and groundwater quality were conducted at a residence adjacent to the Pamlico River Estuary, North Carolina during a two-year field study (October 2009–2011). Rainfall was elevated during the first study year, relative to the annual mean. In the second year, drought was followed by extreme precipitation from Hurricane Irene. Recent meteorological conditions influenced N speciation and concentrations in groundwater. Groundwater total dissolved nitrogen (TDN) beneath the OWTS drainfield was dominated by nitrate during the drought; during wetter periods ammonium and organic N were common. Effective precipitation (P-ET) affected OWTS TDN exports because of its influence on groundwater recharge and discharge. Groundwater nitrate-N concentrations beneath the drainfield were typically higher than 10 mg/l when total bi-weekly precipitation was less than evapotranspiration (precipitation deficit: P15 m downgradient of the drainfield. Although OWTS nitrate inputs caused elevated groundwater nitrate concentrations between the drainfield and the estuary, the majority of nitrate was attenuated via denitrification between the OWTS and 48 m to the estuary. However, DON originating from the OWTS was mobile and contributed to elevated TDN concentrations along the groundwater flowpath to the estuary. PMID:25602204

The Farther the Better: Effects of Multiple Environmental Variables on Reef Fish Assemblages along a Distance Gradient from River Influences.

PubMed

Neves, Leonardo M; Teixeira-Neves, Tatiana P; Pereira-Filho, Guilherme H; Araújo, Francisco G

2016-01-01

The conservation and management of site-attached assemblages of coastal reefs are particularly challenging because of the tremendous environmental variation that exists at small spatial scales. In this sense, understanding the primary sources of variation in spatial patterns of the biota is fundamental for designing effective conservation policies. We investigated spatial variation in fish assemblages around the windward and leeward sides of coastal islands situated across a gradient of riverine influence (13 km in length). Specifically, relationships between rocky reef fish assemblages and benthic, topographic and physical predictors were assessed. We hypothesized that river induced disturbances may overcome local habitat features in modeling spatial patterns of fish distribution. Fish assemblages varied primarily due to the strong directional gradient of riverine influence (22.6% of the estimated components of variation), followed by topographic complexity (15%), wave exposure (9.9%), and benthic cover (8%). The trophic structure of fish assemblages changed from having a high abundance of invertebrate feeders in macroalgae-dominated reefs close to river mouths to a high proportion of herbivores, planktivores and invertebrate feeder species in reefs with large boulders covered by epilithic algal matrices, as the distance from rivers increased. This gradient led to an increase of 4.5-fold in fish richness and fish trophic group diversity, 11-fold in fish biomass and 10-fold in fish abundance. Our results have implications for the conservation and monitoring of assemblages patchily distributed at small spatial scales. The major role of distance from river influences on fish assemblages rather than benthic cover and topographic complexity suggest that managing land-based activities should be a conservation priority toward reef restoration.

The Farther the Better: Effects of Multiple Environmental Variables on Reef Fish Assemblages along a Distance Gradient from River Influences

PubMed Central

Neves, Leonardo M.; Teixeira-Neves, Tatiana P.; Pereira-Filho, Guilherme H.; Araújo, Francisco G.

2016-01-01

The conservation and management of site-attached assemblages of coastal reefs are particularly challenging because of the tremendous environmental variation that exists at small spatial scales. In this sense, understanding the primary sources of variation in spatial patterns of the biota is fundamental for designing effective conservation policies. We investigated spatial variation in fish assemblages around the windward and leeward sides of coastal islands situated across a gradient of riverine influence (13 km in length). Specifically, relationships between rocky reef fish assemblages and benthic, topographic and physical predictors were assessed. We hypothesized that river induced disturbances may overcome local habitat features in modeling spatial patterns of fish distribution. Fish assemblages varied primarily due to the strong directional gradient of riverine influence (22.6% of the estimated components of variation), followed by topographic complexity (15%), wave exposure (9.9%), and benthic cover (8%). The trophic structure of fish assemblages changed from having a high abundance of invertebrate feeders in macroalgae-dominated reefs close to river mouths to a high proportion of herbivores, planktivores and invertebrate feeder species in reefs with large boulders covered by epilithic algal matrices, as the distance from rivers increased. This gradient led to an increase of 4.5-fold in fish richness and fish trophic group diversity, 11-fold in fish biomass and 10-fold in fish abundance. Our results have implications for the conservation and monitoring of assemblages patchily distributed at small spatial scales. The major role of distance from river influences on fish assemblages rather than benthic cover and topographic complexity suggest that managing land-based activities should be a conservation priority toward reef restoration. PMID:27907017

Sele coastal plain flood risk due to wave storm and river flow interaction

NASA Astrophysics Data System (ADS)

Benassai, Guido; Aucelli, Pietro; Di Paola, Gianluigi; Della Morte, Renata; Cozzolino, Luca; Rizzo, Angela

2016-04-01

Wind waves, elevated water levels and river discharge can cause flooding in low-lying coastal areas, where the water level is the interaction between wave storm elevated water levels and river flow interaction. The factors driving the potential flood risk include weather conditions, river water stage and storm surge. These data are required to obtain inputs to run the hydrological model used to evaluate the water surface level during ordinary and extreme events regarding both the fluvial overflow and storm surge at the river mouth. In this paper we studied the interaction between the sea level variation and the river hydraulics in order to assess the location of the river floods in the Sele coastal plain. The wave data were acquired from the wave buoy of Ponza, while the water level data needed to assess the sea level variation were recorded by the tide gauge of Salerno. The water stages, river discharges and rating curves for Sele river were provided by Italian Hydrographic Service (Servizio Idrografico e Mareografico Nazionale, SIMN).We used the dataset of Albanella station (40°29'34.30"N, 15°00'44.30"E), located around 7 km from the river mouth. The extreme river discharges were evaluated through the Weibull equation, which were associated with their return period (TR). The steady state river water levels were evaluated through HEC-RAS 4.0 model, developed by Hydrologic Engineering Center (HEC) of the United States Army Corps of Engineers Hydrologic Engineering Center (USACE,2006). It is a well-known 1D model that computes water surface elevation (WSE) and velocity at discrete cross-sections by solving continuity, energy and flow resistance (e.g., Manning) equation. Data requirements for HEC-RAS include topographic information in the form of a series of cross-sections, friction parameter in the form of Manning's n values across each cross-section, and flow data including flow rates, flow change locations, and boundary conditions. For a steady state sub

Spatially Resolving Ocean Color and Sediment Dispersion in River Plumes, Coastal Systems, and Continental Shelf Waters

NASA Technical Reports Server (NTRS)

Aurin, Dirk Alexander; Mannino, Antonio; Franz, Bryan

2013-01-01

Satellite remote sensing of ocean color in dynamic coastal, inland, and nearshorewaters is impeded by high variability in optical constituents, demands specialized atmospheric correction, and is limited by instrument sensitivity. To accurately detect dispersion of bio-optical properties, remote sensors require ample signal-to-noise ratio (SNR) to sense small variations in ocean color without saturating over bright pixels, an atmospheric correction that can accommodate significantwater-leaving radiance in the near infrared (NIR), and spatial and temporal resolution that coincides with the scales of variability in the environment. Several current and historic space-borne sensors have met these requirements with success in the open ocean, but are not optimized for highly red-reflective and heterogeneous waters such as those found near river outflows or in the presence of sediment resuspension. Here we apply analytical approaches for determining optimal spatial resolution, dominant spatial scales of variability ("patches"), and proportions of patch variability that can be resolved from four river plumes around the world between 2008 and 2011. An offshore region in the Sargasso Sea is analyzed for comparison. A method is presented for processing Moderate Resolution Imaging Spectroradiometer (MODIS) Aqua and Terra imagery including cloud detection, stray lightmasking, faulty detector avoidance, and dynamic aerosol correction using short-wave- and near-infrared wavebands in extremely turbid regions which pose distinct optical and technical challenges. Results showthat a pixel size of approx. 520 mor smaller is generally required to resolve spatial heterogeneity in ocean color and total suspended materials in river plumes. Optimal pixel size increases with distance from shore to approx. 630 m in nearshore regions, approx 750 m on the continental shelf, and approx. 1350 m in the open ocean. Greater than 90% of the optical variability within plume regions is resolvable with

UV filters, ethylhexyl methoxycinnamate, octocrylene and ethylhexyl dimethyl PABA from untreated wastewater in sediment from eastern Mediterranean river transition and coastal zones.

PubMed

Amine, Helmieh; Gomez, Elena; Halwani, Jalal; Casellas, Claude; Fenet, Hélène

2012-11-01

UVF may occur in the aquatic environment through two principal sources: direct inputs from recreational activities and indirect wastewater- and river-borne inputs. The aim of this study was to obtain a first overview of levels of three UVF (EHMC, OC and OD-PABA) in coastal areas subjected to river inputs, untreated wastewater discharges and dumpsite leachates. We selected three eastern Mediterranean rivers that have been impacted for decades by untreated wastewater release and collected sediment in the coastal zone during the hot and humid seasons. Western Mediterranean sites receiving treated wastewaters were analyzed for comparison. The results gave an overview of sediment contamination under these two contrasted situations representative of Mediterranean coastal areas without bathing activities. The analysis of the three UVF revealed the ubiquity and high point source contamination by EHMC and OC in transition and coastal zones, with levels as high as 128 ng g(-1)d.w. OD-PABA was also frequently detected, but at lower concentrations (river input that could be exacerbated by the direct contribution in coastal bathing zones. Copyright © 2012. Published by Elsevier Ltd.

Coastal change from a massive sediment input: Dam removal, Elwha River, Washington, USA

USGS Publications Warehouse

Warrick, Jonathan A.; Gelfenbaum, Guy R.; Stevens, Andrew; Miller, Ian M.; Kaminsky, George M.; Foley, Melissa M.

2015-01-01

The removal of two large dams on the Elwha River, Washington, provides an ideal opportunity to study coastal morphodynamics during increased sediment supply. The dam removal project exposed ~21 million cubic meters (~30 million tonnes) of sediment in the former reservoirs, and this sediment was allowed to erode by natural river processes. Elevated rates of sand and gravel sediment transport in the river occurred during dam removal. Most of the sediment was transported to the coast, and this renewed sediment supply resulted in hundreds of meters of seaward expansion of the river delta since 2011. Our most recent survey in January 2015 revealed that a cumulative ~3.5 million m3 of sediment deposition occurred at the delta since the beginning of the dam removal project, and that aggradation had exceeded 8 m near the river mouth. Some of the newly deposited sediment has been shaped by waves and currents into a series of subaerial berms that appear to move shoreward with time.

The influence of submarine groundwater discharge on greenhouse gas evasion from coastal waters (Invited)

NASA Astrophysics Data System (ADS)

Santos, I. R.

2013-12-01

Coastal waters are thought to play a major role on global carbon budgets but we still lack a quantitative understanding about some mechanisms driving greenhouse gas cycling in coastal waters. Very little is known about the role of submarine groundwater discharge (SGD) in delivering carbon to rivers, estuaries and coastal waters even though the concentrations of most carbon species in groundwater are often much higher than those in surface waters. I hypothesize that SGD plays a significant role in coastal carbon and greenhouse gas budgets even if the volumetric SGD contribution is small. I will report new, detailed observations of radon (a natural groundwater tracer) and carbon dioxide and methane concentrations and stable isotopes in tidal rivers, estuaries, coastal wetlands, mangroves and coral reef lagoons. Groundwater exchange at these contrasting sites was driven by a wide range of processes, including terrestrial hydraulic gradients, tidal pumping, and convection. In all systems, SGD was an important source of carbon dioxide, DIC, and methane to surface waters. In some cases, groundwater seepage alone could account for 100% of carbon dioxide evasion from surface waters to the atmosphere. Combining high precision in situ radon and greenhouse gas concentration and stable isotope observations allows for an effective, unambiguous assessment of how groundwater seepage drives carbon dynamics in surface waters.

The influence of ice on southern Lake Michigan coastal erosion

USGS Publications Warehouse

Barnes, P.W.; Kempema, E.W.; Reimnitz, E.; McCormick, M.

1994-01-01

Coastal ice does not protect the coast but enhances erosion by displacing severe winter wave energy from the beach to the shoreface and by entraining and transporting sediment alongshore and offshore. Three aspects of winter ice in Lake Michigan were studied over a 3-year period and found to have an important influence on coastal sediment dynamics and the coastal sediment budget: (1) the influence of coastal ice on shoreface morphology, (2) the transport of littoral sediments by ice, and (3) the formation of anchor and underwater ice as a frequent and important event entraining and transporting sediment. The nearshore ice complex contains a sediment load (0.2 - 1.2 t/m of coast) that is roughly equivalent to the average amount of sand eroded from the coastal bluffs and to the amount of sand ice- rafted offshore to the deep lake basin each year. -from Authors

Sex-biased survivorship and differences in migration of wild steelhead (Oncorhynchus mykiss) smolts from two coastal Oregon rivers

USGS Publications Warehouse

Thompson, Neil F.; Leblanc, Camille A.; Romer, Jeremy D.; Schreck, Carl B.; Blouin, Michael S.; Noakes, David L. G.

2016-01-01

In salmonids with partial migration, females are more likely than males to undergo smoltification and migrate to the ocean (vs. maturing in freshwater). However, it is not known whether sex affects survivorship during smolt migration (from fresh water to entry into the ocean). We captured wild steelhead (Oncorhynchus mykiss) smolts in two coastal Oregon rivers (USA) and collected fin tissue samples for genetic sex determination (2009; N = 70 in the Alsea and N = 69 in the Nehalem, 2010; N = 25 in the Alsea). We implanted acoustic tags and monitored downstream migration and survival until entry in to the Pacific Ocean. Survival was defined as detection at an estuary/ocean transition array. We found no effect of sex on smolt survivorship in the Nehalem River in 2009, or in the Alsea River in 2010. However, males exhibited significantly lower survival than females in the Alsea River during 2009. Residency did not influence this result as an equal proportion of males and females did not reach the estuary entrance (11% of males, 9% of females). The sexes did not differ in timing or duration of migration, so those variables seem unlikely to explain sex-biased survivorship. Larger males had higher odds of survival than smaller males in 2009, but the body size of females did not affect survivorship. The difference in survivorship between years in the Alsea River could be due to flow conditions, which were higher in 2010 than in 2009. Our findings suggest that sex may affect steelhead smolt survival during migration, but that the difference in survivorship may be weak and not a strong factor influencing adult sex ratios.

Sex biased survival and differences in migration of wild steelhead (Oncorhynchus mykiss) smolts from two coastal Oregon rivers

USGS Publications Warehouse

Thompson, Neil F.; Leblanc, Camille A.; Romer, Jeremy D.; Schreck, Carl B.; Blouin, Michael S.; Noakes, David L. G.

2016-01-01

In salmonids with partial migration, females are more likely than males to undergo smoltification and migrate to the ocean (vs. maturing in freshwater). However, it is not known whether sex affects survivorship during smolt migration (from fresh water to entry into the ocean). We captured wild steelhead (Oncorhynchus mykiss) smolts in two coastal Oregon rivers (USA) and collected fin tissue samples for genetic sex determination (2009; N = 70 in the Alsea and N = 69 in the Nehalem, 2010; N = 25 in the Alsea). We implanted acoustic tags and monitored downstream migration and survival until entry in to the Pacific Ocean. Survival was defined as detection at an estuary/ocean transition array. We found no effect of sex on smolt survivorship in the Nehalem River in 2009, or in the Alsea River in 2010. However, males exhibited significantly lower survival than females in the Alsea River during 2009. Residency did not influence this result as an equal proportion of males and females did not reach the estuary entrance (11% of males, 9% of females). The sexes did not differ in timing or duration of migration, so those variables seem unlikely to explain sex-biased survivorship. Larger males had higher odds of survival than smaller males in 2009, but the body size of females did not affect survivorship. The difference in survivorship between years in the Alsea River could be due to flow conditions, which were higher in 2010 than in 2009. Our findings suggest that sex may affect steelhead smolt survival during migration, but that the difference in survivorship may be weak and not a strong factor influencing adult sex ratios.

Seasonal Changes in Bacterial and Archaeal Gene Expression Patterns across Salinity Gradients in the Columbia River Coastal Margin

PubMed Central

Smith, Maria W.; Herfort, Lydie; Tyrol, Kaitlin; Suciu, Dominic; Campbell, Victoria; Crump, Byron C.; Peterson, Tawnya D.; Zuber, Peter; Baptista, Antonio M.; Simon, Holly M.

2010-01-01

Through their metabolic activities, microbial populations mediate the impact of high gradient regions on ecological function and productivity of the highly dynamic Columbia River coastal margin (CRCM). A 2226-probe oligonucleotide DNA microarray was developed to investigate expression patterns for microbial genes involved in nitrogen and carbon metabolism in the CRCM. Initial experiments with the environmental microarrays were directed toward validation of the platform and yielded high reproducibility in multiple tests. Bioinformatic and experimental validation also indicated that >85% of the microarray probes were specific for their corresponding target genes and for a few homologs within the same microbial family. The validated probe set was used to query gene expression responses by microbial assemblages to environmental variability. Sixty-four samples from the river, estuary, plume, and adjacent ocean were collected in different seasons and analyzed to correlate the measured variability in chemical, physical and biological water parameters to differences in global gene expression profiles. The method produced robust seasonal profiles corresponding to pre-freshet spring (April) and late summer (August). Overall relative gene expression was high in both seasons and was consistent with high microbial abundance measured by total RNA, heterotrophic bacterial production, and chlorophyll a. Both seasonal patterns involved large numbers of genes that were highly expressed relative to background, yet each produced very different gene expression profiles. April patterns revealed high differential gene expression in the coastal margin samples (estuary, plume and adjacent ocean) relative to freshwater, while little differential gene expression was observed along the river-to-ocean transition in August. Microbial gene expression profiles appeared to relate, in part, to seasonal differences in nutrient availability and potential resource competition. Furthermore, our results

40 CFR 81.152 - Southern Coastal Plain Intrastate Air Quality Control Region.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 17 2011-07-01 2011-07-01 false Southern Coastal Plain Intrastate Air Quality Control Region. 81.152 Section 81.152 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Air Quality Control Regions § 81.152 Southern Coastal Plain Intrastate Air Quality Control Region. The...

40 CFR 81.149 - Northern Coastal Plain Intrastate Air Quality Control Region.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 18 2013-07-01 2013-07-01 false Northern Coastal Plain Intrastate Air Quality Control Region. 81.149 Section 81.149 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Air Quality Control Regions § 81.149 Northern Coastal Plain Intrastate Air Quality Control Region. The...

40 CFR 81.149 - Northern Coastal Plain Intrastate Air Quality Control Region.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 17 2010-07-01 2010-07-01 false Northern Coastal Plain Intrastate Air Quality Control Region. 81.149 Section 81.149 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Air Quality Control Regions § 81.149 Northern Coastal Plain Intrastate Air Quality Control Region. The...

40 CFR 81.152 - Southern Coastal Plain Intrastate Air Quality Control Region.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 18 2014-07-01 2014-07-01 false Southern Coastal Plain Intrastate Air Quality Control Region. 81.152 Section 81.152 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Air Quality Control Regions § 81.152 Southern Coastal Plain Intrastate Air Quality Control Region. The...

40 CFR 81.152 - Southern Coastal Plain Intrastate Air Quality Control Region.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 17 2010-07-01 2010-07-01 false Southern Coastal Plain Intrastate Air Quality Control Region. 81.152 Section 81.152 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Air Quality Control Regions § 81.152 Southern Coastal Plain Intrastate Air Quality Control Region. The...

40 CFR 81.152 - Southern Coastal Plain Intrastate Air Quality Control Region.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 18 2013-07-01 2013-07-01 false Southern Coastal Plain Intrastate Air Quality Control Region. 81.152 Section 81.152 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Air Quality Control Regions § 81.152 Southern Coastal Plain Intrastate Air Quality Control Region. The...

40 CFR 81.149 - Northern Coastal Plain Intrastate Air Quality Control Region.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 18 2012-07-01 2012-07-01 false Northern Coastal Plain Intrastate Air Quality Control Region. 81.149 Section 81.149 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Air Quality Control Regions § 81.149 Northern Coastal Plain Intrastate Air Quality Control Region. The...

40 CFR 81.152 - Southern Coastal Plain Intrastate Air Quality Control Region.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 18 2012-07-01 2012-07-01 false Southern Coastal Plain Intrastate Air Quality Control Region. 81.152 Section 81.152 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Air Quality Control Regions § 81.152 Southern Coastal Plain Intrastate Air Quality Control Region. The...

40 CFR 81.149 - Northern Coastal Plain Intrastate Air Quality Control Region.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 18 2014-07-01 2014-07-01 false Northern Coastal Plain Intrastate Air Quality Control Region. 81.149 Section 81.149 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Air Quality Control Regions § 81.149 Northern Coastal Plain Intrastate Air Quality Control Region. The...

40 CFR 81.149 - Northern Coastal Plain Intrastate Air Quality Control Region.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 17 2011-07-01 2011-07-01 false Northern Coastal Plain Intrastate Air Quality Control Region. 81.149 Section 81.149 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Air Quality Control Regions § 81.149 Northern Coastal Plain Intrastate Air Quality Control Region. The...

Urban rivers as hotspots of regional nitrogen pollution.

PubMed

Zhang, Xiaohong; Wu, Yiyun; Gu, Baojing

2015-10-01

Excess nitrogen inputs to terrestrial ecosystems via human activities have deteriorated water qualities on regional scales. Urban areas as settlements of over half global population, however, were usually not considered in the analysis of regional water pollution. Here, we used a 72-month monitoring data of water qualities in Hangzhou, China to test the role of urban rives in regional nitrogen pollution and how they response to the changes of human activities. Concentrations of ammonium nitrogen in urban rivers were 3-5 times higher than that in regional rivers. Urban rivers have become pools of reactive nitrogen and hotspots of regional pollution. Moreover, this river pollution is not being measured by current surface water monitoring networks that are designed to measure broader regional patterns, resulting in an underestimation of regional pollution. This is crucial to urban environment not only in China, but also in other countries, where urban rivers are seriously polluted. Copyright © 2015 Elsevier Ltd. All rights reserved.

Enhancing mud supply from the Lower Missouri River to the Mississippi River Delta USA: Dam bypassing and coastal restoration

NASA Astrophysics Data System (ADS)

Kemp, G. Paul; Day, John W.; Rogers, J. David; Giosan, Liviu; Peyronnin, Natalie

2016-12-01

Sand transport to the Mississippi River Delta (MRD) remains sufficient to build wetlands in shallow, sheltered coastal bays fed by engineered diversions on the Mississippi River (MR) and its Atchafalaya River (AR) distributary. But suspended mud (silt & clay) flux to the coast has dropped from a mean of 390 Mt y-1 in the early 1950s, to 100 Mt y-1 since 1970. This fine-grained sediment travels deeper into receiving estuarine basins and plays a critical role in sustaining existing marshes. Virtually all of the 300 Mt y-1 of missing mud once flowed from the Missouri River (MOR) Basin before nearly 100 dams were built as part of the Pick-Sloan water development project. About 100 Mt y-1 is now intercepted by main-stem Upper MOR dams closed in 1953. But the remaining 200 Mt y-1 is trapped by impoundments built on tributaries to the Lower MOR in the 1950s and 1960s. Sediment flux during the post-dam high MOR discharge years of 1973, 1993 and 2011 approached pre-dam levels when tributaries to the Lower MOR, including the Platte and Kansas Rivers, contributed to flood flows. West bank tributaries drain a vast, arid part of the Great Plains, while those entering from the east bank traverse the lowlands of the MOR floodplain. Both provinces are dominated by highly erodible loess soils. Staunching the continued decline in MR fine-grained sediment flux has assumed greater importance now that engineered diversions are being built to reconnect the Lowermost MR to the MRD. Tributary dam bypassing in the Lower MOR basin could increase mud supply to the MRD by 100-200 Mt y-1 within 1-2 decades. Such emergency measures to save the MRD are compatible with objectives of the Missouri River Restoration and Platte River Recovery Programs to restore MOR riparian habitat for endangered species. Rapid mobilization to shunt fine-grained sediments past as many as 50 Lower MOR tributary dams in several U.S. states will undoubtedly require as much regional coordination and funding in the 21st

The effect of wind on the dispersal of a tropical small river plume

NASA Astrophysics Data System (ADS)

Zhao, Junpeng; Gong, Wenping; Shen, Jian

2018-03-01

Wanquan River is a small river located in Hainan, a tropical island in China. As the third largest river in Hainan, the river plume plays an important role in the regional terrigenous mass transport, coastal circulation, and the coral reef's ecosystem. Studies have shown that wind forcings significantly influence river plume dynamics. In this study, wind effects on the dispersal of the river plume and freshwater transport were examined numerically using a calibrated, unstructured, finite volume numerical model (FVCOM). Both wind direction and magnitude were determined to influence plume dispersal. Northeasterly (downwelling-favorable) winds drove freshwater down-shelf while southeasterly (onshore) winds drove water up-shelf (in the sense of Kelvin wave propagation), and were confined near the coast. Southwesterly (upwelling-favorable) and north-westerly (offshore) winds transport more freshwater offshore. The transport flux is decomposed into an advection, a vertical shear, and an oscillatory component. The advection flux dominates the freshwater transport in the coastal area and the vertical shear flux is dominant in the offshore area. For the upwelling-favorable wind, the freshwater transport becomes more controlled by the advection transport with an increase in wind stress, due to enhanced vertical mixing. The relative importance of wind forcing and buoyancy force was investigated. It was found that, when the Wedderburn number is larger than one, the plume was dominated by wind forcing, although the importance of wind varies in different parts of the plume. The water column stratification decreased as a whole under the prevailing southwesterly wind, with the exception of the up-shelf and offshore areas.

Coral skeletal carbon isotopes (δ13C and Δ14C) record the delivery of terrestrial carbon to the coastal waters of Puerto Rico

USGS Publications Warehouse

Moyer, R.P.; Grottoli, A.G.

2011-01-01

Tropical small mountainous rivers deliver a poorly quantified, but potentially significant, amount of carbon to the world's oceans. However, few historical records of land-ocean carbon transfer exist for any region on Earth. Corals have the potential to provide such records, because they draw on dissolved inorganic carbon (DIC) for calcification. In temperate systems, the stable- (δ13C) and radiocarbon (Δ14C) isotopes of coastal DIC are influenced by the δ13C and Δ14C of the DIC transported from adjacent rivers. A similar pattern should exist in tropical coastal DIC and hence coral skeletons. Here, δ13C and Δ14C measurements were made in a 56-year-old Montastraea faveolata coral growing ~1 km from the mouth of the Rio Fajardo in eastern Puerto Rico. Additionally, the δ13C and Δ14C values of the DIC of the Rio Fajardo and its adjacent coastal waters were measured during two wet and dry seasons. Three major findings were observed: (1) synchronous depletions of both δ13C and Δ14C in the coral skeleton are annually coherent with the timing of peak river discharge, (2) riverine DIC was always more depleted in δ13C and Δ14C than seawater DIC, and (3) the correlation of δ13C and Δ14C was the same in both coral skeleton and the DIC of the river and coastal waters. These results indicate that coral skeletal δ13C and Δ14C are recording the delivery of riverine DIC to the coastal ocean. Thus, coral records could be used to develop proxies of historical land-ocean carbon flux for many tropical regions. Such information could be invaluable for understanding the role of tropical land-ocean carbon flux in the context of land-use change and global climate change.

Coral skeletal carbon isotopes (δ13C and Δ14C) record the delivery of terrestrial carbon to the coastal waters of Puerto Rico

USGS Publications Warehouse

Moyer, R.P.; Grottoli, A.G.

2011-01-01

Tropical small mountainous rivers deliver a poorly quantified, but potentially significant, amount of carbon to the world's oceans. However, few historical records of land-ocean carbon transfer exist for any region on Earth. Corals have the potential to provide such records, because they draw on dissolved inorganic carbon (DIC) for calcification. In temperate systems, the stable- (??13C) and radiocarbon (??14C) isotopes of coastal DIC are influenced by the ??13C and ??14C of the DIC transported from adjacent rivers. A similar pattern should exist in tropical coastal DIC and hence coral skeletons. Here, ??13C and ??14C measurements were made in a 56-year-old Montastraea faveolata coral growing ~1 km from the mouth of the Rio Fajardo in eastern Puerto Rico. Additionally, the ??13C and ??14C values of the DIC of the Rio Fajardo and its adjacent coastal waters were measured during two wet and dry seasons. Three major findings were observed: (1) synchronous depletions of both ??13C and ??14C in the coral skeleton are annually coherent with the timing of peak river discharge, (2) riverine DIC was always more depleted in ??13C and ??14C than seawater DIC, and (3) the correlation of ??13C and ??14C was the same in both coral skeleton and the DIC of the river and coastal waters. These results indicate that coral skeletal ??13C and ??14C are recording the delivery of riverine DIC to the coastal ocean. Thus, coral records could be used to develop proxies of historical land-ocean carbon flux for many tropical regions. Such information could be invaluable for understanding the role of tropical land-ocean carbon flux in the context of land-use change and global climate change. ?? 2011 United States Geological Survey.

Influences of historical and projected changes in climate and land management practices on nutrient fluxes in the Mississippi River Basin, 1948-2100

NASA Astrophysics Data System (ADS)

Spak, S.; Ward, A. S.; Li, Y.; Dalrymple, K. E.

2016-12-01

Nitrogen fertilization is central to contemporary row crop production in the U.S., but resultant nitrate transport leads to eutrophication, hypoxia, and algal blooms throughout the Mississippi River Basin and in coastal waters of the Gulf of Mexico. Effective basin-scale nutrient management requires a comprehensive understanding of the dynamics of nitrate transport in this large river catchment and the roles of individual management practices, that must then be operationalized to optimize management for both local geophysical and agricultural conditions and in response to decadal and inter-annual variations in local and regional climate. Here, we apply ensemble simulations with Agro-IBIS and THMB using spatially and temporally specific land cover, soil, agricultural, topographic, and climate data to simulate the individual and combined effects of land management and climate on historical (1948-2007) nitrate concentrations and transport in the Mississippi River Basin. We further identify sensitivities of in-stream nitrate dynamics to local and regional applications of Best Management Practices. The ensemble resolves the effects of techniques recommended in the Iowa Nutrient Reduction Strategy, including crop rotations, fertilizer management, tillage and residue management, and cover crops. Analysis of the nitrate transport response surfaces identifies non-linear effects of combined nutrient management tactics, and quantifies the stationarity of the relative and absolute influences of land management and climate during the 60-year study period.

Communicating Coastal Risk Analysis in an Age of Climate Change

DTIC Science & Technology

2011-10-01

extratropical storm systems); the geometry and geomorphology of the area (regional and local bathymetry and topography, including rivers, marshes, and...at risk from coastal hazards including storm surge inundation, precipitation driven flooding, waves, and coastal erosion. This population segment...will likely be exposed to increased risk as impacts of a changing climate are felt through elevated sea levels and potentially increased storm

Perfluoroalkyl and polyfluoroalkyl substances in sediments from South Bohai coastal watersheds, China.

PubMed

Zhu, Zhaoyun; Wang, Tieyu; Wang, Pei; Lu, Yonglong; Giesy, John P

2014-08-30

This study investigated the concentrations and distribution of Perfluoroalkyl and polyfluoroalkyl substances (PFAS) in sediments of 12 rivers from South Bohai coastal watersheds. The highest concentrations of ΣPFAS (31.920 ng g(-1) dw) and PFOA (29.021 ng g(-1) dw) were found in sediments from the Xiaoqing River, which was indicative of local point sources in this region. As for other rivers, concentrations of ΣPFAS ranged from 0.218 to 1.583 ng g(-1) dw were found in the coastal sediments and from 0.167 to 1.953 ng g(-1) dw in the riverine sediments. Predominant PFAS from coastal and riverine areas were PFOA and PFBS, with percentages of 30% and 35%, respectively. Partitioning analysis showed the concentrations of PFNA, PFDA and PFHxS were significantly correlated with organic carbon. The results of a preliminary environmental hazard assessment showed that PFOS posed the highest hazard in the Mi River, while PFOA posed a relative higher hazard in the Xiaoqing River. Copyright © 2013 Elsevier Ltd. All rights reserved.

Tools for a sustainable management of coastal seas: analysis of Cullera Bay

NASA Astrophysics Data System (ADS)

Mestres, M.; Sierra, J. P.; Sánchez-Arcilla, A.; Mösso, C.; González del Río, J.; Rodilla, M.

2003-04-01

The quality of the water in Cullera Bay (Eastern Spanish coast) has a relevant influence on the economy of the city of Cullera, which is focused mainly on agriculture, fisheries and tourism.. However, the bay waters are highly eutrophized (e.g., González del Río, 1987) because of the large input of nutrients from the river Júcar and from an existing marine outfall that discharges untreated wastewater during the summer months. Cullera Bay has been chosen, within the framework of the European project ECOSUD, to establish a set of indicators that may be used to assess the “health state” of a coastal or estuarine region. The main goal of the ECOSUD project, which also includes the Brazilian Patos Lagoon, is to develop a methodology and tools that will help coastal managers make decisions taking into account the sustainability of coastal and estuarine resources. The execution of the project involves a combination of field campaigns and numerical modelling. The former include integrated observations of the most relevant physical and biological magnitudes, such as water currents, meteorological characteristics, and concentrations of suspended matter, nutrients and pollutants. The latter include numerical simulations of the hydrodynamic fields induced by wind conditions and river discharge, and the simulation of pollutant and nutrient transport. The combined results allow to estimate what physical, chemical or biological parameters influence the water quality in the Bay, and their effects on selected economically important indicators such as the clam population and tourism. The data obtained from the three field campaigns undertaken during the 2002 summer, and the corresponding numerical simulations, reveal the influence of the riverine and outfall discharges on the nutrient concentration gradients inside the Bay. These are determined by the local hydrodynamics, which are mainly driven by the prevailing wind (mainly from the South and Southeast, during summertime

Interaction of the sea breeze with a river breeze in an area of complex coastal heating

NASA Technical Reports Server (NTRS)

Zhong, Shiyuan; Takle, Eugene S.; Leone, John M., Jr.

1991-01-01

The interaction of the sea-breeze circulation with a river-breeze circulation in an area of complex coastal heating (east coast of Florida) was studied using a 3D finite-element mesoscale model. The model simulations are compared with temperature and wind fields observed on a typical fall day during the Kennedy Space Center Atmospheric Boundary Layer Experiment. The results from numerical experiments designed to isolate the effect of the river breeze indicate that the convergence in the sea-breeze front is suppressed when it passes over the cooler surface of the rivers.

Stream fish colonization but not persistence varies regionally across a large North American river basin

USGS Publications Warehouse

Wheeler, Kit; Wengerd, Seth J.; Walsh, Stephen J.; Martin, Zachary P.; Jelks, Howard L.; Freeman, Mary C.

