SPARROW (SPAtially Referenced Regression On Watershed attributes) models estimate the amount of a contaminant transported from inland watersheds to larger water bodies by linking monitoring data with information on watershed characteristics and contaminant sources. Interactive, online SPARROW mapping tools allow for easy access to explore relations between human activities, natural processes, and contaminant transport.
Featured: Projecting future flow in Southwest streams

Streamflow in the Southwestern U.S. is projected to decrease by as much as 36–80% by the end of this century, reports a new study by the U.S. Geological Survey. These decreases could challenge our ability to meet future water demand in this region.
Integration of monitoring and modeling is critical to our future understanding and management of the Nation’s water quality. Monitoring is the direct observation, often over time, of water-quality properties and characteristics, and models are tools for interpreting these observations.
SPARROW models are used to estimate long-term average values of water characteristics, such as the amount of a contaminant that is delivered downstream, based on existing monitoring data, location and strength of contaminant sources, and characteristics of the landscape.
SPARROW models can help managers:
- Determine options for reducing loads of contaminants
- Design strategies for protection or to meet regulatory requirements
- Predict changes in water quality that might result from management actions
- Identify gaps and priorities in monitoring network design

SPARROW Mappers
SPARROW mappers are interactive tools that allow the user to explore river nutrient loads and yields and the importance of different sources of contaminants in a particular river basin.
Data can be visualized using maps and interactive graphs and tables, and rankings can be shown by catchment, watershed, and state. Modeling results can be exported as an Excel spreadsheet, CSV file, or a geospatial dataset.
New mappers, representing circa 2012 source inputs, are available for 5 regions of the conterminous United States. The Mappers replace the SPARROW Decision Support System (Booth and others, 2011).
Nutrients and the Nation’s Estuaries
Access maps of watershed nutrients flowing to the Nation’s estuaries and download data tables of nutrient sources and loads. Compare nutrient sources and watersheds that contribute elevated nutrient loads to downstream receiving waters, such as the Southeast Atlantic and Gulf of Mexico, inland and coastal waters of the Northeast, the Upper Mississippi and Great Lakes, Puget Sound and the Northwest coast, and the California coast.
National Models
SPARROW models are unique in that they retain the spatial detail of underlying data sets while extending over areas as large as the conterminous United States. This allows the simultaneous assessment of water-quality conditions in many water bodies. National SPARROW models have been developed for a number of water-quality constituents including nutrients and total dissolved solids.
Regional Models
SPARROW models are flexible—they can be applied to any region where there are specific needs for water-quality information and where data to support modeling are abundant. Five new regional models of streamflow, total nitrogen, total phosphorus and suspended sediment have been developed for the conterminous United States. Other regional models have been developed previously for the Chesapeake Bay, Mississippi River and the Great Lakes watersheds.
International Models
SPARROW models can be applied in any part of the world where sufficient data are available to support model development. Examples include models developed for New Zealand to identify the primary sources of nutrients to streams (Alexander and others, 2002), and a joint U.S.-Canadian effort to build nutrient models for the entire Great Lakes watershed, to better understand nutrient loading to the lakes (Robertson and others, 2019).
Applications of SPARROW models
Once built and calibrated, SPARROW models can be applied in a variety of ways to better understand the environmental factors affecting water-quality conditions in streams.
- SPARROW models were applied at the national scale to estimate natural background levels of nutrients to help guide the potential development of nutrient criteria in streams.
- A model developed for the upper Midwest was used to identify the benefits of management practices designed to limit the amount of agricultural nutrients reaching streams (Garcia and others, 2016).
- A Chesapeake Bay SPARROW model was used to identify those areas that export nitrogen to streams with the greatest efficiency (Ator and Garcia, 2016).
- A SPARROW model was used to simulate impacts of climate change on phosphorus load to Lake Michigan (Robertson and others, 2016).
Research using SPARROW models
SPARROW models can be used as tools in research to better understand the environmental processes that affect water-quality conditions. A SPARROW model for the Mississippi drainage was used to evaluate the role of stream size on denitrification and attenuation of nitrogen levels with transport downstream. Previous studies based on a limited number of sites had hypothesized that the rate of denitrification was significantly greater in smaller streams due to greater sediment contact. This was confirmed by the SPARROW model for which the results were consistent with the other studies, but based on a much larger area and many more measurement locations (Alexander and others, 2000).
