Skip to main content
U.S. flag

An official website of the United States government

Alexander Soroka

Alex Soroka is a Physical Scientist and has been with the U.S. Geological Survey since 2016, currently working at the MD-DE-DC Water Science Center in the Baltimore office.

Alex's research interests include surface and groundwater quality and quantity in rural and urban areas.  He serves as a researcher studying the transport of critical nutrients in nontidal waterways. He is also a project coordinator for Chesapeake Bay science, helping align USGS research with partner priorities.  

Professional Experience

  • (2018-Present) Physical Scientist, USGS MD-DE-DC Water Science Center, MD

  • (2016-2017) Pathways Physical Scientist Intern, USGS Dover office, DE

Education and Certifications

  • MS - Water Science and Policy, University of Delaware - 2016

    Thesis:  Effects of In-Season Fertilizer Strategies on the Yield and Nitrogen Use Efficiency of Irrigated Corn

  • BS - Environmental Science, State University of New York at Oneota - 2012

Science and Products

Multiyear crop residue cover mapping using narrow-band vs. broad-band shortwave infrared satellite imagery Multiyear crop residue cover mapping using narrow-band vs. broad-band shortwave infrared satellite imagery

Crop residue serves an important role in agricultural systems as high levels of fractional crop residue cover (fR) can reduce erosion, preserve soil moisture, and build soil organic carbon. However, the ability to accurately quantify fR at scale has been limited. In this study we produced annual maps of fR for farmland in Maryland, USA using WorldView-3 (WV3) imagery paired with on-farm
Authors
Brian T. Lamb, W. Dean Hively, Jyoti Jennewein, Alison Thieme, Alexander M. Soroka, Leticia Santos, Daniela Jones, Steven Mirsky
By
Maryland-Delaware-D.C. Water Science Center, Lower Mississippi-Gulf Water Science Center

Comparison of water quality in shallow groundwater near agricultural areas in the Delaware Coastal Plain, 2014 and 2019 Comparison of water quality in shallow groundwater near agricultural areas in the Delaware Coastal Plain, 2014 and 2019

The State of Delaware has encouraged agricultural conservation practices to improve nutrient uptake by crops and mitigate nutrient transport to groundwater in the surficial aquifer. To study recent changes in groundwater quality, the U.S. Geological Survey and the Delaware Department of Agriculture (DDA) developed a network of shallow wells near agricultural areas throughout the Delaware...
Authors
Alexander M. Soroka, Betzaida Reyes, Brandon J. Fleming, Michael Brownley
By
Maryland-Delaware-D.C. Water Science Center

Atmospheric correction intercomparison of hyperspectral and multispectral imagery over agricultural study sites Atmospheric correction intercomparison of hyperspectral and multispectral imagery over agricultural study sites

In this research effort we assess the performance of atmospheric correction-based surface reflectance (SR) retrievals from two satellite image sources, one with very high spatial resolution (VHR) (
Authors
Brian T. Lamb, W. Dean Hively, Jyoti Jennewein, Alison Thieme, Alexander M. Soroka
By
Lower Mississippi-Gulf Water Science Center

Your land, your water—Using research to guide conservation practices on local farms in the Chesapeake Bay watershed Your land, your water—Using research to guide conservation practices on local farms in the Chesapeake Bay watershed

Agricultural lands are an important part of the economy and heritage of the Chesapeake Bay watershed and are a focus of conservation activities. Streams and rivers around farms provide communities with drinking water and recreational opportunities, but these local benefits can be impaired by elevated nutrient and sediment concentrations. Compared to inputs from the atmosphere, wastewater...
Authors
James S. Webber, John W. Clune, Alexander M. Soroka, Kenneth Hyer
By
Water Resources Mission Area, Chesapeake Bay Activities, Maryland-Delaware-D.C. Water Science Center, Pennsylvania Water Science Center, Virginia and West Virginia Water Science Center

Hydrogeologic characterization of Area B, Fort Detrick, Maryland Hydrogeologic characterization of Area B, Fort Detrick, Maryland

Groundwater in the karst groundwater system at Area B of Fort Detrick in Frederick County, Maryland, is contaminated with chlorinated solvents from the past disposal of laboratory wastes. In cooperation with U.S. Army Environmental Command and U.S. Army Garrison Fort Detrick, the U.S. Geological Survey performed a 3-year study to refine the conceptual model of groundwater flow in and...
Authors
Phillip J. Goodling, Brandon J. Fleming, John Solder, Alexander M. Soroka, Jeff P. Raffensperger
By
Maryland-Delaware-D.C. Water Science Center

Near real-time detection of winter cover crop termination using harmonized Landsat and Sentinel-2 (HLS) to support ecosystem assessment Near real-time detection of winter cover crop termination using harmonized Landsat and Sentinel-2 (HLS) to support ecosystem assessment

Cover crops are planted to reduce soil erosion, increase soil fertility, and improve watershed management. In the Delmarva Peninsula of the eastern United States, winter cover crops are essential for reducing nutrient and sediment losses from farmland. Cost-share programs have been created to incentivize cover crops to achieve conservation objectives. This program required that cover...
Authors
Feng Gao, Jyoti Jennewein, W. Dean Hively, Alexander M. Soroka, Alison Thieme, Dawn Bradley, Jason Keppler, Steven Mirsky, Uvirkaa Akumaga
By
Maryland-Delaware-D.C. Water Science Center, Lower Mississippi-Gulf Water Science Center

Spatial patterns and seasonal timing of increasing riverine specific conductance from 1998 to 2018 suggest legacy contamination in the Delaware River Basin Spatial patterns and seasonal timing of increasing riverine specific conductance from 1998 to 2018 suggest legacy contamination in the Delaware River Basin

Increasing salinization of freshwater threatens water supplies that support a range of human and ecological uses. The latest assessments of Delaware River Basin (DRB) surface-water-quality changes indicate widespread salinization has occurred in recent decades, which may lead to meaningful degradation in water quality. To better understand how and when salinity transport occurs and...
Authors
Christine Rumsey, John C. Hammond, Jennifer C. Murphy, Megan E. Shoda, Alexander M. Soroka
By
Water Resources Mission Area, Maryland-Delaware-D.C. Water Science Center, Utah Water Science Center, Central Midwest Water Science Center

