Point-Source Nutrient Loads to Streams of the Conterminous United States, 1999-2020

This dataset was developed to estimate point-source total nitrogen and phosphorous loads to streams in the conterminous United States (U.S.) from December 1999 to November 2020. This dataset uses discharge and concentration information from point sources to streams in the conterminous United States from the U.S. Environmental Protection Agency (EPA) Integrated Compliance Information System - Permit Compliance System (ICIS-PCS) database. Nutrient concentrations were used to calculate point source loads. However, measured concentration data was often not available so “typical pollutant concentrations” (TPCs) were developed using concentration data from the same facility but a different time or from similar facilities. A new method for calculating TPCs was implemented using concentration data from other time periods to calculate TPCs. This dataset contains the EPA ICIS-PCS National Pollutant Discharge Elimination System (NPDES) facility, flow, and concentration data and updates or changes to the data, along with the TPC values and calculated total nitrogen and phosphorous loads.