Databases
The national data bases used in the SPARROW models have value in themselves and can be used for other scientific evaluations. Attributes, such as point sources discharges, agricultural fertilizer / manure nutrients, atmospheric deposition, climate, geology / soils, land cover, hydrologic characteristics and physical characteristics, are available for all catchments in the RF1 and NHDPlus digital stream networks.
Stream network datasets and watershed attribute data
- The EPA RF1 data set (with attributes) is defined at the 1:500K scale and has stream catchments that are on average 130 km2.
- The NHDPlus data set (with attributes Version 1.1 and Version 2.1) is defined at the 1:100K scale and has stream catchments that are on average 3 km2.
Descriptions of these data sets and how they are used in SPARROW models can be found in Preston and others (2011).
What’s New …
- RSPARROW, now available on the USGS GitLab repository, provides the first open-source version of the USGS SPARROW water-quality model, with new features that improve the utility of the model for conducting studies of contaminants in surface waters and informing water resource management decisions. RSPARROW extends the capabilities of the current proprietary SAS SPARROW version and streamlines user and R developer access to SPARROW modelling technology.
- Although SPARROW models are typically based on a single time period, dynamic versions of SPARROW models are being developed to take advantage of new data sets. Dynamic SPARROW models will account for temporary storage of contaminants and to simulate seasonal variations. They also will allow simulation of contaminant loads through time to estimate the time needed for management actions on the land to affect loads in streams.
Everything you need to know about SPARROW
SPARROW Mappers
SPARROW modeling: Great Lakes, Mississippi River, Ohio River, and Red River Basins
SPARROW: Attributes for NHDPlus Catchments (Version 1.1) for the Conterminous United States
SPARROW: Attributes for MRB_E2RF1 Catchments by Major River Basins in the Conterminous United States
SPARROW Model Assessments of Nutrients and Suspended Sediment in the Pacific Northwest and California
Select Attributes for NHDPlus Version 2.1 Reach Catchments and Modified Network Routed Upstream Watersheds for the Conterminous United States (ver. 4.0, August 2023)
SPARROW model simulated nutrient loads in streams of the Midcontinental Region of Canada and the United States, 2002 Base Year
The links below lead to publications related to SPARROW, including documentation and applications.
Response of nitrogen loading to the Chesapeake Bay to source reduction and land use change scenarios: A SPARROW‐informed analysis
Phosphorus and nitrogen transport in the binational Great Lakes Basin estimated using SPARROW watershed models
Estimates of long-term mean daily streamflow and annual nutrient and suspended-sediment loads considered for use in regional SPARROW models of the Conterminous United States, 2012 base year
Annual wastewater nutrient data preparation and load estimation using the Point Source Load Estimation Tool (PSLoadEsT)
Point-source nutrient loads to streams of the conterminous United States, 2012
Catchment-level estimates of nitrogen and phosphorus agricultural use from commercial fertilizer sales for the conterminous United States, 2012
Spatially referenced models of streamflow and nitrogen, phosphorus, and suspended-sediment loads in the southeastern United States
Spatially referenced models of streamflow and nitrogen, phosphorus, and suspended-sediment loads in streams of the midwestern United States
Spatially referenced models of streamflow and nitrogen, phosphorus, and suspended-sediment loads in streams of the northeastern United States
Spatially referenced models of streamflow and nitrogen, phosphorus, and suspended-sediment loads in streams of the Pacific region of the United States
Spatially referenced models of streamflow and nitrogen, phosphorus, and suspended-sediment transport in streams of the southwestern United States
Application of SPARROW modeling to understanding contaminant fate and transport from uplands to streams
2002 SPARROW Model Results for the Midcontinental Region of North America: Total Phosphorus and Total Nitrogen
SPARROW model results of long-term mean-annual total nitrogen and total phosphorus in streams of the Midcontinental Region of North America. The simulated loads represent source inputs similar to 2002 and normalized to long-term average hydrologic conditions for the period from 1970 to through 2012.
Dissolved Solids Sources, Loads, and Yields For the Conterminous U.S.
Using the SPARROW (SPAtially-Referenced Regression on Watershed Attributes) model, long-term mean annual conditions for dissolved-solids sources, loads, and yields were predicted for nearly 66,000 stream reaches and their corresponding incremental catchments that drain the Nation.