Remote sensing evaluation of winter cover crop springtime performance and the impact of delayed termination Remote sensing evaluation of winter cover crop springtime performance and the impact of delayed termination

In 2019, the Maryland Department of Agriculture's Winter Cover Crop Program introduced a delayed termination incentive (after May 1) to promote springtime biomass accumulation. We used satellite imagery calibrated with springtime in situ measurements collected from 2006–2021 (n = 722) to derive biomass estimates for Maryland fields planted to cereal cover crop species (286,200 ha total...
Authors
Alison Thieme, W. Dean Hively, Feng Gao, Jyoti Jennewein, Steven Mirsky, Alexander M. Soroka, Jason Keppler, Dawn Bradley, Sergii Skakun, Gregory W. McCarty
By
Lower Mississippi-Gulf Water Science Center

Nitrogen in the Chesapeake Bay watershed—A century of change, 1950–2050 Nitrogen in the Chesapeake Bay watershed—A century of change, 1950–2050

Foreword Sustaining the quality of the Nation’s water resources and the health of our diverse ecosystems depends on the availability of sound water-resources data and information to develop effective, science-based policies. Effective management of water resources also brings more certainty and efficiency to important economic sectors. Taken together, these actions lead to immediate and...
Authors
John W. Clune, Paul D. Capel, Matthew P. Miller, Douglas A. Burns, Andrew J. Sekellick, Peter R. Claggett, Richard H. Coupe, Rosemary M. Fanelli, Ana Maria Garcia, Jeff P. Raffensperger, Silvia Terziotti, Gopal Bhatt, Joel D. Blomquist, Kristina G. Hopkins, Jennifer L. Keisman, Lewis C. Linker, Gary W. Shenk, Richard A. Smith, Alexander M. Soroka, James S. Webber, David M. Wolock, Qian Zhang
By
Water Resources Mission Area, Chesapeake Bay Activities, Maryland-Delaware-D.C. Water Science Center, New York Water Science Center, Pennsylvania Water Science Center, South Atlantic Water Science Center (SAWSC), Utah Water Science Center, Virginia and West Virginia Water Science Center

Estimating the effect of winter cover crops on nitrogen leaching using cost-share enrollment data, satellite remote sensing, and Soil and Water Assessment Tool (SWAT) modeling Estimating the effect of winter cover crops on nitrogen leaching using cost-share enrollment data, satellite remote sensing, and Soil and Water Assessment Tool (SWAT) modeling

This study employed a novel combination of data (winter cover crop cost-share enrollment records, satellite remote sensing of wintertime vegetation, and results of Soil and Water Assessment Tool (SWAT) water quality simulations) to estimate the environmental performance of winter cover crops (WCC) at the watershed scale, from 2008 through 2017, within the Tuckahoe sub-watershed of the...
Authors
W. Dean Hively, Sangchul Lee, Ali M. Sadeghi, Gregory W. McCarty, Brian T. Lamb, Alexander M. Soroka, Jason Keppler, In-Young Yeo, Glenn E. Moglen
By
Lower Mississippi-Gulf Water Science Center

Monitoring the water-quality response of agricultural conservation practices in the Bucks Branch watershed, Sussex County, Delaware, 2014–16 Monitoring the water-quality response of agricultural conservation practices in the Bucks Branch watershed, Sussex County, Delaware, 2014–16

The purpose of this study was to evaluate the effects of irrigation and cover crops as conservation practices on water quality in groundwater and streams. Bucks Branch, a stream in the Nanticoke River watershed in southwestern Delaware, was identified as having one of the highest concentrations of nitrate in all surface-water sites sampled by the Delaware Department of Natural Resources...
Authors
Judith M. Denver, Alexander M. Soroka, Betzaida Reyes, Todd R. Lester, Deborah A. Bringman, M.S. Brownley
By
Water Resources Mission Area, Maryland-Delaware-D.C. Water Science Center
Hydrologic technician Fisseha Mengistu reels in a sampling bottle.

Informing Chesapeake Bay Watershed Management by Monitoring Trends in River Nutrient and Sediment Loads

The USGS has computed nutrient and suspended-sediment loads and trends through water year 2023 in Chesapeake Bay rivers. These monitoring-based estimates help federal, state, and local managers evaluate and plan water-quality restoration strategies.
By
Chesapeake Bay Activities, Maryland-Delaware-D.C. Water Science Center, Pennsylvania Water Science Center, Virginia and West Virginia Water Science Center
Informing Chesapeake Bay Watershed Management by Monitoring Trends in River Nutrient and Sediment Loads

Informing Chesapeake Bay Watershed Management by Monitoring Trends in River Nutrient and Sediment Loads

The USGS has computed nutrient and suspended-sediment loads and trends through water year 2023 in Chesapeake Bay rivers. These monitoring-based estimates help federal, state, and local managers evaluate and plan water-quality restoration strategies.
Learn More
Water flows out of a bioreactor through a white PVC pipe before splashing down into a small stream.

Monitoring the Effectiveness of Conservation Practices in Small Agricultural Watersheds

Farmers are an important part of the economy and heritage of the Chesapeake Bay. Farmers also act as stewards of the land and water. Across the Chesapeake Bay Watershed, members of the agricultural community are volunteering to adopt conservation practices on their land. The goal of these practices is to protect the health of the soil, local streams and rivers, and the Chesapeake Bay. These...
By
Chesapeake Bay Activities, Maryland-Delaware-D.C. Water Science Center, Pennsylvania Water Science Center, Virginia and West Virginia Water Science Center
Monitoring the Effectiveness of Conservation Practices in Small Agricultural Watersheds

Monitoring the Effectiveness of Conservation Practices in Small Agricultural Watersheds

Farmers are an important part of the economy and heritage of the Chesapeake Bay. Farmers also act as stewards of the land and water. Across the Chesapeake Bay Watershed, members of the agricultural community are volunteering to adopt conservation practices on their land. The goal of these practices is to protect the health of the soil, local streams and rivers, and the Chesapeake Bay. These...
Learn More
A round bluescale icon showing a trifold map of the chesapeake bay

Summarizing Science to Inform Management in the Chesapeake Bay Watershed

Stakeholders can use scientific insights to address their priority water-quality concerns. The USGS works with Chesapeake Bay stakeholders to identify and address priority questions that can help inform management decisions. These scientific insights can help guide nutrient and sediment management activities undertaken by Chesapeake Bay stakeholders. This webpage summarizes recent scientific...
By
Chesapeake Bay Activities, Virginia and West Virginia Water Science Center
Summarizing Science to Inform Management in the Chesapeake Bay Watershed

Summarizing Science to Inform Management in the Chesapeake Bay Watershed

Stakeholders can use scientific insights to address their priority water-quality concerns. The USGS works with Chesapeake Bay stakeholders to identify and address priority questions that can help inform management decisions. These scientific insights can help guide nutrient and sediment management activities undertaken by Chesapeake Bay stakeholders. This webpage summarizes recent scientific...
Learn More
A USGS technician samples the Rappahannock River from a suspended cable car.