2018-01-01

Many species have distributions that span distinctly different physiographic regions, and effective conservation of such taxa will require a full accounting of all factors that potentially influence populations. Ecologists recognize effects of physiographic differences in topography, geology and climate on local habitat configurations, and thus the relevance of landscape heterogeneity to species distributions and abundances. However, research is lacking that examines how physiography affects the processes underlying metapopulation dynamics. We used data describing occupancy dynamics of stream fishes to evaluate evidence that physiography influences rates at which individual taxa persist in or colonize stream reaches under different flow conditions. Using periodic survey data from a stream fish assemblage in a large river basin that encompasses multiple physiographic regions, we fit multi-species dynamic occupancy models. Our modeling results suggested that stream fish colonization but not persistence was strongly governed by physiography, with estimated colonization rates considerably higher in Coastal Plain streams than in Piedmont and Blue Ridge systems. Like colonization, persistence was positively related to an index of stream flow magnitude, but the relationship between flow and persistence did not depend on physiography. Understanding the relative importance of colonization and persistence, and how one or both processes may change across the landscape, is critical information for the conservation of broadly distributed taxa, and conservation strategies explicitly accounting for spatial variation in these processes are likely to be more successful for such taxa.

Sewage-derived nutrient dynamics in highly urbanized coastal rivers, western Japan

NASA Astrophysics Data System (ADS)

Onodera, S. I.; Saito, M.; Jin, G.; Taniguchi, M.

2016-12-01

Water pollution by domestic sewage is one of the critical environmental problems in the early stage of urbanization with significant growth of population. In case of Osaka metropolitan area in Japan, the pollution was significant until 1970s, while it has been improved by the development of sewage treatment systems. However, removal of nitrogen needs the advanced process therefore relatively large part of dissolved inorganic nitrogen (DIN) is usually discharged by treated sewage effluent. Besides, increase of sewage-derived pollutant loads through the combined sewage systems during rainfall events is recognized as a new problem in recent years. However, the impacts of sewage-derived loads on the water environment of river and coastal area have not been fully evaluated in previous studies. In the present research, we aimed to examine the dynamics of sewage-derived nutrients in highly urbanized coastal rivers. Study area is located on the coastal area of Osaka bay in Seto Inland Sea, western Japan. Treated sewage effluent is discharged from three sewage treatment plants (KH, SU and SA) to a river and channels. Water and sediment samples were collected and electric conductivity (EC), chlorophyll-a (Chl.-a) and dissolved oxygen concentration (DO) were measured from the discharging points to few kilometers offshore at 100-300 m intervals. Nutrients (nitrogen, phosphorus and silica), nitrogen and carbon contents and stable isotope ratios (δ15N and δ13C) of particulate organic matter (POM) and sediment, nitrogen and oxygen stable isotope ratios (δ15N and δ18O) in nitrate (NO3-) were measured. Nitrate-nitrogen (NO3-N) concentration were significantly high near the discharging point then it decreased to offshore suggesting that impact zone of sewage effluent is about 1 km from the discharging point. Significant NO3-N uptake by phytoplankton as well as dilution process were suggested in the area. However, the impact zone expanded more than twofold during the rainfall

A conceptual cross-scale approach for linking empirical discharge measurements and regional groundwater models with application to legacy nitrogen transport and coastal nitrogen management

NASA Astrophysics Data System (ADS)

Barclay, J. R.; Helton, A. M.; Starn, J. J.; Briggs, M. A.

2016-12-01

Despite years of management, seasonal hypoxia from excess nitrogen (N) is a pervasive problem in many coastal waters. Current approaches to managing coastal eutrophication in the United States (USA) focus on surface runoff and river transport of nutrients, and often assume that groundwater N is at steady state. This is not necessarily the case, as terrestrial N inputs are affected by changing land use and nutrient management practices. Furthermore, approximately 70% of surface water in the USA is derived from groundwater and there is widespread N contamination in many of our nation's aquifers. Nitrogen export via groundwater discharge to streams during baseflow may be the reason many impaired coastal systems show little improvement. There is a critical need to develop approaches that consider the effects of groundwater transport on N loading to surface waters. Aquifer transport times, which can be decades or even centuries longer than surface water transport times, introduce lags between changes in terrestrial management and reductions in coastal loads. Ignoring these lags can lead to overly ambitious and unrealistic load reduction goals, or incorrect conclusions regarding the effectiveness of management strategies. Additionally, regional groundwater models typically have a coarse resolution that makes it difficult to incorporate fine-scale processes that drive N transformations, such as groundwater-surface water exchange across steep redox gradients at stream bed interfaces. Despite this challenge, representing these important fine-scale processes well is essential to modeling groundwater transport of N across regional scales and to making informed management decisions. We present 1) a conceptual approach to linking regional models and fine-scale empirical measurements, and 2) preliminary groundwater flow and transport model results for the Housatonic and Farmington Rivers in Connecticut, USA. Our cross-scale approach utilizes thermal infrared imaging and vertical

Characterizing the influence of atmospheric river orientation and intensity on precipitation distributions over North Coastal California

NASA Astrophysics Data System (ADS)

Hecht, Chad W.; Cordeira, Jason M.

2017-09-01

Atmospheric rivers (ARs) are long (>2000 km) and narrow (500-1000 km) corridors of enhanced vertically integrated water vapor and enhanced integrated water vapor transport (IVT) that are responsible for a majority of global poleward moisture transport and can result in extreme orographic precipitation. Observational evidence suggests that ARs within different synoptic-scale flow regimes may contain different water vapor source regions, orientations, and intensities and may result in different precipitation distributions. This study uses k-means clustering to objectively identify different orientations and intensities of ARs that make landfall over the California Russian River watershed. The ARs with different orientations and intensities occur within different synoptic-scale flow patterns in association with variability in IVT direction and quasi-geostrophic forcing for ascent and lead to different precipitation distributions over the Russian River watershed. These differences suggest that both mesoscale upslope moisture flux and synoptic-scale forcing for ascent are important factors in modulating precipitation distributions during landfalling ARs.

Saltwater intrusion in coastal regions of North America

USGS Publications Warehouse

Barlow, Paul M.; Reichard, Eric G.

2010-01-01

Saltwater has intruded into many of the coastal aquifers of the United States, Mexico, and Canada, but the extent of saltwater intrusion varies widely among localities and hydrogeologic settings. In many instances, the area contaminated by saltwater is limited to small parts of an aquifer and to specific wells and has had little or no effect on overall groundwater supplies; in other instances, saltwater contamination is of regional extent and has resulted in the closure of many groundwater supply wells. The variability of hydrogeologic settings, three-dimensional distribution of saline water, and history of groundwater withdrawals and freshwater drainage has resulted in a variety of modes of saltwater intrusion into coastal aquifers. These include lateral intrusion from the ocean; upward intrusion from deeper, more saline zones of a groundwater system; and downward intrusion from coastal waters. Saltwater contamination also has occurred along open boreholes and within abandoned, improperly constructed, or corroded wells that provide pathways for vertical migration across interconnected aquifers. Communities within the coastal regions of North America are taking actions to manage and prevent saltwater intrusion to ensure a sustainable source of groundwater for the future. These actions can be grouped broadly into scientific monitoring and assessment, engineering techniques, and regulatory approaches.

Regional evaluation of particulate matter composition in an Atlantic coastal area (Cantabria region, northern Spain): Spatial variations in different urban and rural environments

NASA Astrophysics Data System (ADS)

Arruti, A.; Fernández-Olmo, I.; Irabien, A.

2011-07-01

The aim of this study was to determine the major components (Na, Ca, K, Mg, Fe, Al, NH 4+, SO 42-, NO 3-, Cl - and TC) and trace-metal levels (As, Ni, Cd, Pb, Ti, V, Cr, Mn, Cu, Mo, Rh and Hg) in PM 10 and PM 2.5 at an Atlantic coastal city (Santander, Cantabria region, Northern Spain). Additional samples were collected in other urban sites of the Cantabria region to assess the metal content found in different urban environments within the region. To control for the mass attributed to inland regional background particulate matter, samples were also collected in Los Tojos village. The spatial variability of the major PM components shows that PM origins are different at inland and coastal sites. In the coastal city of Santander, the most important contributors are (i) the marine aerosol and (ii) the secondary inorganic aerosol (SIA) and the total carbon (TC) in PM 10 and PM 2.5, respectively. Additionally, the influence of the coastal location on the ionic balance of PM is also studied. The trace metal spatial variability is studied using the coefficient of divergence (COD), which shows that the levels of trace metals at the three studied urban sites are mainly influenced by local emission sources. The main local tracers are identified as follows: Mn in the Santander area; Mo, Cr and Pb at Reinosa; and Ni and V at Castro Urdiales. A more detailed source apportionment study of the local trace metals at Santander is conducted by Principal Component Analysis (PCA) and Positive Matrix Factorisation (PMF); these two receptor models report complementary information. From these statistical analyses, the identified sources of trace metals in PM 10 are urban background sources, industrial sources and traffic. The industrial factor was dominated by Mn, Cu and Pb, which are trace metals used in steel production and manganese-ferroalloy production plant. With respect to PM 2.5, the identified emission sources of trace metals are combustion processes as well as traffic and

Coastal Ocean Variability off the Coast of Taiwan in Response to Typhoon Morakot: River Forcing, Atmospheric Forcing, and Cold Dome Dynamics

DTIC Science & Technology

2014-09-01

within a very short time period and in this research, we model and study the effects of this rainfall on Taiwan?s coastal oceans as a result of river...and in this research, we model and study the effects of this rainfall on Taiwan’s coastal oceans as a result of river discharge. We do this through...54 4 Results 57 4.1 Effects of Footprint Shape on the Bulk Mixing Model . . . . . . . . . 57 4.2 Effects of the Horizontal Extent of the Bulk

Red Alder (Alnus rubra) Distribution Influences Nitrate Discharge to Coastal Estuaries: Comparison of Two Oregon Watersheds

EPA Science Inventory

We determined nutrient export from the Yaquina and Alsea Rivers as part of a larger program for evaluating nutrient sources to coastal waters. The Yaquina and Alsea data indicated that one river typically contained twice the amount of dissolved nitrate-N, although temperature, co...

Modeling a three-dimensional river plume over continental shelf using a 3D unstructured grid model

USGS Publications Warehouse

Cheng, R.T.; Casulli, V.; ,

2004-01-01

River derived fresh water discharging into an adjacent continental shelf forms a trapped river plume that propagates in a narrow region along the coast. These river plumes are real and they have been observed in the field. Many previous investigations have reported some aspects of the river plume properties, which are sensitive to stratification, Coriolis acceleration, winds (upwelling or downwelling), coastal currents, and river discharge. Numerical modeling of the dynamics of river plumes is very challenging, because the complete problem involves a wide range of vertical and horizontal scales. Proper simulations of river plume dynamics cannot be achieved without a realistic representation of the flow and salinity structure near the river mouth that controls the initial formation and propagation of the plume in the coastal ocean. In this study, an unstructured grid model was used for simulations of river plume dynamics allowing fine grid resolution in the river and in regions near the coast with a coarse grid in the far field of the river plume in the coastal ocean, in the vertical, fine fixed levels were used near the free surface, and coarse vertical levels were used over the continental shelf. The simulations have demonstrated the uniquely important role played by Coriolis acceleration. Without Coriolis acceleration, no trapped river plume can be formed no matter how favorable the ambient conditions might be. The simulation results show properties of the river plume and the characteristics of flow and salinity within the estuary; they are completely consistent with the physics of estuaries and coastal oceans.

Rethinking the longitudinal stream temperature paradigm: region-wide comparison of thermal infrared imagery reveals unexpected complexity of river temperatures

USGS Publications Warehouse

Fullerton, Aimee H.; Torgersen, Christian E.; Lawler, Joshua J.; Faux, Russell N.; Steel, E. Ashley; Beechie, Timothy J.; Ebersole, Joseph L.; Leibowitz, Scott J.

2015-01-01

Prevailing theory suggests that stream temperature warms asymptotically in a downstream direction, beginning at the temperature of the source in the headwaters and leveling off downstream as it converges to match meteorological conditions. However, there have been few empirical examples of longitudinal patterns of temperature in large rivers due to a paucity of data. We constructed longitudinal thermal profiles (temperature versus distance) for 53 rivers in the Pacific Northwest (USA) using an extensive dataset of remotely sensed summertime river temperatures and classified each profile into one of five patterns of downstream warming: asymptotic (increasing then flattening), linear (increasing steadily), uniform (not changing), parabolic (increasing then decreasing), or complex (not fitting other classes). We evaluated (1) how frequently profiles warmed asymptotically downstream as expected, and (2) whether relationships between river temperature and common hydroclimatic variables differed by profile class. We found considerable diversity in profile shape, with 47% of rivers warming asymptotically, and 53% having alternative profile shapes. Water temperature did not warm substantially over the course of the river for coastal parabolic and uniform profiles, and for some linear and complex profiles. Profile classes showed no clear geographical trends. The degree of correlation between river temperature and hydroclimatic variables differed among profile classes, but there was overlap among classes. Water temperature in rivers with asymptotic or parabolic profiles was positively correlated with August air temperature, tributary temperature and velocity, and negatively correlated with elevation, August precipitation, gradient, and distance upstream. Conversely, associations were less apparent in rivers with linear, uniform, or complex profiles. Factors contributing to the unique shape of parabolic profiles differed for coastal and inland rivers, where downstream cooling

Coastal erosion and accretion rates in Greece

NASA Astrophysics Data System (ADS)

Foteinis, Spyros; Papadopoulos, Costas; Koutsogiannaki, Irini; Synolakis, Costas

2010-05-01

Erosion threatens many coastal regions of Greece. Anthropogenic changes of landforms such as coastal roads built on even narrow beaches, sand mining for construction, poor design of coastal structures that interfere with sediment, and dams without sediment bypasses have significantly reduced beach widths. We present erosion rates for different beaches, some of which are in sensitive ecosystems, otherwise "protected" by local and EU ordinances. By comparing inferences of beach widths in varying intervals from 1933 to 2006, we infer that the construction of dams in Acheloos river in western Greece, built in a faraonic attempt to partially divert its flows to eastern Greece, this is responsible for up to 20m/year erosion rates observed in certain locales in the Acheloos delta. More characteristic erosion rates in the region are ~ 2m/year. By contrast, there appears rapid accretion of up to 4m/year in the beaches around the Nestos delta in northern Greece (Papadopoulos, 2009). In beaches that are not near large river deltas, erosion rates range from 0.5m/year to 1m/year. While we have not done comprehensive comparisons among coastlines with different levels of coastal development, it does appear that rapid coastal development correlates well with erosion rates. The underlying problem is the complete lack of any semblance of coastal zone management in Greece and substandard design of coastal structures, which are often sited without any measurements of waves and currents offshore (Synolakis et al, 2008). Beach maintenance remains an exotic concept for most local authorities, who invariably prefer to build hard coastal structures to "protect" versus nourish, siting lack of experience with nourishment and "environmental" concerns. In certain cases, choices are dictated by costs, the larger the cost the easier the project gets approved by regulatory authorities, hence the preference for concrete or rubble structures. We conclude that, unless urgent salvage measures are

A comparison of remote vs. local influence of El Niño on the coastal circulation of the northeast Pacific

NASA Astrophysics Data System (ADS)

Hermann, Albert J.; Curchitser, Enrique N.; Haidvogel, Dale B.; Dobbins, Elizabeth L.

2009-12-01

A set of spatially nested circulation models is used to explore interannual change in the northeast Pacific (NEP) during 1997-2002, and remote vs. local influence of the 1997-1998 El Niño on this region. Our nested set is based on the primitive equations of motion, and includes a basin-scale model of the north Pacific at ˜40-km resolution (NPac), and a regional model of the Northeast Pacific at ˜10-km resolution. The NEP model spans an area from Baja California through the Bering Sea, from the coast to ˜2000-km offshore. In this context, "remote influence" refers to effects driven by changes in ocean velocity and temperature outside of the NEP domain; "local influence" refers to direct forcing by winds and runoff within the NEP domain. A base run of this model using hindcast winds and runoff for 1996-2002 replicates the dominant spatial modes of sea-surface height anomalies from satellite data, and coastal sea level from tide gauges. We have performed a series of sensitivity runs with the NEP model for 1997-1998, which analyze the response of coastal sea level to: (1) hindcast winds and coastal runoff, as compared to their monthly climatologies and (2) hindcast boundary conditions (from the NPac model), as compared to their monthly climatologies. Results indicate penetration of sea-surface height (SSH) from the basin-scale model into the NEP domain (e.g., remote influence), with propagation as coastal trapped waves from Baja up through Alaska. Most of the coastal sea-level anomaly off Alaska in El Niño years appears due to direct forcing by local winds and runoff (local influence), and such anomalies are much stronger than those produced off California. We quantify these effects as a function of distance along the coastline, and consider how they might impact the coastal ecosystems of the NEP.

Floodplain influence on carbon speciation and fluxes from the lower Pearl River, Mississippi

NASA Astrophysics Data System (ADS)

Cai, Yihua; Shim, Moo-Joon; Guo, Laodong; Shiller, Alan

2016-08-01

To investigate the floodplain influence on carbon speciation and export to the northern Gulf of Mexico, water samples were collected monthly from two sites in the East Pearl River (EPR) basin during 2006-2008. Additionally, four spatial surveys in the river basin between those two sites were also conducted. Compared with the upstream sampling site at Bogalusa, MS, dissolved inorganic carbon (DIC) and particulate organic carbon (POC) concentrations were 36% and 55% lower, respectively, and dissolved organic carbon (DOC) concentration was 49% higher at the downstream Stennis Space Center (SSC) site. In addition, the bulk DOC pool at SSC had a higher colloidal fraction than at Bogalusa (75% vs. 68%). Detailed spatial surveys revealed the differences between the upstream and downstream stations resulted both from input from Hobolochitto Creek, a tributary of the EPR, and from influence of the swamp-rich floodplain. The contributions from Hobolochitto Creek to the carbon pool in the EPR basin were lowest during a high flow event and reached a maximum during the dry season. Meanwhile, the floodplain in the EPR basin acted as a significant sink for DOC, POC and particulate nitrogen during summer and for suspended sediment during a high flow event. However, the floodplain was converted into a source of suspended sediment, DOC, and POC to the EPR during winter, revealing a dynamic nature and seasonality in the floodplain influence. Consistent with its dominant forest coverage, abundant wetlands along the river corridor, and mild anthropogenic disturbance, the Pearl River basin above Bogalusa generally had higher yields of DOC and POC (1903 and 1386 kg-C km-2 yr-1, respectively), but a lower yield of DIC (2126 kg-C km-2 yr-1) compared to other North American rivers. An estimation based on a mass balance approach suggests the interactions between floodplain and the main river stem could reduce the annual DIC and POC export fluxes from downstream of the EPR by 24% and 40

Hydrodynamic modeling of hydrologic surface connectivity within a coastal river-floodplain system

NASA Astrophysics Data System (ADS)

Castillo, C. R.; Guneralp, I.

2017-12-01

Hydrologic surface connectivity (HSC) within river-floodplain environments is a useful indicator of the overall health of riparian habitats because it allows connections amongst components/landforms of the riverine landscape system to be quantified. Overbank flows have traditionally been the focus for analyses concerned with river-floodplain connectivity, but recent works have identified the large significance from sub-bankfull streamflows. Through the use of morphometric analysis and a digital elevation model that is relative to the river water surface, we previously determined that >50% of the floodplain for Mission River on the Coastal Bend of Texas becomes connected to the river at streamflows well-below bankfull conditions. Guided by streamflow records, field-based inundation data, and morphometric analysis; we develop a two-dimensional hydrodynamic model for lower portions of Mission River Floodplain system. This model not only allows us to analyze connections induced by surface water inundation, but also other aspects of the hydrologic connectivity concept such as exchanges of sediment and energy between the river and its floodplain. We also aggregate hydrodynamic model outputs to an object/landform level in order to analyze HSC and associated attributes using measures from graph/network theory. Combining physically-based hydrodynamic models with object-based and graph theoretical analyses allow river-floodplain connectivity to be quantified in a consistent manner with measures/indicators commonly used in landscape analysis. Analyzes similar to ours build towards the establishment of a formal framework for analyzing river-floodplain interaction that will ultimately serve to inform the management of riverine/floodplain environments.

Effects of an introduced piscivorous fish on native benthic fishes in a coastal river

Treesearch

Jason L. White; Bret C. Harvey

2001-01-01

We used field surveys to compare the density and mesohabitat-scale distribution of the native coastrange sculpin (Cottus aleuticus) and the prickly sculpin (C. asper) in coastal rivers in northwestern California, U.S.A., with and without an introduced piscivorous fish, the Sacramento pikeminnow, Ptychocheilus grandis. We also measured mortality of tethered prickly...

Direct connectivity between upstream and downstream promotes rapid response of lower coastal-plain rivers to land-use change

NASA Astrophysics Data System (ADS)

Mattheus, Christopher R.; Rodriguez, Antonio B.; McKee, Brent A.

2009-10-01

Low-relief fluvial systems that originate in the lower coastal plain and discharge into estuaries are common along passive margins. These watersheds are thought to be disconnected from their termini by floodplains, which buffer the sediment-routing system by sequestration. Here, we present a detailed study of the Newport River, a typical lower coastal-plain system, which reveals high connectivity between watershed and delta. Connectivity is measured as the time lag between initiation of a silviculture operation, which increased landscape erosion, and when the sediment appeared at the bay-head delta. The time lag, measured from aerial photographs and sedimentation rates calculated from 210Pb- and 137Cs-activities in cores from the watershed and delta, is <3 years. Most lower coastal-plain rivers are steeper and have less floodplain accommodation available for storage than their larger counterparts that originate landward of the fall line, which promotes higher connectivity between upstream and downstream.

Analysis of Compound Water Hazard in Coastal Urbanized Areas under the Future Climate

NASA Astrophysics Data System (ADS)

Shibuo, Y.; Taniguchi, K.; Sanuki, H.; Yoshimura, K.; Lee, S.; Tajima, Y.; Koike, T.; Furumai, H.; Sato, S.

2017-12-01

Several studies indicate the increased frequency and magnitude of heavy rainfalls as well as the sea level rise under the future climate, which implies that coastal low-lying urbanized areas may experience increased risk against flooding. In such areas, where river discharge, tidal fluctuation, and city drainage networks altogether influence urban inundation, it is necessary to consider their potential interference to understand the effect of compound water hazard. For instance, pump stations cannot pump out storm water when the river water level is high, and in the meantime the river water level shall increase when it receives pumped water from cities. At the further downstream, as the tidal fluctuation regulates the water levels in the river, it will also affect the functionality of pump stations and possible inundation from rivers. In this study, we estimate compound water hazard in the coastal low-lying urbanized areas of the Tsurumi river basin under the future climate. We developed the seamlessly integrated river, sewerage, and coastal hydraulic model that can simulate river water levels, water flow in sewerage network, and inundation from the rivers and/or the coast to address the potential interference issue. As a forcing, the pseudo global warming method, which applies the changes in GCM anomaly to re-analysis data, is employed to produce ensemble typhoons to drive the seamlessly integrated model. The results show that heavy rainfalls caused by the observed typhoon generally become stronger under the pseudo global climate condition. It also suggests that the coastal low-lying areas become extensively inundated if the onset of river flooding and storm surge coincides.

An approach to the coastal water circulation in the Piratuba Lake Biological Reservation, Northeast of Amapa State, Brazil

NASA Astrophysics Data System (ADS)

Takiyama, L. R.; Silveira, O. M.

2007-05-01

This study shows the pioneer results of the water quality characterization of a lake region, including the Piratuba lake (within the limits of the Piratuba Lake Biological Reservation) and the Sucuriju river, localized at the northeast portion of the Amapa State, Brazil, and left margin of the Amazon River mouth. Due to the influence of the Amazon river and another important river, the Araguari river, the northeast coast of Amapa State receive little impact of salty water from the Atlantic ocean. The highest salinity values detected on this coastal area is 20 psu. The Piratuba Lake region which can be described as an unique wetland system formed by recent geological processes (Quaternary), it constitutes a very fragile environment and possesses a number of shallow water lakes distributed into a mixed mangrove and "varzea" type of vegetation and it is considered very important looking at the biological point of view. The borderline between this lake system with the coastal waters is a narrow portion of mangrove containing species of Rizhophora and Avicennia parallel to the coast line. A preliminary water circulation could be accessed through the detection of variation in water quality parameters throughout three field studies conducted on March, 2004, June 2005 and November 2005. Surface water sampling points spatially distributed on the study area with distances less than 2 km were set, covering almost 800 square kilometers. Among the parameters studied (pH, electrical conductivity, turbidity, concentration of suspended solids, depth, temperature, chloride, dissolved oxygen, nitrate, nitrite and phosphate) the turbidity, electrical conductivity and pH were the most important for identifying the entering of coastal waters into the lake region. Mainly, three points of direct contact were identified; one of them is a manmade illegal entrance to the Biological Reservation. The seasonal variation was also very important factor and as expected, during the dry season

In-stream biogeochemical processes of a temporary river.

PubMed

Tzoraki, Ourania; Nikolaidis, Nikolaos P; Amaxidis, Yorgos; Skoulikidis, Nikolaos Th

2007-02-15

A reach at the estuary of Krathis River in Greece was used to assess how in-stream processes alter its hydrologic and biogeochemical regime. Krathis River exhibited high annual flow variability and its transmission losses become significant, especially during the dry months. These transmission losses are enhanced in chemistry due to release of nutrients from river sediments. These fluxes are significant because they correspond to 11% of the dissolved inorganic nitrogen flux of the river. Release of nitrogen species was influenced by temperature, while release of phosphate was not because phosphate levels were below the equilibrium concentration. There is a significant amount of sediments with fine composition that create "hot spot" areas in the river reach. These sediments are mobilized during the first flush events in the fall carrying with them a significant load of nutrient and suspended matter to the coastal zone. The nutrient organic content of sediments was also significant and it was studied in terms of its mineralization capacity. The capacity for mineralization was influenced by soil moisture, exhibiting significant capacity even at moisture levels of 40%. Temporary rivers are sensitive ecosystems, vulnerable to climate changes. In-stream processes play a significant role in altering the hydrology and biogeochemistry of the water and its impacts to the coastal zone.

The Pleistocene rivers of the English Channel region

NASA Astrophysics Data System (ADS)

Antoine, Pierre; Coutard, Jean-Pierre; Gibbard, Philip; Hallegouet, Bernard; Lautridou, Jean-Pierre; Ozouf, Jean-Claude

2003-02-01

The Pleistocene history of river systems that enter the English Channel from northern France and southern England is reviewed. During periods of low sea-level (cold stages) these streams were tributaries of the Channel River. In southern England the largest, the River Solent, is an axial stream that has drained the Hampshire Basin from the Early Pleistocene or late Pliocene. Other streams of southern England may be of similar antiquity but their records are generally short and their sedimentary history have been destroyed, as in northern Brittany, by coastal erosion and valley deepening as a consequence of tectonic uplift. In northern France, the Seine and Somme rivers have very well developed terrace systems recording incision that began at around 1 Ma. The uplift rate, deduced from the study of these terrace systems, is of 55 to 60 m myr-1 since the end of the Early Pleistocene. Generally the facies and sedimentary structures indicate that the bulk of the deposits in these rivers accumulated in braided river environments under periglacial climates in all the area around the Channel. Evolution of the rivers reflects their responses to climatic change, local geological structure and long-term tectonic activity. In this context the Middle Somme valley is characterised by a regular pattern in which incision occurs at the beginning of each glacial period within a general background of uplift. Nevertheless the response of the different rivers to climatic variations, uplift and sea-level changes is complex and variable according to the different parts of the river courses.

Submarine groundwater discharge as an important nutrient source influencing nutrient structure in coastal water of Daya Bay, China

NASA Astrophysics Data System (ADS)

Wang, Xuejing; Li, Hailong; Zheng, Chunmiao; Yang, Jinzhong; Zhang, Yan; Zhang, Meng; Qi, Zhanhui; Xiao, Kai; Zhang, Xiaolang

2018-03-01

As an important nutrient source for coastal waters, submarine groundwater discharge (SGD) has long been largely ignored in Daya Bay, China. In this study, we estimate the fluxes of SGD and associated nutrients into this region using a 224Ra mass balance model and assess the contribution/importance of nutrients by SGD, benthic sediments, local rivers, and atmospheric deposition. The results of 224Ra mass balance show that the estimated SGD ranges from (2.76 ± 1.43) × 106 m3/d to (1.03 ± 0.53) × 107 m3/d with an average of (6.32 ± 2.42) × 106 m3/d, about 16 times the total discharge rate of local rivers. The nutrient loading from SGD is estimated to be (1.05-1.99) × 105 mol/d for NO3-N, (4.04-12.16) × 103 mol/d for DIP, and (3.54-11.35) × 105 mol/d for Si. Among these considered nutrient sources, we find that SGD is the primary source for Si and NO3-N, contributing 68% and 42% of all considered sources, respectively. The atmospheric NO3-N flux is comparable to that from SGD. The local rivers are the most important source for DIP, contributing 75% of all considered sources. SGD with high N:P ratio (NO3-N/DIP) of 37.0 delivers not only a large quantity of nutrients, but also changes nutrient structure in coastal water. Based on a DIP budget, primary productivity is evaluated to be 54-73 mg C/m2 d, in which SGD accounts for approximately 30% of total production. This study indicates that SGD is a key source of nutrients to coastal waters and may cause an obvious change of primary production and nutrient structure in Daya Bay.

Climate change and soil salinity: The case of coastal Bangladesh.

PubMed

Dasgupta, Susmita; Hossain, Md Moqbul; Huq, Mainul; Wheeler, David

2015-12-01

This paper estimates location-specific soil salinity in coastal Bangladesh for 2050. The analysis was conducted in two stages: First, changes in soil salinity for the period 2001-2009 were assessed using information recorded at 41 soil monitoring stations by the Soil Research Development Institute. Using these data, a spatial econometric model was estimated linking soil salinity with the salinity of nearby rivers, land elevation, temperature, and rainfall. Second, future soil salinity for 69 coastal sub-districts was projected from climate-induced changes in river salinity and projections of rainfall and temperature based on time trends for 20 Bangladesh Meteorological Department weather stations in the coastal region. The findings indicate that climate change poses a major soil salinization risk in coastal Bangladesh. Across 41 monitoring stations, the annual median projected change in soil salinity is 39 % by 2050. Above the median, 25 % of all stations have projected changes of 51 % or higher.

A River Discharge Model for Coastal Taiwan during Typhoon Morakot

DTIC Science & Technology

2012-08-01

Multidisciplinary Simulation, Estimation, and Assimilation Systems Reports in Ocean Science and Engineering MSEAS-13 A River Discharge...in this region. The island’s major rivers have correspondingly large drainage basins, and outflow from these river mouths can substantially reduce the...Multidisciplinary Simulation, Estimation, and Assimilation System (MSEAS) has been used to simulate the ocean dynamics and forecast the uncertainty

Regional Sea Level Variation: California Coastal Subsidence (Invited)

NASA Astrophysics Data System (ADS)

Blewitt, G.; Hammond, W. C.; Nerem, R.

2013-12-01

Satellite altimetry over the last two decades has measured variations in geocentric sea level (GSL), relative to the Earth system center of mass, providing valuable data to test models of physical oceanography and the effects of global climate change. The societal impacts of sea level change however relate to variations in local sea level (LSL), relative to the land at the coast. Therefore, assessing the impacts of sea level change requires coastal measurements of vertical land motion (VLM). Indeed, ΔLSL = ΔGSL - ΔVLM, with subsidence mapping 1:1 into LSL. Measurements of secular coastal VLM also allow tide-gauge data to test models of GSL over the last century in some locations, which cannot be provided by satellite data. Here we use GPS geodetic data within 15 km of the US west coast to infer regional, secular VLM. A total of 89 GPS stations met the criteria that time series span >4.5 yr, and do not have obvious non-linear variation, as may be caused by local instability. VLM rates for the GPS stations are derived in the secular reference frame ITRF2008, which aligns with the Earth system center of mass to ×0.5 mm/yr. We find that regional VLM has different behavior north and south of the Mendocino Triple Junction (MTJ). The California coast has a coherent regional pattern of subsidence averaging 0.5 mm/yr, with an increasing trend to the north. This trend generally matches GIA model predictions. Around San Francisco Bay, the observed coastal subsidence of 1.0 mm/yr coherently decreases moving away from the Pacific Ocean to very small subsidence on the east shores of the bay. This gradient is likely caused by San Andreas-Hayward Fault tectonics, and possibly by differential surface loading across the bay and Sacramento-San Joachim River Delta. Thus in addition to the trend in subsidence from GIA going northward along the California coast, tectonics may also play a role where the plate boundary fault system approaches the coast. In contrast, we find that VLM

Isotope geochemistry and fluxes of carbon and organic matter in tropical small mountainous river systems and adjacent coastal waters of the Caribbean

USGS Publications Warehouse

Moyer, Ryan; Bauer, James; Grottoli, Andrea

2012-01-01

Recent studies have shown that small mountainous rivers (SMRs) may act as sources of aged and/or refractory carbon (C) to the coastal ocean, which may increase organic C burial at sea and subsidize coastal food webs and heterotrophy. However, the characteristics and spatial and temporal variability of C and organic matter (OM) exported from tropical SMR systems remain poorly constrained. To address this, the abundance and isotopic character (δ13C and Δ14C) of the three major C pools were measured in two Puerto Rico SMRs with catchments dominated by different land uses (agricultural vs. non-agricultural recovering forest). The abundance and character of C pools in associated estuaries and adjacent coastal waters were also examined. Riverine dissolved and particulate organic C (DOC and POC, respectively) concentrations were highly variable with respect to land use and sampling month, while dissolved inorganic C (DIC) was significantly higher at all times in the agricultural catchment. In both systems, riverine DOC and POC ranged from modern to highly aged (2,340 years before present), while DIC was always modern. The agricultural river and irrigation canals contained very old DOC (1,184 and 2,340 years before present, respectively), which is consistent with findings in temperate SMRs and indicates that these tropical SMRs provide a source of aged DOC to the ocean. During months of high river discharge, OM in estuarine and coastal waters had C isotope signatures reflective of direct terrestrial input, indicating that relatively unaltered OM is transported to the coastal ocean at these times. This is also consistent with findings in temperate SMRs and indicates that C transported to the coastal ocean by SMRs may differ from that of larger rivers because it is exported from smaller catchments that have steeper terrains and fewer land-use types.

Transformations and Fates of Terrigenous Dissolved Organic Matter in River-influenced Ocean Margins

NASA Astrophysics Data System (ADS)

Fichot, Cedric G.