Eastern United States 2002 Nutrient Loading
The U.S. Geological Survey applied the SPARROW model to assess the loads delivered in 2002 for estuaries and coastal waters along the Atlantic Ocean and eastern Gulf of Mexico.
SPARROW Modeling Program
SPARROW is a popular watershed modeling technique, distributed by the USGS, that estimates the amount of a contaminant transported from inland watersheds to larger water bodies by linking monitoring data with information on watershed characteristics and contaminant sources.
RSPARROW
RSPARROW, now available on the USGS GitLab repository, provides the first open-source version of the USGS SPARROW water-quality model
Point-Source Load Estimation Tool (PSLoadEsT)
Software for generating reproducible load calculations for point source dischargers. Includes features to manage common data challenges such as duplicates, incompatible input tables, and missing nutrient concentration or effluent flow data.
- Overview
SPARROW (SPAtially Referenced Regression On Watershed attributes) models estimate the amount of a contaminant transported from inland watersheds to larger water bodies by linking monitoring data with information on watershed characteristics and contaminant sources. Interactive, online SPARROW mapping tools allow for easy access to explore relations between human activities, natural processes, and contaminant transport.
Featured: Projecting future flow in Southwest streamsStreamflow in the Southwestern U.S. is projected to decrease by as much as 36–80% by the end of this century, reports a new study by the U.S. Geological Survey. These decreases could challenge our ability to meet future water demand in this region.
Integration of monitoring and modeling is critical to our future understanding and management of the Nation’s water quality. Monitoring is the direct observation, often over time, of water-quality properties and characteristics, and models are tools for interpreting these observations.
SPARROW models are used to estimate long-term average values of water characteristics, such as the amount of a contaminant that is delivered downstream, based on existing monitoring data, location and strength of contaminant sources, and characteristics of the landscape.
SPARROW models can help managers:
- Determine options for reducing loads of contaminants
- Design strategies for protection or to meet regulatory requirements
- Predict changes in water quality that might result from management actions
- Identify gaps and priorities in monitoring network design
Sources/Usage: Public Domain. Visit Media to see details.The regions delineated for use in Spatially Referenced Regressions on Watershed Attributes (SPARROW) models in the conterminous United States SPARROW Mappers
SPARROW mappers are interactive tools that allow the user to explore river nutrient loads and yields and the importance of different sources of contaminants in a particular river basin.
Data can be visualized using maps and interactive graphs and tables, and rankings can be shown by catchment, watershed, and state. Modeling results can be exported as an Excel spreadsheet, CSV file, or a geospatial dataset.
New mappers, representing circa 2012 source inputs, are available for 5 regions of the conterminous United States. The Mappers replace the SPARROW Decision Support System (Booth and others, 2011).
Nutrients and the Nation’s Estuaries
Access maps of watershed nutrients flowing to the Nation’s estuaries and download data tables of nutrient sources and loads. Compare nutrient sources and watersheds that contribute elevated nutrient loads to downstream receiving waters, such as the Southeast Atlantic and Gulf of Mexico, inland and coastal waters of the Northeast, the Upper Mississippi and Great Lakes, Puget Sound and the Northwest coast, and the California coast.
The San Francisco Bay Estuary. National Models
SPARROW models are unique in that they retain the spatial detail of underlying data sets while extending over areas as large as the conterminous United States. This allows the simultaneous assessment of water-quality conditions in many water bodies. National SPARROW models have been developed for a number of water-quality constituents including nutrients and total dissolved solids.
Regional Models
SPARROW models are flexible—they can be applied to any region where there are specific needs for water-quality information and where data to support modeling are abundant. Five new regional models of streamflow, total nitrogen, total phosphorus and suspended sediment have been developed for the conterminous United States. Other regional models have been developed previously for the Chesapeake Bay, Mississippi River and the Great Lakes watersheds.
International Models
SPARROW models can be applied in any part of the world where sufficient data are available to support model development. Examples include models developed for New Zealand to identify the primary sources of nutrients to streams (Alexander and others, 2002), and a joint U.S.-Canadian effort to build nutrient models for the entire Great Lakes watershed, to better understand nutrient loading to the lakes (Robertson and others, 2019).
Applications of SPARROW models
Once built and calibrated, SPARROW models can be applied in a variety of ways to better understand the environmental factors affecting water-quality conditions in streams.
- SPARROW models were applied at the national scale to estimate natural background levels of nutrients to help guide the potential development of nutrient criteria in streams.