Science to Inform Management Priorities from Loads to Endpoints (SIMPLE)

Resource managers are working to improve water-quality in the Chesapeake to benefit the people who live in the region and the birds, fish, and other animals who rely on clean water in the watershed and the Bay. The U.S Geological Survey (USGS) supports resource managers and other Chesapeake stakeholders by providing science that informs restoration and conservation in the Chesapeake region. The...
By
Chesapeake Bay Activities, Virginia and West Virginia Water Science Center
Science to Inform Management Priorities from Loads to Endpoints (SIMPLE)

Science to Inform Management Priorities from Loads to Endpoints (SIMPLE)

Resource managers are working to improve water-quality in the Chesapeake to benefit the people who live in the region and the birds, fish, and other animals who rely on clean water in the watershed and the Bay. The U.S Geological Survey (USGS) supports resource managers and other Chesapeake stakeholders by providing science that informs restoration and conservation in the Chesapeake region. The...
Learn More
Table of Trends in nitrogen, phosphorus, and suspended-sediment loads for RIM (2021)

USGS calculates loads and trends through 2021 for the nine major rivers entering Chesapeake Bay

Issue: The amount of nutrients and suspended sediment entering the Chesapeake Bay affect water-quality conditions in tidal waters. Excess nutrients contribute to algal blooms that lower the oxygen levels in tidal waters that are important for fish and shellfish. The algal blooms, along with suspended sediment, also decrease visibility in shallow waters for submerged aquatic grasses. The grasses...
By
Chesapeake Bay Activities, Maryland-Delaware-D.C. Water Science Center, Virginia and West Virginia Water Science Center
USGS calculates loads and trends through 2021 for the nine major rivers entering Chesapeake Bay

USGS calculates loads and trends through 2021 for the nine major rivers entering Chesapeake Bay

Issue: The amount of nutrients and suspended sediment entering the Chesapeake Bay affect water-quality conditions in tidal waters. Excess nutrients contribute to algal blooms that lower the oxygen levels in tidal waters that are important for fish and shellfish. The algal blooms, along with suspended sediment, also decrease visibility in shallow waters for submerged aquatic grasses. The grasses...
Learn More
Chesapeake Bay at Edgewater, MD

Summarizing Scientific Findings for Common Stakeholder Questions to Inform Nutrient and Sediment Management Activities in the Chesapeake Bay Watershed

Issue: The Chesapeake Bay Program (CBP) partnership is striving to improve water-quality conditions in the Bay by using a variety of management strategies to reduce nutrient and sediment loads. The partnership uses monitoring results and modeling tools to implement management strategies, relying on the scientific community to synthesize existing information and direct new research to address...
By
Chesapeake Bay Activities, Maryland-Delaware-D.C. Water Science Center, Pennsylvania Water Science Center, Virginia and West Virginia Water Science Center
Summarizing Scientific Findings for Common Stakeholder Questions to Inform Nutrient and Sediment Management Activities in the Chesapeake Bay Watershed

Summarizing Scientific Findings for Common Stakeholder Questions to Inform Nutrient and Sediment Management Activities in the Chesapeake Bay Watershed

Issue: The Chesapeake Bay Program (CBP) partnership is striving to improve water-quality conditions in the Bay by using a variety of management strategies to reduce nutrient and sediment loads. The partnership uses monitoring results and modeling tools to implement management strategies, relying on the scientific community to synthesize existing information and direct new research to address...
Learn More
Photograph of Pequea Creek, Pennsylvania

Updated 2020 Nutrient and Suspended-Sediment Trends for the Nine Major Rivers Entering the Chesapeake Bay

Issue: The amount of nutrients and suspended sediment entering the Chesapeake Bay affect water-quality conditions in tidal waters. Excess nutrients contribute to algal blooms that lower the oxygen levels in tidal waters that are important for fish and shellfish. The algal blooms, along with suspended sediment, also decrease visibility in shallow waters for submerged aquatic grasses. The grasses...
By
Core Science Systems Mission Area, Chesapeake Bay Activities, Virginia and West Virginia Water Science Center
Updated 2020 Nutrient and Suspended-Sediment Trends for the Nine Major Rivers Entering the Chesapeake Bay

Updated 2020 Nutrient and Suspended-Sediment Trends for the Nine Major Rivers Entering the Chesapeake Bay

Issue: The amount of nutrients and suspended sediment entering the Chesapeake Bay affect water-quality conditions in tidal waters. Excess nutrients contribute to algal blooms that lower the oxygen levels in tidal waters that are important for fish and shellfish. The algal blooms, along with suspended sediment, also decrease visibility in shallow waters for submerged aquatic grasses. The grasses...
Learn More
Filter Total Items: 13

Nitrogen, phosphorus, and suspended-sediment loads and trends measured at the Chesapeake Bay River Input Monitoring stations: Water years 1985-2022 Nitrogen, phosphorus, and suspended-sediment loads and trends measured at the Chesapeake Bay River Input Monitoring stations: Water years 1985-2022

Nitrogen, phosphorus, and suspended-sediment loads, and changes in loads, in major rivers across the Chesapeake Bay watershed have been calculated using monitoring data from the Chesapeake Bay River Input Monitoring (RIM) Network stations for the period 1985 through 2022. Nutrient and suspended-sediment loads and changes in loads were determined by applying a weighted regression approach...
By
Chesapeake Bay Activities, Virginia and West Virginia Water Science Center

Data supporting a spatiotemporal trend analysis of specific conductivity, streamflow, and landscape attributes of selected sub-basins within the Delaware River watershed, 1980 to 2018 Data supporting a spatiotemporal trend analysis of specific conductivity, streamflow, and landscape attributes of selected sub-basins within the Delaware River watershed, 1980 to 2018