Rivers contribute about 0.25 Pg of terrigenous dissolved organic carbon (tDOC) to the ocean each year. The fate and transformations of this material have important ramifications for the metabolic state of the ocean, air-sea CO2 exchange, and the global carbon cycle. Stable isotopic compositions and terrestrial biomarkers suggest tDOC must be efficiently mineralized in ocean margins. Nonetheless, the extent of tDOC mineralization in these environments remains unknown, as no quantitative estimate is available. The complex interplay of biogeochemical and physical processes in these systems compounded by the limited practicality of chemical proxies (organic biomarkers, isotopic compositions) make the quantification of tDOC mineralization in these dynamic systems particularly challenging. In this dissertation, new optical proxies were developed (Chapters 1 and 2) and facilitated the first quantitative assessment of tDOC mineralization in a dynamic river-influenced ocean margin (Chapter 3) and the monitoring of continental runoff distributions in the coastal ocean using remote sensing (Chapter 4). The optical properties of chromophoric dissolved organic matter (CDOM) were used as optical proxies for dissolved organic carbon concentration ([DOC]) and %tDOC. In both proxies, the CDOM spectral slope coefficient ( S275-295) was exploited for its informative properties on the chemical nature and composition of dissolved organic matter. In the first proxy, a strong relationship between S275-295 and the ratio of CDOM absorption to [DOC] facilitated accurate retrieval (+/- 4%) of [DOC] from CDOM. In the second proxy, the existence of a strong relationship between S275-295 and the DOC-normalized lignin yield facilitated the estimation of the %tDOC from S 275-295. Using the proxies, the tDOC concentration can be retrieved solely from CDOM absorption coefficients (lambda = 275-295 nm) in river-influenced ocean margins. The practicality of optical proxies facilitated the calculation

Lagrangian Turbulence and Transport in Semi-enclosed Basins and Coastal Regions

DTIC Science & Technology

2009-01-01

enclosed Basins and Coastal Regions Annalisa Griffa Division of Meteorology and Physical Oceanography Rosenstiel School of Marine and Atmospheric...enclosed Basins and Coastal Regions 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER...variables. A set of diagnostics is then performed, including hydrological sections, transport, mean circulation and variability, aimed at quantifying

Leachable particulate iron in the Columbia River, estuary, and near-field plume

NASA Astrophysics Data System (ADS)

Lippiatt, Sherry M.; Brown, Matthew T.; Lohan, Maeve C.; Berger, Carolyn J. M.; Bruland, Kenneth W.

2010-03-01

This study examines the distribution of leachable particulate iron (Fe) in the Columbia River, estuary, and near-field plume. Surface samples were collected during late spring and summer of 2004-2006 as part of four River Influence on Shelf Ecosystems (RISE) cruises. Tidal amplitude and river flow are the primary factors influencing the estuary leachable particulate Fe concentrations, with greater values during high flow and/or spring tides. Near the mouth of the estuary, leachable particulate Fe [defined as the particulate Fe solubilized with a 25% acetic acid (pH 2) leach containing a weak reducing agent to reduce Fe oxyhydroxides and a short heating step to access intracellular Fe] averaged 770 nM during either spring tide or high flow, compared to 320 nM during neap tide, low flow conditions. In the near-field Columbia River plume, elevated leachable particulate Fe concentrations occur during spring tides and/or higher river flow, with resuspended shelf sediment as an additional source to the plume during periods of coastal upwelling and spring tides. Near-field plume concentrations of leachable particulate Fe (at a salinity of 20) averaged 660 nM during either spring tide or high flow, compared to 300 nM during neap tide, low flow conditions. Regardless of tidal amplitude and river flow, leachable particulate Fe concentrations in both the river/estuary and near-field plume are consistently one to two orders of magnitude greater than dissolved Fe concentrations. The Columbia River is an important source of reactive Fe to the productive coastal waters off Oregon and Washington, and leachable particulate Fe is available for solubilization following biological drawdown of the dissolved phase. Elevated leachable Fe concentrations allow coastal waters influenced by the Columbia River plume to remain Fe-replete and support phytoplankton production during the spring and summer seasons.

Assess Climate Change's Impact on Coastal Rivers using a Coupled Climate-Hydrology Model

NASA Astrophysics Data System (ADS)

Xue, Z. G.; Gochis, D.; Yu, W.; Zang, Z.; Sampson, K. M.; Keim, B. D.

2016-12-01

In this study we present a coupled climate-hydrological model reproducing the water cycle of three coastal river basins along the northern Gulf of Mexico for the past three decades (1985-2014). Model simulated climate condition, surface physics, and streamflow were well validated against in situ data and satellite-derived products, giving us the confidence that the newly developed WRF-Hydro model can be a robust tool for evaluating climate change's impact on hydrological regime. Trend analysis of model simulated monthly and annual time series indicates that local climate is getting hotter and dryer, specifically during the growing season. Wavelet analysis reveals that local evapotranspiration is strongly correlated with temperature, while soil moisture, water surplus, and streamflow are coupled with precipitation. In addition, local climate is closely correlated with large-scale climate dynamics such as AMO and ENSO. A possible change-point is detected around year 2004, after which, the monthly precipitation decreased by 14.2%, evapotranspiration increased by 2.9%, and water surplus decreased by 36.5%. The implication of the difference between the water surplus (runoff) calculated using the classic Thornthwaite method and river discharge estimated using streamflow records to the coastal environment is also discussed.

Hydrogeomorphic factors and ecosystem responses in coastal wetlands of the Great Lakes

USGS Publications Warehouse

Keough, Janet R.; Thompson, Todd A.; Guntenspergen, Glenn R.; Wilcox, Douglas A.

1999-01-01

Gauging the impact of manipulative activities, such as rehabilitation or management, on wetlands requires having a notion of the unmanipulated condition as a reference. And understanding of the reference condition requires knowledge of dominant factors influencing ecosystem processes and biological communities. In this paper, we focus on natural physical factors (conditions and processes) that drive coastal wetland ecosystems of the Laurentian Great Lakes. Great Lakes coastal wetlands develop under conditions of large-lake hydrology and disturbance imposed at a hiearchy of spatial and temporal scales and contain biotic communities adapted to unstable and unpredictable conditions. Coastal wetlands are configured along a continuum of hydrogeomorphic types: open coastal wetlands, drowned river mouth and flooded delta wetlands, and protected wetlands, each developing distinct ecosystem propertics and biotic communities. Hydrogeomorphic factors associated with the lake and watershed operate at a hierarchy of scales: a) local and short-term (seiches and ice action), b) watershed / lakewide / annual (seasonal water-level change), and c) larger or year-to-year and longer (regional and/or greater than one-year). Other physical factors include the unique water quality features of each lake. The aim of this paper is to provide scientists and managers with a framework for considering regional and site-specific geomorphometry and a hierarchy of physical processes in planning management and conservation projects.

Rates and trends of coastal change in california and the regional behavior of the beach and cliff system

USGS Publications Warehouse

Hapke, C.J.; Reid, Don; Richmond, B.

2009-01-01

The U.S. Geological Survey (USGS) recently completed an analysis of shoreline change and cliff retreat along the California coast. This is the first regional, systematic measurement of coastal change conducted for the West Coast. Long-term (-120 y) and short-term (-25 y) shoreline change rates were calculated for more than 750 km of coastline, and 70 year cliff-retreat rates were generated for 350 km of coast. Results show that 40% of California's beaches were eroding in the long term. This number increased to 66% in the short term, indicating that many beaches have shifted toward a state of chronic erosion. The statewide average net shoreline change rates for the long and short term were 0.2 m/y and -0.2 m/y, respectively. The long-term accretional signal is likely related to large coastal engineering projects in some parts of the state and to large fluxes of sediment from rivers in other areas. The cliff-retreat assessment yielded a statewide average of -0.3 m/y. It was found that Northern California has the highest overall retreat rates, which are influenced by erosion hot spots associated with large coastal landslides and slumps. The databases established as part of the shoreline change and cliff-retreat analyses were further investigated to examine the dynamics of the beach/cliff system. A correlation analysis identified a strong relationship between the geomorphology of the coast and the behavior of the beach/cliff system. Areas of high-relief coast show negative correlations, indicating that higher rates of cliff retreat correlate with lower rates of shoreline erosion. In contrast, low- to moderate-relief coasts show strong positive correlations, wherein areas of high shoreline change correspond to areas of high cliff retreat.

A Synoptic Assessment of the Amazon River-Ocean Continuum during Boreal Autumn: From Physics to Plankton Communities and Carbon Flux.

PubMed

Araujo, Moacyr; Noriega, Carlos; Hounsou-Gbo, Gbekpo Aubains; Veleda, Doris; Araujo, Julia; Bruto, Leonardo; Feitosa, Fernando; Flores-Montes, Manuel; Lefèvre, Nathalie; Melo, Pedro; Otsuka, Amanda; Travassos, Keyla; Schwamborn, Ralf; Neumann-Leitão, Sigrid

2017-01-01

The Amazon generates the world's largest offshore river plume, which covers extensive areas of the tropical Atlantic. The data and samples in this study were obtained during the oceanographic cruise Camadas Finas III in October 2012 along the Amazon River-Ocean Continuum (AROC). The cruise occurred during boreal autumn, when the river plume reaches its maximum eastward extent. In this study, we examine the links between physics, biogeochemistry and plankton community structure along the AROC. Hydrographic results showed very different conditions, ranging from shallow well-mixed coastal waters to offshore areas, where low salinity Amazonian waters mix with open ocean waters. Nutrients, mainly [Formula: see text] and [Formula: see text], were highly depleted in coastal regions, and the magnitude of primary production was greater than that of respiration (negative apparent oxygen utilization). In terms of phytoplankton groups, diatoms dominated the region from the river mouth to the edge of the area affected by the North Brazil Current (NBC) retroflection (with chlorophyll a concentrations ranging from 0.02 to 0.94 mg m -3 ). The North Equatorial Counter Current (NECC) region, east of retroflection, is fully oligotrophic and the most representative groups are Cyanobacteria and dinoflagellates. Additionally, in this region, blooms of cyanophyte species were associated with diatoms and Mesozooplankton (copepods). A total of 178 zooplankton taxa were observed in this area, with Copepoda being the most diverse and abundant group. Two different zooplankton communities were identified: a low-diversity, high-abundance coastal community and a high-diversity, low-abundance oceanic community offshore. The CO 2 fugacity (fCO 2 sw), calculated from total alkalinity (1,450 < TA < 2,394 μmol kg -1 ) and dissolved inorganic carbon (1,303 < DIC < 2,062 μmol kg -1 ) measurements, confirms that the Amazon River plume is a sink of atmospheric CO 2 in areas with salinities <35 psu

A Synoptic Assessment of the Amazon River-Ocean Continuum during Boreal Autumn: From Physics to Plankton Communities and Carbon Flux

PubMed Central

Araujo, Moacyr; Noriega, Carlos; Hounsou-gbo, Gbekpo Aubains; Veleda, Doris; Araujo, Julia; Bruto, Leonardo; Feitosa, Fernando; Flores-Montes, Manuel; Lefèvre, Nathalie; Melo, Pedro; Otsuka, Amanda; Travassos, Keyla; Schwamborn, Ralf; Neumann-Leitão, Sigrid

2017-01-01

The Amazon generates the world's largest offshore river plume, which covers extensive areas of the tropical Atlantic. The data and samples in this study were obtained during the oceanographic cruise Camadas Finas III in October 2012 along the Amazon River-Ocean Continuum (AROC). The cruise occurred during boreal autumn, when the river plume reaches its maximum eastward extent. In this study, we examine the links between physics, biogeochemistry and plankton community structure along the AROC. Hydrographic results showed very different conditions, ranging from shallow well-mixed coastal waters to offshore areas, where low salinity Amazonian waters mix with open ocean waters. Nutrients, mainly NO3− and SiO2−, were highly depleted in coastal regions, and the magnitude of primary production was greater than that of respiration (negative apparent oxygen utilization). In terms of phytoplankton groups, diatoms dominated the region from the river mouth to the edge of the area affected by the North Brazil Current (NBC) retroflection (with chlorophyll a concentrations ranging from 0.02 to 0.94 mg m−3). The North Equatorial Counter Current (NECC) region, east of retroflection, is fully oligotrophic and the most representative groups are Cyanobacteria and dinoflagellates. Additionally, in this region, blooms of cyanophyte species were associated with diatoms and Mesozooplankton (copepods). A total of 178 zooplankton taxa were observed in this area, with Copepoda being the most diverse and abundant group. Two different zooplankton communities were identified: a low-diversity, high-abundance coastal community and a high-diversity, low-abundance oceanic community offshore. The CO2 fugacity (fCO2sw), calculated from total alkalinity (1,450 < TA < 2,394 μmol kg−1) and dissolved inorganic carbon (1,303 < DIC < 2,062 μmol kg−1) measurements, confirms that the Amazon River plume is a sink of atmospheric CO2 in areas with salinities <35 psu, whereas, in regions with

A buoyant plume adjacent to a headland-Observations of the Elwha River plume

USGS Publications Warehouse

Warrick, J.A.; Stevens, A.W.

2011-01-01

Small rivers commonly discharge into coastal settings with topographic complexities - such as headlands and islands - but these settings are underrepresented in river plume studies compared to more simplified, straight coasts. The Elwha River provides a unique opportunity to study the effects of coastal topography on a buoyant plume, because it discharges into the Strait of Juan de Fuca on the western side of its deltaic headland. Here we show that this headland induces flow separation and transient eddies in the tidally dominated currents (O(100. cm/s)), consistent with other headlands in oscillatory flow. These flow conditions are observed to strongly influence the buoyant river plume, as predicted by the "small-scale" or "narrow" dynamical classification using Garvine's (1995) system. Because of the transient eddies and the location of the river mouth on the headland, flow immediately offshore of the river mouth is directed eastward twice as frequently as it is westward. This results in a buoyant plume that is much more frequently "bent over" toward the east than the west. During bent over plume conditions, the plume was attached to the eastern shoreline while having a distinct, cuspate front along its westernmost boundary. The location of the front was found to be related to the magnitude and direction of local flow during the preceding O(1. h), and increases in alongshore flow resulted in deeper freshwater mixing, stronger baroclinic anomalies, and stronger hugging of the coast. During bent over plume conditions, we observed significant convergence of river plume water toward the frontal boundary within 1. km of the river mouth. These results show how coastal topography can strongly influence buoyant plume behavior, and they should assist with understanding of initial coastal sediment dispersal pathways from the Elwha River during a pending dam removal project. ?? 2010.

Identifying the effects of human pressure on groundwater quality to support water management strategies in coastal regions: a multi-tracer and statistical approach (Bou-Areg region, Morocco).

PubMed

Re, V; Sacchi, E; Mas-Pla, J; Menció, A; El Amrani, N

2014-12-01

Groundwater pollution from anthropogenic sources is a serious concern affecting several coastal aquifers worldwide. Increasing groundwater exploitation, coupled with point and non-point pollution sources, are the main anthropogenic impacts on coastal environments and are responsible for severe health and food security issues. Adequate management strategies to protect groundwater from contamination and overexploitation are of paramount importance, especially in arid prone regions, where coastal aquifers often represent the main freshwater resource to sustain human needs. The Bou-Areg Aquifer (Morocco) is a perfect example of a coastal aquifer constantly exposed to all the negative externalities associated with groundwater use for agricultural purposes, which lead to a general increase in aquifer salinization. In this study data on 61 water samples, collected in June and November 2010, were used to: (i) track groundwater composition changes related to the use of irrigation water from different sources, (ii) highlight seasonal variations to assess aquifer vulnerability, and (iii) present a reproducible example of multi-tracer approach for groundwater management in rural coastal areas. Hydrogeochemical results show that Bou-Areg groundwater is characterized by - high salinity, associated with a remarkable increase in bicarbonate content in the crop growing season, due to more intense biological activity in irrigated soils. The coupled multi-tracer and statistical analysis confirms the strong dependency on irrigation activities as well as a clear identification of the processes governing the aquifer's hydrochemistry in the different seasons. Water Rock Interaction (WRI) dominates the composition of most of groundwater samples in the Low Irrigation season (L-IR) and Agricultural Return Flow (ARF) mainly affects groundwater salinization in the High Irrigation season (H-IR) in the same areas naturally affected by WRI. In the central part of the plain River Recharge (RR

Coastal erosion vs riverline sediment discharge in the Arctic shelfx seas

USGS Publications Warehouse

Rachold, V.; Grigoriev, M.N.; Are, F.E.; Solomon, Sean C.; Reimnitz, E.; Kassens, H.; Antonow, M.

2000-01-01

This article presents a comparison of sediment input by rivers and by coastal erosion into both the Laptev Sea and the Canadian Beaufort Sea (CBS). New data on coastal erosion in the Laptev Sea, which are based on field measurements and remote sensing information and existing data on coastal erosion in the CBS as well as riverine sediment discharge into both the Laptev Sea and the CBS are included. Strong regional differences in the percentages of coastal ero- sion and riverine sediment supply are observed. The CBS is dominated by the riverine sediment discharge (64.45x106 t a-1) mainly of the Mackenzie River. which is the largest single source of sediments in the Arctic. Riverine sediment discharge into the Laptev Sea amounts to 24.10x106 t a-1, more than 70% of which are related to the Lena River. In comparison with the CBS. the Laptev Sea coast on average delivers approximately twice as much sediment mass per kilometer, a result of higher erosion rates due to higher cliffs and seasonal ice melting. In the Laptev Sea sediment input by coastal erosion (58.4x106 t a-1) is therefore more important than in the CBS and the ratio between riverine and coastal sediment input amounts to 0.4. Coastal erosion supplying 5.6x106 t a-1 is less significant for the sediment budget of the CBS where riverine sediment discharge exceeds coastal sediment input by a factor of ca. 10.

Ecological risk caused by land use change in the coastal zone: a case study in the Yellow River Delta High-Efficiency Ecological Economic Zone

NASA Astrophysics Data System (ADS)

Di, X. H.; Wang, Y. D.; Hou, X. Y.

2014-03-01

China's coastal zone plays an important role in ecological services production and social-economic development; however, extensive and intensive land resource utilization and land use change have lead to high ecological risk in this area during last decade. Regional ecological risk assessment can provide fundamental knowledge and scientific basis for better understanding of the relationship between regional landscape ecosystem and human activities or climate changes, facilitating the optimization strategy of land use structure and improving the ecological risk prevention capability. In this paper, the Yellow River Delta High-Efficiency Ecological Economic Zone is selected as the study site, which is undergoing a new round of coastal zone exploitation and has endured substantial land use change in the past decade. Land use maps of 2000, 2005 and 2010 were generated based on Landsat images by visual interpretation method, and the ecological risk index was then calculated. The index was 0.3314, 0.3461 and 0.3176 in 2000, 2005 and 2010 respectively, which showed a positive transition of regional ecological risk in 2005.

Trace element fluxes in sediments of an environmentally impacted river from a coastal zone of Brazil.

PubMed

da Silva, Yuri Jacques Agra Bezerra; Cantalice, José Ramon Barros; Singh, Vijay P; do Nascimento, Clístenes Williams Araújo; Piscoya, Victor Casimiro; Guerra, Sérgio M S

2015-10-01

Data regarding trace element concentrations and fluxes in suspended sediments and bedload are scarce. To fill this gap and meet the international need to include polluted rivers in future world estimation of trace element fluxes, this study aimed to determine the trace element fluxes in suspended sediment and bedload of an environmentally impacted river in Brazil. Water, suspended sediment, and bedload from both the upstream and the downstream cross sections were collected. To collect both the suspended sediment and water samples, we used the US DH-48. Bedload measurements were carried out using the US BLH 84 sampler. Concentrations of Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn were determined by inductively coupled plasma (ICP-OES). As and Hg were determined by an atomic absorption spectrophotometer (AA-FIAS). The suspended sediments contributed more than 99 % of the trace element flux. By far Pb and to a less extent Zn at the downstream site represents major concerns. The yields of Pb and Zn in suspended sediments were 4.20 and 2.93 kg km(2) year(-1), respectively. These yields were higher than the values reported for Pb and Zn for Tuul River (highly impacted by mining activities), 1.60 and 1.30 kg km(2) year(-1), respectively, as well as the Pb yield (suspended + dissolved) to the sea of some Mediterranean rivers equal to 3.4 kg km(2) year(-1). Therefore, the highest flux and yield of Pb and Zn in Ipojuca River highlighted the importance to include medium and small rivers-often overlooked in global and regional studies-in the future estimation of world trace element fluxes in order to protect estuaries and coastal zones.

Sources of sediment to the coastal waters of the Southern California Bight

USGS Publications Warehouse

Warrick, J.A.; Farnsworth, K.L.

2009-01-01

The sources of sediment to the Southern California Bight were investigated with new calculations and published records of sediment fluxes, both natural and anthropogenic. We find that rivers are by far the largest source of sediment, producing over 10 ?? 106 t/yr on average, or over 80% of the sediment input to the Bight. This river flux is variable, however, over both space and time. The rivers draining the Transverse Ranges produce sediment at rates approximately an order of magnitude greater than the Peninsular Ranges (600-1500 t/km2/yr versus <90 t/km2/yr, respectively). Although the Transverse Range rivers represent only 23% of the total Southern California watershed drainage area, they are responsible for over 75% of the total sediment flux. River sediment flux is ephemeral and highly pulsed due to the semiarid climate and the influence of infrequent large storms. For more than 90% of the time, negligible amounts of sediment are discharged from the region's rivers, and over half of the post-1900 sediment load has been discharged during events with recurrence intervals greater than 10 yr. These rare, yet important, events are related to the El Ni??o-Southern Oscillation (ENSO), and the majority of sediment flux occurs during ENSO periods. Temporal trends in sediment discharge due to land-use changes and river damming are also observed. We estimate that there has been a 45% reduction in suspended-sediment flux due to the construction of dams. However, pre-dam sediment loads were likely artificially high due to the massive land-use changes of coastal California to rangeland during the nineteenth century. This increase in sediment production is observed in estuarine deposits throughout coastal California, which reveal that sedimentation rates were two to ten times higher during the nineteenth and twentieth centuries than during pre-European colonization. ?? 2009 The Geological Society of America.

A Modelling Study of the Coastal Current in the Northwestern South China Sea: Response to Strong and Weak Southwest Monsoon

NASA Astrophysics Data System (ADS)

Ding, Y.; Yu, J.; Bao, X.; Yao, Z.

2016-02-01

The characteristics and dynamical mechanism of summer-time coastal current over the northwestern South China Sea (NSCS) shelf have been investigated based on a high resolution unstructured-grid finite volume community ocean model (FVCOM). Model-data comparison demonstrates that model well resolves the coastal dynamics over the NSCS shelf. The coastal current on the NSCS shelf is intensively influenced by monsoon and freshwater discharge of the Pearl River. Strong southwesterly wind drive the coastal current northeastward. However, under weak southwest monsoon, the coastal current west of Pearl River estuary (PRE) advects toward southwest, and splits into two parts when reaching east of the Qiongzhou Strait, with one branch entering the Gulf of Tonkin through the Qiongzhou Strait, transporting low salinity water into the Gulf of Tonkin, and the other part flows cyclonic and interacts with the northeastward current around southeast of Hainan Island, forming a cyclonic eddy east of the Qiongzhou Strait. A variety of model experiments focused on freshwater discharge, wind forcing, tidal rectification, and stratification are performed to study the physical mechanism of the southwestward coastal current which is usually against the summer wind. Process-oriented experiment results indicate that the southwest monsoon and freshwater discharge are important factors influencing the formation of southwestward coastal current during summer. Momentum balance analysis suggests that the along shelf barotropic pressure gradient due to the Pearl River discharge and wind forcing provides the main driving force for the southwestward coastal current.

The influence of the hydrologic cycle on the extent of sea ice with climatic implications

NASA Technical Reports Server (NTRS)

Dean, Ken; Gosink, Joan

1991-01-01

The role was analyzed of the hydrologic cycle on the distribution of sea ice, and its influence on forcings and fluxes between the marine environment and the atmosphere. River discharge plays a significant role in degrading the sea ice before any melting occurs elsewhere along the coast. The influence is considered of river discharge on the albedo, thermal balance, and distribution of sea ice. Quantitative atmospheric-hydrologic models are being developed to describe these processes in the coastal zone. Input for the models will come from satellite images, hydrologic data, and field observations. The resulting analysis provides a basis for the study of the significance of the hydrologic cycle throughout the Arctic Basin and its influence on the regional climate as a result of possible climatic scenarios. The area offshore from the Mackenzie River delta was selected as the study area.

Po river plume patterns variability and dynamics: a numerical modeling and statistical approach.

NASA Astrophysics Data System (ADS)

Falcieri, Francesco M.; Benetazzo, Alvise; Bergamasco, Andrea; Bonaldo, Davide; Carniel, Sandro; Sclavo, Mauro; Russo, Aniello

2013-04-01

Processes and dynamics of estuarine-shelf environments are defined by many drivers, some of the most important being riverine inputs, winds (and wind driven currents) and tides. Two of them are directly involved in the formation and spatial evolution of a coastal river plume: on the one hand the amount of fresh water entering into the sea through river' discharge, on the other hand the direction and intensity of winds blowing over the domain. The Adriatic Sea is generally considered a dilution basin due to the large amount of freshwater inputs received. These inputs have a significant influence on the basin, both from a physical point of view (by affecting buoyancy) and on the biogeochemical characteristics (by introducing large quantities of nutrients, which sustain primary production in the areas interested by the rivers' plumes). The Po River (mean daily discharge between 275 and 11600 m3/s, yearly mean of 1500 m3/s) is the single largest freshwater source of the Adriatic; its discharges result in a plume that directly influences the characteristics of the coastal areas of the whole Northern sub-basin and as far South as Ancona. The development of strong lateral gradients in salinity is an all year around driver (particularly in Spring and Autumn) of the general and coastal circulation, and influences the water column vertical structure and an important process such as the formation of the Northern Adriatic Dense Water. The Po plume generally follows two major patterns of evolution: southward along the Italian coasts in a ribbon that can fill the whole water column, or across the northern part of the basin toward the Istrian coasts in a generally more stratified condition. A model-based assessment, albeit semi-quantitative, of the dynamics and variability of the Po plume has not been yet reported in literature. In this work we investigated its dynamics by means of an 8 years (2003-2010) numerical simulation with the Regional Ocean Modelling System (ROMS). The

77 FR 35357 - Atlantic Highly Migratory Species; Commercial Atlantic Region Non-Sandbar Large Coastal Shark...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-13

... Highly Migratory Species; Commercial Atlantic Region Non-Sandbar Large Coastal Shark Fishery Opening Date... commercial Atlantic region non-sandbar large coastal shark fishery. This action is necessary to inform... large coastal shark fishery will open on July 15, 2012. FOR FURTHER INFORMATION CONTACT: Karyl Brewster...

Nitrogen dynamics in a tidal river zone influenced by highly urbanization, western Japan

NASA Astrophysics Data System (ADS)

Saito, M.; Onodera, S. I.; Shimizu, Y.; Maruyama, Y.; Jin, G.; Aritomi, D.

2014-12-01

Tidal river and estuary are the transition zone between freshwater and seawater with high biological production. These areas have characteristics of water level fluctuation which causes surface water-groundwater interaction and the associated change in dynamics of nitrogen. Generally in coastal megacities, severe groundwater depression and high contaminants load influence on the environment of tidal river. However, these effects on the nitrogen dynamics and its load from a river to sea have not been fully evaluated in previous studies. Therefore, we aimed to clarify the characteristics of the nitrogen dynamics with the surface water-groundwater interaction in the tidal river zone of Osaka metropolitan city, western Japan. We conducted the field survey from the river mouth to the 7km upstream area of Yamato River, which has a length of 68km and a watershed area of 1,070 km2. Spatial variations in radon (222Rn) concentrations and the difference of hydraulic potential between river waters and the pore waters suggest that the groundwater discharges to the river channel in the upstream area. In contrast, the river water recharged into the groundwater near the river mouth area. It may be caused by the lowering of groundwater level associated with the excess abstraction in the urban area. The spatial and temporal variations in nutrient concentration indicate that nitrate-nitrogen (NO3-N) concentration changed temporally and it was negatively correlated with dissolved organic nitrogen (DON) concentration. Based on the mass balance estimation in winter and summer periods, nitrogen was removed in tidal river zone in both periods which was estimated to be about 10 % of total nitrogen (TN) load from the upstream. However, dissolved inorganic nitrogen (DIN) and DON was re-produced in winter and summer periods, respectively. NO3-N concentrations were negatively correlated with velocity of river water, which suggests the progress of denitrification in the tidal river zone under

Recent crustal movements and seismicity in the western coastal region of peninsular India

NASA Astrophysics Data System (ADS)

Kailasam, L. N.

1983-09-01

Recent crustal movements, tectonics and seismicity of the western coastal region of peninsular India have been studied in detail in the very recent past. Prominent geomorphic features and large-scale manifestation of Holocene deformation and crustal movements have been noticed and studied over this coastal region from the Gulf of Cambay to the southernmost parts of Kerala, evidence for which is afforded in the form of Recent and sub-Recent raised beaches, sandbars, raised old terraces, pebble beds, etc. The sedimentary formations in this narrow coastal belt include Neogene and Quaternary sediments. The Bouguer gravity map of the western coastal tract shows some prominent gravity features extending into the offshore regions, suggestive of some significant tectonic and structural features. The seismic data in the offshore regions bring out some prominent roughly northwest-southeast as well as east-west faults and shears, in addition to prominent structural "highs" off the Bombay and Ratnagiri coast which have proved oil. The seismicity in this coastal tract as well as the faulted western margin of the western continental shelf in the Arabian Sea is generally of magnitude 3-6.

Influence of reservoirs on solute transport: A regional-scale approach

USGS Publications Warehouse

Kelly, V.J.

2001-01-01

Regional transport of water and dissolved constituents through heavily regulated river systems is influenced by the presence of reservoirs. Analysis of seasonal patterns in solute fluxes for salinity and nutrients indicates that in-reservoir processes within large storage reservoirs in the Rio Grande and Colorado basins (southwestern USA) are superimposed over the underlying watershed processes that predominate in relatively unregulated stream reaches. Connectivity of the aquatic system with the landscape is apparently disrupted by processes within the reservoir systems; these processes result in large changes in characteristics for solute transport that persist downstream in the absence of significant inputs. Additionally, reservoir processes may be linked for upstream/downstream reservoirs that are located relatively close in a series. In contrast, the regional effect of in-reservoir processes is negligible for solute transport through run-of-river reservoirs in the lower Columbia River (northwestern USA).

Factors influencing the dissolved iron input by river water to the open ocean

NASA Astrophysics Data System (ADS)

Krachler, R.; Jirsa, F.; Ayromlou, S.

The influence of natural metal chelators on the bio-available iron input to the ocean by river water was studied. Ferrous and ferric ions present as suspended colloidal particles maintaining the semblance of a dissolved load are coagulated and settled as their freshwater carrier is mixed with seawater at the continental boundary. However, we might argue that different iron-binding colloids become sequentially destabilized in meeting progressively increasing salinities. By use of a 59Fe tracer method, the partitioning of the iron load from the suspended and dissolved mobile fraction to storage in the sediments was measured with high accuracy in mixtures of natural river water with artificial sea water. The results show a characteristic sequence of sedimentation. Various colloids of different stability are removed from a water of increasing salinity, such as it is the case in the transition from a river water to the open sea. However, the iron transport capacities of the investigated river waters differed greatly. A mountainous river in the Austrian Alps would add only about 5% of its dissolved Fe load, that is about 2.0 µg L-1 Fe, to coastal waters. A small tributary draining a sphagnum peat-bog, which acts as a source of refractory low-molecular-weight fulvic acids to the river water, would add approximately 20% of its original Fe load, that is up to 480 µg L-1 Fe to the ocean's bio-available iron pool. This points to a natural mechanism of ocean iron fertilization by terrigenous fulvic-iron complexes originating from weathering processes occurring in the soils upstream.

Factors influencing the dissolved iron input by river water to the open ocean

NASA Astrophysics Data System (ADS)

Krachler, R.; Jirsa, F.; Ayromlou, S.

2005-05-01

The influence of natural metal chelators on the bio-available iron input to the ocean by river water was studied. Ferrous and ferric ions present as suspended colloidal particles maintaining the semblance of a dissolved load are coagulated and settled as their freshwater carrier is mixed with seawater at the continental boundary. However, we might argue that different iron-binding colloids become sequentially destabilized in meeting progressively increasing salinities. By use of a 59Fe tracer method, the partitioning of the iron load from the suspended and dissolved mobile fraction to storage in the sediments was measured with high accuracy in mixtures of natural river water with artificial sea water. The results show a characteristic sequence of sedimentation. Various colloids of different stability are removed from a water of increasing salinity, such as it is the case in the transition from a river water to the open sea. However, the iron transport capacities of the investigated river waters differed greatly. A mountainous river in the Austrian Alps would add only about 5% of its dissolved Fe load, that is about 2.0 µg L-1 Fe, to coastal waters. A small tributary draining a sphagnum peat-bog, which acts as a source of refractory low-molecular-weight fulvic acids to the river water, would add approximately 20% of its original Fe load, that is up to 480 µg L-1 Fe to the ocean's bio-available iron pool. This points to a natural mechanism of ocean iron fertilization by terrigenous fulvic-iron complexes originating from weathering processes occurring in the soils upstream.

Uncertainty In Greenhouse Gas Emissions On Carbon Sequestration In Coastal and Freshwater Wetlands of the Mississippi River Delta: A Subsiding Coastline as a Proxy for Future Global Sea Level

NASA Astrophysics Data System (ADS)

White, J. R.; DeLaune, R. D.; Roy, E. D.; Corstanje, R.

2014-12-01

The highly visible phenomenon of wetland loss in coastal Louisiana (LA) is examined through the prism of carbon accumulation, wetland loss and greenhouse gas (GHG) emissions. The Mississippi River Deltaic region experiences higher relative sea level rise due to coupled subsidence and eustatic sea level rise allowing this region to serve as a proxy for future projected golbal sea level rise. Carbon storage or sequestration in rapidly subsiding LA coastal marsh soils is based on vertical marsh accretion and areal change data. While coastal marshes sequester significant amount of carbon through vertical accretion, large amounts of carbon, previously sequested in the soil profile is lost through annual deterioration of these coastal marshes as well as through GHG emissions. Efforts are underway in Louisiana to access the carbon credit market in order to provide significant funding for coastal restoration projects. However, there is very large uncertainty on GHG emission rates related to both marsh type and temporal (daily and seasonal) effects. Very little data currently exists which addresses this uncertainty which can significantly affect the carbon credit value of a particular wetland system. We provide an analysis of GHG emission rates for coastal freshwater, brackish and and salt marshes compared to the net soil carbon sequestration rate. Results demonstrate that there is very high uncertainty on GHG emissions which can substantially alter the carbon credit value of a particular wetland system.

Tidal river dynamics: Implications for deltas

NASA Astrophysics Data System (ADS)

Hoitink, A. J. F.; Jay, D. A.

