A5072448596- Soil and Water Nutrient Dynamics
- Hydrology and Watershed Management Studies
- Water Quality and Resources Studies
- Fish Ecology and Management Studies
- Smart Materials for Construction
- Groundwater flow and contamination studies
- Groundwater and Isotope Geochemistry
- Soil erosion and sediment transport
- Cryospheric studies and observations
- Icing and De-icing Technologies
- Water Quality Monitoring Technologies
- Coastal wetland ecosystem dynamics
- Urban Stormwater Management Solutions
- Water Quality Monitoring and Analysis
- Marine and fisheries research
- Ecology and biodiversity studies
- Peatlands and Wetlands Ecology
- Climate change and permafrost
- Marine and coastal ecosystems
- Freshwater macroinvertebrate diversity and ecology
- Radioactive contamination and transfer
- Water Quality and Pollution Assessment
- Hydrology and Sediment Transport Processes
United States Geological Survey
2013-2024
District of Columbia Water and Sewer Authority
2019-2024
University of Vienna
2020
Entertainment Industries Council
2018
Abstract This review aims to synthesize the current knowledge of sediment dynamics using insights from long‐term research conducted in watershed draining Chesapeake Bay, largest estuary U.S., inform management actions restore and its watershed. The are typical many impaired watersheds estuaries around world, this synthesis is intended be relevant transferable other sediment‐impaired systems. watershed's sources, transport, delivery, impacts discussed with implications for effectively...
Increasing specific conductance (SC) and chloride concentrations [Cl] negatively affect many stream ecosystems. We characterized spatial variability in SC, [Cl], exceedances of Environmental Protection Agency criteria using nearly 30 million high-frequency observations (2–15 min intervals) for SC modeled from 93 sites across three regions the eastern United States: Southeast, Mid-Atlantic, New England. increase substantially south to north within with impervious surface cover (ISC). In...
Abstract Understanding trends in stream chemistry is critical to watershed management, and often complicated by multiple contaminant sources landscape conditions changing over varying time scales. We adapted spatially referenced regression (SPARROW) infer causes of recent nutrient Chesapeake Bay tributaries relating observed fluxes during 1992, 2002, 2012 contemporary inputs conditions. The annual flow‐normalized nitrogen flux the bay from its declined 14% 127,000 Mg (metric tons) between...
Recent and ongoing innovations in SPAtially Referenced Regression On Watershed attributes (SPARROW) modeling provide improved representation of nutrient dynamics identify opportunities to optimize surface-water monitoring over large regional catchments. Efficient effective monitoring, management, restoration quality requires adequate understanding the upstream sources, fate, transport contaminants contributing For nutrients, such is often confounded by multiple nitrogen phosphorus sources...
Causal attribution of changes in water quality often consists correlation, qualitative reasoning, listing references to the work others, or speculation. To better support statements for water-quality trends, structural equation modeling was used model causal factors total phosphorus loads Chesapeake Bay watershed. By transforming, scaling, and standardizing variables, grouping similar sites, some into latent variable models, using methods that correct assumption violations, we developed a...
Abstract Understanding effects of climate change on nitrogen fate and transport in the environment is critical to nutrient management. We used projections within a previously calibrated spatially referenced regression (SPARROW) model predict expected over 1995 through 2025 total fluxes Chesapeake Bay watershed streams. Assuming inputs other conditions remain at 2012 levels, increasing temperature, runoff, streamflow, stream velocity between will include an estimated net 6.5% decline annual...
First posted November 10, 2021 For additional information, contact: Director, Pennsylvania Water Science CenterU.S. Geological Survey215 Limekiln RoadNew Cumberland, PA 17070 Sustaining the quality of Nation's water resources and health our diverse ecosystems depends on availability sound water-resources data information to develop effective, science-based policies. Effective management also brings more certainty efficiency important economic sectors. Taken together, these actions lead...
First posted August 9, 2018 For additional information, contact: Director, MD-DE-DC Water Science CenterU.S. Geological Survey5522 Research Park DriveBaltimore, MD 21228 Understanding changing nutrient concentrations in surface waters requires quantitative information on sources contributing watersheds. example, the proportion of inputs reaching streams and rivers is directly affected by when where those nutrients enter landscape. The goal this report to contribute U.S. Survey's efforts...