This data release makes available three data tables supporting a spatiotemporal analysis of riverine conductivity and streamflow trends within the Delaware River Basin. The listed datasets include baseflow and total flow time series for selected gaged basins, watershed attributes, water quality information and trend analysis results.
By
Maryland-Delaware-D.C. Water Science Center

Soil-Water-Balance (SWB) model archive used to simulate water budget components in Pennsylvania and Maryland, 2000-2020 Soil-Water-Balance (SWB) model archive used to simulate water budget components in Pennsylvania and Maryland, 2000-2020

This model archive documents the Soil-Water-Balance (SWB) model used to simulate potential recharge for portions of Pennsylvania and Maryland from 2000 to 2021. The Pennsylvania and Maryland SWB model was used to create output at a 250 meter grid scale. Model parameters were adjusted using baseflow estimates from 36 reference watersheds varying in area from 0.37 to 817 square miles. The
By
Maryland-Delaware-D.C. Water Science Center

Possible Cattle Access Points on Select Streams within the Smith Creek Watershed Derived from 2018 NAIP Imagery Possible Cattle Access Points on Select Streams within the Smith Creek Watershed Derived from 2018 NAIP Imagery

This data release contains one shapefile describing cattle access to a total of 36 different sub basins within the Smith Creek Watershed located in Virginia and West Virginia. This data release identifies areas in satellite imagery where cattle were observed to have access to the stream (confirmed access), areas where cattle exist, and are not fenced off from the stream (unrestricted...
By
Maryland-Delaware-D.C. Water Science Center

Nitrogen, phosphorus, and suspended-sediment loads and trends measured at the Chesapeake Bay River Input Monitoring stations: Water years 1985-2021 Nitrogen, phosphorus, and suspended-sediment loads and trends measured at the Chesapeake Bay River Input Monitoring stations: Water years 1985-2021

Nitrogen, phosphorus, and suspended-sediment loads, and changes in loads, in major rivers across the Chesapeake Bay watershed have been calculated using monitoring data from the Chesapeake Bay River Input Monitoring (RIM) Network stations for the period 1985 through 2021. Nutrient and suspended-sediment loads and changes in loads were determined by applying a weighted regression approach...
By
Chesapeake Bay Activities, Virginia and West Virginia Water Science Center

Possible Cattle Access Points on Steams within the USGS Showcase Watersheds Derived from 2018 and 2019 NAIP Imagery Possible Cattle Access Points on Steams within the USGS Showcase Watersheds Derived from 2018 and 2019 NAIP Imagery

This data release contains one point shapefile describing cattle access to streams for three USGS showcase watersheds: Smith Creek, Conewago Creek, and Upper Chester River. This data release identifies areas where cattle were able to access the stream, as well as possible cattle access areas. Streams were defined using a combination of geospatial data and aerial imagery and cattle access...
By
Maryland-Delaware-D.C. Water Science Center

Nitrogen, phosphorus, and suspended-sediment loads and trends measured at the Chesapeake Bay River Input Monitoring stations: Water years 1985-2020 Nitrogen, phosphorus, and suspended-sediment loads and trends measured at the Chesapeake Bay River Input Monitoring stations: Water years 1985-2020

Nitrogen, phosphorus, and suspended-sediment loads, and changes in loads, in major rivers across the Chesapeake Bay watershed have been calculated using monitoring data from the Chesapeake Bay River Input Monitoring (RIM) Network stations for the period 1985 through 2020. Nutrient and suspended-sediment loads and changes in loads were determined by applying a weighted regression approach...
By
Chesapeake Bay Activities, Virginia and West Virginia Water Science Center

Nitrogen flux estimates in support of Chesapeake Bay Hypoxia and Anoxia forecasts, 1985-2021 Nitrogen flux estimates in support of Chesapeake Bay Hypoxia and Anoxia forecasts, 1985-2021

Data release includes the U.S. Geological Survey (USGS) estimate of spring nitrogen fluxes summed from nine tributaries to the Chesapeake Bay from 1985 to 2021. Data are presented as the sum from tributaries within the USGS River Input Monitoring (RIM) network identified by site numbers: 01491000, 01578310, 01594440, 01646580, 01668000, 01673000, 01674500, 02035000, 02041650. Periods of...
By
Chesapeake Bay Activities, Maryland-Delaware-D.C. Water Science Center

Water bodies within 500 meters of poultry feeding operations on the Delmarva Peninsula in 2016 and 2017 Water bodies within 500 meters of poultry feeding operations on the Delmarva Peninsula in 2016 and 2017

Data release contains 1710 polygons representing small bodies of water within 500 meters of poultry feeding operations on the Delmarva Peninsula. Ponds were identified using the USDA's National Agriculture Imagery Program's 2016 and 2017 products. Poultry feeding operations were described in location by Soroka and Duren (2020).
By
Maryland-Delaware-D.C. Water Science Center

Nitrogen flux estimates in support of Chesapeake Bay Hypoxia and Anoxia forecasts, 1985-2020 Nitrogen flux estimates in support of Chesapeake Bay Hypoxia and Anoxia forecasts, 1985-2020

Data release includes the U.S. Geological Survey (USGS) estimate of spring nitrogen fluxes from nine tributaries to the Chesapeake Bay from 1985 to 2020. Data are presented from tributaries within the USGS River Input Monitoring (RIM) network identified by site numbers: 01491000, 01578310, 01594440, 01646580, 01668000, 01673000, 01674500, 02035000, 02041650. Periods of estimation include...
By
Chesapeake Bay Activities, Maryland-Delaware-D.C. Water Science Center

Poultry Feeding Operations on the Delaware, Maryland, and Virginia Peninsula from 2016 to 2017 Poultry Feeding Operations on the Delaware, Maryland, and Virginia Peninsula from 2016 to 2017

Data release contains two shapefiles related to poultry houses on the Delmarva Peninsula (Delaware, Eastern Shore Maryland and, Eastern Shore Virginia). One dataset is a polygon shapefile representing 5747 poultry houses identified using 2016 and 2017 aerial imagery from the U.S. Department of Agricultures National Aerial Imagery Program (NAIP). The second dataset is a point shapefile of
By
Chesapeake Bay Activities, Maryland-Delaware-D.C. Water Science Center

Poultry production houses in the Upper Choptank watershed identified using aerial imagery from 1968 to 2018 Poultry production houses in the Upper Choptank watershed identified using aerial imagery from 1968 to 2018

Dataset contains a polygon shapefile representing poultry houses in the Upper Choptank watershed in Queen Anne's County, Maryland, and Kent County, Delaware.
By
Maryland-Delaware-D.C. Water Science Center
No results found.