2016-03-01

Tidal rivers are a vital and little studied nexus between physical oceanography and hydrology. It is only in the last few decades that substantial research efforts have been focused on the interactions of river discharge with tidal waves and storm surges into regions beyond the limit of salinity intrusion, a realm that can extend inland hundreds of kilometers. One key phenomenon resulting from this interaction is the emergence of large fortnightly tides, which are forced long waves with amplitudes that may increase beyond the point where astronomical tides have become extinct. These can be larger than the linear tide itself at more landward locations, and they greatly influence tidal river water levels and wetland inundation. Exploration of the spectral redistribution and attenuation of tidal energy in rivers has led to new appreciation of a wide range of consequences for fluvial and coastal sedimentology, delta evolution, wetland conservation, and salinity intrusion under the influence of sea level rise and delta subsidence. Modern research aims at unifying traditional harmonic tidal analysis, nonparametric regression techniques, and the existing understanding of tidal hydrodynamics to better predict and model tidal river dynamics both in single-thread channels and in branching channel networks. In this context, this review summarizes results from field observations and modeling studies set in tidal river environments as diverse as the Amazon in Brazil, the Columbia, Fraser and Saint Lawrence in North America, the Yangtze and Pearl in China, and the Berau and Mahakam in Indonesia. A description of state-of-the-art methods for a comprehensive analysis of water levels, wave propagation, discharges, and inundation extent in tidal rivers is provided. Implications for lowland river deltas are also discussed in terms of sedimentary deposits, channel bifurcation, avulsion, and salinity intrusion, addressing contemporary research challenges.

An AIS-based high-resolution ship emission inventory and its uncertainty in Pearl River Delta region, China.

PubMed

Li, Cheng; Yuan, Zibing; Ou, Jiamin; Fan, Xiaoli; Ye, Siqi; Xiao, Teng; Shi, Yuqi; Huang, Zhijiong; Ng, Simon K W; Zhong, Zhuangmin; Zheng, Junyu

2016-12-15

Ship emissions contribute significantly to air pollution and impose health risks to residents along the coastal area. By using the refined data from the Automatic Identification System (AIS), this study developed a highly resolved ship emission inventory for the Pearl River Delta (PRD) region, China, home to three of ten busiest ports in the world. The region-wide SO 2 , NO X , CO, PM 10 , PM 2.5 , and VOC emissions in 2013 were estimated to be 61,484, 103,717, 10,599, 7155, 6605, and 4195t, respectively. Ocean going vessels were the largest contributors of the total emissions, followed by coastal vessels and river vessels. In terms of ship type, container ship was the leading contributor, followed by conventional cargo ship, dry bulk carrier, fishing ship, and oil tanker. These five ship types accounted for >90% of total emissions. The spatial distributions of emissions revealed that the key emission hot spots all concentrated within the newly proposed emission control area (ECA) and ship emissions within ECA covered >80% of total ship emissions in the PRD, highlighting the importance of ECA in emissions reduction in the PRD. The uncertainties of emission estimates of pollutants were quantified, with lower bounds of -24.5% to -21.2% and upper bounds of 28.6% to 33.3% at 95% confidence intervals. The lower uncertainties in this study highlighted the powerfulness of AIS data in improving ship emission estimates. The AIS-based bottom-up methodology can be used for developing and upgrading ship emission inventory and formulating effective control measures on ship emissions in other port regions wherever possible. Copyright © 2016 Elsevier B.V. All rights reserved.

Statistical Field Estimation for Complex Coastal Regions and Archipelagos (PREPRINT)

DTIC Science & Technology

2011-04-09

and study the computational properties of these schemes. Specifically, we extend a multiscale Objective Analysis (OA) approach to complex coastal...computational properties of these schemes. Specifically, we extend a multiscale Objective Analysis (OA) approach to complex coastal regions and... multiscale free-surface code builds on the primitive-equation model of the Harvard Ocean Predic- tion System (HOPS, Haley et al. (2009)). Additionally

MODELING THE IMPACTS OF DECADAL CHANGES IN RIVERINE NUTRIENT FLUXES ON COASTAL EUTROPHICATION NEAR THE MISSISSIPPI RIVER DELTA. (R827785E02)

EPA Science Inventory

A mathematical model was used to link decadal changes in the Mississippi River nutrient flux to coastal eutrophication near the Mississippi River Delta. Model simulations suggest that bottom water hypoxia intensified about 30 years ago, as a probable consequence of increased n...

Quantifying landscape change in an arctic coastal lowland using repeat airborne LiDAR

USGS Publications Warehouse

Jones, Benjamin M.; Stoker, Jason M.; Gibbs, Ann E.; Grosse, Guido; Romanovsky, Vladimir E.; Douglas, Thomas A.; Kinsman, Nichole E.M.; Richmond, Bruce M.

2013-01-01

Increases in air, permafrost, and sea surface temperature, loss of sea ice, the potential for increased wave energy, and higher river discharge may all be interacting to escalate erosion of arctic coastal lowland landscapes. Here we use airborne light detection and ranging (LiDAR) data acquired in 2006 and 2010 to detect landscape change in a 100 km2 study area on the Beaufort Sea coastal plain of northern Alaska. We detected statistically significant change (99% confidence interval), defined as contiguous areas (>10 m2) that had changed in height by at least 0.55 m, in 0.3% of the study region. Erosional features indicative of ice-rich permafrost degradation were associated with ice-bonded coastal, river, and lake bluffs, frost mounds, ice wedges, and thermo-erosional gullies. These features accounted for about half of the area where vertical change was detected. Inferred thermo-denudation and thermo-abrasion of coastal and river bluffs likely accounted for the dominant permafrost-related degradational processes with respect to area (42%) and volume (51%). More than 300 thermokarst pits significantly subsided during the study period, likely as a result of storm surge flooding of low-lying tundra (<1.4 m asl) as well as the lasting impact of warm summers in the late-1980s and mid-1990s. Our results indicate that repeat airborne LiDAR can be used to detect landscape change in arctic coastal lowland regions at large spatial scales over sub-decadal time periods.

Compound simulation of fluvial floods and storm surges in a global coupled river-coast flood model: Model development and its application to 2007 Cyclone Sidr in Bangladesh

NASA Astrophysics Data System (ADS)

Ikeuchi, Hiroaki; Hirabayashi, Yukiko; Yamazaki, Dai; Muis, Sanne; Ward, Philip J.; Winsemius, Hessel C.; Verlaan, Martin; Kanae, Shinjiro

2017-08-01

Water-related disasters, such as fluvial floods and cyclonic storm surges, are a major concern in the world's mega-delta regions. Furthermore, the simultaneous occurrence of extreme discharges from rivers and storm surges could exacerbate flood risk, compared to when they occur separately. Hence, it is of great importance to assess the compound risks of fluvial and coastal floods at a large scale, including mega-deltas. However, most studies on compound fluvial and coastal flooding have been limited to relatively small scales, and global-scale or large-scale studies have not yet addressed both of them. The objectives of this study are twofold: to develop a global coupled river-coast flood model; and to conduct a simulation of compound fluvial flooding and storm surges in Asian mega-delta regions. A state-of-the-art global river routing model was modified to represent the influence of dynamic sea surface levels on river discharges and water levels. We conducted the experiments by coupling a river model with a global tide and surge reanalysis data set. Results show that water levels in deltas and estuaries are greatly affected by the interaction between river discharge, ocean tides and storm surges. The effects of storm surges on fluvial flooding are further examined from a regional perspective, focusing on the case of Cyclone Sidr in the Ganges-Brahmaputra-Meghna Delta in 2007. Modeled results demonstrate that a >3 m storm surge propagated more than 200 km inland along rivers. We show that the performance of global river routing models can be improved by including sea level dynamics.

Influence of synoptic condition and holiday effects on VOCs and ozone production in the Yangtze River Delta region, China

NASA Astrophysics Data System (ADS)

Xu, Zhengning; Huang, Xin; Nie, Wei; Chi, Xuguang; Xu, Zheng; Zheng, Longfei; Sun, Peng; Ding, Aijun

2017-11-01

Both anthropogenic emission and synoptic conditions play important roles in ozone (O3) formation and accumulation. In order to understand the influence of synoptic condition and holiday effects on ozone production in the Yangtze River Delta region, China, concentrations of speciated volatile organic compounds (VOCs) and O3 as well as other relevant trace gases were simultaneously measured at the Station for Observing Regional Processes of the Earth System (SORPES) in Nanjing around the National Day holidays of China in 2014, which featured substantial change of emissions and dominated by typical anti-cyclones. Different groups of VOC species and their chemical reactivities were comprehensively analyzed. We observed clear diurnal variations of short alkenes during the measurement period, considerable amount of short alkenes were observed during night (more than 10 ppb) while almost no alkenes were measured during daytime, which might be attributed to different chemical processes. The obvious enhancement of the VOC tracers during the National Day holidays (Oct. 1st-Oct. 7th) indicated that the holiday effect strongly influenced the distribution of VOC profile and chemical reactivity in the atmosphere. At the same time, two meso-scale anticyclone processes were also observed during the measurement period. The synoptic condition contributed to the accumulation of VOCs and other precursors, which consequently impacted the ozone production in this region. The integrated influence of synoptic and holiday effects was also analyzed with an Observation Based Model (OBM) based on simplified MCM (Master Chemical Mechanism) chemical mechanism. The calculated relative increment reactivity (RIR) of different VOC groups revealed that during the holidays, this region was in VOC-limited regime and the variation of RIR shows a close linkage to the development and elimination of anti-cyclones, indicating an in-negligible contribution of synoptic effect toward ozone production in this

Regional multi-compartment ecological risk assessment: Establishing cadmium pollution risk in the northern Bohai Rim, China.

PubMed

Shi, Yajuan; Wang, Ruoshi; Lu, Yonglong; Song, Shuai; Johnson, Andrew C; Sweetman, Andrew; Jones, Kevin

2016-09-01

Ecological risk assessment (ERA) has been widely applied in characterizing the risk of chemicals to organisms and ecosystems. The paucity of toxicity data on local biota living in the different compartments of an ecosystem and the absence of a suitable methodology for multi-compartment spatial risk assessment at the regional scale has held back this field. The major objective of this study was to develop a methodology to quantify and distinguish the spatial distribution of risk to ecosystems at a regional scale. A framework for regional multi-compartment probabilistic ecological risk assessment (RMPERA) was constructed and corroborated using a bioassay of a local species. The risks from cadmium (Cd) pollution in river water, river sediment, coastal water, coastal surface sediment and soil in northern Bohai Rim were examined. The results indicated that the local organisms in soil, river, coastal water, and coastal sediment were affected by Cd. The greatest impacts from Cd were identified in the Tianjin and Huludao areas. The overall multi-compartment risk was 31.4% in the region. The methodology provides a new approach for regional multi-compartment ecological risk assessment. Copyright © 2016 Elsevier Ltd. All rights reserved.

77 FR 23547 - Taking and Importing Marine Mammals; Taking Marine Mammals Incidental to Columbia River Crossing...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-19

... at Astoria, Oregon. Coastal tides influence the flow rate and river level up to Bonneville Dam at.... Contractor schedules, weather, materials, and equipment could also influence construction duration. CRC would...

Sea Level Rise Drove Enhanced Coastal Erosion following the Last Glacial Maximum, Southern California, U.S.A.

NASA Astrophysics Data System (ADS)

Sharman, G.; Covault, J. A.; Stockli, D. F.; Sickmann, Z.; Malkowski, M. A.; Johnstone, S.

2017-12-01

Seacliff erosion poses a major threat to southern California coastal communities, including the propensity for episodic cliff failure and damage to residential and commercial property. Rising sea level is predicted to accelerate seacliff retreat, yet few constraints exist on how rapid sea level rise influenced coastal erosion rates in pre-modern timescales. Here we look to the geologic record in submarine fans to investigate changes in relative sediment supply from rivers and coastal erosion, the latter including seacliff retreat and bluffland erosion. To understand how sea level rise driven by past global warming impacted coastal erosion rates, we sampled modern rivers of the Peninsular Ranges and latest Pleistocene-Holocene submarine canyon-fan systems in southern California for detrital zircon U-Pb geochronology (1369 analyses from 10 samples). Modern river samples show a systematic north-south change in grain age populations broadly distributed across Cretaceous time (ca. 70-135 Ma) to a predominance of middle Cretaceous grain ages (ca. 95-115 Ma), reflecting variations in the geologic age of units within each river catchment. The Carlsbad and La Jolla submarine canyon-fan systems, deposited during sea level lowstand and highstand, respectively, exhibit detrital zircon age distributions consistent with derivation from upstream rivers, with mixing in the littoral zone. However, a sample from the Oceanside fan, deposited during rapid sea level rise at ca. 13 ka, is dominated by detrital ages that lack a local source in the northern Peninsular Ranges, including latest Cretaceous, late Jurassic, and Proterozoic ages. However, such grain ages are widespread in Paleogene sedimentary rocks that comprise the shelf and coastal area, suggesting increased sediment supply from coastal and shelf erosion. Assuming that the Oceanside sample is representative of sediment production during sea level rise, sediment mixing calculations suggest a one to two orders of magnitude

Three decadal inputs of total organic carbon from four major coastal river basins to the summer hypoxic zone of the Northern Gulf of Mexico.

PubMed

He, Songjie; Xu, Y Jun

2015-01-15

This study investigated long-term (1980-2009) yields and variability of total organic carbon (TOC) from four major coastal rivers in Louisiana entering the Northern Gulf of Mexico where a large-area summer hypoxic zone has been occurring since the middle 1980s. Two of these rivers drain agriculture-intensive (>40%) watersheds, while the other two rivers drain forest-pasture dominated (>50%) watersheds. The study found that these rivers discharged a total of 13.0×10(4)t TOC annually, fluctuating from 5.9×10(4) to 22.8×10(4)t. Seasonally, the rivers showed high TOC yield during the winter and early spring months, corresponding to the seasonal trend of river discharge. While river hydrology controlled TOC yields, land use has played an important role in fluxes, seasonal variations, and characteristics of TOC. The findings fill in a critical information gap of quantity and quality of organic carbon transport from coastal watersheds to one of the world's largest summer hypoxic zones. Copyright © 2014 Elsevier Ltd. All rights reserved.

Spatio-Temporal Migration Patterns of Pacific Salmon Smolts in Rivers and Coastal Marine Waters

PubMed Central

Melnychuk, Michael C.; Welch, David W.; Walters, Carl J.

2010-01-01

Background Migrations allow animals to find food resources, rearing habitats, or mates, but often impose considerable predation risk. Several behavioural strategies may reduce this risk, including faster travel speed and taking routes with shorter total distance. Descriptions of the natural range of variation in migration strategies among individuals and populations is necessary before the ecological consequences of such variation can be established. Methodology/Principal Findings Movements of tagged juvenile coho, steelhead, sockeye, and Chinook salmon were quantified using a large-scale acoustic tracking array in southern British Columbia, Canada. Smolts from 13 watersheds (49 watershed/species/year combinations) were tagged between 2004–2008 and combined into a mixed-effects model analysis of travel speed. During the downstream migration, steelhead were slower on average than other species, possibly related to freshwater residualization. During the migration through the Strait of Georgia, coho were slower than steelhead and sockeye, likely related to some degree of inshore summer residency. Hatchery-reared smolts were slower than wild smolts during the downstream migration, but after ocean entry, average speeds were similar. In small rivers, downstream travel speed increased with body length, but in the larger Fraser River and during the coastal migration, average speed was independent of body length. Smolts leaving rivers located towards the northern end of the Strait of Georgia ecosystem migrated strictly northwards after ocean entry, but those from rivers towards the southern end displayed split-route migration patterns within populations, with some moving southward. Conclusions/Significance Our results reveal a tremendous diversity of behavioural migration strategies used by juvenile salmon, across species, rearing histories, and habitats, as well as within individual populations. During the downstream migration, factors that had strong effects on travel

Application of multiple geochemical markers to investigate organic pollution in a dynamic coastal zone.

PubMed

Liu, Liang-Ying; Wang, Ji-Zhong; Wong, Charles S; Qiu, Jian-Wen; Zeng, Eddy Y

2013-02-01

Multiple geochemical markers, including aliphatic hydrocarbons (n-alkanes), linear alkylbenzenes (LABs), and polycyclic aromatic hydrocarbons (PAHs), were employed to relate sediment organic chemical pollution in the coastal zone off South China to socioeconomic development there. Concentrations of Σn-C(15-35) (n-alkanes with 15-35 carbon atoms), ΣLAB (sum of C(10) to C(13) LABs), and Σ(26) PAH (sum of 26 PAH compounds) ranged from 110 to 3,160, 11 to 160, and 26 to 600 ng/g, with medians of 730, 40, and 230 ng/g, respectively. Natural hydrocarbons were mainly derived from terrestrial higher plant waxes, and in minor amounts from aquatic plankton and bacteria. Compositions of LABs indicated that considerable amounts of poorly treated wastewater had been directly discharged or transported to the eastern and western coastal areas of Guangdong Province. In addition, anthropogenic hydrocarbons were derived largely from vehicular emissions and combustion of domestic coal and biomass and to a lesser extent from oil spills. Eastern and western coastal sediments contained higher levels of LABs but lower levels of PAHs than those of the Pearl River Estuary, a coastal area of the Pearl River Delta. This spatial pattern of organic pollution was consistent with chemical use patterns. The eastern and western regions of Guangdong Province are economically less developed than the Pearl River Delta region, where more domestic wastewater treatment plants have been built. However, greater amounts of energy are consumed in the latter region to produce more combustion-derived PAH contamination. Copyright © 2012 SETAC.

Tannat grape composition responses to spatial variability of temperature in an Uruguay's coastal wine region

NASA Astrophysics Data System (ADS)

Fourment, Mercedes; Ferrer, Milka; González-Neves, Gustavo; Barbeau, Gérard; Bonnardot, Valérie; Quénol, Hervé

2017-09-01

Spatial variability of temperature was studied in relation to the berry basic composition and secondary compounds of the Tannat cultivar at harvest from vineyards located in Canelones and Montevideo, the most important wine region of Uruguay. Monitoring of berries and recording of temperature were performed in 10 commercial vineyards of Tannat situated in the southern coastal wine region of the country for three vintages (2012, 2013, and 2014). Results from a multivariate correlation analysis between berry composition and temperature over the three vintages showed that (1) Tannat responses to spatial variability of temperature were different over the vintages, (2) correlations between secondary metabolites and temperature were higher than those between primary metabolites, and (3) correlation values between berry composition and climate variables increased when ripening occurred under dry conditions (below average rainfall). For a particular studied vintage (2013), temperatures explained 82.5% of the spatial variability of the berry composition. Daily thermal amplitude was found to be the most important spatial mode of variability with lower values recorded at plots nearest to the sea and more exposed to La Plata River. The highest levels in secondary compounds were found in berries issued from plots situated as far as 18.3 km from La Plata River. The increasing knowledge of temperature spatial variability and its impact on grape berry composition contributes to providing possible issues to adapt grapevine to climate change.

River terrace development in the NE Mediterranean region (Syria and Turkey): Patterns in relation to crustal type

NASA Astrophysics Data System (ADS)

Bridgland, David R.; Demir, Tuncer; Seyrek, Ali; Daoud, Mohamad; Abou Romieh, Mohammad; Westaway, Rob

2017-06-01

It is widely recognized that the optimal development of river terraces globally has been in the temperate latitudes, with NW and Central Europe being areas of particular importance for the preservation of such archives of Quaternary environmental change. There is also a growing consensus that the principal drivers of terrace formation have been climatic fluctuation against a background of progressive (but variable) uplift. Nonetheless river terraces are widely preserved in the Mediterranean region, where they have often been attributed to the effects of neotectonic activity, with a continuing debate about the relative significance of fluctuating temperature (glacials-interglacials) and precipitation (pluvials-interpluvials). Research in Syria and southern-central Turkey (specifically in the valleys of the Tigris and Ceyhan in Turkey, the Kebir in Syria and the trans-border rivers Orontes and Euphrates) has underlined the importance of uplift rates in dictating the preservation pattern of fluvial archives and has revealed different patterns that can be related to crustal type. The NE Mediterranean coastal region has experienced unusually rapid uplift in the Late Quaternary. The relation between the Kebir terraces and the staircase of interglacial raised beaches preserved along the Mediterranean coastline of NW Syria reinforces previous conclusions that the emplacement of the fluvial terrace deposits in the Mediterranean has occurred during colder climatic episodes.

Moderate effect of damming the Romaine River (Quebec, Canada) on coastal plankton dynamics

NASA Astrophysics Data System (ADS)

Senneville, Simon; Schloss, Irene R.; St-Onge Drouin, Simon; Bélanger, Simon; Winkler, Gesche; Dumont, Dany; Johnston, Patricia; St-Onge, Isabelle

2018-04-01

Rivers' damming disrupts the seasonal cycle of freshwater and nutrient inputs into the marine system, which can lead to changes in coastal plankton dynamics. Here we use a 3-D 5-km resolution coupled biophysical model and downscale it to a 400-m resolution to simulate the effect of damming the Romaine River in Québec, Canada, which discharges on average 327 m3 s-1 of freshwater into the northern Gulf of St. Lawrence. Model results are compared with environmental data obtained from 2 buoys and in situ sampling near the Romaine River mouth during the 2013 spring-summer period. Noteworthy improvements are made to the light attenuation parametrization and the trophic links of the biogeochemical model. The modelled variables reproduced most of the observed levels of variability. Comparisons between natural and regulated discharge simulation show differences in primary production and in the dominance of plankton groups in the Romaine River plume. The maximum increase in primary production when averaged over the inner part of Mingan Archipelago is 41%, but 7.1% when the primary production anomaly is averaged from March to September.

Sedimentological and geochronological evidences of anthropogenic impacts on river basins in the Northern Latium coastal area (Italy)

NASA Astrophysics Data System (ADS)

Piazzolla, Daniele; Paladini de Mendoza, Francesco; Scanu, Sergio; Marcelli, Marco

2015-04-01

In this work we aimed to compare sedimentological and geochronological data from three sediment core samples (MIG50, MRT50, and GRT50) taken in the Northern Latium (Italy) coastal area, at -50 m depth, to data regarding rainfall, river flows and the land use in the three most important hydrographic basins (Mignone, Marta and Fiora) and in the coastal area. Different trends of sediment mass accumulation rate (MAR) are detected in the three cores: a strongly increasing trend was identified in MIG50 and MRT50 cores while GRT50 doesn't show significant variation. Data from the sedimentological analysis of GRT50 core identify a progressive decrease in the sandy component, which declined from about 30% to the current level of 7% over the last 36 years, while MRT50 and MIG50 cores (mainly composed by pelitic fraction > 95%) showed slight variations of textural ratio between silt and clay. According to the general decrease of pluviometric trend observed in Italy, related to teleconnection pattern tendency (NAO), the statistical analysis of rain identified significative decrease only in the Fiora river basin, whereas in the other two locations the decrease was not as significant. Regarding the Fiora river flow, a significative decreasing trend of average flow is detected, while the flood regime remained unaffected over the past 30 years. The analysis of the land use shows that the human activities are increased of 6-10% over the available time steps (1990 - 2006) in Fiora and Mignone river basins, while the Marta river basin has a strong human impact since 1990 highligting more than 80% of artificial soil covering. The largest variation is observed on the Fiora basin (10%) where the antrhopic activities have expanded to an area of about 85 Km2. Moreover, in the last ten years a large beach nourishment in 2004 (570000 m3) and dredging activities in the early second half of 2000s (1000000 m3 moved) were performed in Marina di Tarquinia beach and in front of the Torrevaldaliga

Temperature anomalies in the Lower Suwannee River and tidal creeks, Florida, 2005

USGS Publications Warehouse

Raabe, Ellen A.; Bialkowska-Jelinska, Elzbieta

2007-01-01

Temperature anomalies in coastal waters were detected with Thermal Infrared imagery of the Lower Suwannee River (LSR) and nearshore tidal marshes on Florida’s Gulf Coast. Imagery included 1.5-m-resolution day and night Thermal Infrared (TIR) and 0.75-m-resolution Color Infrared (CIR) imagery acquired on 2-3 March 2005. Coincident temperature readings were collected on the ground and used to calibrate the imagery. The Floridan aquifer is at or near the land surface in this area and bears a constant temperature signature of ~ 22 degrees Celsius. This consistent temperature contrasts sharply with ambient temperatures during winter and summer months. Temperature anomalies identified in the imagery during a late-winter cold spell may be correlated with aquifer seeps. Hot spots were identified as those areas exceeding ambient water temperature by 4 degrees Celsius or more. Warm-water plumes were also mapped for both day and night imagery. The plume from Manatee Spring, a first-order magnitude spring, influenced water temperature in the lower river. Numerous temperature anomalies were identified in small tributaries and tidal creeks from Shired Island to Cedar Key and were confirmed with field reconnaissance. Abundant warm-water features were identified along tidal creeks south of the Suwannee River and near Waccasassa Bay. Features were mapped in the tidal creeks north of the river but appear to be less common or have lower associated discharge. The imagery shows considerable promise in mapping coastal-aquifer seeps and understanding the underlying geology of the region. Detection of seep locations may aid research in groundwater/surface-water interactions and water quality, and in the management of coastal habitats.

Ecology of tidal freshwater forests in coastal deltaic Louisiana and northeastern South Carolina: Chapter 9

USGS Publications Warehouse

Conner, William H.; Krauss, Ken W.; Doyle, Thomas W.

2007-01-01

Tidal freshwater swamps in the southeastern United States are subjected to tidal hydroperiods ranging in amplitude from microtidal (<0.1 m) to mesotidal (2-4 m), both having different susceptibilities to anthropogenic change. Small alterations in flood patterns, for example, can switch historically microtidal swamps to permanently flooded forests, scrub-shrub stands, marsh, or open water but are less likely to convert mesotidal swamps. Changes to hydrological patterns tend to be more noticeable in Louisiana than do those in South Carolina.The majority of Louisiana’s coastal wetland forests are found in the Mississippi River deltaic plain region. Coastal wetland forests in the deltaic plain have been shaped by the sediments, water, and energy of the Mississippi River and its major distributaries. Baldcypress (Taxodium distichum [L.] L.C. Rich.) and water tupelo (Nyssa aquatica L.) are the primary tree species in the coastal swamp forests of Louisiana. Sites where these species grow usually hold water for most of the year; however, some of the more seaward sites were historically microtidal, especially where baldcypress currently dominates. In many other locations, baldcypress and water tupelo typically grow in more or less pure stands or as mixtures of the two with common associates such as black willow (Salix nigra Marsh.), red maple (Acer rubrum L.), water locust (Gleditsia aquatic Marsh.), overcup oak (Quercus lyrata Walt.), water hickory (Carya aquatica [Michx. f.] Nutt.), green ash (Fraxinus pennsylvanica Marsh.), pumpkin ash (F. profunda Bush.), and redbay (Persea borbonia [L.] Sprengel) (Brown and Montz 1986).The South Carolina coastal plain occupies about two-thirds of the state and rises gently to 150 m from the Atlantic Ocean up to the Piedmont plateau. Many rivers can be found in the Coastal Plain with swamps near the coast that extend inland along the rivers. Strongly tidal freshwater forests occur along the lower reaches of redwater rivers (Santee

SEDIMENTATION IN PACIFIC NORTHWEST COASTAL STREAMS -- EVIDENCE FROM REGIONAL SURVEY OF BED SUBSTRATE SIZE AND STABILITY

EPA Science Inventory

Excessive erosion, transport and deposition of sediment are major problems in streams and rivers throughout the United States. We examined evidence of anthropogenic sedimentation in Oregon and Washington coastal streams using relatively rapid measurements taken from surveys duri...

Exposure of coastal ecosystems to river plume spreading across a near-equatorial continental shelf

NASA Astrophysics Data System (ADS)

Tarya, A.; Hoitink, A. J. F.; Vegt, M. Van der; van Katwijk, M. M.; Hoeksema, B. W.; Bouma, T. J.; Lamers, L. P. M.; Christianen, M. J. A.

2018-02-01

The Berau Continental Shelf (BCS) in East Kalimantan, Indonesia, harbours various tropical marine ecosystems, including mangroves, seagrass meadows and coral reefs. These ecosystem are located partly within reach of the Berau River plume, which may affect ecosystem health through exposure to land-derived sediments, nutrients and pollutants carried by the plume. This study aims (1) to assess the exposure risk of the BCS coastal ecosystems to river plume water, measured as exposure time to three different salinity levels, (2) to identify the relationships between these salinity levels and the abundance and diversity of coral and seagrass ecosystems, and (3) to determine a suitable indicator for the impacts of salinity on coral reef and seagrass health. We analysed hydrodynamic models, classified salinity levels, and quantified the correlations between the salinity model parameters and ecological metrics for the BCS systems. An Empirical Orthogonal Functions (EOF) analysis revealed three modes of river plume dispersal patterns, which strongly reflect monsoon seasonality. The first mode, explaining 39% of the variability, was associated with the southward movement of the plume due to northerly winds, while the second and third modes (explaining 29% and 26% of the variability, respectively) were associated with the northeastward migration of the plume related to southwesterly and southerly winds. Exposure to low salinity showed higher correlations with biological indicators than mean salinity, indicating that low salinity is a more suitable indicator for coastal ecosystem health. Significant correlations (R2) were found between exposure time to low salinity (days with salinity values below 25 PSU) with coral cover, coral species richness, seagrass cover, the number of seagrass species, seagrass leaf phosphorus, nitrogen, C:N ratio and iron content. By comparing the correlation coefficients and the slopes of the regression lines, our study suggests that coral reefs are

Preliminary assessment of recent deposition related to a crevasse splay on the Mississippi River delta: Implications for coastal restoration

USGS Publications Warehouse

Ferina, N.F.; Flocks, J.G.; Kingdinger, Jack L.; Miner, M.D.; Motti, J. P.; Chadwick, Paul C.; Johnston, James B.

2005-01-01

Historically, the Mississippi River has replenished sediment across the lower deltaic plain, abating land loss. However, flood-control structures along the river now restrict this natural process and divert sediment from the modern delta offshore to the shelf break, thereby removing it from the coastal system. Localized crevasse splays, however, can deposit significant amounts of sediment in a short span of time.Satellite imagery and field investigations, including eight sediment vibracores, have identified a recent crevasse splay originating from Brant Bayou within the Delta National Wildlife Refuge on the lower Mississippi River delta. The splay deposits are estimated to be as much as 3 m thick and are located stratigraphically above shallow interdistributary-bay deposits. In addition, the deposits exhibit physical characteristics similar to those of large scale prograded deltas. The Bayou Brant crevasse splay began forming in 1978 and has built approximately 3.7 km2 of land. Coastal planners hope to utilize on this natural process of sediment dispersion to create new land within the deltaic plain.

The influence of sea-level changes on tropical coastal lowlands; the Pleistocene Coropina Formation, Suriname

NASA Astrophysics Data System (ADS)

Wong, Th. E.; de Kramer, R.; de Boer, P. L.; Langereis, C.; Sew-A-Tjon, J.

2009-04-01

The Pleistocene Coropina Formation largely constitutes the Old Coastal Plain of Suriname. It is exposed fully only in open-pit bauxite mines in the central coastal plain as part of the unconsolidated overburden of Paleocene-Eocene bauxites. This study deals with the stratigraphy, sedimentology and chronology of this formation, and is based on a study in the recently closed Lelydorp-III bauxite mine operated by N.V. BHP Billiton Maatschappij Suriname. The Coropina Formation consists of the Para and Lelydorp Members. We present a detailed lithological subdivision of these members. In the Para Member, four units are discerned which are grouped in two transgressive cycles, both ranging upward from terrestrial towards chenier and coastal mudflat deposits reflecting glacio-eustatic sea-level changes. The sandy sediments represent fluviatile and beach-bar (chenier) deposits, and were supplied by rivers from the Precambrian basement and to a lesser extent by westward longshore coastal drift. Clays, largely derived from the Amazon River and transported alongshore over the shelf, were deposited in extensive coastal mudflats. The Lelydorp Member, also comprising four units, represents a depositional system that is closely comparable to the recent Suriname coastal setting, i.e., a lateral and vertical alternation of mudflat and chenier deposits formed over a period characterised by more or less constant sea level. Palaeomagnetic data indicate a dominantly reversed magnetic polarity in the Para Member, whereas the Lelydorp Member shows a normal magnetic polarity with a minor reversed polarity overprint. The reversed polarities of the Para Member exclude a Brunhes Chron (0.78-0.0 Ma) age, and thus assign it to the Matuyama Chron (2.58-0.78 Ma). This implies that the Coropina Formation is much older than hitherto assumed, and that one or more (long-term) hiatuses are not recognizable in the lithological succession.

Diurnal changes in ocean color in coastal waters

NASA Astrophysics Data System (ADS)

Arnone, Robert; Vandermeulen, Ryan; Ladner, Sherwin; Ondrusek, Michael; Kovach, Charles; Yang, Haoping; Salisbury, Joseph

2016-05-01

Coastal processes can change on hourly time scales in response to tides, winds and biological activity, which can influence the color of surface waters. These temporal and spatial ocean color changes require satellite validation for applications using bio-optical products to delineate diurnal processes. The diurnal color change and capability for satellite ocean color response were determined with in situ and satellite observations. Hourly variations in satellite ocean color are dependent on several properties which include: a) sensor characterization b) advection of water masses and c) diurnal response of biological and optical water properties. The in situ diurnal changes in ocean color in a dynamic turbid coastal region in the northern Gulf of Mexico were characterized using above water spectral radiometry from an AErosol RObotic NETwork (AERONET -WavCIS CSI-06) site that provides up to 8-10 observations per day (in 15-30 minute increments). These in situ diurnal changes were used to validate and quantify natural bio-optical fluctuations in satellite ocean color measurements. Satellite capability to detect changes in ocean color was characterized by using overlapping afternoon orbits of the VIIRS-NPP ocean color sensor within 100 minutes. Results show the capability of multiple satellite observations to monitor hourly color changes in dynamic coastal regions that are impacted by tides, re-suspension, and river plume dispersion. Hourly changes in satellite ocean color were validated with in situ observation on multiple occurrences during different times of the afternoon. Also, the spatial variability of VIIRS diurnal changes shows the occurrence and displacement of phytoplankton blooms and decay during the afternoon period. Results suggest that determining the temporal and spatial changes in a color / phytoplankton bloom from the morning to afternoon time period will require additional satellite coverage periods in the coastal zone.

Pollution status of polycyclic aromatic hydrocarbons in surface sediments from the Yangtze River Estuary and its adjacent coastal zone.

