The National Wetland Condition Assessment (NWCA) is a statistical survey of the condition of wetlands in the conterminous United States. It is designed to provide information on the extent of wetlands that support healthy biological condition, estimate how widespread major stressors are that impact wetland quality, and provide insight into the ecological integrity of wetlands nationwide.

This dataset is an archived (zipped) file comprised of chemical, physical and biological files used in developing the NWCA 2016 report. Sampling was conducted in the spring and summer of 2016 at approximately 1,000 sites in the conterminous U.S. Sites were selected using a statistical survey (probabilistic) design. The files include site information, vegetation characteristics, soil properties and chemistry, hydrology sources and disturbances, physical habitat, landscape metrics, algal toxins (microcystin), and water chemistry. Users are encouraged to visit the NARS data webpage for 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 NWCA 2016 archived data: U.S. Environmental Protection Agency. National Aquatic Resource Surveys. National Wetland Condition Assessment 2016 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-wetland-condition-assessment-2016. DOI: 10.23719/1531014

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 Wetland Condition Assessment 2016 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: NWCA 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.