Science and Products

Multiyear crop residue cover mapping using narrow-band vs. broad-band shortwave infrared satellite imagery Multiyear crop residue cover mapping using narrow-band vs. broad-band shortwave infrared satellite imagery

Crop residue serves an important role in agricultural systems as high levels of fractional crop residue cover (fR) can reduce erosion, preserve soil moisture, and build soil organic carbon. However, the ability to accurately quantify fR at scale has been limited. In this study we produced annual maps of fR for farmland in Maryland, USA using WorldView-3 (WV3) imagery paired with on-farm
Authors
Brian T. Lamb, W. Dean Hively, Jyoti Jennewein, Alison Thieme, Alexander M. Soroka, Leticia Santos, Daniela Jones, Steven Mirsky
By
Maryland-Delaware-D.C. Water Science Center, Lower Mississippi-Gulf Water Science Center

Comparison of water quality in shallow groundwater near agricultural areas in the Delaware Coastal Plain, 2014 and 2019 Comparison of water quality in shallow groundwater near agricultural areas in the Delaware Coastal Plain, 2014 and 2019

The State of Delaware has encouraged agricultural conservation practices to improve nutrient uptake by crops and mitigate nutrient transport to groundwater in the surficial aquifer. To study recent changes in groundwater quality, the U.S. Geological Survey and the Delaware Department of Agriculture (DDA) developed a network of shallow wells near agricultural areas throughout the Delaware...
Authors
Alexander M. Soroka, Betzaida Reyes, Brandon J. Fleming, Michael Brownley
By
Maryland-Delaware-D.C. Water Science Center

Atmospheric correction intercomparison of hyperspectral and multispectral imagery over agricultural study sites Atmospheric correction intercomparison of hyperspectral and multispectral imagery over agricultural study sites

In this research effort we assess the performance of atmospheric correction-based surface reflectance (SR) retrievals from two satellite image sources, one with very high spatial resolution (VHR) (
Authors
Brian T. Lamb, W. Dean Hively, Jyoti Jennewein, Alison Thieme, Alexander M. Soroka
By
Lower Mississippi-Gulf Water Science Center

Your land, your water—Using research to guide conservation practices on local farms in the Chesapeake Bay watershed Your land, your water—Using research to guide conservation practices on local farms in the Chesapeake Bay watershed

Agricultural lands are an important part of the economy and heritage of the Chesapeake Bay watershed and are a focus of conservation activities. Streams and rivers around farms provide communities with drinking water and recreational opportunities, but these local benefits can be impaired by elevated nutrient and sediment concentrations. Compared to inputs from the atmosphere, wastewater...
Authors
James S. Webber, John W. Clune, Alexander M. Soroka, Kenneth Hyer
By
Water Resources Mission Area, Chesapeake Bay Activities, Maryland-Delaware-D.C. Water Science Center, Pennsylvania Water Science Center, Virginia and West Virginia Water Science Center

Hydrogeologic characterization of Area B, Fort Detrick, Maryland Hydrogeologic characterization of Area B, Fort Detrick, Maryland

Groundwater in the karst groundwater system at Area B of Fort Detrick in Frederick County, Maryland, is contaminated with chlorinated solvents from the past disposal of laboratory wastes. In cooperation with U.S. Army Environmental Command and U.S. Army Garrison Fort Detrick, the U.S. Geological Survey performed a 3-year study to refine the conceptual model of groundwater flow in and...
Authors
Phillip J. Goodling, Brandon J. Fleming, John Solder, Alexander M. Soroka, Jeff P. Raffensperger
By
Maryland-Delaware-D.C. Water Science Center

Near real-time detection of winter cover crop termination using harmonized Landsat and Sentinel-2 (HLS) to support ecosystem assessment Near real-time detection of winter cover crop termination using harmonized Landsat and Sentinel-2 (HLS) to support ecosystem assessment

Cover crops are planted to reduce soil erosion, increase soil fertility, and improve watershed management. In the Delmarva Peninsula of the eastern United States, winter cover crops are essential for reducing nutrient and sediment losses from farmland. Cost-share programs have been created to incentivize cover crops to achieve conservation objectives. This program required that cover...
Authors
Feng Gao, Jyoti Jennewein, W. Dean Hively, Alexander M. Soroka, Alison Thieme, Dawn Bradley, Jason Keppler, Steven Mirsky, Uvirkaa Akumaga
By
Maryland-Delaware-D.C. Water Science Center, Lower Mississippi-Gulf Water Science Center

Spatial patterns and seasonal timing of increasing riverine specific conductance from 1998 to 2018 suggest legacy contamination in the Delaware River Basin Spatial patterns and seasonal timing of increasing riverine specific conductance from 1998 to 2018 suggest legacy contamination in the Delaware River Basin

Increasing salinization of freshwater threatens water supplies that support a range of human and ecological uses. The latest assessments of Delaware River Basin (DRB) surface-water-quality changes indicate widespread salinization has occurred in recent decades, which may lead to meaningful degradation in water quality. To better understand how and when salinity transport occurs and...
Authors
Christine Rumsey, John C. Hammond, Jennifer C. Murphy, Megan E. Shoda, Alexander M. Soroka
By
Water Resources Mission Area, Maryland-Delaware-D.C. Water Science Center, Utah Water Science Center, Central Midwest Water Science Center

Remote sensing evaluation of winter cover crop springtime performance and the impact of delayed termination Remote sensing evaluation of winter cover crop springtime performance and the impact of delayed termination

In 2019, the Maryland Department of Agriculture's Winter Cover Crop Program introduced a delayed termination incentive (after May 1) to promote springtime biomass accumulation. We used satellite imagery calibrated with springtime in situ measurements collected from 2006–2021 (n = 722) to derive biomass estimates for Maryland fields planted to cereal cover crop species (286,200 ha total...
Authors
Alison Thieme, W. Dean Hively, Feng Gao, Jyoti Jennewein, Steven Mirsky, Alexander M. Soroka, Jason Keppler, Dawn Bradley, Sergii Skakun, Gregory W. McCarty
By
Lower Mississippi-Gulf Water Science Center