PubMed

Wang, Chenglong; Zou, Xinqing; Gao, Jianhua; Zhao, Yifei; Yu, Wenwen; Li, Yali; Song, Qiaochu

2016-11-01

Polycyclic aromatic hydrocarbons (PAHs) are mainly produced by incomplete combustion and are used as indicators of anthropogenic activities on the environment. This study analyses the PAHs level in the Yangtze River Estuary (YRE), an important component of Yangtze River and a developed and populated region in China. Surface sediments were collected from 77 sites at the YRE and its adjacent coastal zone (IACZ) for a comprehensive study of PAHs. Kriging interpolation technology and Positive matrix factorization (PMF) model were applied to explore the spatial distribution and sources of PAHs. Concentrations of 16 PAHs (ΣPAHs) varied from 27.2 ng g(-1) to 621.6 ng g(-1) dry weight, with an average value of 158.2 ng g(-1). Spatially, ΣPAHs exhibited wide fluctuation and exhibited an increasing tendency from north to south. In addition, ΣPAHs exhibited a decreasing trend with increasing distance between the estuary and IACZ. The deposition flux of PAHs indicated that more than 107.8 t a(-1) PAHs was deposited in the study area annually. The results of the PMF model revealed that anthropogenic activities were the main sources of PAHs in the study area. Vehicle emissions and marine engines were the most important sources and accounted for 40.9% of the pollution. Coal combustion, petrogenic sources, and wood combustion were other sources that contributed 23.9%, 23.6%, and 11.5%, respectively. The distribution patterns of PAHs in the YRE and IACZ were influenced by many complicated factors such as sediment grain size, hydrodynamics and so on. Copyright © 2016 Elsevier Ltd. All rights reserved.

Water quality in select regions of Cauvery Delta River basin, southern India, with emphasis on monsoonal variation.

PubMed

Solaraj, Govindaraj; Dhanakumar, Selvaraj; Murthy, Kuppuraj Rutharvel; Mohanraj, Rangaswamy

2010-07-01

Delta regions of the Cauvery River basin are one of the significant areas of rice production in India. In spite of large-scale utilization of the river basin for irrigation and drinking purposes, the lack of appropriate water management has seemingly deteriorated the water quality due to increasing anthropogenic activities. To assess the extent of deterioration, physicochemical characteristics of surface water were analyzed monthly in select regions of Cauvery Delta River basin, India, during July 2007 to December 2007. Total dissolved solids, chemical oxygen demand, and phosphate recorded maximum levels of 1,638, 96, and 0.43 mg/l, respectively, exceeding the permissible levels at certain sampling stations. Monsoonal rains in Cauvery River basin and the subsequent increase in river flow rate influences certain parameters like dissolved solids, phosphate, and dissolved oxygen. Agricultural runoff from watershed, sewage, and industrial effluents are suspected as probable factors of water pollution.

Evidence of local and regional freshening of Northeast Greenland coastal waters.

PubMed

Sejr, Mikael K; Stedmon, Colin A; Bendtsen, Jørgen; Abermann, Jakob; Juul-Pedersen, Thomas; Mortensen, John; Rysgaard, Søren

2017-10-13

The supply of freshwater to fjord systems in Greenland is increasing as a result of climate change-induced acceleration in ice sheet melt. However, insight into the marine implications of the melt water is impaired by lack of observations demonstrating the fate of freshwater along the Greenland coast and providing evaluation basis for ocean models. Here we present 13 years of summer measurements along a 120 km transect in Young Sound, Northeast Greenland and show that sub-surface coastal waters are decreasing in salinity with an average rate of 0.12 ± 0.05 per year. This is the first observational evidence of a significant freshening on decadal scale of the waters surrounding the ice sheet and comes from a region where ice sheet melt has been less significant. It implies that ice sheet dynamics in Northeast Greenland could be of key importance as freshwater is retained in southward flowing coastal currents thus reducing density of water masses influencing major deep water formation areas in the Subarctic Atlantic Ocean. Ultimately, the observed freshening could have implications for the Atlantic meridional overturning circulation.

Associations between accelerated glacier mass wastage and increased summer temperature in coastal regions

USGS Publications Warehouse

Dyurgerov, M.; McCabe, G.J.

2006-01-01

Low-elevation glaciers in coastal regions of Alaska, the Canadian Arctic, individual ice caps around the Greenland ice sheet, and the Patagonia Ice Fields have an aggregate glacier area of about 332 ?? 103 km 2 and account for approximately 42% of all the glacier area outside the Greenland and Antarctic ice sheets. They have shown volume loss, especially since the end of the 1980s, increasing from about 45% in the 1960s to nearly 67% in 2003 of the total wastage from all glaciers on Earth outside those two largest ice sheets. Thus, a disproportionally large contribution of coastal glacier ablation to sea level rise is evident. We examine cumulative standardized departures (1961-2000 reference period) of glacier mass balances and air temperature data in these four coastal regions. Analyses indicate a strong association between increases in glacier volume losses and summer air temperature at regional and global scales. Increases in glacier volume losses in the coastal regions also coincide with an accelerated rate of ice discharge from outlet glaciers draining the Greenland and West Antarctic ice sheets. These processes imply further increases in sea level rise. ?? 2006 Regents of the University of Colorado.

Influence of Offshore Initial Moisture Field and Convection on the Development of Coastal Convection in a Heavy Rainfall Event over South China during the Pre-summer Rainy Season

NASA Astrophysics Data System (ADS)

Lu, Rong; Sun, Jianhua; Fu, Shenming

2017-04-01

This paper utilizes the observation data from the Southern China Monsoon Rainfall Experiment (SCMREX) and the numerical experiments to investigate the influence of moisture amount and convection development over the northern South China Sea on a heavy rainfall event in coastal South China on May 8, 2014. Intensive sounding and wind profiles data reveal that there existed a convergence region formed by the southwesterly and easterly jet in the Pearl River delta, which provided favorable conditions for the development of convection. Whether the initial relative humidity field was increased or decreased in the offshore area, or turning off sensible and latent heat release from the cumulus and microphysical processes, had significant effects on the intensity and movement of convection in the coastal areas of Guangdong owing to the adjustment of temperature and wind fields. Especially, when increasing offshore initial humidity, prosperous sea convection modified the circulation in the entire simulation area, and suppressed the development of convection over land. Moreover, if sensible and latent heat from cumulus and microphysical processes was turned off, the low-level jets could reach further north, and the convective system moved to the northeast in the later stage. These experiments indicate that offshore initial moisture filed and convection activity are indeed important for precipitation forecast in the coastal areas, therefore it's necessary to enhance offshore observation and data assimilation methods in the future.

The NAO Influence on the Early to Mid-Holocene North Atlantic Coastal Upwelling

NASA Astrophysics Data System (ADS)

Hernandez, A.; Cachão, M.; Sousa, P.; Trigo, R. M.; Freitas, M. C.

2017-12-01

Coastal upwelling regions yield some of the oceanic most productive ecosystems, being crucial for the worldwide social and economic development. Most upwelling systems, emerging cold nutrient-rich deep waters, are located in the eastern boundaries of the Atlantic and Pacific basins, and are driven by meridional wind fields parallel to the coastal shore. These winds are associated with the subsiding branch of the large-scale Anticyclonic high pressure systems that dominate the subtropical ocean basins, and therefore can be displaced or intensified within the context of past and future climate changes. However, the role of the current global warming influencing the coastal upwelling is, as yet, unclear. Therefore it is essential to derive a long-term perspective, beyond the era of instrumental measurements, to detect similar warm periods in the past that have triggered changes in the upwelling patterns. In this work, the upwelling dynamics in the Iberian North Atlantic margin during the early and mid-Holocene is reconstructed, using calcareous nannofossils from a decadally resolved estuarine sediment core located in southwestern Portugal. Results suggest that the coastal dynamics reflects changes in winds direction likely related to shifts in the NAO-like conditions. Furthermore, the reconstructed centennial-scale variations in the upwelling are synchronous with changes in solar irradiance, a major external forcing factor of the climate system that is known to exert influence in atmospheric circulation patterns. In addition, these proxy-based data interpretations are in agreement with wind field and solar irradiance simulation modelling for the mid-Holocene. Therefore, the conclusion that the solar activity via the NAO modulation controlled the North Atlantic upwelling of western Iberia during the early and mid-Holocene at decadal to centennial timescales can be derived. The financial support for attending this meeting was possible through FCT project UID/GEO/50019

PT conditions of metamorphism in the Wami River granulite complex, central coastal Tanzania: implications for Pan-African geotectonics in the Mozambique Belt of eastern Africa

NASA Astrophysics Data System (ADS)

Maboko, M. A. H.

1997-02-01

Solid-solution equilibria for gamet-clinopyroxene pairs in the early Pan-African Wami River granulite complex of central coastal Tanzania indicate metamorphic recrystallization at a temperature of about 700°C and a pressure of 8-9 kb, corresponding to metamorphism at a depth of 30-40 km. This suggests that granulite formation was preceded by an anomalous regional crustal thickening, similar to the crustal doubling that accompanies Phanerozoic continent-continent collisions of the Himalaya type. The analogy prompts the interpretation of the Wami River granulite complex, and possibly the rest of the granulite complexes in the Mozambique Belt, as slices of the underthrusted plate, which were accreted to the present day African plate following a continent-continent collision during early Pan-African time.

Spatial Scaling of Floods in Atlantic Coastal Watersheds

NASA Astrophysics Data System (ADS)

Plank, C.

2013-12-01

Climate and land use changes are altering global, regional and local hydrologic cycles. As a result, past events may not accurately represent the events that will occur in the future. Methods for hydrologic prediction, both statistical and deterministic, require adequate data for calibration. Streamflow gauges tend to be located on large rivers. As a result, statistical flood frequency analysis, which relies on gauge data, is biased towards large watersheds. Conversely, the complexity of parameterizing watershed processes in deterministic hydrological models limits these to small watersheds. Spatial scaling relationships between drainage basin area and discharge can be used to bridge these two methodologies and provide new approaches to hydrologic prediction. The relationship of discharge (Q) to drainage basin area (A) can be expressed as a power function: Q = αAθ. This study compares scaling exponents (θ) and coefficients (α) for floods of varying magnitude across a selection of major Atlantic Coast watersheds. Comparisons are made by normalizing flood discharges to a reference area bankfull discharge for each watershed. These watersheds capture the geologic and geomorphic transitions along the Atlantic Coast from narrow bedrock-dominated river valleys to wide coastal plain watersheds. Additionally, there is a range of hydrometeorological events that cause major floods in these basins including tropical storms, thunderstorm systems and winter-spring storms. The mix of flood-producing events changes along a gradient as well, with tropical storms and hurricanes increasing in dominance from north to south as a significant cause of major floods. Scaling exponents and coefficients were determined for both flood quantile estimates (e.g. 1.5-, 10-, 100-year floods) and selected hydrometeorological events (e.g. hurricanes, summer thunderstorms, winter-spring storms). Initial results indicate that southern coastal plain watersheds have lower scaling exponents (θ) than

Late Holocene evolution of a coupled, mud-dominated delta plain-chenier plain system, coastal Louisiana, USA

NASA Astrophysics Data System (ADS)

Hijma, Marc P.; Shen, Zhixiong; Törnqvist, Torbjörn E.; Mauz, Barbara

2017-11-01

Major deltas and their adjacent coastal plains are commonly linked by means of coast-parallel fluxes of water, sediment, and nutrients. Observations of the evolution of these interlinked systems over centennial to millennial timescales are essential to understand the interaction between point sources of sediment discharge (i.e. deltaic distributaries) and adjacent coastal plains across large spatial (i.e. hundreds of kilometres) scales. This information is needed to constrain future generations of numerical models to predict coastal evolution in relation to climate change and other human activities. Here we examine the coastal plain (Chenier Plain, CP) adjacent to the Mississippi River delta, one of the world's largest deltas. We use a refined chronology based on 22 new optically stimulated luminescence and 22 new radiocarbon ages to test the hypothesis that cyclic Mississippi subdelta shifting has influenced the evolution of the adjacent CP. We show that over the past 3 kyr, accumulation rates in the CP were generally 0-1 Mt yr-1. However, between 1.2 and 0.5 ka, when the Mississippi River shifted to a position more proximal to the CP, these rates increased to 2.9 ±1.1 Mt yr-1 or 0.5-1.5 % of the total sediment load of the Mississippi River. We conclude that CP evolution during the past 3 kyr was partly a direct consequence of shifting subdeltas, in addition to changing regional sediment sources and modest rates of relative sea-level (RSL) rise. The RSL history of the CP during this time period was constrained by new limiting data points from the base of overwash deposits associated with the cheniers. These findings have implications for Mississippi River sediment diversions that are currently being planned to restore portions of this vulnerable coast. Only if such diversions are located in the western portion of the Mississippi Delta plain could they potentially contribute to sustaining the CP shoreline. Our findings highlight the importance of a better

Impact of the river nutrient load variability on the North Aegean ecosystem functioning over the last decades

NASA Astrophysics Data System (ADS)

Tsiaras, K. P.; Petihakis, G.; Kourafalou, V. H.; Triantafyllou, G.

2014-02-01

The impact of river load variability on the North Aegean ecosystem functioning over the last decades (1980-2000) was investigated by means of a coupled hydrodynamic/biogeochemical model simulation. Model results were validated against available SeaWiFS Chl-a and in situ data. The simulated food web was found dominated by small cells, in agreement with observations, with most of the carbon channelled through the microbial loop. Diatoms and dinoflagellates presented a higher relative abundance in the more productive coastal areas. The increased phosphate river loads in the early 80s resulted in nitrogen and silicate deficiency in coastal, river-influenced regions. Primary production presented a decreasing trend for most areas. During periods of increased phosphate/nitrate inputs, silicate deficiency resulted in a relative decrease of diatoms, triggering an increase of dinoflagellates. Such an increase was simulated in the late 90s in the Thermaikos Gulf, in agreement with the observed increased occurrence of Harmful Algal Blooms. Microzooplankton was found to closely follow the relative increase of dinoflagellates under higher nutrient availability, showing a faster response than mesozooplankton. Sensitivity simulations with varying nutrient river inputs revealed a linear response of net primary production and plankton biomass. A stronger effect of river inputs was simulated in the enclosed Thermaikos Gulf, in terms of productivity and plankton composition, showing a significant increase of dinoflagellates relative abundance under increased nutrient loads.

Role of mesoscale eddies on exchanges between coastal regions

NASA Astrophysics Data System (ADS)

Kersalé, M.; Petrenko, A. A.; Doglioli, A. M.; Nencioli, F.; Bouffard, J.; Dekeyser, I.

2012-04-01

The general circulation in the northwestern Mediterranean Sea is characterized by a cyclonic circulation. The northern part of this gyre is formed by the Northern Current (NC), which flows along the continental slope from the Ligurian Sea towards the Catalan Shelf. The NC has an important influence on the Gulf of Lion (GoL), a large continental margin in the northern part of the basin. The NC constitutes an effective dynamical barrier which blocks coastal waters on the continental shelf. The western part of the GoL is a key region for regulating the outflow from the continental shelf to the Catalan Basin. These exchanges are mainly induced by partially ageostrophic processes originating from the interaction between the NC and mesoscale activity like meanders, filaments and eddies. Both GoL and Catalan shelf are characterized by an intense mesoscale activity. Eddies in the GoL are baroclinic structures extending throughout the mixed layer (30 to 50m), often elliptic in shape and about 20-30km in diameter. Catalan eddies are characterized by a vertical extension between 70 and 100m and a diameter of about 45km. The LAgrangian Transport EXperiment (LATEX, 2008-2011) was designed to study the mechanisms of formation of anticyclones in the western part of the GoL and their influence on cross-shelf exchanges. Mesoscale anticyclones have been observed in the western part of the GoL and over the Catalan shelf by the combined use of data from satellite observations, in situ measurements and numerical modeling. Recent numerical experiments show an anticyclonic circulation extending over a large part of the coastal area (latitudinal range : 41°50' to 43°N ; longitudinal range : 3°10' to 4°10'E). Interaction with a meander of the NC induces the separation of this circulation in two different eddies, one in the GoL and the other in the Catalan shelf. These eddies exhibit strong interaction between them, resulting in important exchanges between the two coastal regions. On

Lafourche Parish Coastal Zone Curriculum Resource Unit. Bulletin 1834.

ERIC Educational Resources Information Center

Daigle, Bobby; And Others

The Louisiana coastal zone is a unique geographic feature. Soil carried by the Mississippi River has been deposited in Louisiana for the last 6,000 years to form the coastal area. All natural features in coastal Louisiana relate to materials and processes associated with the emptying of the Mississippi River into the Gulf of Mexico. The…

Local and regional scale exchanges of dissolved organic carbon (DOC) between tidal wetlands and their adjacent coastal waters

NASA Astrophysics Data System (ADS)

Osburn, C. L.; Joshi, I.; Lebrasse, M. C.; Oviedo-Vargas, D.; Bianchi, T. S.; Bohnenstiehl, D. R.; D'Sa, E. J.; He, R.; Ko, D.; Arellano, A.; Ward, N. D.

2017-12-01

The contribution of blue carbon from tidal wetlands to the coastal ocean in the form of dissolved organic carbon (DOC) represents a terrestrial-aquatic linkage of increasing importance. DOC flux results will be presented from local (tidal creek) and regional (bays) scale studies in which various combinations of field observations, ocean-color satellite observations, and the outputs of high-resolution hydrodynamic models were used to estimate DOC export. The first project was located in Bald Head Creek, a tributary to the Cape Fear River estuary in eastern North Carolina (NC). DOC fluxes were computed using a bathymetric data collected via unmanned surface vehicle (USV) and a numerical hydrodynamic model (SCHISM) based on the relationships between colored dissolved organic matter (CDOM) absorption, DOC concentration, and salinity taken from field observations. Model predictions estimated an annual net export of DOC at 54 g C m-2 yr-1 from the tidal creek to the adjacent estuary. Carbon stable isotope (δ13C) values were used to estimate the contribution of wetland carbon to this export. In the second project, DOC fluxes from the Apalachicola Bay, FL, Barataria Bay, LA, were based on the development of algorithms between DOC and CDOM absorption derived from the VIIRS ocean color sensor. The Navy Coastal Ocean Model (NCOM) was used to compute salt flux estimates from each bay to the Louisiana-Texas shelf. The relationship between salinity and CDOM was used to estimate net annual DOC exports of 8.35 x 106 g C m-2 y-1 (Apalachicola Bay) and 7.14 x 106 g C m-2 yr-1 (Barataria Bay). These values approximate 13% and 9% of the annual loads of DOC from the Mississippi River to the Gulf of Mexico, respectively. CDOM and lignin were used in a mixing model to estimate wetland-derived DOC were 2% for Apalachicola Bay and 13% for Barataria Bay, the latter having one of the highest rates of relative sea level rise in North America. Results from our project demonstrated the utility

Modeling global mangrove soil carbon stocks: filling the gaps in coastal environments

NASA Astrophysics Data System (ADS)

Rovai, A.; Twilley, R.

2017-12-01

We provide an overview of contemporaneous global mangrove soil organic carbon (SOC) estimates, focusing on a framework to explain disproportionate differences among observed data as a way to improve global estimates. This framework is based on a former conceptual model, the coastal environmental setting, in contrast to the more popular latitude-based hypotheses largely believed to explain hemispheric variation in mangrove ecosystem properties. To demonstrate how local and regional estimates of SOC linked to coastal environmental settings can render more realistic global mangrove SOC extrapolations we combined published and unpublished data, yielding a total of 106 studies, reporting on 552 sites from 43 countries. These sites were classified into distinct coastal environmental setting types according to two concurrent worldwide typology of nearshore coastal systems classifications. Mangrove SOC density varied substantially across coastal environmental settings, ranging from 14.9 ± 0.8 in river dominated (deltaic) soils to 53.9 ± 1.6 mg cm-3 (mean ± SE) in karstic coastlines. Our findings reveal striking differences between published values and contemporary global mangrove SOC extrapolation based on country-level mean reference values, particularly for karstic-dominated coastlines where mangrove SOC stocks have been underestimated by up to 50%. Correspondingly, climate-based global estimates predicted lower mangrove SOC density values (32-41 mg C cm-3) for mangroves in karstic environments, differing from published (21-126 mg C cm-3) and unpublished (47-58 mg C cm-3) values. Moreover, climate-based projections yielded higher SOC density values (27-70 mg C cm-3) for river-dominated mangroves compared to lower ranges reported in the literature (11-24 mg C cm-3). We argue that this inconsistent reporting of SOC stock estimates between river-dominated and karstic coastal environmental settings is likely due to the omission of geomorphological and geophysical

Groundwater Discharges to Rivers in the Western Canadian Oil Sands Region

NASA Astrophysics Data System (ADS)

Ellis, J.; Jasechko, S.

2016-12-01

Groundwater discharges into rivers impacts the movement and fate of nutrients and contaminants in the environment. Understanding groundwater-surface water interactions is especially important in the western Canadian oil sands, where groundwater contamination risks are elevated and baseline water chemistry data is lacking, leading to substantial uncertainties about anthropogenic influences on local river quality. High salinity groundwater springs sourced from deep aquifers, comprised of Pleistocene-aged glacial meltwater, are known to discharge into many rivers in the oil sands. Understanding connections between deep aquifers and surficial waterways is important in order to determine natural inputs into these rivers and to assess the potential for injected wastewater or oil extraction fluids to enter surface waters. While these springs have been identified, their spatial distribution along rivers has not been fully characterized. Here we present river chemistry data collected along a number of major river corridors in the Canadian oil sands region. We show that saline groundwater springs vary spatially along the course of these rivers and tend to be concentrated where the rivers incise Devonian- or Cretaceous-aged aquifers along an evaporite dissolution front. Our results suggest that water sourced from Devonian aquifers may travel through bitumen-bearing Cretaceous units and discharge into local rivers, implying a strong groundwater-surface water connection in specialized locations. These findings indicate that oil sands process-affected waters that are injected at depth have the potential to move through these aquifers and reach the rivers at the surface at some time in the future. Groundwater-surface water interactions remain key to understanding the risks oil sands activities pose to aquatic ecosystems and downstream communities.

The "shallow-waterness" of the wave climate in European coastal regions

NASA Astrophysics Data System (ADS)

Håkon Christensen, Kai; Carrasco, Ana; Bidlot, Jean-Raymond; Breivik, Øyvind

2017-07-01

In contrast to deep water waves, shallow water waves are influenced by bottom topography, which has consequences for the propagation of wave energy as well as for the energy and momentum exchange between the waves and the mean flow. The ERA-Interim reanalysis is used to assess the fraction of wave energy associated with shallow water waves in coastal regions in Europe. We show maps of the distribution of this fraction as well as time series statistics from eight selected stations. There is a strong seasonal dependence and high values are typically associated with winter storms, indicating that shallow water wave effects can occasionally be important even in the deeper parts of the shelf seas otherwise dominated by deep water waves.

Coherence of river and ocean conditions along the US West Coast during storms

USGS Publications Warehouse

Kniskern, T.A.; Warrick, J.A.; Farnsworth, K.L.; Wheatcroft, R.A.; Goni, M.A.

2011-01-01

The majority of water and sediment discharge from the small, mountainous watersheds of the US West Coast occurs during and immediately following winter storms. The physical conditions (waves, currents, and winds) within and acting upon the proximal coastal ocean during these winter storms strongly influence dispersal patterns. We examined this river-ocean temporal coherence for four coastal river-shelf systems of the US West Coast (Umpqua, Eel, Salinas, and Santa Clara) to evaluate whether specific ocean conditions occur during floods that may influence coastal dispersal of sediment. Eleven years of corresponding river discharge, wind, and wave data were obtained for each river-shelf system from USGS and NOAA historical records, and each record was evaluated for seasonal and event-based patterns. Because near-bed shear stresses due to waves influence sediment resuspension and transport, we used spectral wave data to compute and evaluate wave-generated bottom-orbital velocities. The highest values of wave energy and discharge for all four systems were consistently observed between October 15 and March 15, and there were strong latitudinal patterns observed in these data with lower discharge and wave energies in the southernmost systems. During floods we observed patterns of river-ocean coherence that differed from the overall seasonal patterns. For example, downwelling winds generally prevailed during floods in the northern two systems (Umpqua and Eel), whereas winds in the southern systems (Salinas and Santa Clara) were generally downwelling before peak discharge and upwelling after peak discharge. Winds not associated with floods were generally upwelling on all four river-shelf systems. Although there are seasonal variations in river-ocean coherence, waves generally led floods in the three northern systems, while they lagged floods in the Santa Clara. Combined, these observations suggest that there are consistent river-ocean coherence patterns along the US West

Spatial variability of coastal wetland resilience to sea-level rise using Bayesian inference

NASA Astrophysics Data System (ADS)

Hardy, T.; Wu, W.

2017-12-01

The coastal wetlands in the Northern Gulf of Mexico (NGOM) account for 40% of coastal wetland area in the United States and provide various ecosystem services to the region and broader areas. Increasing rates of relative sea-level rise (RSLR), and reduced sediment input have increased coastal wetland loss in the NGOM, accounting for 80% of coastal wetland loss in the nation. Traditional models for predicting the impact of RSLR on coastal wetlands in the NGOM have focused on coastal erosion driven by geophysical variables only, and/or at small spatial extents. Here we developed a model in Bayesian inference to make probabilistic prediction of wetland loss in the entire NGOM as a function of vegetation productivity and geophysical attributes. We also studied how restoration efforts help maintain the area of coastal wetlands. Vegetation productivity contributes organic matter to wetland sedimentation and was approximated using the remotely sensed normalized difference moisture index (NDMI). The geophysical variables include RSLR, tidal range, river discharge, coastal slope, and wave height. We found a significantly positive relation between wetland loss and RSLR, which varied significantly at different river discharge regimes. There also existed a significantly negative relation between wetland loss and NDMI, indicating that in-situ vegetation productivity contributed to wetland resilience to RSLR. This relation did not vary significantly between river discharge regimes. The spatial relation revealed three areas of high RSLR but relatively low wetland loss; these areas were associated with wetland restoration projects in coastal Louisiana. Two projects were breakwater projects, where hard materials were placed off-shore to reduce wave action and promote sedimentation. And one project was a vegetation planting project used to promote sedimentation and wetland stabilization. We further developed an interactive web tool that allows stakeholders to develop similar wetland

Climate Outreach Using Regional Coastal Ocean Observing System Portals

NASA Astrophysics Data System (ADS)

Anderson, D. M.; Hernandez, D. L.; Wakely, A.; Bochenek, R. J.; Bickel, A.

2015-12-01

Coastal oceans are dynamic, changing environments affected by processes ranging from seconds to millennia. On the east and west coast of the U.S., regional observing systems have deployed and sustained a remarkable diverse array of observing tools and sensors. Data portals visualize and provide access to real-time sensor networks. Portals have emerged as an interactive tool for educators to help students explore and understand climate. Bringing data portals to outreach events, into classrooms, and onto tablets and smartphones enables educators to address topics and phenomena happening right now. For example at the 2015 Charleston Science Technology Engineering and Math (STEM) Festival, visitors navigated the SECOORA (Southeast Coastal Ocean Observing regional Association) data portal to view the real-time marine meteorological conditions off South Carolina. Map-based entry points provide an intuitive interface for most students, an array of time series and other visualizations depict many of the essential principles of climate science manifest in the coastal zone, and data down-load/ extract options provide access to the data and documentation for further inquiry by advanced users. Beyond the exposition of climate principles, the portal experience reveals remarkable technologies in action and shows how the observing system is enabled by the activity of many different partners.

Multi-scalar interactions between infrastructure, smallholder water management, and coastal dynamics in the Bengal Delta, Bangladesh

NASA Astrophysics Data System (ADS)

Rogers, K. G.; Brondizio, E.; Roy, K.; Syvitski, J. P.

2016-12-01

Because of their low-lying elevations and large number of inhabitants and infrastructure, river deltas are ground zero for climate change impacts, particularly from sea-level rise and storm surges. The increased vulnerability of downstream delta communities to coastal flooding as a result of upstream engineering has been acknowledged for decades. What has received less attention is the sensitivity of deltas to the interactions of these processes and increasing intensity of cultivation and irrigation in their coastal regions. Beyond basin-scale damming, regional infrastructure affects the movement of sediment and water on deltas, and combined with upstream modifications may exacerbate the risk of expanded tidal flooding, erosion of arable land, and salinization of soils and groundwater associated with sea level rise. To examine the social-biophysical feedbacks associated with regional-scale infrastructure, smallholder water management practices and coastal dynamics, a nested framework was applied to two districts of the coastal southwest region of Bangladesh. The two districts vary in tidal range, salinity, freshwater availability and socioeconomic structures, and are spatially varied in farmer's adaptations. Both districts contain numerous large embankment systems initially designed to protect cropland from tidal flooding, but that have been poorly maintained since their construction in the 1960's. The framework was co-produced using local-level stakeholder input collected during group interviews with rural farmers in 8 villages within the two districts, and explicitly accounts for engineered and natural biophysical variables as well as governance and institutional structures at 3 levels of analysis. Household survey results indicate that the presence or absence of embankments as a result of poor management and dynamic coastal processes is the primary control on freshwater availability and thus influences farming strategies, socioeconomic conditions and social

Drivers, trends, and potential impacts of long-term coastal reclamation in China from 1985 to 2010

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

Tian, Bo; Wu, Wenting; Yang, Zhaoqing

Driven by rapid economic development, population growth, and urbanization, China has experienced severe coastal land reclamation over the last decades, which resulted in significant loss of coastal wetland and wildlife habitat, and degradation of marine ecosystems. This study used advanced remote-sensing techniques to analyze the spatial and temporal distributions of coastal reclamation in China and investigated the relationships between coastal land reclamation and coastal economy, population growth, and urbanization. Analysis of long-term Landsat images time series from 1985 to 2010 in 5-year intervals, in combination with remotely sensed image techniques, indicated a sharp increasing trend of land reclamation after 2005,more » which accounted for over 35% of China’s total reclamation during the 25-year period since 1985. High-intensity coastal reclamation in China was mainly driven by the booming economy associated with urbanization and industrial development in the coastal region. Analysis indicated that coastal land reclamation is closely correlated with the GDP per capita in China. Study results of Landsat images showed that 754,697 ha of coastal wetlands have been reclaimed across all coastal provinces and metropolises from 1985 to 2010, at an annual rate of 5.9%. Coastal areas within the three major economic zones (Bohai Bay, Yangtze River Delta, and Pearl River Delta) were found to generally have higher reclamation rates. For example, the built-up area in Shanghai, which is located in the Yangtze River Delta, increased more than five times from 1985 to 2010. Approximately 35% of the reclamation occurred in Bohai Bay, in which the CRI between 2005 and 2010 was three times higher than the average CRI over the 25-year period.« less

Multi-scale modeling of Puget Sound using an unstructured-grid coastal ocean model: from tide flats to estuaries and coastal waters

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

Yang, Zhaoqing; Khangaonkar, Tarang

2010-11-19

Water circulation in Puget Sound, a large complex estuary system in the Pacific Northwest coastal ocean of the United States, is governed by multiple spatially and temporally varying forcings from tides, atmosphere (wind, heating/cooling, precipitation/evaporation, pressure), and river inflows. In addition, the hydrodynamic response is affected strongly by geomorphic features, such as fjord-like bathymetry and complex shoreline features, resulting in many distinguishing characteristics in its main and sub-basins. To better understand the details of circulation features in Puget Sound and to assist with proposed nearshore restoration actions for improving water quality and the ecological health of Puget Sound, a high-resolutionmore » (around 50 m in estuaries and tide flats) hydrodynamic model for the entire Puget Sound was needed. Here, a threedimensional circulation model of Puget Sound using an unstructured-grid finite volume coastal ocean model is presented. The model was constructed with sufficient resolution in the nearshore region to address the complex coastline, multi-tidal channels, and tide flats. Model open boundaries were extended to the entrance of the Strait of Juan de Fuca and the northern end of the Strait of Georgia to account for the influences of ocean water intrusion from the Strait of Juan de Fuca and the Fraser River plume from the Strait of Georgia, respectively. Comparisons of model results, observed data, and associated error statistics for tidal elevation, velocity, temperature, and salinity indicate that the model is capable of simulating the general circulation patterns on the scale of a large estuarine system as well as detailed hydrodynamics in the nearshore tide flats. Tidal characteristics, temperature/salinity stratification, mean circulation, and river plumes in estuaries with tide flats are discussed.« less

Influence of the Minho River plume on the Rias Baixas (NW of the Iberian Peninsula)

NASA Astrophysics Data System (ADS)

Sousa, M. C.; Vaz, N.; Alvarez, I.; Gomez-Gesteira, M.; Dias, J. M.

2014-11-01

The buoyancy generated by the Minho estuarine plume can flood the Rias Baixas for long periods, reversing the normal salinity gradients. Thus, the main purpose of this work was to study the propagation of Minho estuarine plume to the Rias Baixas, establishing the wind and river discharge conditions in which this plume affects the circulation and hydrography features of these coastal systems as well as the plume characteristics under the most probable forcing conditions, through the application of the numerical model MOHID. For this purpose, several scenarios with different river discharges and wind were simulated. The numerical results revealed that the Minho estuarine plume responds rapidly to wind variations and is influenced by coastline geometry. Under Minho River discharges higher than 700 m3 s- 1 and weak northward winds (3 m s- 1) the circulation patterns of the Rias de Vigo and Pontevedra are reversed. On the other hand, moderate northward winds (6 m s- 1) combined with Minho River discharges higher than 200 m3 s- 1, 300 m3 s- 1 and 700 m3 s- 1 reverse the circulation pattern of the Rias de Vigo, Pontevedra and Arousa, respectively. Under the same conditions, the water exchange between Rias Baixas was analyzed using a particle-tracking model following the trajectories of particles released close to the Minho River mouth. Over 5 days, under Minho River discharges higher than 2100 m3 s- 1 combined with northward winds of 6 m s- 1, an intense water exchange between Rias was observed. However, only 20% of the particles found in Ria de Pontevedra come directly from the Minho River.

Rare earth elements in coastal sediments of the northern Galician shelf: Influence of geological features

NASA Astrophysics Data System (ADS)

Prego, Ricardo; Caetano, Miguel; Bernárdez, Patricia; Brito, Pedro; Ospina-Alvarez, Natalia; Vale, Carlos

2012-03-01

The Northern coast of Galicia, NW Iberian Peninsula, exhibits a variety of geological features: Ortegal allochthonous complex, Ollo-de-Sapo autochthonous domain and massifs of Bares, Barqueiro and San-Ciprian. In order to examine the influence of terrestrial lithologies on coastal sediments, 103 samples were collected in the Rias of Ortigueira, Barqueiro and Viveiro, their neighbouring shelf and the estuaries of Mera, Sor and Landro rivers. Aluminium, Fe, Sc, particulate inorganic and organic carbon and rare earth elements (REE) were determined in the <2 mm fraction. In addition, calcite, muscovite, quartz and riebeckite minerals were identified and quantified in 33 selected samples. The distributions of riebeckite and Fe reflect the influence of Ortegal complex on the coastal areas around the Cape Ortegal. The highest concentrations of ΣREE were found in fine sediments from confined inner parts of the Rias (up to 233 mg kg-1), while most of the sands contained 11-70 mg kg-1. ΣREE normalised to European Shale (ES) highlights the relative abundance of lanthanides (ΣREEN>6) near Cape Ortegal and the innermost ria zones. The ratio between light and heavy REE (L/H) showed lower values (4-11) around Cape Ortegal and the shelf while higher ratios (15-23) were detected in west of the Cape Estaca-de-Bares and in the inner Viveiro Ria due to elevated contributions of La and Ce. The L/H values normalised to ES reflects the importance of HREE in the adjacent area to Ortegal Complex (LN/HN<0.8) and the LREE (LN/HN>1.4) in the inner estuaries and west Cape Estaca-de-Bares. The highest REE individual ES normalised were measured in fine-grained sediments of the Mera and Sor estuaries. Sediments from the eastern shelf of Cape Ortegal presented enhanced ratios only for HREE. These results indicate that distribution of REE in the northern Galician region is highly depending on the neighbouring lithological pattern, contrasting with the situation found in the western Galician

Linkages between the spatial toxicity of sediments and sediment dynamics in the Yangtze River Estuary and neighboring East China Sea.

