The National Lakes Assessment (NLA) is a statistical survey of the condition of our nation's lakes, ponds, and reservoirs. It is designed to provide information on the extent of lakes that support healthy biological condition and recreation, estimate how widespread major stressors are that impact lake quality, and provide insight into whether lakes nationwide are getting cleaner. This dataset is an archived (zipped) file comprised of chemical, physical and biological files used in developing the NLA 2017 report. Sampling was conducted in the summer of 2017 at approximately 1000 sites in the conterminous U.S. Sites were selected using a statistical survey (probabilistic) design. The files include water chemistry, profile data, benthic macroinvertebrates, physical habitat, landscape metrics, phytoplankton data, secchi depth, data, tropic status, zooplankton, etc. Users are encouraged to visit the NARS data webpage for updates to data files (e.g., for example updated zooplankton files) and data from other surveys. https://www.epa.gov/national-aquatic-resource-surveys/data-national-aquatic-resource-surveys Citation for the NLA 2017 archived data: U.S. Environmental Protection Agency. National Aquatic Resource Surveys. National Lakes Assessment 2017 Report. Archived Data. (INSERT data and metadata files used). Available from U.S. EPA web page: https://www.epa.gov/national-aquatic-resource-surveys/reports-and-data-national-lakes-assessment-2017. DOI: 10.23719/1529585 EPA encourages users who are publishing subsets of the data (say as part of a journal article publication) to include the above citation. EPA also encourages users of the data to include the following acknowledgement: “The National Lakes Assessment 2017 data were a result of the collective efforts of dedicated field crews, laboratory staff, data management and quality control staff, analysts and many others from EPA, states, tribes, federal agencies, universities, and other organizations. Please contact nars-hq@epa.gov with any questions.” Additional information: NLA is part of the National Aquatic Resource Surveys, an EPA/State/Tribal partnership. The National Aquatic Resource Surveys (NARS) are statistical surveys designed to assess the status of and changes in quality of the nation’s coastal waters, lakes and reservoirs, rivers and streams, and wetlands. Using sample sites selected at random, these surveys provide a snapshot of the overall condition of the nation’s water. Because the surveys use standardized field and lab methods, we can compare results from different parts of the country and between years. Citation information for this dataset can be found in Data.gov's References section.

The National Lakes Assessment (NLA) is a statistical survey of the condition of our nation's lakes, ponds, and reservoirs. It is designed to provide information on the extent of lakes that support healthy biological condition and recreation, estimate how widespread major stressors are that impact lake quality, and provide insight into whether lakes nationwide are getting cleaner. This dataset is an archived (zipped) file comprised of chemical, physical and biological files used in developing the NLA 2017 report. Sampling was conducted in the summer of 2017 at approximately 1000 sites in the conterminous U.S. Sites were selected using a statistical survey (probabilistic) design. The files include water chemistry, profile data, benthic macroinvertebrates, physical habitat, landscape metrics, phytoplankton data, secchi depth, data, tropic status, zooplankton, etc. Users are encouraged to visit the NARS data webpage for updates to data files (e.g., for example updated zooplankton files) and data from other surveys. https://www.epa.gov/national-aquatic-resource-surveys/data-national-aquatic-resource-surveys Citation for the NLA 2017 archived data: U.S. Environmental Protection Agency. National Aquatic Resource Surveys. National Lakes Assessment 2017 Report. Archived Data. (INSERT data and metadata files used). Available from U.S. EPA web page: https://www.epa.gov/national-aquatic-resource-surveys/reports-and-data-national-lakes-assessment-2017. DOI: 10.23719/1529585 EPA encourages users who are publishing subsets of the data (say as part of a journal article publication) to include the above citation. EPA also encourages users of the data to include the following acknowledgement: “The National Lakes Assessment 2017 data were a result of the collective efforts of dedicated field crews, laboratory staff, data management and quality control staff, analysts and many others from EPA, states, tribes, federal agencies, universities, and other organizations. Please contact nars-hq@epa.gov with any questions.” Additional information: NLA is part of the National Aquatic Resource Surveys, an EPA/State/Tribal partnership. The National Aquatic Resource Surveys (NARS) are statistical surveys designed to assess the status of and changes in quality of the nation’s coastal waters, lakes and reservoirs, rivers and streams, and wetlands. Using sample sites selected at random, these surveys provide a snapshot of the overall condition of the nation’s water. Because the surveys use standardized field and lab methods, we can compare results from different parts of the country and between years. Citation information for this dataset can be found in Data.gov's References section.