Nitrogen in the Chesapeake Bay watershed—A century of change, 1950–2050 Nitrogen in the Chesapeake Bay watershed—A century of change, 1950–2050

Foreword Sustaining the quality of the Nation’s water resources and the health of our diverse ecosystems depends on the availability of sound water-resources data and information to develop effective, science-based policies. Effective management of water resources also brings more certainty and efficiency to important economic sectors. Taken together, these actions lead to immediate and...
Authors
John W. Clune, Paul D. Capel, Matthew P. Miller, Douglas A. Burns, Andrew J. Sekellick, Peter R. Claggett, Richard H. Coupe, Rosemary M. Fanelli, Ana Maria Garcia, Jeff P. Raffensperger, Silvia Terziotti, Gopal Bhatt, Joel D. Blomquist, Kristina G. Hopkins, Jennifer L. Keisman, Lewis C. Linker, Gary W. Shenk, Richard A. Smith, Alexander M. Soroka, James S. Webber, David M. Wolock, Qian Zhang
By
Water Resources Mission Area, Chesapeake Bay Activities, Maryland-Delaware-D.C. Water Science Center, New York Water Science Center, Pennsylvania Water Science Center, South Atlantic Water Science Center (SAWSC), Utah Water Science Center, Virginia and West Virginia Water Science Center

Estimating the effect of winter cover crops on nitrogen leaching using cost-share enrollment data, satellite remote sensing, and Soil and Water Assessment Tool (SWAT) modeling Estimating the effect of winter cover crops on nitrogen leaching using cost-share enrollment data, satellite remote sensing, and Soil and Water Assessment Tool (SWAT) modeling

This study employed a novel combination of data (winter cover crop cost-share enrollment records, satellite remote sensing of wintertime vegetation, and results of Soil and Water Assessment Tool (SWAT) water quality simulations) to estimate the environmental performance of winter cover crops (WCC) at the watershed scale, from 2008 through 2017, within the Tuckahoe sub-watershed of the...
Authors
W. Dean Hively, Sangchul Lee, Ali M. Sadeghi, Gregory W. McCarty, Brian T. Lamb, Alexander M. Soroka, Jason Keppler, In-Young Yeo, Glenn E. Moglen
By
Lower Mississippi-Gulf Water Science Center

Monitoring the water-quality response of agricultural conservation practices in the Bucks Branch watershed, Sussex County, Delaware, 2014–16 Monitoring the water-quality response of agricultural conservation practices in the Bucks Branch watershed, Sussex County, Delaware, 2014–16

The purpose of this study was to evaluate the effects of irrigation and cover crops as conservation practices on water quality in groundwater and streams. Bucks Branch, a stream in the Nanticoke River watershed in southwestern Delaware, was identified as having one of the highest concentrations of nitrate in all surface-water sites sampled by the Delaware Department of Natural Resources...
Authors
Judith M. Denver, Alexander M. Soroka, Betzaida Reyes, Todd R. Lester, Deborah A. Bringman, M.S. Brownley
By
Water Resources Mission Area, Maryland-Delaware-D.C. Water Science Center
Hydrologic technician Fisseha Mengistu reels in a sampling bottle.

Informing Chesapeake Bay Watershed Management by Monitoring Trends in River Nutrient and Sediment Loads

The USGS has computed nutrient and suspended-sediment loads and trends through water year 2023 in Chesapeake Bay rivers. These monitoring-based estimates help federal, state, and local managers evaluate and plan water-quality restoration strategies.
By
Chesapeake Bay Activities, Maryland-Delaware-D.C. Water Science Center, Pennsylvania Water Science Center, Virginia and West Virginia Water Science Center
Informing Chesapeake Bay Watershed Management by Monitoring Trends in River Nutrient and Sediment Loads

Informing Chesapeake Bay Watershed Management by Monitoring Trends in River Nutrient and Sediment Loads

The USGS has computed nutrient and suspended-sediment loads and trends through water year 2023 in Chesapeake Bay rivers. These monitoring-based estimates help federal, state, and local managers evaluate and plan water-quality restoration strategies.
Learn More
Water flows out of a bioreactor through a white PVC pipe before splashing down into a small stream.

Monitoring the Effectiveness of Conservation Practices in Small Agricultural Watersheds

Farmers are an important part of the economy and heritage of the Chesapeake Bay. Farmers also act as stewards of the land and water. Across the Chesapeake Bay Watershed, members of the agricultural community are volunteering to adopt conservation practices on their land. The goal of these practices is to protect the health of the soil, local streams and rivers, and the Chesapeake Bay. These...
By
Chesapeake Bay Activities, Maryland-Delaware-D.C. Water Science Center, Pennsylvania Water Science Center, Virginia and West Virginia Water Science Center
Monitoring the Effectiveness of Conservation Practices in Small Agricultural Watersheds

Monitoring the Effectiveness of Conservation Practices in Small Agricultural Watersheds

Farmers are an important part of the economy and heritage of the Chesapeake Bay. Farmers also act as stewards of the land and water. Across the Chesapeake Bay Watershed, members of the agricultural community are volunteering to adopt conservation practices on their land. The goal of these practices is to protect the health of the soil, local streams and rivers, and the Chesapeake Bay. These...
Learn More
A round bluescale icon showing a trifold map of the chesapeake bay

Summarizing Science to Inform Management in the Chesapeake Bay Watershed

Stakeholders can use scientific insights to address their priority water-quality concerns. The USGS works with Chesapeake Bay stakeholders to identify and address priority questions that can help inform management decisions. These scientific insights can help guide nutrient and sediment management activities undertaken by Chesapeake Bay stakeholders. This webpage summarizes recent scientific...
By
Chesapeake Bay Activities, Virginia and West Virginia Water Science Center
Summarizing Science to Inform Management in the Chesapeake Bay Watershed

Summarizing Science to Inform Management in the Chesapeake Bay Watershed

Stakeholders can use scientific insights to address their priority water-quality concerns. The USGS works with Chesapeake Bay stakeholders to identify and address priority questions that can help inform management decisions. These scientific insights can help guide nutrient and sediment management activities undertaken by Chesapeake Bay stakeholders. This webpage summarizes recent scientific...
Learn More
A USGS technician samples the Rappahannock River from a suspended cable car.