First posted April 10, 2019 For additional information, contact: Director, MD-DE-DC Water Science CenterU.S. Geological Survey5522 Research Park DriveBaltimore, MD 21228 Efforts to restore water quality in Chesapeake Bay and its tributaries often include extensive Best Management Practice (BMP) implementation on agricultural developed lands. These BMPs a variety of methods reduce nutrient sediment loads, such as cover crops, conservation tillage, urban filtering systems, other...
Stream water-quality and its drivers vary across time space, but we only monitor a small fraction of streams consistently over long periods time. Such limited monitoring necessitates the development application spatially explicit dynamic models to predict water quality at unmonitored locations. Historically, data computational limitations have hindered temporally variable prediction efforts large spatial scales. However, hybrid statistical process models, such as Spatially Referenced...
Quantifying nutrient sources in streams, their temporal and spatial variability, drivers of that variability can support effective water resources management. Yet a lack data modeling capabilities has previously prevented comprehensive quantification across both space time. Here dynamic SPARROW (Spatially Referenced Regressions on Watershed attributes) model accounts for lagged delivery nutrients to streams was developed applied simulate seasonal source-specific total nitrogen (TN)...
Spatial data provided by the U.S. Department of Agriculture National Resource Conservation Service representing implementation at field-level for a selection agricultural conservation practices were incorporated within spatially referenced regression model to estimate their effects on nitrogen loads in streams Chesapeake Bay watershed. classified as “high-impact” estimated be effective ( p = 0.017) reducing contemporary watershed areas where groundwater ages are less than 14-years old....
To assist in understanding sediment loadings and the management of water resources, a bathymetric survey was conducted part Lake Linganore between Boyers Mill Road Bridge Bens Branch Frederick County, Maryland. The performed January 2012 by U.S. Geological Survey, cooperation with City County. A separate, but related, field effort to collect 18 cores March April 2012. Depth location data from for were compiled edited using geographic information system (GIS) software. three-dimensional...
Nitrogen from nonpoint sources contributes to eutrophication, hypoxia, and related ecological degradation in Atlantic Coastal Plain streams adjacent coastal estuaries such as Chesapeake Bay Pamlico Sound. Although denitrification depressional (non-riparian) wetlands common the can be a significant landscape sink for nitrogen, effectiveness of individual at removing nitrogen varies substantially due varying hydrogeologic, geochemical, other conditions, which are often poorly or inconsistently...
To assist in understanding sediment and phosphorus loadings the management of water resources, a bathymetric survey was conducted at Lake Linganore Frederick County, Maryland June 2009 by U.S. Geological Survey, cooperation with City Maryland. Position data water-depth were collected using grade echo sounder differentially corrected global positioning system. Data compiled edited geographic information system software. A three-dimensional triangulated irregular network model lake bottom...
Elevated conductivity (i.e., specific conductance or SC) causes osmotic stress in freshwater aquatic organisms and may increase the toxicity of some contaminants. Indices benthic macroinvertebrate integrity have declined urban areas across Chesapeake Bay watershed (CBW), more information is needed about whether these declines be due to elevated conductivity. A predictive SC model for CBW was developed using monitoring data from National Water Quality Portal. Predictor variables representing...
This dataset contains estimates of the yearly sum nitrogen and phosphorus inputs from fertilizer applications manure in Chesapeake Bay watershed 1950 to 2012. For data, county -level loads were used three published sources. Data for 1985 are Alexander Smith (1990). year 1986 Battaglin Goolsby (1995). 1987 through 2012 Brakebill, Gronberg, Spahr (2016). These data conjunction with 30-meter resolution land cover National Land Cover Dataset 2001 distribute county-level cropland summed selected...
Hydrogeologic regions in the fractured rock area of Maryland were classified using geographic information system tools with principal components and cluster analyses. A study consisting 8-digit Hydrologic Unit Code (HUC) watersheds rivers that flow through bounded by Fall Line was further subdivided into 21,431 catchments from National Hydrography Dataset Plus. The then used as a common hydrologic unit to compile relevant climatic, topographic, geologic variables. analysis performed on 10...
Abstract The salinity of inland freshwaters is rising globally, particularly in human dominated landscapes that receive deicers the winter. Here we show salinization an urban stream Northern Virginia (USA) can be linked to salt sources using water age as a master variable. Younger associated with either low rain or high snow melt, while older geology-specific groundwater salinity. Long-term deicer use increases over time, transforming acute melt problem into chronic problem. Framing...