- A model developed for the upper Midwest was used to identify the benefits of management practices designed to limit the amount of agricultural nutrients reaching streams (Garcia and others, 2016).
- A Chesapeake Bay SPARROW model was used to identify those areas that export nitrogen to streams with the greatest efficiency (Ator and Garcia, 2016).
- A SPARROW model was used to simulate impacts of climate change on phosphorus load to Lake Michigan (Robertson and others, 2016).
Research using SPARROW models
SPARROW models can be used as tools in research to better understand the environmental processes that affect water-quality conditions. A SPARROW model for the Mississippi drainage was used to evaluate the role of stream size on denitrification and attenuation of nitrogen levels with transport downstream. Previous studies based on a limited number of sites had hypothesized that the rate of denitrification was significantly greater in smaller streams due to greater sediment contact. This was confirmed by the SPARROW model for which the results were consistent with the other studies, but based on a much larger area and many more measurement locations (Alexander and others, 2000).
Databases
The national data bases used in the SPARROW models have value in themselves and can be used for other scientific evaluations. Attributes, such as point sources discharges, agricultural fertilizer / manure nutrients, atmospheric deposition, climate, geology / soils, land cover, hydrologic characteristics and physical characteristics, are available for all catchments in the RF1 and NHDPlus digital stream networks.
Stream network datasets and watershed attribute data
- The EPA RF1 data set (with attributes) is defined at the 1:500K scale and has stream catchments that are on average 130 km2.
- The NHDPlus data set (with attributes Version 1.1 and Version 2.1) is defined at the 1:100K scale and has stream catchments that are on average 3 km2.
Descriptions of these data sets and how they are used in SPARROW models can be found in Preston and others (2011).
What’s New …
- RSPARROW, now available on the USGS GitLab repository, provides the first open-source version of the USGS SPARROW water-quality model, with new features that improve the utility of the model for conducting studies of contaminants in surface waters and informing water resource management decisions. RSPARROW extends the capabilities of the current proprietary SAS SPARROW version and streamlines user and R developer access to SPARROW modelling technology.
- Although SPARROW models are typically based on a single time period, dynamic versions of SPARROW models are being developed to take advantage of new data sets. Dynamic SPARROW models will account for temporary storage of contaminants and to simulate seasonal variations. They also will allow simulation of contaminant loads through time to estimate the time needed for management actions on the land to affect loads in streams.
- Science
Everything you need to know about SPARROW
What is SPARROW? SPARROW (SPAtially Referenced Regression On Watershed attributes) is a watershed modeling technique for relating water-quality measurements made at a network of monitoring stations to attributes of the watersheds such as contaminant sources and environmental factors that affect rates of delivery to streams and in-stream processing. The core of the model consists of a nonlinear...SPARROW Mappers
SPARROW mappers are interactive tools that allow the user to explore river streamflow and nutrient and sediment loads and yields and the importance of different sources of contaminants in a particular river basin. Data can be visualized using maps and interactive graphs and tables, and rankings can be shown by state, major watershed, hydrologic unit (HUC), and catchment.SPARROW modeling: Great Lakes, Mississippi River, Ohio River, and Red River Basins
SPARROW models for the Great Lakes, Ohio River, Upper Mississippi River, and Red River Basins predict long-term mean annual loads, yields, concentrations, and source contributions of water, nitrogen, phosphorus, and sediment throughout the Midwest.SPARROW: Attributes for NHDPlus Catchments (Version 1.1) for the Conterminous United States
The national databases used in USGS SPARROW models are available for download. Attributes from the NHDPlus data set, such as climate, geology, soils, land cover, hydrologic variables, physical characteristics, chemicals, and nutrients, are available for all catchments in the digital stream networks (1:500K scale).SPARROW: Attributes for MRB_E2RF1 Catchments by Major River Basins in the Conterminous United States
The national databases used in USGS SPARROW models are available for download. Attributes from the RF1 data set, such as climate, geology, soils, land cover, hydrologic variables, physical characteristics, chemicals, and nutrients, are available for all catchments in the digital stream networks (1:100K scale).SPARROW Model Assessments of Nutrients and Suspended Sediment in the Pacific Northwest and California
SPARROW can be used to relate water-quality data to landscape characteristics, such as natural properties and human activities - Data
Select Attributes for NHDPlus Version 2.1 Reach Catchments and Modified Network Routed Upstream Watersheds for the Conterminous United States (ver. 4.0, August 2023)
This metadata record describes a series of data sets of natural and anthropogenic landscape features linked to NHDPlus Version 2.1's (NHDPlusV2) approximately 2.7 million stream segments, their associated catchments, and their upstream watersheds within the conterminous United States. These data were developed by the Hydrologic Sytem's Team (HST) within the the United States Geological Survey's (SPARROW model simulated nutrient loads in streams of the Midcontinental Region of Canada and the United States, 2002 Base Year
The U.S. Geological Survey's (USGS) SPAtially Referenced Regression On Watershed attributes (SPARROW) model was developed to aid in the interpretation of monitoring data and simulate water-quality conditions in streams across the Midcontinental Region of Canada and the Unites States. SPARROW is a hybrid empirical⁄process-based mass balance model that can be used to estimate the major sources and e - Multimedia
- Publications
The links below lead to publications related to SPARROW, including documentation and applications.