Science to Inform Management Priorities from Loads to Endpoints (SIMPLE)

Resource managers are working to improve water-quality in the Chesapeake to benefit the people who live in the region and the birds, fish, and other animals who rely on clean water in the watershed and the Bay. The U.S Geological Survey (USGS) supports resource managers and other Chesapeake stakeholders by providing science that informs restoration and conservation in the Chesapeake region. The...
By
Chesapeake Bay Activities, Virginia and West Virginia Water Science Center
Science to Inform Management Priorities from Loads to Endpoints (SIMPLE)

Science to Inform Management Priorities from Loads to Endpoints (SIMPLE)

Resource managers are working to improve water-quality in the Chesapeake to benefit the people who live in the region and the birds, fish, and other animals who rely on clean water in the watershed and the Bay. The U.S Geological Survey (USGS) supports resource managers and other Chesapeake stakeholders by providing science that informs restoration and conservation in the Chesapeake region. The...
Learn More
Table of Trends in nitrogen, phosphorus, and suspended-sediment loads for RIM (2021)

USGS calculates loads and trends through 2021 for the nine major rivers entering Chesapeake Bay

Issue: The amount of nutrients and suspended sediment entering the Chesapeake Bay affect water-quality conditions in tidal waters. Excess nutrients contribute to algal blooms that lower the oxygen levels in tidal waters that are important for fish and shellfish. The algal blooms, along with suspended sediment, also decrease visibility in shallow waters for submerged aquatic grasses. The grasses...
By
Chesapeake Bay Activities, Maryland-Delaware-D.C. Water Science Center, Virginia and West Virginia Water Science Center
USGS calculates loads and trends through 2021 for the nine major rivers entering Chesapeake Bay

USGS calculates loads and trends through 2021 for the nine major rivers entering Chesapeake Bay

Issue: The amount of nutrients and suspended sediment entering the Chesapeake Bay affect water-quality conditions in tidal waters. Excess nutrients contribute to algal blooms that lower the oxygen levels in tidal waters that are important for fish and shellfish. The algal blooms, along with suspended sediment, also decrease visibility in shallow waters for submerged aquatic grasses. The grasses...
Learn More
Chesapeake Bay at Edgewater, MD

Summarizing Scientific Findings for Common Stakeholder Questions to Inform Nutrient and Sediment Management Activities in the Chesapeake Bay Watershed

Issue: The Chesapeake Bay Program (CBP) partnership is striving to improve water-quality conditions in the Bay by using a variety of management strategies to reduce nutrient and sediment loads. The partnership uses monitoring results and modeling tools to implement management strategies, relying on the scientific community to synthesize existing information and direct new research to address...
By
Chesapeake Bay Activities, Maryland-Delaware-D.C. Water Science Center, Pennsylvania Water Science Center, Virginia and West Virginia Water Science Center
Summarizing Scientific Findings for Common Stakeholder Questions to Inform Nutrient and Sediment Management Activities in the Chesapeake Bay Watershed

Summarizing Scientific Findings for Common Stakeholder Questions to Inform Nutrient and Sediment Management Activities in the Chesapeake Bay Watershed

Issue: The Chesapeake Bay Program (CBP) partnership is striving to improve water-quality conditions in the Bay by using a variety of management strategies to reduce nutrient and sediment loads. The partnership uses monitoring results and modeling tools to implement management strategies, relying on the scientific community to synthesize existing information and direct new research to address...
Learn More
Photograph of Pequea Creek, Pennsylvania

Updated 2020 Nutrient and Suspended-Sediment Trends for the Nine Major Rivers Entering the Chesapeake Bay

Issue: The amount of nutrients and suspended sediment entering the Chesapeake Bay affect water-quality conditions in tidal waters. Excess nutrients contribute to algal blooms that lower the oxygen levels in tidal waters that are important for fish and shellfish. The algal blooms, along with suspended sediment, also decrease visibility in shallow waters for submerged aquatic grasses. The grasses...
By
Core Science Systems Mission Area, Chesapeake Bay Activities, Virginia and West Virginia Water Science Center
Updated 2020 Nutrient and Suspended-Sediment Trends for the Nine Major Rivers Entering the Chesapeake Bay

Updated 2020 Nutrient and Suspended-Sediment Trends for the Nine Major Rivers Entering the Chesapeake Bay

Issue: The amount of nutrients and suspended sediment entering the Chesapeake Bay affect water-quality conditions in tidal waters. Excess nutrients contribute to algal blooms that lower the oxygen levels in tidal waters that are important for fish and shellfish. The algal blooms, along with suspended sediment, also decrease visibility in shallow waters for submerged aquatic grasses. The grasses...
Learn More
Filter Total Items: 13

Nitrogen, phosphorus, and suspended-sediment loads and trends measured at the Chesapeake Bay River Input Monitoring stations: Water years 1985-2022 Nitrogen, phosphorus, and suspended-sediment loads and trends measured at the Chesapeake Bay River Input Monitoring stations: Water years 1985-2022

Nitrogen, phosphorus, and suspended-sediment loads, and changes in loads, in major rivers across the Chesapeake Bay watershed have been calculated using monitoring data from the Chesapeake Bay River Input Monitoring (RIM) Network stations for the period 1985 through 2022. Nutrient and suspended-sediment loads and changes in loads were determined by applying a weighted regression approach...
By
Chesapeake Bay Activities, Virginia and West Virginia Water Science Center

Data supporting a spatiotemporal trend analysis of specific conductivity, streamflow, and landscape attributes of selected sub-basins within the Delaware River watershed, 1980 to 2018 Data supporting a spatiotemporal trend analysis of specific conductivity, streamflow, and landscape attributes of selected sub-basins within the Delaware River watershed, 1980 to 2018

This data release makes available three data tables supporting a spatiotemporal analysis of riverine conductivity and streamflow trends within the Delaware River Basin. The listed datasets include baseflow and total flow time series for selected gaged basins, watershed attributes, water quality information and trend analysis results.
By
Maryland-Delaware-D.C. Water Science Center

