Estimated nitrogen from septic for the conterminous United States, 2010 (SepN_CONUS_bg_2010)

This metadata record documents a rudimentary estimate of nitrogen from septic for the conterminous United States for 2010, derived from block-group 1990 and 2010 Decennial Census of Population and Housing data. Specifically, the data were computed from 1990 population and housing data where a ratio of the total population to the people on septic was obtained and applied to 2010 population data by block group. All input data were acquired from the National Historical Geographic Information System (NHGIS, Manson and others, 2017). The amount of nitrogen in pounds per person per year was derived from documentation supporting the Chesapeake Bay Program's Phase 5.3 Community Watershed Model (USEPA, 2010). The Supplemental Information element in this metadata record contains more detailed accounting of methods, sources, and limitations.