Filter Total Items: 64Response of nitrogen loading to the Chesapeake Bay to source reduction and land use change scenarios: A SPARROW‐informed analysis
In response to concerns regarding the health of streams and receiving waters, the United States Environmental Protection Agency established a total maximum daily load for nitrogen in the Chesapeake Bay watershed for which practices must be in place by 2025 resulting in an expected 25% reduction in load from 2009 levels. The response of total nitrogen (TN) loads delivered to the Bay to nine sourceAuthorsMatthew P. Miller, Paul D. Capel, Ana M. Garcia, Scott W. AtorPhosphorus and nitrogen transport in the binational Great Lakes Basin estimated using SPARROW watershed models
Eutrophication problems in the Great Lakes are caused by excessive nutrient inputs (primarily phosphorus, P, and nitrogen, N) from various sources throughout its basin. In developing protection and restoration plans, it is important to know where and from what sources the nutrients originate. As part of a binational effort, Midcontinent SPARROW (SPAtially Referenced Regression On Watershed attribuAuthorsDale M. Robertson, David A. Saad, Glenn A. Benoy, Ivana Vouk, Gregory E. Schwarz, Michael T LaittaEstimates of long-term mean daily streamflow and annual nutrient and suspended-sediment loads considered for use in regional SPARROW models of the Conterminous United States, 2012 base year
Streamflow, nutrient, and sediment concentration data needed to estimate long-term mean daily streamflow and annual constituent loads were compiled from Federal, State, Tribal, and regional agencies, universities, and nongovernmental organizations. The streamflow and loads are used to develop Spatially Referenced Regressions on Watershed Attributes (SPARROW) models. SPARROW models help describe thAuthorsDavid A. Saad, Gregory E. Schwarz, Denise M. Argue, David W. Anning, Scott A. Ator, Anne B. Hoos, Stephen D. Preston, Dale M. Robertson, Daniel WiseAnnual wastewater nutrient data preparation and load estimation using the Point Source Load Estimation Tool (PSLoadEsT)
The Point-Source Load Estimation Tool (PSLoadEsT) provides a user-friendly interface for generating reproducible load calculations for point source dischargers while managing common data challenges including duplicates, incompatible input tables, and incomplete or missing nutrient concentration or effluent flow data. Maintaining a consistent method across an entire study area is important when estAuthorsLillian E. Gorman Sanisaca, Kenneth D. Skinner, Molly A. MaupinPoint-source nutrient loads to streams of the conterminous United States, 2012
Total nitrogen and phosphorous loads were estimated for 5,430 major point-source facilities (all types) and 11,537 minor wastewater treatment facilities discharging to streams in the conterminous United States during 2012. Facilities classified as a major discharger are typically a facility that discharges greater than one million gallons of water per day however some industrial facilities are claAuthorsKenneth D. Skinner, Molly A. MaupinCatchment-level estimates of nitrogen and phosphorus agricultural use from commercial fertilizer sales for the conterminous United States, 2012
Nutrient inputs from commercial agricultural fertilizer, particularly nitrogen and phosphorus, are important factors contributing to the degradation of surface-water quality and the alteration of aquatic ecosystems. Despite this importance, information about the application of fertilizer to agricultural land is not available in a consistent manner across the United States at a scale useful for regAuthorsJana S. Stewart, Gregory E. Schwarz, John W. Brakebill, Stephen D. PrestonSpatially referenced models of streamflow and nitrogen, phosphorus, and suspended-sediment loads in the southeastern United States
Spatially Referenced Regression On Watershed attributes (SPARROW) models were applied to describe and estimate mean-annual streamflow and transport of total nitrogen (TN), total phosphorus (TP), and suspended sediment (SS) in streams and delivered to coastal waters of the southeastern United States on the basis of inputs and management practices centered near 2012, the base year of the model. PrevAuthorsAnne B. Hoos, Victor L. RolandSpatially referenced models of streamflow and nitrogen, phosphorus, and suspended-sediment loads in streams of the midwestern United States