PubMed

Gao, Jinjuan; Shi, Huahong; Dai, Zhijun; Mei, Xuefei; Zong, Haibo; Yang, Hongwei; Hu, Lingling; Li, Shushi

2018-02-01

Anthropogenic activities are driving an increase in sediment contamination in coastal areas. This poses significant challenges for the management of estuarine ecosystems and their adjacent seas worldwide. However, few studies have been conducted on how dynamic mechanisms affect the sediment toxicity in the estuarine environment. This study was designed to investigate the linkages between sediment toxicity and hydrodynamics in the Yangtze River Estuary (YRE) area. High sediment toxicity was found in the Yangtze River mouth (Region I), the depocenter of the Yangtze River Delta (Region II), and the southeastern area of the adjacent sea (Region III), while low sediment toxicity was found in the northeastern offshore region (Region IV). A spatial comparison analysis and regression model indicated that the distributed pattern of sediment toxicity was likely related to hydrodynamics and circumfluence in the East China Sea (ECS) shelf. Specifically, high sediment toxicity in Region I may be affected by the Yangtze River Pump (YRP) and the low hydrodynamics there, and high toxicity in Region II can be influenced by the low sediment dynamics and fine sediment in the depocenter. The high sediment toxicity in Region III might be related to the combination of the YRP and Taiwan Warm Current, while the low toxicity in Region IV may be influenced by the local coarse-grained relict sand with strong sediment dynamics there. The present research results further suggest that it is necessary to link hydrodynamics and the spatial behavior of sediment and sediment-derived pollutants when assessing the pollution status of estuarine environments, especially for those mega-estuaries and their neighboring ocean environments with complex waves, tides and ocean currents. Copyright © 2017 Elsevier Ltd. All rights reserved.

Task 3: PNNL Visit by JAEA Researchers to Participate in TODAM Code Applications to Fukushima Rivers and to Evaluate the Feasibility of Adaptation of FLESCOT Code to Simulate Radionuclide Transport in the Pacific Ocean Coastal Water Around Fukushima

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

Onishi, Yasuo

Four JAEA researchers visited PNNL for two weeks in February, 2013 to learn the PNNL-developed, unsteady, one-dimensional, river model, TODAM and the PNNL-developed, time-dependent, three dimensional, coastal water model, FLESCOT. These codes predict sediment and contaminant concentrations by accounting sediment-radionuclide interactions, e.g., adsorption/desorption and transport-deposition-resuspension of sediment-sorbed radionuclides. The objective of the river and coastal water modeling is to simulate • 134Cs and 137Cs migration in Fukushima rivers and the coastal water, and • their accumulation in the river and ocean bed along the Fukushima coast. Forecasting the future cesium behavior in the river and coastal water under various scenariosmore » would enable JAEA to assess the effectiveness of various on-land remediation activities and if required, possible river and coastal water clean-up operations to reduce the contamination of the river and coastal water, agricultural products, fish and other aquatic biota. PNNL presented the following during the JAEA visit to PNNL: • TODAM and FLESCOT’s theories and mathematical formulations • TODAM and FLESCOT model structures • Past TODAM and FLESCOT applications • Demonstrating these two codes' capabilities by applying them to simple hypothetical river and coastal water cases. • Initial application of TODAM to the Ukedo River in Fukushima and JAEA researchers' participation in its modeling. PNNL also presented the relevant topics relevant to Fukushima environmental assessment and remediation, including • PNNL molecular modeling and EMSL computer facilities • Cesium adsorption/desorption characteristics • Experiences of connecting molecular science research results to macro model applications to the environment • EMSL tour • Hanford Site road tour. PNNL and JAEA also developed future course of actions for joint research projects on the Fukushima environmental and remediation assessments.« less

Towards a regional coastal ocean observing system: An initial design for the Southeast Coastal Ocean Observing Regional Association

NASA Astrophysics Data System (ADS)

Seim, H. E.; Fletcher, M.; Mooers, C. N. K.; Nelson, J. R.; Weisberg, R. H.

2009-05-01

A conceptual design for a southeast United States regional coastal ocean observing system (RCOOS) is built upon a partnership between institutions of the region and among elements of the academic, government and private sectors. This design envisions support of a broad range of applications (e.g., marine operations, natural hazards, and ecosystem-based management) through the routine operation of predictive models that utilize the system observations to ensure their validity. A distributed information management system enables information flow, and a centralized information hub serves to aggregate information regionally and distribute it as needed. A variety of observing assets are needed to satisfy model requirements. An initial distribution of assets is proposed that recognizes the physical structure and forcing in the southeast U.S. coastal ocean. In-situ data collection includes moorings, profilers and gliders to provide 3D, time-dependent sampling, HF radar and surface drifters for synoptic sampling of surface currents, and satellite remote sensing of surface ocean properties. Nested model systems are required to properly represent ocean conditions from the outer edge of the EEZ to the watersheds. An effective RCOOS will depend upon a vital "National Backbone" (federally supported) system of in situ and satellite observations, model products, and data management. This dependence highlights the needs for a clear definition of the National Backbone components and a Concept of Operations (CONOPS) that defines the roles, functions and interactions of regional and federal components of the integrated system. A preliminary CONOPS is offered for the Southeast (SE) RCOOS. Thorough system testing is advocated using a combination of application-specific and process-oriented experiments. Estimates of costs and personnel required as initial components of the SE RCOOS are included. Initial thoughts on the Research and Development program required to support the RCOOS are

Molecular composition and bioavailability of dissolved organic nitrogen in a lake flow-influenced river in south Florida, USA

USDA-ARS?s Scientific Manuscript database

Dissolved organic nitrogen (DON) represents a large percentage of the total nitrogen in rivers and estuaries, and can contribute to coastal eutrophication and hypoxia. This study reports on the composition and bioavailability of DON along the Caloosahatchee River (Florida), a heavily managed system ...

Ecological health of river basins in forested regions of eastern Washington and Oregon.

Treesearch

Robert C. Wissmar; Jeanette E. Smith; Bruce A. McIntosh; Hiram W. Li; Gordon H. Reeves; James R. Sedell

1994-01-01

A retrospective examination of the history of the cumulative influences of past land and water uses on the ecological health of select river basins in forest regions of eastern Washington and Oregon indicates the loss of fish and riparian habitat diversity and quality since the 19th century. A physiographic framework of the eastern Washington and Oregon in terms of...

The effects of wastewater effluent and river discharge on benthic heterotrophic production, organic biomass and respiration in marine coastal sediments.

PubMed

Burd, B; Macdonald, T; Bertold, S

2013-09-15

We examine effects of high river particulate flux and municipal wastewater effluent on heterotrophic organic carbon cycling in coastal subtidal sediments. Heterotrophic production was a predictable (r(2)=0.95) proportion (56%) of oxidized OC flux and strongly correlated with organic/inorganic flux. Consistent growth efficiencies (36%) occurred at all stations. Organic biomass was correlated with total, OC and buried OC fluxes, but not oxidized OC flux. Near the river, production was modest and biomass high, resulting in low P/B. Outfall deposition resulted in depleted biomass and high bacterial production, resulting in the highest P/B. These patterns explain why this region is production "saturated". The δ(15)N in outfall effluent, sediments and dominant taxa provided insight into where, and which types of organisms feed directly on fresh outfall particulates, on older, refractory material buried in sediments, or utilize chemosynthetic symbiotic bacteria. Results are discussed in the context of declining bottom oxygen conditions along the coast. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

Continental patterns of submarine groundwater discharge reveal coastal vulnerabilities.

PubMed

Sawyer, Audrey H; David, Cédric H; Famiglietti, James S

2016-08-12

Submarine groundwater discharge (SGD) delivers water and dissolved chemicals from continents to oceans, and its spatial distribution affects coastal water quality. Unlike rivers, SGD is broadly distributed and relatively difficult to measure, especially at continental scales. We present spatially resolved estimates of fresh (land-derived) SGD for the contiguous United States based on historical climate records and high-resolution hydrographic data. Climate controls regional patterns in fresh SGD, while coastal drainage geometry imparts strong local variability. Because the recharge zones that contribute fresh SGD are densely populated, the quality and quantity of fresh SGD are both vulnerable to anthropogenic disturbance. Our analysis unveils hot spots for contaminant discharge to marine waters and saltwater intrusion into coastal aquifers. Copyright © 2016, American Association for the Advancement of Science.

Groundwater Discharge of Legacy Nitrogen to River Networks: Linking Regional Groundwater Models to Streambed Groundwater-Surface Water Exchange and Nitrogen Processing

NASA Astrophysics Data System (ADS)

Barclay, J. R.; Helton, A. M.; Briggs, M. A.; Starn, J. J.; Hunt, A.

2017-12-01

Despite years of management, excess nitrogen (N) is a pervasive problem in many aquatic ecosystems. More than half of surface water in the United States is derived from groundwater, and widespread N contamination in aquifers from decades of watershed N inputs suggest legacy N discharging from groundwater may contribute to contemporary N pollution problems in surface waters. Legacy N loads to streams and rivers are controlled by both regional scale flow paths and fine-scale processes that drive N transformations, such as groundwater-surface water exchange across steep redox gradients that occur at stream bed interfaces. Adequately incorporating these disparate scales is a challenge, but it is essential to understanding legacy N transport and making informed management decisions. We developed a regional groundwater flow model for the Farmington River, a HUC-8 basin that drains to the Long Island Sound, a coastal estuary that suffers from elevated N loads despite decades of management, to understand broad patterns of regional transport. To evaluate and refine the regional model, we used thermal infrared imagery paired with vertical temperature profiling to estimate groundwater discharge at the streambed interface. We also analyzed discharging groundwater for multiple N species to quantify fine scale patterns of N loading and transformation via denitrification at the streambed interface. Integrating regional and local estimates of groundwater discharge of legacy N to river networks should improve our ability to predict spatiotemporal patterns of legacy N loading to and transformation within surface waters.

Regional flow in the Baltic Shield during Holocene coastal regression

USGS Publications Warehouse

Voss, Clifford I.; Andersson, Johan

1993-01-01

The occurrence of saline waters in the Baltic Shield in Sweden is consistent with ongoing but incomplete Holocene flushing and depends on the geometry and connectivity of conductive structures at both regional and local scales, and on the surface topography. Numerical simulation of regional variable-density fluid flow during Holocene land-rise and coastal regression shows that the existence of any old saline water, whether derived from submarine recharge in regions below Sweden's highest postglacial coastline or geochemical processes in the crystalline rock, is an indication either of slow fluid movements through the bedrock over long times, or of long travel distances through fracture systems before arriving at measurement points. During the land-rise period, regional flow is not affected by the variable density of fluids in the upper few kilometers of the shield, and the topography of the water table is the only driving force. The spatial distribution of meteoric flushing water and pre-Holocene waters may be complex, with the possibility of relatively fresh water in fracture zones below salty units even at depths of a few kilometers. The domination of the topographic driving force implies that deep saline water is not necessarily stagnant, and significant flow may be expected to occur in well-connected horizons even at depth. Local topography variation and fracture zone location combine to create a complex flow field in which local topographic driving forces extend to considerable depth in some areas, whereas regional topographic forces predominate in others. Thus, a pattern may be difficult to discern in measurements of the regional salinity distribution, although it is clear that the coastal region is the major zone of discharge for deeper pre-Holocene fluids. During the land-rise period, the regional flow field equilibrates with changing climatic conditions and coastal positions, while the distribution of flushing water and older water lags and will

Sea-Based Infrared Scene Interpretation by Background Type Classification and Coastal Region Detection for Small Target Detection

PubMed Central

Kim, Sungho

2015-01-01

Sea-based infrared search and track (IRST) is important for homeland security by detecting missiles and asymmetric boats. This paper proposes a novel scheme to interpret various infrared scenes by classifying the infrared background types and detecting the coastal regions in omni-directional images. The background type or region-selective small infrared target detector should be deployed to maximize the detection rate and to minimize the number of false alarms. A spatial filter-based small target detector is suitable for identifying stationary incoming targets in remote sea areas with sky only. Many false detections can occur if there is an image sector containing a coastal region, due to ground clutter and the difficulty in finding true targets using the same spatial filter-based detector. A temporal filter-based detector was used to handle these problems. Therefore, the scene type and coastal region information is critical to the success of IRST in real-world applications. In this paper, the infrared scene type was determined using the relationships between the sensor line-of-sight (LOS) and a horizontal line in an image. The proposed coastal region detector can be activated if the background type of the probing sector is determined to be a coastal region. Coastal regions can be detected by fusing the region map and curve map. The experimental results on real infrared images highlight the feasibility of the proposed sea-based scene interpretation. In addition, the effects of the proposed scheme were analyzed further by applying region-adaptive small target detection. PMID:26404308

Chemical characterization of PM2.5 from a southern coastal city of China: applications of modeling and chemical tracers in demonstration of regional transport.

PubMed

Zhou, Jiamao; Ho, Steven Sai Hang; Cao, Junji; Zhao, Zhuzi; Zhao, Shuyu; Zhu, Chongshu; Wang, Qiyuan; Liu, Suixin; Zhang, Ting; Zhao, Youzhi; Wang, Ping; Tie, Xuexi

2018-05-11

An intensive sampling campaign of airborne fine particles (PM 2.5 ) was conducted at Sanya, a coastal city in Southern China, from January to February 2012. Chemical analyses and mass reconstruction were used identify potential pollution sources and investigate atmospheric reaction mechanisms. A thermodynamic model indicated that low ammonia and high relative humidity caused the aerosols be acidic and that drove heterogeneous reactions which led to the formation of secondary inorganic aerosol. Relationships among neutralization ratios, free acidity, and air-mass trajectories suggest that the atmosphere at Sanya was impacted by both local and regional emissions. Three major transport pathways were identified, and flow from the northeast (from South China) typically brought the most polluted air to Sanya. A case study confirmed strong impact from South China (e.g., Pearl River Delta region) (contributed 76.8% to EC, and then this result can be extended to primary pollutants) when the northeast winds were dominant. The Weather Research Forecasting Black carbon model and trace organic markers were used to apportion local pollution versus regional contributions. Results of the study offer new insights into the atmospheric conditions and air pollution at this coastal city.

U.S. Geological Survey (USGS) Western Region: Coastal and Ocean Science

USGS Publications Warehouse

Kinsinger, Anne E.

2009-01-01

USGS Western Region Coastal and Ocean Science is interdisciplinary, collaborative, and integrates expertise from all USGS Disciplines, and ten of its major Science Centers, in Alaska, Hawai'i, California, Washington, and Oregon. The scientific talent, laboratories, and research vessels in the Western Region and across the Nation, strategically position the USGS to address broad geographic and oceanographic research topics. USGS information products inform resource managers and policy makers who must balance conservation mandates with increasing demands for resources that sustain the Nation's economy. This fact sheet describes but a few examples of the breadth of USGS science conducted in coastal, nearshore, and ocean environments along our Nation's West Coast and Pacific Islands.

Regional implications of heat flow of the Snake River Plain, Northwestern United States

NASA Astrophysics Data System (ADS)

Blackwell, D. D.

1989-08-01

The Snake River Plain is a major topographic feature of the Northwestern United States. It marks the track of an upper mantle and crustal melting event that propagated across the area from southwest to northeast at a velocity of about 3.5 cm/yr. The melting event has the same energetics as a large oceanic hotspot or plume and so the area is the continental analog of an oceanic hotspot track such as the Hawaiian Island-Emperor Seamount chain. Thus, the unique features of the area reflect the response of a continental lithosphere to a very energetic hotspot. The crust is extensively modified by basalt magma emplacement into the crust and by the resulting massive rhyolite volcanism from melted crustal material, presently occurring at Yellowstone National Park. The volcanism is associated with little crustal extension. Heat flow values are high along the margins of the Eastern and Western Snake River Plains and there is abundant evidence for low-grade geothermal resources associated with regional groundwater systems. The regional heat flow pattern in the Western Snake River Plains reflects the influence of crustal-scale thermal refraction associated with the large sedimentary basin that has formed there. Heat flow values in shallow holes in the Eastern Snake River Plains are low due to the Snake River Plains aquifer, an extensive basalt aquifer where water flow rates approach 1 km/yr. Below the aquifer, conductive heat flow values are about 100 mW m -2. Deep holes in the region suggest a systematic eastward increase in heat flow in the Snake River Plains from about 75-90 mW m -2 to 90-110 mW m -2. Temperatures in the upper crust do not behave similarly because the thermal conductivity of the Plio-Pleistocene sedimentary rocks in the west is lower than that in the volcanic rocks characteristic of the Eastern Snake River Plains. Extremely high heat loss values (averaging 2500 mW m -2) and upper crustal temperatures are characteristic of the Yellowstone caldera.

A modeling study of the characteristics and mechanism of the westward coastal current during summer in the northwestern South China Sea

NASA Astrophysics Data System (ADS)

Ding, Yang; Bao, Xianwen; Yao, Zhigang; Zhang, Cong; Wan, Kai; Bao, Min; Li, Ruixiang; Shi, Maochong

2017-03-01

The characteristics and dynamical mechanism of summer-time coastal current over the North South China Sea shelf have been investigated based on a high resolution unstructuredgrid finite volume community ocean model (FVCOM). Modeldata comparison demonstrates that the model describes and explains well the coastal dynamics over the North South China Sea shelf. The coastal current on the North South China Sea shelf is greatly influenced by monsoon and the freshwater discharge of the Pearl River. Strong southwesterly wind drives the coastal current northeastward. However, under weak southwest monsoon, the coastal current west of the Pearl River estuary (PRE) advects toward the southwest, and splits into two parts when reaching east of the Qiongzhou Strait, with one branch entering the Gulf of Tonkin through the Qiongzhou Strait, transporting low salinity water into the Gulf of Tonkin, and the other part flows cyclonic and interacts with the northeastward current around southeast of Hainan Island, forming a cyclonic eddy east of the Qiongzhou Strait. A variety of model experiments focused on freshwater discharge, wind forcing, tidal rectification, and stratification are performed to study the physical mechanism of the southwestward coastal current which is usually against the summer wind. Process-oriented experiment results indicate that the southwest monsoon and freshwater discharge are important factors influencing the formation of southwestward coastal current during summer.

Microbial Gene Abundance and Expression Patterns across a River to Ocean Salinity Gradient

PubMed Central

Fortunato, Caroline S.; Crump, Byron C.

2015-01-01

Microbial communities mediate the biogeochemical cycles that drive ecosystems, and it is important to understand how these communities are affected by changing environmental conditions, especially in complex coastal zones. As fresh and marine waters mix in estuaries and river plumes, the salinity, temperature, and nutrient gradients that are generated strongly influence bacterioplankton community structure, yet, a parallel change in functional diversity has not been described. Metagenomic and metatranscriptomic analyses were conducted on five water samples spanning the salinity gradient of the Columbia River coastal margin, including river, estuary, plume, and ocean, in August 2010. Samples were pre-filtered through 3 μm filters and collected on 0.2 μm filters, thus results were focused on changes among free-living microbial communities. Results from metagenomic 16S rRNA sequences showed taxonomically distinct bacterial communities in river, estuary, and coastal ocean. Despite the strong salinity gradient observed over sampling locations (0 to 33), the functional gene profiles in the metagenomes were very similar from river to ocean with an average similarity of 82%. The metatranscriptomes, however, had an average similarity of 31%. Although differences were few among the metagenomes, we observed a change from river to ocean in the abundance of genes encoding for catabolic pathways, osmoregulators, and metal transporters. Additionally, genes specifying both bacterial oxygenic and anoxygenic photosynthesis were abundant and expressed in the estuary and plume. Denitrification genes were found throughout the Columbia River coastal margin, and most highly expressed in the estuary. Across a river to ocean gradient, the free-living microbial community followed three different patterns of diversity: 1) the taxonomy of the community changed strongly with salinity, 2) metabolic potential was highly similar across samples, with few differences in functional gene abundance

Microbial Gene Abundance and Expression Patterns across a River to Ocean Salinity Gradient.

PubMed

Fortunato, Caroline S; Crump, Byron C

2015-01-01

Microbial communities mediate the biogeochemical cycles that drive ecosystems, and it is important to understand how these communities are affected by changing environmental conditions, especially in complex coastal zones. As fresh and marine waters mix in estuaries and river plumes, the salinity, temperature, and nutrient gradients that are generated strongly influence bacterioplankton community structure, yet, a parallel change in functional diversity has not been described. Metagenomic and metatranscriptomic analyses were conducted on five water samples spanning the salinity gradient of the Columbia River coastal margin, including river, estuary, plume, and ocean, in August 2010. Samples were pre-filtered through 3 μm filters and collected on 0.2 μm filters, thus results were focused on changes among free-living microbial communities. Results from metagenomic 16S rRNA sequences showed taxonomically distinct bacterial communities in river, estuary, and coastal ocean. Despite the strong salinity gradient observed over sampling locations (0 to 33), the functional gene profiles in the metagenomes were very similar from river to ocean with an average similarity of 82%. The metatranscriptomes, however, had an average similarity of 31%. Although differences were few among the metagenomes, we observed a change from river to ocean in the abundance of genes encoding for catabolic pathways, osmoregulators, and metal transporters. Additionally, genes specifying both bacterial oxygenic and anoxygenic photosynthesis were abundant and expressed in the estuary and plume. Denitrification genes were found throughout the Columbia River coastal margin, and most highly expressed in the estuary. Across a river to ocean gradient, the free-living microbial community followed three different patterns of diversity: 1) the taxonomy of the community changed strongly with salinity, 2) metabolic potential was highly similar across samples, with few differences in functional gene abundance

Quantifying the dilution of the radiocesium contamination in Fukushima coastal river sediment (2011-2015)

NASA Astrophysics Data System (ADS)

Evrard, Olivier; Laceby, J. Patrick; Onda, Yuichi; Wakiyama, Yoshifumi; Jaegler, Hugo; Lefèvre, Irène

2016-10-01

Fallout from the Fukushima Dai-ichi nuclear power plant accident resulted in a 3000-km2 radioactive contamination plume. Here, we model the progressive dilution of the radiocesium contamination in 327 sediment samples from two neighboring catchments with different timing of soil decontamination. Overall, we demonstrate that there has been a ~90% decrease of the contribution of upstream contaminated soils to sediment transiting the coastal plains between 2012 (median - M - contribution of 73%, mean absolute deviation - MAD - of 27%) and 2015 (M 9%, MAD 6%). The occurrence of typhoons and the progress of decontamination in different tributaries of the Niida River resulted in temporary increases in local contamination. However, the much lower contribution of upstream contaminated soils to coastal plain sediment in November 2015 demonstrates that the source of the easily erodible, contaminated material has potentially been removed by decontamination, diluted by subsoils, or eroded and transported to the Pacific Ocean.

A review on the patterns of river material fluxes, coastal plume dispersal, shelf sediment facies, and anthropogenic impacts of the Tropical Land-Sea Interface, Sergipe/Alagoas, Northeast Brazil

NASA Astrophysics Data System (ADS)

Knoppers, B.; Medeiros, P. R. P.; de Souza, W. F. L.; Oliveira, E. N.; Fontes, L. C. da S.; do Carmo, M. S.; Carvalho, I. S.; Silva, M. C.; Brandini, N.; Carneiro, M. E.

2012-04-01

This study couples published and unpublished information on the alterations of continental material fluxes, plume dispersal patterns and coastal erosion induced by natural and human impacts to the distribution of sediment facies and sedimentation rates of the continental shelf of the States of Sergipe and Alagoas, northeastern Brazil (Lats. 8o56,2' and 11o20,0' S, Longs. 35o07,7' and 37o14,2' W). Historical data on river flow and material fluxes of 7 rivers, including the São Francisco river (L = 2850 km, AB = 634000 km2), were obtained from own measurements and from the national data bank of ANA (National Agency of Waters, www.ana.gov.br) with the softwares HIDRO 1.2 and SisCAH 1.0. Historical data on the distribution of sediments and their elemental composition of the shelf from the AKAROA (1965) campaign with 190 sampling stations (scale 1:1.000.000; Kempf, 1972, Summerhayes et al. 1975 & 1976, Coutinho, 1976) were revisited and new digital maps constructed with ArcGIS 9.3. Comparisons are made from new maps from recent campaigns (scale 1:250.000) performed by the consortium GEORIOEMAR/ UFS/ CENPES/ PETROBRÁS (2010). Statistical analyses with all parameters revealed that the shelf harbors 4 major regional sedimentary domains (i.e. A to D), reflecting the interaction between continental inputs and the impact of the oligotrophic South Equatorial Current (SEC) upon the shelf. The domains are: A- The Alagoas shelf. Set north of the São Francisco river with low fluvial input, dominance of SEC, recent organogenetic carbonate sediments with the calcareous algae Lithothamnium sp. and Halimeda sp. B- The São Francisco river alluvial fan and canyon. The river harbors a cascade of dams and after 1995, river flow declined by 40 % and was modulated to a constant flow of 2060 m3s-1, 95 % of the suspended matter load was retained within the reservoirs and nutrients (N,P) were impoverished by 90 % . The estuarine waters are now transparent and oligotrophic and the coastal

Coastal environment of the Beaufort Sea from field data and ERTS-1 imagery, summer 1972

NASA Technical Reports Server (NTRS)

Reimnitz, E. (Principal Investigator); Barnes, P. W.

1972-01-01

The author has identified the following significant results. An extensive field program during the spring and summer in the coastal Beaufort Sea test site has been completed using a wide variety of sensing techniques. Reduction of field data and ERTS-1 image analysis have shown the coastal environment to be complexly influenced by unique processes, most of which involve or are related to sea ice. Active sedimentologic processes along the Arctic coast are set in motion by the melting, flooding, and eventual overflow of rivers onto the sea ice. It is now apparent that only minor amounts of sediment are transported offshore at this stage; however, scouring of the bottom is significant beneath the strudels (drain holes) which develop in the fast ice canopy in the region of overflow. Areal salinity and turbidity patterns together with ERTS-1 imagery confirm a consistent influx of colder, clearer, saltier water towards the coast just east of the Colville River. Strong (up to 3 knots) bidirectional but intermittent currents often manifest themselves in imagery and aerial photographs as wakes behind grounded ice. Ice movement vectors generated from repetitive images indicate that ice drift is closely associated with wind direction, especially in shallow bays, and displacements of 4-22 kilometers were noted in 24 hours.

Regional Sea Level Scenarios for Coastal Risk Management: Managing the Uncertainty of Future Sea Level Change and Extreme Water Levels for Department of Defense Coastal Sites Worldwide

DTIC Science & Technology

2016-04-01

SERDP NOAA USACE Ocean MANAGING THE UNCERTAINTY OF FUTURE SEA LEVEL CHANGE AND EXTREME WATER LEVELS FOR DEPARTMENT OF DEFENSE COASTAL SITES...WORLDWIDE APRIL 2016 REGIONAL SEA LEVEL SCENARIOS FOR COASTAL RISK MANAGEMENT: COVER PHOTOS, FROM LEFT TO RIGHT: - Overwash of the island of Roi-Namur on...J.A., S. Gill, J. Obeysekera, W. Sweet, K. Knuuti, and J. Marburger. 2016. Regional Sea Level Scenarios for Coastal Risk Management: Managing the

Monitoring Coastal Embankment Subsidence and Relative Sea Level Rise in Coastal Bangladesh Using Satellite Geodetic Data

NASA Astrophysics Data System (ADS)

Guo, Q.; Shum, C. K.; Jia, Y.; Yi, Y.; Zhu, K.; Kuo, C. Y.; Liibusk, A.

2015-12-01

The Bangladesh Delta is located at the confluence of the mega Ganges, Brahmaputra and Meghan Rivers in the Bay of Bengal. It is home to over 160 million people and is one of the most densely populated countries in the world. It is prone to seasonal transboundary monsoonal flooding, potentially aggravated by more frequent and intensified cyclones resulting from anthropogenic climate change. Sea level rise, along with tectonic, sediment compaction/load and groundwater extraction induced land uplift/subsidence, have significantly exacerbated these risks and Bangladesh's coastal vulnerability. Bangladesh has built 123 coastal embankments or polders since the 1960's, to protect the coastal regions from cyclone/tidal flooding and to reduce salinity incursions. Since then, many coastal polders have suffered severe erosion and anthropogenic damage, and require repairs or rebuilding. However, the physical and anthropogenic processes governing the historic relative sea level rise and its future projection towards its quantification remain poorly understood or known, and at present not accurate enough or with an adequately fine local spatial scale for practical mitigation of coastal vulnerability or coastal resilience studies. This study reports on our work in progress to use satellite geodetic and remote sensing observations, including satellite radar altimetry/backscatter measurements over land and in coastal oceans, optical/infrared imageries, and SAR backscatter/InSAR data, to study the feasibility of coastal embankment/polder erosion monitoring, quantify seasonal polder water intrusions, observing polder subsidence, and finally, towards the goal of improving the relative sea level rise hazards assessment at the local scale in coastal Bangladesh.

Regional vicarious gain adjustment for coastal VIIRS products

NASA Astrophysics Data System (ADS)

Bowers, Jennifer; Arnone, Robert; Ladner, Sherwin; Fargion, Giulietta S.; Lawson, Adam; Martinolich, Paul; Vandermeulen, Ryan

2014-05-01

As part of the Joint Polar Satellite System (JPSS) Ocean Cal/Val Team, Naval Research Lab - Stennis Space Center (NRL-SSC) has been working to facilitate calibration and validation of the Visible Infrared Imaging Radiometer Suite (VIIRS) ocean color products. By relaxing the constraints of the NASA Ocean Biology Processing Group (OBPG) methodology for vicarious calibration of ocean color satellites and utilizing the Aerosol Robotic Network Ocean Color (AERONET-OC) system to provide in situ data, we investigated differences between remotely sensed water leaving radiance and the expected in situ response in coastal areas and compare the results to traditional Marine Optical Buoy (MOBY) calibration/validation activities. An evaluation of the Suomi National Polar-Orbiting Partnership (SNPP)-VIIRS ocean color products was performed in coastal waters using the time series data obtained from the Northern Gulf of Mexico AERONET-OC site, WaveCIS. The coastal site provides different water types with varying complexity of CDOM, sedimentary, and chlorophyll components. Time series data sets were used to develop a vicarious gain adjustment (VGA) at this site, which provides a regional top of the atmospheric (TOA) spectral offset to compare the standard MOBY spectral calibration gain in open ocean waters.

Nineteenth Century Harbors: Accounting for Coastal Urban Development in Hydrologic Change

NASA Astrophysics Data System (ADS)

Schlichting, K. M.; Ruffing, C. M.; McCormack, S. M.; Urbanova, T.; Powell, L. J.; Hermans, C. M.

2009-12-01

Harbors complicate the analytical framework of quantifying nineteenth-century hydrologic change in the northeastern United States. The hydrology of the region was fundamentally altered by the growth of water engineering such as canals as well as by land cover changes as deforestation in the region peaked and urban centers grew. Urban coastal growth epitomized nineteenth-century development as northeastern colonial ports evolved into manufacturing and industrial centers. Coastal urban industrial development concentrated tanneries, machineries, and paper processing companies along cities’ trading rivers. Additionally, the populations of cities such as Boston, New Haven, New York, Newark, and Baltimore reached unprecedented numbers, forcing urban municipalities to confront sewerage and drinking water infrastructure in the face of shortages and waterborne disease. We discuss how the concentration of industry and population at river mouths complicates the process of quantifying the effects of municipal drinking water and sewage infrastructure on regional hydrology and how the growth of nineteenth-century urban centers shaped regional hydrologic hinterlands. Additionally, harbors oblige a reconsideration of hydrologic boundaries by forcing hydrologists and environmental historians to account for fisheries and harbor engineering alongside population and industry as factors in changes to water quality and quantity in and human response to urban nineteenth-century hydrologic change.

Genetic investigation of natural hybridization between rainbow and coastal cutthroat trout in the copper River Delta, Alaska

USGS Publications Warehouse

Williams, I.; Reeves, G.H.; Graziano, S.L.; Nielsen, J.L.

2007-01-01

Molecular genetic methods were used to quantify natural hybridization between rainbow trout Oncorhynchus mykiss or steelhead (anadromous rainbow trout) and coastal cutthroat trout O. clarkii clarkii collected in the Copper River delta, Southeast Alaska. Eleven locations were sampled to determine the extent of hybridization and the distribution of hybrids. Four diagnostic nuclear microsatellite loci and four species-specific simple sequence repeat markers were used in combination with restriction fragment length polymorphism analyses of NADH dehydrogenase 5/6 (ND5/6) mitochondrial DNA (mtDNA) to investigate the genetic structure of trout from both species and identify putative interspecific hybrids. Hybrids were found in 7 of the 11 streams sampled in the Copper River delta, the extent of hybridization across all streams varying from 0% to 58%. Hybrid trout distribution appeared to be nonrandom, most individuals of mixed taxonomic ancestry being detected in streams containing rainbow trout rather than in streams containing coastal cutthroat trout. Genotypic disequilibrium was observed among microsatellite loci in populations with high levels of hybridization. We found no significant correlation between unique stream channel process groups and the number of hybrid fish sampled. Eighty-eight percent of fish identified as first-generation hybrids (F1) in two populations contained coastal cutthroat trout mtDNA, suggesting directionality in hybridization. However, dominance of coastal cutthroat trout mtDNA was not observed at a third location containing F1 hybrids, indicating that interspecific mating behavior varied among locations. Backcrossed individuals were found in drainages lacking F1 hybrids and in populations previously thought to contain a single species. The extent and distribution of backcrossed individuals suggested that at least some hybrids are reproductively viable and backcrossed hybrid offspring move throughout the system.

A Coastal Risk Assessment Framework Tool to Identify Hotspots at the Regional Scale

NASA Astrophysics Data System (ADS)

Van Dongeren, A.; Viavattene, C.; Jimenez, J. A.; Ferreira, O.; Bolle, A.; Owen, D.; Priest, S.