National Lakes Assessment 2007 Datafiles for Report “National Lakes Assessment: A Collaborative Survey of the Nation’s Lakes”: The National Lakes Assessment (NLA) is a statistical survey of the condition of our nation's lakes, ponds, and reservoirs. It is designed to provide information on the extent of lakes that support healthy biological condition and recreation, estimate how widespread major stressors are that impact lake quality, and provide insight into whether lakes nationwide are getting cleaner. The first NLA was conducted in 2007. This dataset is an archived (zipped) file comprised of chemical, physical and biological files used in developing the NLA report. Sampling was conducted in the summer of 2007 at approximately 1000 sites in the conterminous U.S. Sites were selected using a statistical survey (probabilistic) design. The files include water chemistry, profile data, benthic macroinvertebrates, physical habitat, landscape metrics, phytoplankton data, secchi depth, data, tropic status, water isotopes, zooplankton, etc. Users are encouraged to visit the NARS data webpage for potential updates to data files and data from other surveys. https://www.epa.gov/national-aquatic-resource-surveys/data-national-aquatic-resource-surveys Citation for the NLA 2007 archived data: U.S. Environmental Protection Agency. National Aquatic Resource Surveys. National Lakes Assessment 2007 Report. Archived Data. (INSERT data and metadata files used). Available from U.S. EPA web page: https://www.epa.gov/national-aquatic-resource-surveys/national-lakes-assessment-2007-report. DOI: 10.23719/1529550 EPA encourages users who are publishing subsets of the data (say as part of a journal article publication) to include the above citation. EPA also encourages users of the data to include the following acknowledgement: “The National Lakes Assessment 2007 data were a result of the collective efforts of dedicated field crews, laboratory staff, data management and quality control staff, analysts and many others from EPA, states, tribes, federal agencies, universities, and other organizations. Please contact nars-hq@epa.gov with any questions.” Additional information: NLA is part of the National Aquatic Resource Surveys, an EPA/State/Tribal partnership. The National Aquatic Resource Surveys (NARS) are statistical surveys designed to assess the status of and changes in quality of the nation’s coastal waters, lakes and reservoirs, rivers and streams, and wetlands. Using sample sites selected at random, these surveys provide a snapshot of the overall condition of the nation’s water. Because the surveys use standardized field and lab methods, we can compare results from different parts of the country and between years. Citation information for this dataset can be found in Data.gov's References section.

National Lakes Assessment 2007 Datafiles for Report “National Lakes Assessment: A Collaborative Survey of the Nation’s Lakes”: The National Lakes Assessment (NLA) is a statistical survey of the condition of our nation's lakes, ponds, and reservoirs. It is designed to provide information on the extent of lakes that support healthy biological condition and recreation, estimate how widespread major stressors are that impact lake quality, and provide insight into whether lakes nationwide are getting cleaner. The first NLA was conducted in 2007. This dataset is an archived (zipped) file comprised of chemical, physical and biological files used in developing the NLA report. Sampling was conducted in the summer of 2007 at approximately 1000 sites in the conterminous U.S. Sites were selected using a statistical survey (probabilistic) design. The files include water chemistry, profile data, benthic macroinvertebrates, physical habitat, landscape metrics, phytoplankton data, secchi depth, data, tropic status, water isotopes, zooplankton, etc. Users are encouraged to visit the NARS data webpage for potential updates to data files and data from other surveys. https://www.epa.gov/national-aquatic-resource-surveys/data-national-aquatic-resource-surveys Citation for the NLA 2007 archived data: U.S. Environmental Protection Agency. National Aquatic Resource Surveys. National Lakes Assessment 2007 Report. Archived Data. (INSERT data and metadata files used). Available from U.S. EPA web page: https://www.epa.gov/national-aquatic-resource-surveys/national-lakes-assessment-2007-report. DOI: 10.23719/1529550 EPA encourages users who are publishing subsets of the data (say as part of a journal article publication) to include the above citation. EPA also encourages users of the data to include the following acknowledgement: “The National Lakes Assessment 2007 data were a result of the collective efforts of dedicated field crews, laboratory staff, data management and quality control staff, analysts and many others from EPA, states, tribes, federal agencies, universities, and other organizations. Please contact nars-hq@epa.gov with any questions.” Additional information: NLA is part of the National Aquatic Resource Surveys, an EPA/State/Tribal partnership. The National Aquatic Resource Surveys (NARS) are statistical surveys designed to assess the status of and changes in quality of the nation’s coastal waters, lakes and reservoirs, rivers and streams, and wetlands. Using sample sites selected at random, these surveys provide a snapshot of the overall condition of the nation’s water. Because the surveys use standardized field and lab methods, we can compare results from different parts of the country and between years. Citation information for this dataset can be found in Data.gov's References section.

