Attributes for NHDPlus version 2.1 catchments and modified routing of upstream watersheds for the conterminous United States: estimated nitrogen from septic, 2010
This metadata record documents an ascii comma-delimited file representing estimated nitrogen in kilograms by NHDPlus v2.1 catchments for the conterminous United States. Nitrogen estimates were taken from Estimated nitrogen from septic for the conterminous United States, 2010 published by the U.S. Geological Survey. …