2016-02-01

Extreme events in combination with an increasing population on the coast, future sea level rise and the deterioration of coastal defences can lead to catastrophic consequences for coastal communities and their activities. The Resilience-Increasing Strategies for Coasts - toolkit (RISC-KIT) FP7 EU project is producing a set of EU-coherent open-source and open-access tools in support of coastal managers and decision-makers. This paper presents one of these tools, the Coastal Risk Assessment Framework (CRAF) which assesses coastal risk at a regional scale to identify potential impact hotspots for more detailed assessment. Applying a suite of complex models at a full and detailed regional scale remains difficult and may not be efficient, therefore a 2-phase approach is adopted. CRAF Phase 1 is a screening process based on a coastal-index approach delimiting several hotspots in alongshore length by assessing the potential exposure for every kilometre along the coast. CRAF Phase 2 uses a suite of more complex modelling process (including X-beach 1D, inundation model, impact assessment and Multi-Criteria Analysis approach) to analyse and compare the risks between the aforementioned identified hotspots. Results of its application are compared on 3 European Case Studies, the Flemish highly protected low-lying coastal plain with important urbanization and harbors, a Portuguese coastal lagoon protected by a multi-inlet barrier system, the highly urbanized Catalonian coast with touristic activities at threat. The flexibility of the tool allows tailoring the comparative analysis to these different contexts and to adapt to the quality of resources and data available. Key lessons will be presented.

Carbon, nitrogen, and phosphorus accumulation in floodplains of Atlantic Coastal Plain rivers, USA

USGS Publications Warehouse

Noe, G.B.; Hupp, C.R.

2005-01-01

Net nutrient accumulation rates were measured in riverine floodplains of the Atlantic Coastal Plain in Virginia, Maryland, and Delaware, USA. The floodplains were located in watersheds with different land use and included two sites on the Chickahominy River (urban), one site on the Mattaponi River (forested), and five sites on the Pocomoke River (agricultural). The Pocomoke River floodplains lie along reaches with natural hydrogeomorphology and on reaches with restricted flooding due to channelization and levees. A network of feldspar clay marker horizons was placed on the sediment surface of each floodplain site 3-6 years prior to sampling. Sediment cores were collected from the material deposited over the feldspar clay pads. This overlying sediment was separated from the clay layer and then dried, weighed, and analyzed for its total carbon (C), nitrogen (N), and phosphorus (P) content. Mean C accumulation rates ranged from 61 to 212 g??m-2??yr-1, N accumulation rates ranged from 3.5 to 13.4 g??m -2??yr-1, and P accumulation rates ranged from 0.2 to 4.1 g??m-2??yr-1 among the eight floodplains. Patterns of intersite variation in mineral sediment and P accumulation rates were similar to each other, as was variation in organic sediment and C and N accumulation rates. The greatest sediment and C, N, and P accumulation rates were observed on Chickahominy River floodplains downstream from the growing metropolitan area of Richmond, Virginia. Nutrient accumulation rates were lowest on Pocomoke River floodplains that have been hydraulically disconnected from the main channel by channelization and levees. Sediment P concentrations and P accumulation rates were much greater on the hydraulically connected floodplain immediately downstream of the limit of channelization and dense chicken agriculture of the upper Pocomoke River watershed. These findings indicate that (1) watershed land use has a large effect on sediment and nutrient retention in floodplains, and (2) limiting

River salinity on a mega-delta, an unstructured grid model approach.

NASA Astrophysics Data System (ADS)

Bricheno, Lucy; Saiful Islam, Akm; Wolf, Judith

2014-05-01

With an average freshwater discharge of around 40,000 m3/s the BGM (Brahmaputra Ganges and Meghna) river system has the third largest discharge worldwide. The BGM river delta is a low-lying fertile area covering over 100,000 km2 mainly in India and Bangladesh. Approximately two-thirds of the Bangladesh people work in agriculture and these local livelihoods depend on freshwater sources directly linked to river salinity. The finite volume coastal ocean model (FVCOM) has been applied to the BGM delta in order to simulate river salinity under present and future climate conditions. Forced by a combination of regional climate model predictions, and a basin-wide river catchment model, the 3D baroclinic delta model can determine river salinity under the current climate, and make predictions for future wet and dry years. The river salinity demonstrates a strong seasonal and tidal cycle, making it important for the model to be able to capture a wide range of timescales. The unstructured mesh approach used in FVCOM is required to properly represent the delta's structure; a complex network of interconnected river channels. The model extends 250 km inland in order to capture the full extent of the tidal influence and grid resolutions of 10s of metres are required to represent narrow inland river channels. The use of FVCOM to simulate flows so far inland is a novel challenge, which also requires knowledge of the shape and cross-section of the river channels.

Changing Course: navigating the future of the Lower Mississippi River

NASA Astrophysics Data System (ADS)

Cochran, S.

2016-02-01

Changing Course is a design competition to reimagine a more sustainable Lower Mississippi River Delta, bringing teams together from around the world to create innovative visions for one of America's greatest natural resources. Building off of Louisiana's Coastal Master Plan, and answering a key question from that plan, three winning teams (Baird & Associates, Moffatt & Nichol and Studio Misi-Ziibi) have generated designs for how the Mississippi River's water and sediment can be used to maximize rebuilding of delta wetlands while also continuing to meet the needs of navigation, flood protection, and coastal industries and communities. While each of the winning teams offered a different vision, all three identified the same key requirements as critical to sustaining the Mississippi River Delta today and into the future: Reconnecting the Mississippi River to its wetlands to help restore southeast Louisiana's first line of defense against powerful storms and rising sea levels. Planning for a more sustainable delta, including a gradual shift in population to create more protected and resilient communities. Protecting and maximizing the region's port and maritime activities, including a deeper more sustainable navigation channel upriver from Southwest Pass. Increasing economic opportunities in a future smaller delta through expanding shipping capacity, coastal restoration infrastructure, outdoor recreation and tourism and commercial fishing. This session will give a high level overview of the design competition process, results and common themes, similarities and differences in their designs, and how the ideas generated will inform coastal stakeholders and official government processes.

Genotoxicity Biomonitoring Along a Coastal Zone Under Influence of Offshore Petroleum Exploration (Southeastern Brazil).

PubMed

Gutiérrez, Juan Manuel; da Conceição, Moisés Basilio; Molisani, Mauricio Mussi; Weber, Laura Isabel

2018-03-01

Offshore oil exploration creates threats to coastal ecosystems, including increasing urbanization and associated effluent releases. Genotoxicity biomarkers in mussels were determined across a gradient of coastal zone influences of offshore petroleum exploration in southeastern Brazil. Coastal ecosystems such as estuaries, beaches and islands were seasonally monitored for genotoxicity evaluation using the brown mussel Perna perna. The greatest DNA damage (5.2% ± 1.9% tail DNA and 1.5‰  ± 0.8‰ MN) were observed in urban estuaries, while Santana Archipelago showed levels of genotoxicity near zero and is considered a reference site. Mussels from urban and pristine beaches showed intermediate damage levels, but were also influenced by urbanization. Thus, mussel genotoxicity biomarkers greatly indicated the proposed oil exploration and urbanization scenarios that consequently are genetically affecting coastal organisms.

Marine geology and oceanography of Arabian Sea and coastal Pakistan

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

Haq, B.U.; Milliman, J.D.

This volume is a collection of papers presented at the first US-Pakistan workshop in marine science held in Karachi, Pakistan, in November 1982. Of the twenty-four contributions in this book, fourteen cover topics specific to the Arabian Sea-coastal Pakistan region. These include six papers on the geology, tectonics, and petroleum potential of Pakistan, four papers on sedimentary processes in the Indus River delta-fan complex, and four papers on the biological oceanography of the Arabian Sea and coastal Pakistan. The additional ten papers are overviews of shelf sedimentation processes, paleoceanography, the marine nutrient cycle, and physical and chemical oceanography.

Geochemical evolution of groundwater in the Western Delta region of River Godavari, Andhra Pradesh, India

NASA Astrophysics Data System (ADS)

Nageswara Rao, P. V.; Appa Rao, S.; Subba Rao, N.

2017-05-01

The present study on geochemical evolution of groundwater is taken up to assess the controlling processes of water chemistry in the Western Delta region of the River Godavari (Andhra Pradesh), which is one of the major rice-producing centers in India. The study region is underlain by coarse sand with black clay (buried channels), black silty clay of recent origin (floodplain) and gray/white fine sand of modern beach sediment of marine source (coastal zone), including brown silty clay with fine sand (paleo-beach ridges). Groundwater is mostly brackish and very hard. It is characterized by Na+ > Mg2+ > Ca2+:HCO3 - > Cl- > SO4 2- > NO3 -, Na+ > Mg2+ > Ca2+:Cl- > HCO3 - > SO4 2-, and Mg2+ > Na+ > Ca2+ > or < K+:HCO3 - > Cl- > or > SO4 2- facies. The ionic relations (Ca2+ + Mg2+:HCO3 -, Ca2+ + Mg2+:SO4 2- + HCO3 -, Na+ + K+:TC, Na+ + K+:Cl- + SO4 2-, HCO3 -:TC, HCO3 -:Ca2+ + Mg2+, Na+:Cl- and Na+:Ca2+) indicate that the rock weathering, mineral dissolution, evaporation and ion exchange are the processes to control the aquifer chemistry. Anthropogenic and marine sources are also the supplementary factors for brackish water quality. These observations are further supported by Gibbs mechanisms that control the water chemistry. Thus, the study suggests that the initial quality of groundwater of geogenic origin has been subsequently modified by the influences of anthropogenic and marine sources.

Transport and fate of river waters under flood conditions and rim current influence: the Mississippi River test case

NASA Astrophysics Data System (ADS)

Kourafalou, Villy; Androulidakis, Yannis

2013-04-01

Large river plumes are a major supplier of freshwater, sediments and nutrients in coastal and shelf seas. Novel processes controlling the transport and fate of riverine waters (and associated materials) will be presented, under flood conditions and in the presence of complex topography, ambient shelf circulation and slope processes, controlled by the interaction with rim currents. The Mississippi River (MR) freshwater outflow is chosen as a test case, as a major circulation forcing mechanism for the Northern Gulf of Mexico and a unique river plume for the intense interactions with a large scale ocean current, namely the Loop Current branch of the Gulf Stream, and associated eddy field. The largest MR outflow in history (45,000 m3/sec in 2011) is compared with the second largest outflow in the last 8 years (41,000 m3/sec in 2008). Realistically forced simulations, based on the Hybrid Coordinate Ocean Model (HYCOM) with careful treatment of river plume dynamics and nested to a data assimilated, basin-wide model, reveal the synergistic effect of enhanced discharge, winds, stratification of ambient shelf waters and offshore circulation over the transport of plume waters. The investigation targets a broader understanding of the dynamics of large scale river plumes in general, and of the MR plume in particular. In addition, in situ observations from ship surveys and satellite chl-a data showed that the mathematical simulations with high temporal resolution river outflow input may reproduce adequately the buoyant waters spreading over the Northern Gulf of Mexico shelf and offshore areas. The fate of the river plume is strongly determined and affected by deep basin processes. The strong impacts of the Loop Current system (and its frontal eddies) on river plume evolution are of particular importance under conditions of increased offshore spreading, which is presumed under large discharge rates and can cause loss of riverine materials to the basin interior. Flood conditions

Downwelling dynamics of the western Adriatic Coastal Current

NASA Astrophysics Data System (ADS)

Geyer, W. R.; Mullenbach, B. L.; Kineke, G. C.; Sherwood, C. R.; Signell, R. P.; Ogston, A. S.; Puig, P.; Traykovski, P.

2004-12-01

The western Adriatic coastal current (WACC) flows for hundreds of kilometers along the east coast of Italy at speeds of 20 to 100 cm/s. It is fed by the buoyancy input from the Po River and other rivers of the northern Adriatic Sea, with typical freshwater discharge rates of 2000 m**3/s. The Bora winds provide the dominant forcing agent of the WACC during the winter months, resulting in peak southeastward flows reaching 100 cm/s. The energy input of the Bora is principally in the northern Adriatic, and the coastal current response is due mainly to the set up of the pressure field, although there is sometimes an accompanying local component of down-coast winds that further augments the coastal current. Downwelling conditions occur during Bora, with or without local wind-forcing, because the bottom Ekman transport occurs in either case. Downwelling results in destratification of the coastal current, due to both vertical mixing and straining of the cross-shore density gradient. The relative contributions of mixing and straining depends on the value of the Kelvin number K=Lf/(g_Oh)**1/2, where L is the width of the coastal current, f is the Coriolis parameter, g_O is reduced gravity, and h is the plume thickness. For a narrow coastal current (K<1), straining occurs more rapidly than vertical mixing. This is the case in the WACC during Bora events, with strain-induced destratification occurring in less than 24 hours. The straining process limits vertical mixing of the coastal current with the ambient Adriatic water, because once the isopycnals become vertical, no more mixing can occur. This limitation of mixing may explain the persistence of the density anomaly of the coastal current in the presence of high stresses. The straining process also has important implications for sediment transport: destratification allows sediment to be distributed throughout the water column during Bora events, resulting in enhanced down-coast fluxes. The influence of the downwelling

The comparison of vernacular residences' thermal comfort in coastal with that in mountainous regions of tropical areas

NASA Astrophysics Data System (ADS)

Hermawan, Prianto, Eddy; Setyowati, Erni; Sunaryo

2017-11-01

Adaptive thermal comfort is the latest theory used to analyze thermal acceptability of the naturally ventilated buildings for occupants in tropical areas. Vernacular residences are considered capable to meet the thermal comfort for the occupants. The combination between adaptive and passive theory is still rarely conducted. This study aims to compare the adaptive and passive thermal comfort for occupants of vernacular residences in mountainous and coastal regions using AMV (Actual Mean Vote) and PMV (Predicted Mean Vote). This research uses a quantitative method with a statistical analysis on variables of air temperature, globe temperature, velocity, relative humidity, age, weight, and height. AMV data are collected based on questionnaires with ASHRAE (American Society of Heating, Refrigeration, Air conditioning Engineering) standards. The samples consist of 100 vernacular residences of both coastal and mountainous regions. The results show that there are AMV and PMV differences in each region. The AMV values in those vernacular residences in mountainous and coastal regions are respectively -0.4982 and 0.1673. It indicates that the occupants of vernacular residences in coastal regions accept the thermal conditions better. Thus, it can be concluded that vernacular residences in coastal areas comfort the occupants more.

Influence of Hydrodynamic Sorting on the Composition and Age of Yellow River Suspended Particulate Organic Matter

NASA Astrophysics Data System (ADS)

Yu, M.; Eglinton, T. I.; Haghipour, N.; Montluçon, D. B.; Wacker, L.; Hou, P.; Zhao, M.

2016-12-01

The transport of organic carbon (OC) by rivers to coastal oceans is an important component of the global carbon cycle. The Yellow River (YR), the second largest river in China, transports large amounts of particulate organic carbon (POC) to the Chinese marginal seas, with fossil and pre-aged (ca, 1600 yr) OC comprising the dominant components. However, the influence of hydrodynamic processes on the origin, composition and age of POC exported by the YR remains poorly understood, yet these processes likely ultimately play an important role in determining OC fate in the Chinese marginal seas. We address this question through bulk, biomarker and carbon isotopic (δ13C and Δ14C) characterization of organic matter associated with different grain size fractions of total suspended particles (TSP) in the YR. Surface TSP samples were collected in the spring, summer, fall and during the Water-Sediment Regulation period (WSR, July) of 2015. TSP samples were separated into five grain-size fractions (<8μm, 8-16μm, 16-32μm, 32-63μm and >63μm) for organic geochemical and isotope analysis. Generally, the 16-32 and 32-63μm fractions contributed most of the TSP mass and the majority of OC resided in 16-32μm fraction. TOC% decreased with increasing grain size and 14C ages exhibited significant variability, ranging from 3,335 yr (<8μm fraction in summer) to 11,120 yr (>63μm fraction in autumn), but did not show any systematic trend among grain size fractions or across sampling times. In contrast, compound-specific 14C analysis of long-chain n-fatty acids (C26-30 FAs) revealed two clear patterns: first, C26-30 FAs age decreased with increasing grain size for all sampling times; second, the C26-30 FAs age difference was the largest among the different size fractions during the WSR period, and smallest after the WSR. These findings have important implications for our understanding of riverine POC transport mechanisms and their influence on the dispersal and burial efficiency of

Influence of land-based Kaliningrad (Primorsky) amber mining on coastal zone.

PubMed

Krek, Alexander; Ulyanova, Marina; Koschavets, Svetlana

2018-06-01

In this paper, we report on the pollution in the coastal zone of the South-Eastern Baltic Sea (Russian coast). It was studied through a range of methods, including analyses potential water quality indicators (WQIs) and potentially harmful elements (PHEs). A contamination factor and modified degree of contamination were used for describing the contamination of the sediments by toxic substances. Special attention was paid to activity of the Kaliningrad Amber Combine (KAC), the biggest world amber mining company, located onshore close to the coastal zone (Kaliningrad Region). The amber extraction contribution to the ecological state of the coastal zone was estimated. Contamination of the quarry by metals (Cr, Co, Ni, Cu, Pb, Zn) was comparable with contamination of abrasion bench. The pollution of the western coastal zone of the Sambia Peninsula is caused both by land-based anthropogenic developments (including KAC) and natural processes (coastal abrasion). Copyright © 2018 Elsevier Ltd. All rights reserved.

Low Frequencies of Interference to EPA Quantitative Polymerase Chain Reaction (qPCR) Methods for Microbial Water Quality Monitoring in U.S. Rivers and Streams and Coastal Waters

EPA Science Inventory

In collaboration with U.S States and Tribes, the United States Environmental Protection Agency (EPA) conducts periodic and rotating, statistically based surveys of U.S. rivers and streams (National Rivers and Streams Assessment, NRSA), estuarine and Great Lakes nearshore coastal ...

River-derived humic substances as iron chelators in seawater

PubMed Central

Krachler, Regina; Krachler, Rudolf F.; Wallner, Gabriele; Hann, Stephan; Laux, Monika; Cervantes Recalde, Maria F.; Jirsa, Franz; Neubauer, Elisabeth; von der Kammer, Frank; Hofmann, Thilo; Keppler, Bernhard K.

2015-01-01

The speciation of iron(III) in oxic seawater is dominated by its hydrolysis and sedimentation of insoluble iron(III)-oxyhydroxide. As a consequence, many oceanic areas have very low iron levels in surface seawater which leads to iron deficiency since phytoplankton require iron as a micronutrient in order to grow. Fortunately, iron solubility is not truly as low as Fe(III) solubility measurements in inorganic seawater would suggest, since oceanic waters contain organic molecules which tend to bind the iron and keep it in solution. Various iron-binding organic ligands which combine to stabilize dissolved iron have been detected and thoroughly investigated in recent years. However, the role of iron-binding ligands from terrestrial sources remains poorly constrained. Blackwater rivers supply large amounts of natural organic material (NOM) to the ocean. This NOM (which consists mainly of vascular plant-derived humic substances) is able to greatly enhance iron bioavailability in estuaries and coastal regions, however, breakdown processes lead to a rapid decrease of river-derived NOM concentrations with increasing distance from land. It has therefore been argued that the influence of river-derived NOM on iron biogeochemistry in offshore seawater does not seem to be significant. Here we used a standard method based on 59Fe as a radiotracer to study the solubility of Fe(III)-oxyhydroxide in seawater in the presence of riverine NOM. We aimed to address the question how effective is freshwater NOM as an iron chelator under open ocean conditions where the concentration of land-derived organic material is about 3 orders of magnitude smaller than in coastal regions, and does this iron chelating ability vary between NOM from different sources and between different size fractions of the river-borne NOM. Our results show that the investigated NOM fractions were able to substantially enhance Fe(III)-oxyhydroxide solubility in seawater at concentrations of the NOM ≥ 5�

Dominance of organic nitrogen from headwater streams to large rivers across the conterminous United States

USGS Publications Warehouse

Scott, D.; Harvey, J.; Alexander, R.; Schwarz, G.

2007-01-01

The frequency and magnitude of hypoxic areas in coastal waterbodies are increasing across the globe, partially in response to the increase in nitrogen delivery from the landscape (Diaz, 2001; Rabalais et al., 2002). Although studies of annual total nitrogen and nitrate yields have greatly improved understanding of the contaminant sources that contribute to riverine nitrogen loads (Alexander et al., 2000; Caraco and Cole, 1999), the emphasis of these studies on annual timescales and selected nitrogen forms is not sufficient to understand the factors that control the cycling, transport, and fate of reactive nitrogen. Here we use data from 850 river stations to calculate long-term mean-annual and interannual loads of organic, ammonia, and nitrate-nitrite nitrogen suitable for spatial analysis. We find that organic nitrogen is the dominant nitrogen pool within rivers across most of the United States and is significant even in basins with high anthropogenic sources of nitrogen. Downstream organic nitrogen patterns illustrate that organic nitrogen is an abundant fraction of the nitrogen loads in all regions. Although the longitudinal patterns are not consistent across regions, these patterns are suggestive of cycling between ON and NO3- on seasonal timescales influenced by land use, stream morphology, and riparian connectivity with active floodplains. Future regional studies need to incorporate multinitrogen species at intraannual timescales, as well as stream characteristics beyond channel depth, to elucidate the roles of nitrogen sources and in-stream transformations on the fate and reactivity of riverine nitrogen transported to coastal seas.

Dominance of organic nitrogen from headwater streams to large rivers across the conterminous United States

NASA Astrophysics Data System (ADS)

Scott, Durelle; Harvey, Judson; Alexander, Richard; Schwarz, Gregory

2007-03-01

The frequency and magnitude of hypoxic areas in coastal waterbodies are increasing across the globe, partially in response to the increase in nitrogen delivery from the landscape (Diaz, 2001; Rabalais et al., 2002). Although studies of annual total nitrogen and nitrate yields have greatly improved understanding of the contaminant sources that contribute to riverine nitrogen loads (Alexander et al., 2000; Caraco and Cole, 1999), the emphasis of these studies on annual timescales and selected nitrogen forms is not sufficient to understand the factors that control the cycling, transport, and fate of reactive nitrogen. Here we use data from 850 river stations to calculate long-term mean-annual and interannual loads of organic, ammonia, and nitrate-nitrite nitrogen suitable for spatial analysis. We find that organic nitrogen is the dominant nitrogen pool within rivers across most of the United States and is significant even in basins with high anthropogenic sources of nitrogen. Downstream organic nitrogen patterns illustrate that organic nitrogen is an abundant fraction of the nitrogen loads in all regions. Although the longitudinal patterns are not consistent across regions, these patterns are suggestive of cycling between ON and NO3- on seasonal timescales influenced by land use, stream morphology, and riparian connectivity with active floodplains. Future regional studies need to incorporate multinitrogen species at intraannual timescales, as well as stream characteristics beyond channel depth, to elucidate the roles of nitrogen sources and in-stream transformations on the fate and reactivity of riverine nitrogen transported to coastal seas.

Dispersal and deposition of river sediments in coastal seas: Models from Asia and the tropics

NASA Astrophysics Data System (ADS)

Wright, L. D.

The diverse mechanisms by which river-borne sediments are dispersed into coastal oceans and the associated patterns of deposition are considered for some tropical and Asian river mouth dispersal systems: the Huanghe (Yellow River), which enters the Bohai Gulf (China), the Purari River which enters the Gulf of Papua (Papua New Guinea) and the Jaba River, which enters Empress Augusta Bay (Bougainville, Papua New Guinea). These models contrast sharply with 'conventional' models such as that of the Mississippi, although in different respects. Extremely high suspended sediment concentrations off the Huanghe mouth cause sinking, gravity-driven plumes which produce rapid deposition very near the mouth; extremely rapid seaward growth of the subaqueous delta results. Although the average water discharge of the Purari exceeds that of the Huanghe, the average sediment discharge from the Purari is an order of magnitude less than that of the Huanghe. Suspended sediments transported via buoyant plumes from the Purari mouth are trapped inshore by the southeasterly trades and have their ultimate sink in the tidal estuaries to the west of the mouths rather than offshore. The Jaba is a small river with a very steep gradient and an extremely high bed load relative to water discharge. It has constructed a protruding and rapidly evolving delta. Literature on the Indonesian rivers Solo and Porong dispersal systems suggests that those systems may, at different times, be subject to processes similar to those which operate off the mouths of the Huanghe, Purari and Jaba although no single, direct analogies can be made.

Precipitable water vapor characterization in the coastal regions of China based on ground-based GPS

NASA Astrophysics Data System (ADS)

Wang, Zhaoyang; Zhou, Xinghua; Liu, Yanxiong; Zhou, Dongxu; Zhang, Huayi; Sun, Weikang

2017-12-01

Water vapor plays an important role in climate change; thus, studying the spatial distribution and temporal variation of precipitable water vapor (PWV) in the coastal regions of China would help researchers to understand the climate characteristics of those regions. In this paper, 6-year 1-h interval PWV were derived from 27 Global Positioning System stations observations of Chinese coastal GPS observation network, surface meteorological data and European Center for Medium-Range Weather Forecasts (ERA-Interim) reanalysis products. The present study provides the use of these data to investigate the spatial-temporal variability of water vapor throughout the coastal regions of China. Latitude is the main factor affecting the spatial distribution of GPS-derived PWV; that is, PWV decreased by about 1.5 mm for each 1° increase of latitude. For regions at the same latitude, a region that is relatively close to the ocean will have a higher content of PWV. The PWV in the southeastern and southwestern coastal regions of China is significantly higher in summer; this may be influenced by the southeastern and southwestern water vapor inflow corridors. The PWV obviously varies monthly, reaching a minimum in January; however, the timing of the maximum varied but usually appeared in June, July or August and was affected by the monsoons. The PWV varies largely between summer and winter with a larger gradient of change in PWV with latitude in winter than in summer. The positive correlation coefficient between PWV and the surface temperature varied in different seasons; this is related to the changes of temperature and the horizontal motion of water vapor. Use of the Fast Fourier Transform method showed that the PWV time series data have multi-scale characteristics. The amplitude and phase of the PWV time series in annual, semiannual, four month and seasonal cycles were extracted through harmonic wave analysis. The amplitude of four month and seasonal cycles did not pass

The quality of our Nation's waters: water quality in the Mississippi embayment-Texas coastal uplands aquifer system and Mississippi River Valley alluvial aquifer, south-central United States, 1994-2008

USGS Publications Warehouse

Kingsbury, James A.; Barlow, Jeannie R.; Katz, Brian G.; Welch, Heather L.; Tollett, Roland W.; Fahlquist, Lynne S.

2015-01-01

About 8 million people rely on groundwater from the Mississippi embayment—Texas coastal uplands aquifer system for drinking water. The Mississippi River Valley alluvial aquifer also provides drinking water for domestic use in rural areas but is of primary importance to the region as a source of water for irrigation. Irrigation withdrawals from this aquifer are among the largest in the Nation and play a key role in the economy of the area, where annual crop sales total more than $7 billion. The reliance of the region on both aquifers for drinking water and irrigation highlights the importance of long-term management to sustain the availability and quality of these resources.

Development of a regional macroinvertebrate index for large river bioassessment

EPA Science Inventory

Large river bioassessment protocols lag far behind those of wadeable streams and often rely on fish assemblages of individual rivers. We developed a regional macroinvertebrate index and assessed relative condition of six large river tributaries to the upper Mississippi and Ohio r...

Metal concentrations in aquatic environments of Puebla River basin, Mexico: natural and industrial influences.

PubMed

Morales-García, S S; Rodríguez-Espinosa, P F; Shruti, V C; Jonathan, M P; Martínez-Tavera, E

2017-01-01

The rapid urban expansion and presence of volcanoes in the premises of Puebla River basin in central Mexico exert significant influences over its aquatic environments. Twenty surface sediment samples from Puebla River basin consisting of R. Alseseca, R. Atoyac, and Valsequillo dam were collected during September 2009 and analyzed for major (Al, Fe, Mg, Ba, Ca, and K) and trace elements (As, Cd, Co, Cr, Cu, Mn, Ni, Pb, Sr, V, and Zn) in order to identify the metal concentrations and their enrichment. R. Atoyac sediments presented higher concentrations of Ba (1193.8 μg g -1 ) and Pb (27.1 μg g -1 ) in comparison with the local reference sample values. All the metal concentrations except Sr for R. Alseseca sediments were within the range of local reference sample values indicating no significant external influence, whereas Valsequillo dam sediments had elevated concentrations of all the metals suggesting both natural and external influences in the study region. The magnitude of metal contamination was assessed using several indices such as geoaccumulation index (I geo ), enrichment factor (EF), degree of contamination (C d ), and pollution load index (PLI). The results suggest that As, Pb, and Zn were predominantly enriched in the Puebla River basin sediments. Comparing with sediment quality guidelines and ecotoxicological values, it is revealed that Cd, Cr, Cu, and Ni have possible harmful effects on the biological community. The present study provides an outlook of metal enrichment in Puebla River basin sediments, highlighting the necessity to conserve this river ecosystem for the near future.

Homogenization of regional river dynamics by dams and global biodiversity implications.

PubMed

Poff, N Leroy; Olden, Julian D; Merritt, David M; Pepin, David M

2007-04-03

Global biodiversity in river and riparian ecosystems is generated and maintained by geographic variation in stream processes and fluvial disturbance regimes, which largely reflect regional differences in climate and geology. Extensive construction of dams by humans has greatly dampened the seasonal and interannual streamflow variability of rivers, thereby altering natural dynamics in ecologically important flows on continental to global scales. The cumulative effects of modification to regional-scale environmental templates caused by dams is largely unexplored but of critical conservation importance. Here, we use 186 long-term streamflow records on intermediate-sized rivers across the continental United States to show that dams have homogenized the flow regimes on third- through seventh-order rivers in 16 historically distinctive hydrologic regions over the course of the 20th century. This regional homogenization occurs chiefly through modification of the magnitude and timing of ecologically critical high and low flows. For 317 undammed reference rivers, no evidence for homogenization was found, despite documented changes in regional precipitation over this period. With an estimated average density of one dam every 48 km of third- through seventh-order river channel in the United States, dams arguably have a continental scale effect of homogenizing regionally distinct environmental templates, thereby creating conditions that favor the spread of cosmopolitan, nonindigenous species at the expense of locally adapted native biota. Quantitative analyses such as ours provide the basis for conservation and management actions aimed at restoring and maintaining native biodiversity and ecosystem function and resilience for regionally distinct ecosystems at continental to global scales.

Tidal-Fluvial and Estuarine Processes in the Lower Columbia River: I. Along-channel Water Level Variations, Pacific Ocean to Bonneville Dam

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

Jay, D. A.; Leffler, K.; Diefenderfer, Heida L.

This two-part paper provides comprehensive time and frequency domain analyses and models of along-channel water level variations in the 234km-long Lower Columbia River and Estuary (LCRE) and documents the response of floodplain wetlands thereto. In Part I, power spectra, continuous wavelet transforms, and harmonic analyses are used to understand the influences of tides, river flow, upwelling and downwelling, and hydropower operations ("power-peaking") on the water level regime. Estuarine water levels are influenced primarily by astronomical tides and coastal processes, and secondarily by river flow. The importance of coastal and tidal influences decreases in the landward direction, and water levels aremore » increasingly controlled by river flow variations at periods from ≤1 day to years. Water level records are only slightly non-stationary near the ocean, but become increasingly irregular upriver. Although astronomically forced tidal constituents decrease above the estuary, tidal fortnightly and overtide variations increase for 80-200km landward, both relative to major tidal constituents and in absolute terms.« less

Numerical simulation of the river and urban discharges into the Sea: Application to the Catalan Coast.

NASA Astrophysics Data System (ADS)

Liste, M.; Grifoll, M.; Keupers, I.; Monbaliu, J.

2012-04-01

Introduction The coastal oceans are the recipient of freshwater and land/drained materials that are primarily brought in through river and urban discharge [Kourafalou et al., 1996]. Freshwater discharge from rivers and urban outflows to the ocean water has profound effects on the physical, chemical, and biological processes in coastal waters. It induces circulation patterns and modifies mixing processes [Milliman and Farnsworth, 2011]. Due to their ecological and dynamical importance, a good understanding of the mixing and transport processes in river plumes is required for the maintenance of coastal ecosystems and their resources. In this paper will discuss the results of the land boundary fluxes implementation into the coastal circulation model. As a demonstration part of the Catalan coast has been chosen. The combination of local topography with torrential rainfall can produce considerable local runoff on a short time with a large impact on the receiving coastal waters. Methodology and aim For the coastal circulation model, version 3.0 of the Regional Ocean Modeling System [ROMS, Shchepetkin and McWilliams, 2005] has been implemented for small portion of the Catalan coast. ROMS uses sigma coordinates and solves the 3-D Reynolds-Averaged Navier-Stokes equations. The code design is modular, so that different choices for advection and mixing, for example, may be applied by simply modifying preprocessor flags. Nested increasing-resolution models have been implemented in order to reproduce with enough resolution the coastal circulation and the river plume evolution. The boundary conditions are obtained from the MyOcean products. River and urban run-off are estimated based on rainfall (predictions) form the contributing catchments areas. Conceptual models based on a reservoir-type schematization of the river and sewer network have been set up to allow the fast prediction of the different point source boundary conditions [Keupers et al., 2011]. Model output for

The fatty acid composition of colostrum in three geographic regions of China.

PubMed

Gao, Yi-Xiong; Zhang, Jian; Wang, Chunrong; Li, Lixiang; Man, Qingqing; Song, Pengkun; Meng, Liping; Lie, Ovyind; Frøyland, Livar

2013-01-01

To describe the fatty acid composition of human colostrum in three different regions of China. Women were recruited from river/lake, coastal and inland regions of China during late pregnancy. Their diet frequency was assessed during the 34th week of pregnancy. Colostrum samples were collected between postpartum days 3 and 5. Thirty-one different fatty acids were separated and identified in colostrum. There were significant differences among the women in the three regions with respect to food and culinary oil consumption patterns. The mean±SD fat content (g/100 g) of colostrum from river/lake, coastal and inland regions was 2.17±1.26, 2.50±1.39 and 2.68±1.26, respectively (p=0.265, adjusted by pregnant women's age). The main saturated, monounsaturated, n-6 polyunsaturated and n-3 polyunsaturated fatty acids in colostrum were 16:0, 18:1n9, 18:2n6 and 18:3n3, respectively. Colostrum from river/lake region had the lowest composition of total SFA and of total n-6 PUFA and the highest composition of total MUFA and of total n-3 PUFA. The amount of DHA (22:6n3) in colostrum (mean±SD, % wt/wt) was 0.51±0.18, 0.52±0.20 and 0.35±0.13 in the river/lake, coastal and inland regions, respectively (p=0.0002, adjusted by pregnant women's age). Frequency of maternal marine fish intake during the late pregnancy was positively correlated with DHA in colostrum (r=0.203, p=0.040). The fatty acid composition of colostrum differs across geographical regions in China, which may be related to differences in maternal dietary pattern.

Multidecadal simulation of coastal fog with a regional climate model

NASA Astrophysics Data System (ADS)

O'Brien, Travis A.; Sloan, Lisa C.; Chuang, Patrick Y.; Faloona, Ian C.; Johnstone, James A.