National Lakes Assessment 2012 Datafiles for Report “National Lakes Assessment 2012: A Collaborative Survey of lakes in the United States”: The National Lakes Assessment (NLA) is a statistical survey of the condition of our nation's lakes, ponds, and reservoirs. It is designed to provide information on the extent of lakes that support healthy biological condition and recreation, estimate how widespread major stressors are that impact lake quality, and provide insight into whether lakes nationwide are getting cleaner. This dataset is an archived (zipped) file comprised of chemical, physical and biological files used in developing the NLA 2012 report. Sampling was conducted in the summer of 2012 at approximately 1000 sites in the conterminous U.S. Sites were selected using a statistical survey (probabilistic) design. The files include water chemistry, profile data, benthic macroinvertebrates, physical habitat, landscape metrics, phytoplankton data, secchi depth, data, tropic status, zooplankton, etc. Users are encouraged to visit the NARS data webpage for updates to data files (e.g., for example updated zooplankton files) and data from other surveys. https://www.epa.gov/national-aquatic-resource-surveys/data-national-aquatic-resource-surveys Citation for the NLA 2012 archived data: U.S. Environmental Protection Agency. National Aquatic Resource Surveys. National Lakes Assessment 2012 Report. Archived Data. (INSERT data and metadata files used). Available from U.S. EPA web page: https://www.epa.gov/national-aquatic-resource-surveys/national-results-and-regional-highlights-national-lakes. DOI: 10.23719/1529584 EPA encourages users who are publishing subsets of the data (say as part of a journal article publication) to include the above citation. EPA also encourages users of the data to include the following acknowledgement: “The National Lakes Assessment 2012 data were a result of the collective efforts of dedicated field crews, laboratory staff, data management and quality control staff, analysts and many others from EPA, states, tribes, federal agencies, universities, and other organizations. Please contact nars-hq@epa.gov with any questions.” Additional information: NLA is part of the National Aquatic Resource Surveys, an EPA/State/Tribal partnership. The National Aquatic Resource Surveys (NARS) are statistical surveys designed to assess the status of and changes in quality of the nation’s coastal waters, lakes and reservoirs, rivers and streams, and wetlands. Using sample sites selected at random, these surveys provide a snapshot of the overall condition of the nation’s water. Because the surveys use standardized field and lab methods, we can compare results from different parts of the country and between years. Citation information for this dataset can be found in Data.gov's References section.

The National Recommended Water Quality Criteria is a compilation of national recommended water quality criteria for the protection of aquatic life and human health in surface water for approximately 150 pollutants. These criteria provide guidance for states and tribes to use in adopting water quality standards.

NRSA siteinfo, water chemistry, and physical habitat datasets from 2008-9, 2013-14, and 2018-19, StreamCat for wetland variables for each site. This dataset is associated with the following publication: Flotemersch, J., K. Blocksom, A. Herlihy, P. Kaufmann, R. Mitchell, and D. Peck. Distribution and Characteristics of Blackwater Rivers and Streams of the Contiguous United States. WATER RESOURCES RESEARCH. American Geophysical Union, Washington, DC, USA, 60(2): e2023WR035529, (2024).

US National Lake Assessment data. Citation information for this dataset can be found in the EDG's Metadata Reference Information section and Data.gov's References section.

US National Lake Assessment data. Citation information for this dataset can be found in the EDG's Metadata Reference Information section and Data.gov's References section.

This is a coverage of the boundaries and codes used for the U.S. Geological Survey's National Water-Quality Assessment (NAWQA) Program Study-Unit investigations in the conterminous United States, excluding the High Plains Regional Ground-Water Study. The data set represents the areas studied during the first decade of the NAWQA Program, from 1991-2001 ("cycle 1").