Soil-Water-Balance (SWB) model archive used to simulate water budget components in Pennsylvania and Maryland, 2000-2020 Soil-Water-Balance (SWB) model archive used to simulate water budget components in Pennsylvania and Maryland, 2000-2020

This model archive documents the Soil-Water-Balance (SWB) model used to simulate potential recharge for portions of Pennsylvania and Maryland from 2000 to 2021. The Pennsylvania and Maryland SWB model was used to create output at a 250 meter grid scale. Model parameters were adjusted using baseflow estimates from 36 reference watersheds varying in area from 0.37 to 817 square miles. The
By
Maryland-Delaware-D.C. Water Science Center

Possible Cattle Access Points on Select Streams within the Smith Creek Watershed Derived from 2018 NAIP Imagery Possible Cattle Access Points on Select Streams within the Smith Creek Watershed Derived from 2018 NAIP Imagery

This data release contains one shapefile describing cattle access to a total of 36 different sub basins within the Smith Creek Watershed located in Virginia and West Virginia. This data release identifies areas in satellite imagery where cattle were observed to have access to the stream (confirmed access), areas where cattle exist, and are not fenced off from the stream (unrestricted...
By
Maryland-Delaware-D.C. Water Science Center

Nitrogen, phosphorus, and suspended-sediment loads and trends measured at the Chesapeake Bay River Input Monitoring stations: Water years 1985-2021 Nitrogen, phosphorus, and suspended-sediment loads and trends measured at the Chesapeake Bay River Input Monitoring stations: Water years 1985-2021

Nitrogen, phosphorus, and suspended-sediment loads, and changes in loads, in major rivers across the Chesapeake Bay watershed have been calculated using monitoring data from the Chesapeake Bay River Input Monitoring (RIM) Network stations for the period 1985 through 2021. Nutrient and suspended-sediment loads and changes in loads were determined by applying a weighted regression approach...
By
Chesapeake Bay Activities, Virginia and West Virginia Water Science Center

Possible Cattle Access Points on Steams within the USGS Showcase Watersheds Derived from 2018 and 2019 NAIP Imagery Possible Cattle Access Points on Steams within the USGS Showcase Watersheds Derived from 2018 and 2019 NAIP Imagery

This data release contains one point shapefile describing cattle access to streams for three USGS showcase watersheds: Smith Creek, Conewago Creek, and Upper Chester River. This data release identifies areas where cattle were able to access the stream, as well as possible cattle access areas. Streams were defined using a combination of geospatial data and aerial imagery and cattle access...
By
Maryland-Delaware-D.C. Water Science Center

Nitrogen, phosphorus, and suspended-sediment loads and trends measured at the Chesapeake Bay River Input Monitoring stations: Water years 1985-2020 Nitrogen, phosphorus, and suspended-sediment loads and trends measured at the Chesapeake Bay River Input Monitoring stations: Water years 1985-2020

Nitrogen, phosphorus, and suspended-sediment loads, and changes in loads, in major rivers across the Chesapeake Bay watershed have been calculated using monitoring data from the Chesapeake Bay River Input Monitoring (RIM) Network stations for the period 1985 through 2020. Nutrient and suspended-sediment loads and changes in loads were determined by applying a weighted regression approach...
By
Chesapeake Bay Activities, Virginia and West Virginia Water Science Center

Nitrogen flux estimates in support of Chesapeake Bay Hypoxia and Anoxia forecasts, 1985-2021 Nitrogen flux estimates in support of Chesapeake Bay Hypoxia and Anoxia forecasts, 1985-2021

Data release includes the U.S. Geological Survey (USGS) estimate of spring nitrogen fluxes summed from nine tributaries to the Chesapeake Bay from 1985 to 2021. Data are presented as the sum from tributaries within the USGS River Input Monitoring (RIM) network identified by site numbers: 01491000, 01578310, 01594440, 01646580, 01668000, 01673000, 01674500, 02035000, 02041650. Periods of...
By
Chesapeake Bay Activities, Maryland-Delaware-D.C. Water Science Center

Water bodies within 500 meters of poultry feeding operations on the Delmarva Peninsula in 2016 and 2017 Water bodies within 500 meters of poultry feeding operations on the Delmarva Peninsula in 2016 and 2017

Data release contains 1710 polygons representing small bodies of water within 500 meters of poultry feeding operations on the Delmarva Peninsula. Ponds were identified using the USDA's National Agriculture Imagery Program's 2016 and 2017 products. Poultry feeding operations were described in location by Soroka and Duren (2020).
By
Maryland-Delaware-D.C. Water Science Center

Nitrogen flux estimates in support of Chesapeake Bay Hypoxia and Anoxia forecasts, 1985-2020 Nitrogen flux estimates in support of Chesapeake Bay Hypoxia and Anoxia forecasts, 1985-2020

Data release includes the U.S. Geological Survey (USGS) estimate of spring nitrogen fluxes from nine tributaries to the Chesapeake Bay from 1985 to 2020. Data are presented from tributaries within the USGS River Input Monitoring (RIM) network identified by site numbers: 01491000, 01578310, 01594440, 01646580, 01668000, 01673000, 01674500, 02035000, 02041650. Periods of estimation include...
By
Chesapeake Bay Activities, Maryland-Delaware-D.C. Water Science Center

Poultry Feeding Operations on the Delaware, Maryland, and Virginia Peninsula from 2016 to 2017 Poultry Feeding Operations on the Delaware, Maryland, and Virginia Peninsula from 2016 to 2017

Data release contains two shapefiles related to poultry houses on the Delmarva Peninsula (Delaware, Eastern Shore Maryland and, Eastern Shore Virginia). One dataset is a polygon shapefile representing 5747 poultry houses identified using 2016 and 2017 aerial imagery from the U.S. Department of Agricultures National Aerial Imagery Program (NAIP). The second dataset is a point shapefile of
By
Chesapeake Bay Activities, Maryland-Delaware-D.C. Water Science Center

Poultry production houses in the Upper Choptank watershed identified using aerial imagery from 1968 to 2018 Poultry production houses in the Upper Choptank watershed identified using aerial imagery from 1968 to 2018

Dataset contains a polygon shapefile representing poultry houses in the Upper Choptank watershed in Queen Anne's County, Maryland, and Kent County, Delaware.
By
Maryland-Delaware-D.C. Water Science Center
No results found.
Was this page helpful?