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National Aquatic Resource Surveys

Frequent Questions about Data from the National Aquatic Resource Surveys

On this page:

What types of data are available for download?

Data are provided in flat files (.csv) and are organized by survey and indicator. View a summary table of the parameters that were collected for each of the survey years and water resource types.

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Where can I find a description of the column headings within the data files?

Detailed descriptions of the data column headings can be found in the metadata file that accompanies each data file.

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Where can I get more information on the data analyses that were performed?

See the survey technical document below

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How do I find the data for the sites that I am interested in?

  • Select the survey of interest (waterbody type and year) in the pull-down menu.
  • Download the Site Information data file. Each row within the file includes the location (e.g., latitude and longitude coordinates, state, EPA region), sample collection date, and unique identification number (UID) for each sample collected in the survey.
  • Download the data files for the indicators of interest for the same survey. In each of the data files, locate the same UID from the Site Information file to match the data collected and analyzed to the site location of interest. (Note: For surveys 2007 and prior, use the SITE_ID and VISIT_NO to match the data with the site information).

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How should the NARS data be cited?

Please include the following citation and acknowledgment when the data are used:

Citation: U.S. Environmental Protection Agency. [insert the year the survey report was published]. National Aquatic Resource Surveys. [insert the survey name and survey year] (data and metadata files). Available from U.S. EPA web page: Date accessed: YYYY-MM-DD.

Survey Report Year
Wadeable Streams Assessment 2004 2006
National Lakes Assessment 2007 2010
National Rivers and Streams Assessment 2008-2009 2016
National Coastal Condition Assessment 2010 2016
National Wetland Condition Assessment 2011 2016
National Lakes Assessment 2012 2016
National Rivers and Streams Assessment 2013-2014 2020

Example citation for NLA 2007
U.S. Environmental Protection Agency. 2010. National Aquatic Resource Surveys. National Lakes Assessment 2007 (data and metadata files). Available from U.S. EPA website: Date accessed: YYYY-MM-DD.

Acknowledgment: The [insert the survey name and survey year] 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 with any questions.

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