2013-06-01

In order to model stratocumulus clouds and coastal fog, we have coupled the University of Washington boundary layer model to the regional climate model, RegCM (RegCM-UW). By comparing fog occurrences observed at various coastal airports in the western United States, we show that RegCM-UW has success at modeling the spatial and temporal (diurnal, seasonal, and interannual) climatology of northern California coastal fog. The quality of the modeled fog estimate depends on whether coast-adjacent ocean or land grid cells are used; for the model runs shown here, the oceanic grid cells seem to be most appropriate. The interannual variability of oceanic northern California summertime fog, from a multi-decadal simulation, has a high and statistically significant correlation with the observed interannual variability ( r = 0.72), which indicates that RegCM-UW is capable of investigating the response of fog to long-term climatological forcing. While RegCM-UW has a number of aspects that would benefit from further investigation and development, RegCM-UW is a new tool for investigating the climatology of coastal fog and the physical processes that govern it. We expect that with appropriate physical parameterizations and moderate horizontal resolution, other climate models should be capable of simulating coastal fog. The source code for RegCM-UW is publicly available, under the GNU license, through the International Centre for Theoretical Physics.

Increasing Incidence of Tuberculosis Infection in the Coastal Region of Northern Miyagi after the Great East Japan Earthquake.

PubMed

Sakurai, Masahiro; Takahashi, Tatsuya; Ohuchi, Miyako; Terui, Yuki; Kiryu, Kouji; Shikano, Kazuo

2016-03-01

On March 11, 2011, the Great East Japan Earthquake struck off the northeast coast of Japan. Within an hour of the earthquake, devastating tsunamis swept over the coastal region of the Miyagi Prefecture, facing Pacific Ocean. Accordingly, more than 400,000 residents were forced to stay at evacuation shelters. We investigated the changes in tuberculosis prevalence after the disaster. Annual data for all tuberculosis patients between April 1, 2009 and March 31, 2013 were extracted from the database of the Miyagi Prefectural Government. In the coastal region of Northern Miyagi, the number of tuberculosis patients increased in the post-disaster period (p < 0.001, 9.6 vs.19.1 per 100,000 people), compared to the pre-disaster period. In contrast, its prevalence did not change in the inland region of Northern Miyagi and the coastal and inland regions of Southern Miyagi. Importantly, in the inland and coastal regions of Northern Miyagi, the number of patients with latent tuberculosis infection (LTBI) increased in the post-disaster period (p < 0.001). Furthermore, in the coastal shelters, 11 evacuees with the history of contacting tuberculosis patients were diagnosed with LTBI, whereas no cases of LTBI patients were observed in the inland shelters. Thus, staying in the coastal shelters was a risk factor for contracting tuberculosis (OR: 19.31, 95% CI: 1.11-334.80); indeed, twice as many evacuees visited each coastal shelter on April 1, 2011, compared to the inland region. We should prepare the shelters to avoid overcrowding, and long-term observation is required to detect the prevalence of tuberculosis infection.

Taking the measure of a landscape: Comparing a simulated and natural landscape in the Virginia Coastal Plain

NASA Astrophysics Data System (ADS)

Howard, Alan D.; Tierney, Heather E.

2012-01-01

A landform evolution model is used to investigate the historical evolution of a fluvial landscape along the Potomac River in Virginia, USA. The landscape has developed on three terraces whose ages span 3.5 Ma. The simulation model specifies the temporal evolution of base level control by the river as having a high-frequency component of the response of the Potomac River to sea level fluctuations superimposed on a long-term epeirogenic uplift. The wave-cut benches are assumed to form instantaneously during sea level highstands. The region is underlain by relatively soft coastal plain sediments with high intrinsic erodibility. The survival of portions of these terrace surfaces, up to 3.5 Ma, is attributable to a protective cover of vegetation. The vegetation influence is parameterized as a critical shear stress to fluvial erosion whose magnitude decreases with increasing contributing area. The simulation model replicates the general pattern of dissection of the natural landscape, with decreasing degrees of dissection of the younger terrace surfaces. Channel incision and relief increase in headwater areas are most pronounced during the relatively brief periods of river lowstands. Imposition of the wave-cut terraces onto the simulated landscape triggers a strong incisional response. By qualitative and quantitative measures the model replicates, in a general way, the landform evolution and present morphology of the target region.

Organic carbon and fine sediment production potential from decaying permafrost in a small watershed, Sheldrake River, Eastern coastal region of Hudson Bay

NASA Astrophysics Data System (ADS)

Jolivel, M.; Allard, M.

2010-12-01

Recent evaluations indicate that large amounts of organic carbon and fine sediment can be released in fluvial and coastal systems because of permafrost degradation, with impacts on ecosystems. In order to estimate the organic carbon and fine sediment potential production from a river basin, we have made a spatiotemporal comparison between 1957 aerial photographs and a 2009 GeoEye satellite image. A gauging station was installed near the river mouth and measurements of the extent and volume of permafrost degradation were made in the watershed where permafrost degradation is very active. The Sheldrake river watershed is located on the eastern coast of Hudson Bay near the Inuit community of Umiujaq, in the discontinuous permafrost zone. The tree line passes across the watershed. Permafrost mounds (palsas, lithalsas) and plateaus are the most abundant permafrost landforms in this area. They developed principally in east-west oriented valleys, in postglacial marine silts of the Tyrrell Sea. Signs of degradation are numerous. Lithalsas and palsas (with peat cover) weather out and collapse. Thermokarst ponds are replacing permafrost mounds and sometimes, eroded clay and peat are remobilized in the drainage network. Moreover, several retrogressive landslides, mudflows and gully erosion are active along the Sheldrake river banks. The first step consisted in mapping the 80 km2 watershed area and representing surface deposits, drainage network and permafrost distribution (1957 and 2009). First results show that 40 to 70% of the 1957 permafrost has disappeared in 2009 in various sector of the watershed. The percentage of permafrost degradation is positively correlated with distance from the sea and the presence of a well-developed drainage network. The second step is to calculate an equation which will allow changing the missing permafrost surface between 1957 and 2009 into a volume. The equation will take into account the average depth of permafrost and active layer, the mean

A new species of freshwater eel-tailed catfish of the genus Tandanus (Teleostei: Plotosidae) from coastal rivers of mid-northern New South Wales, Australia

USGS Publications Warehouse

Welsh, Stuart A.; Jerry, Dean R.; Burrows, Damien; Rourke, Meaghan L.

2017-01-01

Tandanus bellingerensis, new species, is described based on specimens from four river drainages (Bellinger, Macleay, Hastings, and Manning rivers) of the mid-northern coast of New South Wales, Australia. Previously, three species were recognized in the genus Tandanus: T. tropicanus of the wet tropics region of northeast Queensland, T. tandanus of the Murray-Darling drainage and coastal streams of central-southern Queensland and New South Wales, and T. bostocki of southwestern Western Australia. The new species is distinguished from all congeners by a combination of the following morphologic characters: a high count of rays in the continuous caudodorsal and anal fins (range 153–169, mode 159), a high count of gill rakers on the first arch (range 35–39, mode 36), and strongly recurved posterior serrae of the pectoral-fin spine. Additionally, results from previously conducted genetic studies corroborate morphologic and taxonomic distinctness of the new species.

Osmotically driven membrane process for the management of urban runoff in coastal regions.

PubMed

Li, Zhenyu; Valladares Linares, Rodrigo; Abu-Ghdaib, Muhannad; Zhan, Tong; Yangali-Quintanilla, Victor; Amy, Gary

2014-01-01

An osmotic detention pond was proposed for the management of urban runoff in coastal regions. Forward osmosis was employed as a bridge to utilize natural osmotic energy from seawater for concentrating and reusing urban runoff water, and as a barrier to reject runoff-derived contaminants. The process was demonstrated by a lab scale testing using synthetic urban runoff (as the feed solution) and synthetic seawater (as the draw solution). The submerged forward osmosis process was conducted under neutral, acidic and natural organic matter fouling condition, respectively. Forward osmosis flux decline was mainly attributed to the dilution of seawater during a semi-batch process in lab scale testing. However, it is possible to minimize flux decrease by maintaining a constant salinity at the draw solution side. Various changes in urban runoff water quality, including acidic conditions (acid rain) and natural organic matter presence, did not show significant effects on the rejection of trace metals and phosphorus, but influenced salt leakage and the rejection of nitrate and total nitrogen. Rejection of trace metals varied from 98% to 100%, phosphorus varied from 97% to 100, nitrate varied from 52% to 94% and total nitrogen varied from 65% to 85% under different feed water conditions. The work described in this study contributes to an integrated system of urban runoff management, seawater desalination and possible power generation in coastal regions to achieve a sustainable solution to the water-energy nexus. Copyright © 2013 Elsevier Ltd. All rights reserved.

Fragmented coastal boundary layer induced by gap winds

NASA Astrophysics Data System (ADS)

Caldeira, Rui M. A.; Iglesias, Isabel; Sala, Iria; Vieira, Rui R.; Bastos, Luísa

2015-04-01

The oceanic impact of offshore-localized winds in the NW Iberian Peninsula was studied. Satellite and in situ observations showed the formation of plumes protruding offshore from the coast. To study the dynamics of such episodes tee Coupled-Ocean-Atmosphere-Wave- Sediment Transport Modeling System (COAWST) was used to reproduce the coastal conditions of the nortwestern Iberian Peninsula, allowing the concurrent representation of local winds, waves, currents, and rivers runoff. The use of coupled models is of outmost importance in order to accurately study the impact of the local winds on the coastal currents. The NW Iberian Peninsula has prominent capes, promontories and submarine canyons, which produce persistent hydrodynamic features. Thus far, the scientific literature shows that the western Iberian rivers produce a recurrent combined plume often denominated as the Western Iberian Buoyant Plume (WIBP) which increases the stratification of the water column and produces a vertical retention mechanism that keeps the biological material inshore. The WIBP extends northward along the coast (over the inner-shelf), and forms a front with the warmer and more saline surface (offshore) waters. However during episodes of strong offshore winds this coastal boundary layer is broken interrupting the WIBP. Coastal orography allows the formation of down-valley winds that produce coastal jets, promoting the offshore transport of pollutants, larvae and sediments. Acknowledgments: Acknowledgments: Numerical model solutions were calculated at CIIMARs HPC unit, acquired and maintained by FCT pluriannual funds (PesTC/Mar/LA0015/2013), and RAIA (0313-RAIA-1-E) and RAIA.co (0520-RAIACO-1-E) projects. The NICC (POCTI/CTA/49563/2002) project provided databases for this work. Rui Caldeira was supported by funds from the ECORISK project (NORTE-07-0124-FEDER-000054), co-financed by the North Portugal Regional Operational Programme (ON.2 - O Novo Norte), under the National Strategic Reference

Alkane, terpene and polycyclic aromatic hydrocarbon geochemistry of the Mackenzie River and Mackenzie shelf: Riverine contributions to Beaufort Sea coastal sediment

NASA Astrophysics Data System (ADS)

Yunker, Mark B.; Macdonald, Robie W.; Cretney, Walter J.; Fowler, Brian R.; McLaughlin, Fiona A.

1993-07-01

To study the largest source of river sediment to the Arctic Ocean, we have collected suspended particulates from the Mackenzie River in all seasons and sediments from the Mackenzie shelf between the river mouth and the shelf edge. These samples have been analyzed for alkanes, triterpenes and polycyclic aromatic hydrocarbons (PAHs). We found that naturally occurring hydrocarbons predominate in the river and on the shelf. These hydrocarbons include biogenic alkanes and triterpenes with a higher plant/peat origin, diagenetic PAHs from peat and plant detritus, petrogenic alkanes, triterpenes and PAHs from oil seeps and/or bitumens and combustion PAHs that are likely relict in peat deposits. Because these components vary independently, the season is found to strongly influence the concentration and composition of hydrocarbons in the Mackenzie River. While essentially the same pattern of alkanes, diagenetic hopanes and alkyl PAHs is observed in all river and most shelf sediment samples, alkane and triterpene concentration variations are strongly linked to the relative amount of higher plant/peat material. Polycyclic aromatic hydrocarbon molecular-mass profiles also appear to be tied primarily to varying proportions of peat, with an additional petrogenic component which is most likely associated with lithic material mobilized by the Mackenzie River at freshet. Consistent with the general lack of alkyl PAHs in peat, the higher PAHs found in the river are probably derived from forest and tundra fires. A few anthropogenic/pyrogenic compounds are manifest only at the shelf edge, probably due to a weakening of the river influence. We take this observation of pyrogenic PAHs and the pronounced source differences between two sediment samples collected at the shelf edge as evidence of a transition from dominance by the Mackenzie River to the geochemistry prevalent in Arctic regions far removed from major rivers.

Dispersal of river sediment in the Southern California Bight

USGS Publications Warehouse

Warrick, J.A.; Farnsworth, K.L.

2009-01-01

The rivers of Southern California deliver episodic pulses of water, sediment, nutrients, and pollutants to the region's coastal waters. Although river-sediment dispersal is observed in positively buoyant (hypopycnal) turbid plumes extending tens of kilometers from river mouths, very little of the river sediment is found in these plumes. Rather, river sediment settles quickly from hypopycnal plumes to the seabed, where transport is controlled by bottom-boundary layer processes, presumably including fluid-mud (hyperpycnal) gravity currents. Here we investigate the geographical patterns of river-sediment dispersal processes by examining suspended-sediment concentrations and loads and the continental shelf morphology offshore river mouths. Throughout Southern California, river sediment is discharged at concentrations adequately high to induce enhanced sediment settling, including negative buoyancy. The rivers draining the Western Transverse Range produce suspended-sediment concentrations that are orders of magnitude greater than those in the urbanized region and Peninsular Range to the south, largely due to differences in sediment yield. The majority of sediment discharge from the Santa Clara River and Calleguas Creek occurs above the theoretical negative buoyancy concentration (>40 g/l). These rivers also produce event sediment loading as great as the Eel River, where fluid-mud gravity currents are observed. The continental shelf of Southern California has variable morphology, which influences the ability to transport via gravity currents. Over half of the rivers examined are adjacent to shelf slopes greater than 0.01, which are adequately steep to sustain auto-suspending gravity currents across the shelf, and have little (<10 m) Holocene sediment accumulation. Shelf settings of the Ventura, Santa Clara, and Tijuana Rivers are very broad and low sloped (less than 0.004), which suggests that fluid-mud gravity currents could transport across these shelves, albeit slowly

Sources, dispersal, and fate of fine sediment supplied to coastal California

USGS Publications Warehouse

Farnsworth, Katherine L.; Warrick, Jonathan A.

2007-01-01

We have investigated the sources, dispersal, and fate of fine sediment supplied to California coastal waters in a partnership between the U.S. Geological Survey (USGS) and the California Sediment Management Workgroup (CSMW). The purpose of this study was to document the rates and characteristics of these processes so that the State can better manage its coastal resources, including sediment. In this study, we made the following observations: - Rivers dominate the supply of fine sediment to the California coastal waters, with an average annual flux of 34 megatonnes (Mt). - Cliff and bluff erosion in central and southern California is a source of fine sediment, with a delivery rate of approximately 10 percent of river loads. In the southern most part of the State, however, where river-sediment loads are low, cliff and bluff erosion represent approximately 40 percent of the total fine-sediment flux. - Temporal variation in the sources of fine sediment is high. River floods and bluff erosion are episodic and dominated by winter storms, which supply most sediment flux to the coast. The magnitude of winter storms is generally related to the El Niño-Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO) climate cycles. - The three rivers that dominate fine-sediment flux to the California coast are the Eel, Salinas, and Santa Clara Rivers. Because the sediment delivery from these and all other California coastal watersheds is episodic, individual rivers discharge most of their annual loads over the course of only a few days per year. - Spatial variation in river-sediment discharge is high and generally related to such watershed characteristics as geology, precipitation, and drainage area. For example, the Transverse Range of southern California represents only 9 percent of the watershed-drainage area but 18 percent of the fine-sediment flux, a function of the young sedimentary bedrock and active tectonics of this region. The urban rivers of southern California

The Lower Chesapeake Bay LTAR: A coastal urban-agricultural region

NASA Astrophysics Data System (ADS)

Mccarty, G.; Alfieri, J. G.; Cavigelli, M.; Cosh, M. H.; Hapeman, C. J.; Kustas, W. P.; Maul, J.; Mirsky, S.; Pooler, M.; Sadeghi, A. M.; Schomberg, H.; Timlin, D. J.; Rice, C. P.

2015-12-01

The Chesapeake Bay, located in the mid-Atlantic region of the U.S., is the largest estuary in North America. The watershed area includes six states from New York to Virginia and is nearly 167,000 km2 in size with more than 150 rivers and streams entering the 300-km Bay main stem. Forested and agricultural lands make up 58 and 22 percent of the land use, respectively. Nearly 9 percent is urban and suburban use, and the watershed is home to over 17 million people. However, the population is expected to reach 19 million by 2025, raising the potential for conflict between the agricultural and urban communities over land and water use and in protecting natural resources, especially in the lower portion of the Chesapeake Bay watershed. The Lower Chesapeake Bay study area, part of the USDA-ARS Long-Term Agroecosystem Research (LTAR) network, will provide much-needed data to support decisions at this critical agriculture-urban interface. Current long-term projects seek to assess the economic, production, and environmental performance of conventional and organic cropping systems and to evaluate the resilience of these systems to climate change. Large-scale studies are being conducted to examine the effects of land-use and landscape characteristics on ecosystem services and on energy, water, nutrient, carbon, and pest dynamics within watersheds. New in-situ measurement and remote sensor technologies are being considered with the expectancy that the data streams will be available on-line and for use in modeling. Results and outcomes of these research efforts will greatly benefit the national LTAR network and will be applicable to other US coastal urban-agricultural regions.

Investigation of different coastal processes in Indonesian waters using SeaWiFS data

NASA Astrophysics Data System (ADS)

Hendiarti, Nani; Siegel, Herbert; Ohde, Thomas

2004-01-01

SeaWiFS data were applied to investigate coastal processes in Indonesian waters around the most populated island of Java. Coastal processes due to wind forcing were studied the first time using SeaWiFS-derived chlorophyll and TSM concentrations in combination with AVHRR-derived SST in the period from September 1997 to December 2001. Upwelling events were studied along the southern coast of Java during the southeast monsoon (June to September). Satellite-derived chlorophyll concentrations higher than 0.8 mg/ m3 and sea-surface temperatures lower than 28°C are indications of upwelling. Upwelling events influence the distribution and growth of phytoplankton and provide by that good feeding condition for zooplankton, larvae, juvenile and adult of pelagic fish. Coastal discharge into the western Java Sea contains organic and inorganic materials originating from different sources. Diffuse impacts, particularly from fish farms and aquaculture, as well as coastal erosion influence large coastal areas during the rainy season (December to March), and to a lesser extent during the dry season. Strong Citarum river discharge was observed during the transition phase from the rainy to the dry season (March and April), when the maximum amount of transported material reaches the sea. The river plume is evident from chlorophyll concentrations higher than 2.5 mg/ m3, and suspended particulate matter concentrations of more than 8 mg/dm3. The Sunda Strait is seasonally influenced by water transport from the Java Sea and from the Indian Ocean. The satellite data show that water transport from the Java Sea occurs during the pre-dominantly easterly winds period (June to September). This is characterized by warm water (SST higher than 29.5°C) and chlorophyll concentrations higher than 0.5 mg/ m3. This water transport influences the fish abundance in the Sunda Strait. High fish catches coincide with the presence of Java Sea water, while the surface currents lead to the migration of

THE POTENTIAL IMPACTS OF CLIMATE CHANGE ON THE MID-ATLANTIC COASTAL REGION

EPA Science Inventory

This paper assesses the potential impacts of climate change on the mid-Atlantic coastal (MAC) region of the United States. In order of increasing uncertainty, it is projected that sea level, temperature and streamflow will increase in the MAC region in response to higher levels o...

Quantifying the Influence of Urbanization on a Coastal Floodplain

NASA Astrophysics Data System (ADS)

Sebastian, A.; Juan, A.; Bedient, P. B.

2016-12-01

The U.S. Gulf Coast is the fastest growing region in the United States; between 1960 and 2010, the number of housing units along the Gulf of Mexico increased by 246%, vastly outpacing growth in other parts of the country (NOAA 2013). Numerous studies have shown that increases in impervious surface associated with urbanization reduce infiltration and increase surface runoff. While empirical evidence suggests that changes in land use are leading to increased flood damage in overland areas, earlier studies have largely focused on the impacts of urbanization on surface runoff and watershed hydrology, rather than quantifying its influence on the spatial extent of flooding. In this study, we conduct a longitudinal assessment of the evolution of flood risk since 1970 in an urbanizing coastal watershed. Utilizing the distributed hydrologic model, Vflo®, in combination with the hydraulic model, HEC-RAS, we quantify the impact of localized land use/land cover (LULC) change on the spatial extent of flooding in the watershed and the underlying flood hazard structure. The results demonstrate that increases in impervious cover between 1970 and 2010 (34%) and 2010 and 2040 (18%) increase the size of the floodplain by 26 and 17%, respectively. Furthermore, the results indicate that the depth and frequency of flooding in neighborhoods within the 1% floodplain have increased substantially (see attached figure). Finally, this analysis provides evidence that outdated FEMA floodplain maps could be underestimating the extent of the floodplain by upwards of 25%, depending on the rate of urbanization in the watershed; and, that by incorporating physics-based distributed hydrologic models into floodplain studies, floodplain maps can be easily updated to reflect the most recent LULC information available. The methods presented in this study have important implications for the development of mitigation strategies in coastal areas, such as deterring future development in flood prone areas

Organic Carbon and Trace Element Cycling in a River-Dominated Tidal Coastal Wetland System (Tampa Bay, FL, USA)

NASA Astrophysics Data System (ADS)

Moyer, R. P.; Smoak, J. M.; Engelhart, S. E.; Powell, C. E.; Chappel, A. R.; Gerlach, M. J.; Kemp, A.; Breithaupt, J. L.

2016-02-01

Tampa Bay is the largest open water, river-fed estuary in Florida (USA), and is characterized by the presence of both mangrove and salt marsh ecosystems. Both coastal wetland systems, and small rivers such as the ones draining into Tampa Bay have historically been underestimated in terms of their role in the global carbon and elemental cycles. Climate change and sea-level rise (SLR) are major threats in Tampa Bay and stand to disrupt hydrologic cycles, compromising sediment accumulation and the rate of organic carbon (OC) burial. This study evaluates organic carbon content, sediment accumulation, and carbon burial rates in salt marsh and mangrove ecosystems, along with measurements of fluxes of dissolved OC (DOC) and trace elements in the water column of the Little Manatee River (LMR) in Tampa Bay. The characterization of OC and trace elements in tidal rivers and estuaries is critical for quantitatively constraining these systems in local-to-regional scale biogeochemical budgets, and provide insight into biogeochemical processes occurring with the estuary and adjacent tidal wetlands. Material fluxes of DOC and trace elements were tied to discharge irrespective of season, and the estuarine habitats removed 15-65% of DOC prior to export to Tampa Bay and the Gulf of Mexico. Thus, material is available for cycling and burial within marsh and mangrove peats, however, LMR mangrove peats have higher OC content and burial rates than adjacent salt marsh peats. Sedimentary accretion rates in LMR marshes are not currently keeping pace with SLR, thus furthering the rapid marsh-to-mangrove conversions that have been seen in Tampa Bay over the past half-century. Additionally, wetlands in Tampa Bay tend to have a lower rate of carbon burial than other Florida tidal wetlands, demonstrating their high sensitivity to climate change and SLR.

Metacommunity theory as a multispecies, multiscale framework for studying the influence of river network structure on riverine communities and ecosystems

USGS Publications Warehouse

Brown, B.L.; Swan, C.M.; Auerbach, D.A.; Campbell, Grant E.H.; Hitt, N.P.; Maloney, K.O.; Patrick, C.

2011-01-01

Explaining the mechanisms underlying patterns of species diversity and composition in riverine networks is challenging. Historically, community ecologists have conceived of communities as largely isolated entities and have focused on local environmental factors and interspecific interactions as the major forces determining species composition. However, stream ecologists have long embraced a multiscale approach to studying riverine ecosystems and have studied both local factors and larger-scale regional factors, such as dispersal and disturbance. River networks exhibit a dendritic spatial structure that can constrain aquatic organisms when their dispersal is influenced by or confined to the river network. We contend that the principles of metacommunity theory would help stream ecologists to understand how the complex spatial structure of river networks mediates the relative influences of local and regional control on species composition. From a basic ecological perspective, the concept is attractive because new evidence suggests that the importance of regional processes (dispersal) depends on spatial structure of habitat and on connection to the regional species pool. The role of local factors relative to regional factors will vary with spatial position in a river network. From an applied perspective, the long-standing view in ecology that local community composition is an indicator of habitat quality may not be uniformly applicable across a river network, but the strength of such bioassessment approaches probably will depend on spatial position in the network. The principles of metacommunity theory are broadly applicable across taxa and systems but seem of particular consequence to stream ecology given the unique spatial structure of riverine systems. By explicitly embracing processes at multiple spatial scales, metacommunity theory provides a foundation on which to build a richer understanding of stream communities.

Hawaii Regional Sediment Management: Regional Sediment Budget for the Kekaha Region of Kauai, HI

DTIC Science & Technology

2013-06-01

Waimea River . Some sediment passes from the Waimea cell to the west and is deposited in the Kikiaola Harbor entrance channel and basin . Upland... study regions, have been developed by the University of Hawaii Coastal Geology Group (UH CGG) (Fletcher et al. 2012) for the US Geological Survey... Study (WIS) (Hubertz 1992) hindcast dataset were used as input to the model STeady WAVE (STWAVE) (Smith et al. 2001). The model output provides

Effects of olive oil wastes on river basins and an oligotrophic coastal marine ecosystem: a case study in Greece.

PubMed

Pavlidou, A; Anastasopoulou, E; Dassenakis, Μ; Hatzianestis, I; Paraskevopoulou, V; Simboura, N; Rousselaki, E; Drakopoulou, P

2014-11-01

This work aims to contribute to the knowledge of the impacts of olive oil waste discharge to freshwater and oligotrophic marine environments, since the ecological impact of olive oil wastes in riverine and coastal marine ecosystems, which are the final repositories of the pollutants, is a great environmental problem on a global scale, mostly concerning all the Mediterranean countries with olive oil production. Messinia, in southwestern Greece, is one of the greatest olive oil production areas in Europe. During the last decade around 1.4×10(6)tons of olive oil mill wastewater has been disposed in the rivers of Messinia and finally entered the marine ecosystem of Messiniakos gulf. The pollution from olive oil mill wastewater in the main rivers of Messinia and the oligotrophic coastal zone of Messiniakos gulf and its effects on marine organisms were evaluated, before, during and after the olive oil production period. Elevated amounts of phenols (36.2-178 mg L(-1)) and high concentrations of ammonium (7.29-18.9 mmol L(-1)) and inorganic phosphorus (0.5-7.48 mmol L(-1)) were measured in small streams where the liquid disposals from several olive oil industries were gathered before their discharge in the major rivers of Messinia. The large number of olive oil units has downgraded the riverine and marine ecosystems during the productive period and a period more than five months is needed for the recovery of the ecosystem. Statistical analysis showed that the enrichment of freshwater and the coastal zone of Messiniakos gulf in ammonia, nitrite, phenols, total organic carbon, copper, manganese and nickel was directly correlated with the wastes from olive oil. Toxicity tests using 24h LC50 Palaemonidae shrimp confirm that olive mill wastewater possesses very high toxicity in the aquatic environment. Copyright © 2014 Elsevier B.V. All rights reserved.

Po River plume and Northern Adriatic Dense Waters: a modeling and statistical approach.

NASA Astrophysics Data System (ADS)

Marcello Falcieri, Francesco; Benetazzo, Alvise; Sclavo, Mauro; Carniel, Sandro; Bergamasco, Andrea; Bonaldo, Davide; Barbariol, Francesco; Russo, Aniello

2014-05-01

The semi enclosed Adriatic Sea, located in the North-Eastern part of the Mediterranean Sea, is a small regional sea strongly influenced by riverine inputs. In its northern shallow sub-basin both the physical and biogeochemical features are strongly influenced by the Po River (together with some other minor ones) through its freshwater plume, by buoyancy changes and nutrients and sediments loads. The major outcomes of this interaction are on primary production, on the rising of hypoxic and anoxic bottom water conditions, on the formation of strong salinity gradients (that influence the water column structure and both coastal and basinwide circulation) and on the formation processes of the Northern Adriatic Dense Water (NAdDW). The NAdDW is a dense water mass that is formed during winter in the shallow Northern Adriatic under buoyancy loss conditions; it then travels southwardly along the Italian coasts reaching the Southern Adriatic after a few months. The NAdDW formation process is mostly locally wind driven but it has been proved that freshwater discharges play an important preconditioning role, starting since the summer previous to the formation period. To investigate the relationship between the Po plume (as a preconditioning factor) and the subsequent dense water formation, the results obtained by a numerical simulation with the Regional Ocean Modelling System (ROMS) have been statistically analyzed. The model has been implemented over the whole basin with a 2 km regular grid, and surface fluxes computed through a bulk fluxes formulation using an high resolution meteorological model (COSMO I7). The only open boundary (the Otranto Strait) is imposed from an operational Mediterranean model (MFS) and main rivers discharges are introduced as a freshwater mass fluxes measured by river gauges closest to the rivers' mouths. The model was run for 8 years, from 2003 to 2010. The Po plume was analysed with a 2x3 Self-Organizing Map (SOM) and two major antithetic patterns

International Trade, Pollution Accumulation and Sustainable Growth: A VAR Estimation from the Pearl River Delta Region

NASA Astrophysics Data System (ADS)

Zuo, Hui; Tian, Lu

2018-03-01

In order to investigate international trade influence in the regional environment. This paper constructs a vector auto-regression (VAR) model and estimates the equations with the environment and trade data of the Pearl River Delta Region. The major mechanisms to the lag are discussed and the fit simulation of the environmental change by the international impulse is given. The result shows that impulse of pollution-intensive export deteriorates the environment continuously and impulse of such import improves it. These effects on the environment are insignificantly correlated with contemporary regional income but significantly correlative to early-stage trade feature. To a typical trade-dependent economy, both export and import have hysteresis influence in the regional environment. The lagged impulse will change environmental development in the turning point, maximal pollution level and convergence.

Factors influencing bank geomorphology and erosion of the Haw River, a high order river in North Carolina, since European settlement.

PubMed

Macfall, Janet; Robinette, Paul; Welch, David

2014-01-01

The Haw River, a high order river in the southeastern United States, is characterized by severe bank erosion and geomorphic change from historical conditions of clear waters and connected floodplains. In 2014 it was named one of the 10 most threatened rivers in the United States by American Rivers. Like many developed areas, the region has a history of disturbance including extensive upland soil loss from agriculture, dams, and upstream urbanization. The primary objective of this study was to identify the mechanisms controlling channel form and erosion of the Haw River. Field measurements including bank height, bankfull height, bank angle, root depth and density, riparian land cover and slope, surface protection, river width, and bank retreat were collected at 87 sites along 43.5 km of river. A Bank Erosion Hazard Index (BEHI) was calculated for each study site. Mean bank height was 11.8 m, mean width was 84.3 m, and bank retreat for 2005/2007-2011/2013 was 2.3 m. The greatest bank heights, BEHI values, and bank retreat were adjacent to riparian areas with low slope (<2). This is in contrast to previous studies which identify high slope as a risk factor for erosion. Most of the soils in low slope riparian areas were alluvial, suggesting sediment deposition from upland row crop agriculture and/or flooding. Bank retreat was not correlated to bank heights or BEHI values. Historical dams (1.2-3 m height) were not a significant factor. Erosion of the Haw River in the study section of the river (25% of the river length) contributed 205,320 m3 of sediment and 3759 kg of P annually. Concentration of suspended solids in the river increased with discharge. In conclusion, the Haw River is an unstable system, with river bank erosion and geomodification potential influenced by riparian slope and varied flows.

Factors Influencing Bank Geomorphology and Erosion of the Haw River, a High Order River in North Carolina, since European Settlement

PubMed Central

Macfall, Janet; Robinette, Paul; Welch, David

2014-01-01

The Haw River, a high order river in the southeastern United States, is characterized by severe bank erosion and geomorphic change from historical conditions of clear waters and connected floodplains. In 2014 it was named one of the 10 most threatened rivers in the United States by American Rivers. Like many developed areas, the region has a history of disturbance including extensive upland soil loss from agriculture, dams, and upstream urbanization. The primary objective of this study was to identify the mechanisms controlling channel form and erosion of the Haw River. Field measurements including bank height, bankfull height, bank angle, root depth and density, riparian land cover and slope, surface protection, river width, and bank retreat were collected at 87 sites along 43.5 km of river. A Bank Erosion Hazard Index (BEHI) was calculated for each study site. Mean bank height was 11.8 m, mean width was 84.3 m, and bank retreat for 2005/2007-2011/2013 was 2.3 m. The greatest bank heights, BEHI values, and bank retreat were adjacent to riparian areas with low slope (<2). This is in contrast to previous studies which identify high slope as a risk factor for erosion. Most of the soils in low slope riparian areas were alluvial, suggesting sediment deposition from upland row crop agriculture and/or flooding. Bank retreat was not correlated to bank heights or BEHI values. Historical dams (1.2–3 m height) were not a significant factor. Erosion of the Haw River in the study section of the river (25% of the river length) contributed 205,320 m3 of sediment and 3759 kg of P annually. Concentration of suspended solids in the river increased with discharge. In conclusion, the Haw River is an unstable system, with river bank erosion and geomodification potential influenced by riparian slope and varied flows. PMID:25302956

The Fall River Long-Term Site Productivity study in coastal Washington: site characteristics, methods, and biomass and carbon and nitrogen stores before and after harvest.

Treesearch

Adrian Ares; Thomas A. Terry; Kathryn B. Piatek; Robert B. Harrison; Richard E. Miller; Barry L. Flaming; ChristopherW Licata; Brian D. Strahm; Constance A. Harrington; Rodney Meade; Harry W. Anderson; Leslie C. Brodie; Joseph M. Kraft

2007-01-01

The Fall River research site in coastal Washington is an affiliate installation of the North American Long-Term Soil Productivity (LTSP) network, which constitutes one of the world’s largest coordinated research programs addressing forest management impacts on sustained productivity. Overall goals of the Fall River study are to assess effects of biomass removals, soil...

Mercury in tropical and subtropical coastal environments

PubMed Central

Costa, Monica F.; Landing, William M.; Kehrig, Helena A.; Barletta, Mário; Holmes, Christopher D.; Barrocas, Paulo R. G.; Evers, David C.; Buck, David G.; Vasconcellos, Ana Claudia; Hacon, Sandra S.; Moreira, Josino C.; Malm, Olaf

2012-01-01