In this report, SPAtially Referenced Regression On Watershed attributes (SPARROW) models developed to describe long-term (2000–14) mean-annual streamflow, total nitrogen (TN), total phosphorus (TP), and suspended-sediment (SS) transport in streams of the Midwestern part of the United States (the Mississippi River, Great Lakes, and Red River of the North Basins) are described. The nutrient and suspAuthorsDale M. Robertson, David A. SaadSpatially referenced models of streamflow and nitrogen, phosphorus, and suspended-sediment loads in streams of the northeastern United States
SPAtially Referenced Regression On Watershed attributes (SPARROW) models were developed to quantify and improve the understanding of the sources, fate, and transport of nitrogen, phosphorus, and suspended sediment in the northeastern United States. Excessive nutrients and suspended sediment from upland watersheds and tributary streams have contributed to ecological and economic degradation of nortAuthorsScott W. AtorSpatially referenced models of streamflow and nitrogen, phosphorus, and suspended-sediment loads in streams of the Pacific region of the United States
Although spatial information describing the supply and quality of surface water is critical for managing water resources for human uses and for ecological health, monitoring is expensive and cannot typically be done over large scales or in all streams or waterbodies. To address the need for such data, the U.S. Geological Survey developed SPAtially Referenced Regression On Watershed attributes (SPAAuthorsDaniel R. WiseSpatially referenced models of streamflow and nitrogen, phosphorus, and suspended-sediment transport in streams of the southwestern United States
Given the predicted imbalance between water supply and demand in the Southwest region of the United States, and the widespread problems with excessive nutrients and suspended sediment, there is a growing need to quantify current streamflow and water quality conditions throughout the region. Furthermore, current monitoring stations exist at a limited number of locations, and many streams lack streaAuthorsDaniel R. Wise, David W. Anning, Olivia L. MillerApplication of SPARROW modeling to understanding contaminant fate and transport from uplands to streams
Understanding spatial variability in contaminant fate and transport is critical to efficient regional water-quality restoration. An approach to capitalize on previously calibrated spatially referenced regression (SPARROW) models to improve the understanding of contaminant fate and transport was developed and applied to the case of nitrogen in the 166,000 km2 Chesapeake Bay watershed. A continuousAuthorsScott Ator, Ana María García - Web Tools
2002 SPARROW Model Results for the Midcontinental Region of North America: Total Phosphorus and Total Nitrogen
SPARROW model results of long-term mean-annual total nitrogen and total phosphorus in streams of the Midcontinental Region of North America. The simulated loads represent source inputs similar to 2002 and normalized to long-term average hydrologic conditions for the period from 1970 to through 2012.
Dissolved Solids Sources, Loads, and Yields For the Conterminous U.S.
Using the SPARROW (SPAtially-Referenced Regression on Watershed Attributes) model, long-term mean annual conditions for dissolved-solids sources, loads, and yields were predicted for nearly 66,000 stream reaches and their corresponding incremental catchments that drain the Nation.
Eastern United States 2002 Nutrient Loading
The U.S. Geological Survey applied the SPARROW model to assess the loads delivered in 2002 for estuaries and coastal waters along the Atlantic Ocean and eastern Gulf of Mexico.
- Software
SPARROW Modeling Program
SPARROW is a popular watershed modeling technique, distributed by the USGS, that estimates the amount of a contaminant transported from inland watersheds to larger water bodies by linking monitoring data with information on watershed characteristics and contaminant sources.
RSPARROW
RSPARROW, now available on the USGS GitLab repository, provides the first open-source version of the USGS SPARROW water-quality model
Point-Source Load Estimation Tool (PSLoadEsT)
Software for generating reproducible load calculations for point source dischargers. Includes features to manage common data challenges such as duplicates, incompatible input tables, and missing nutrient concentration or effluent flow data.
- News