Forest streamwater concentrations of nitrogen and phosphorus: A comparison with EPA's proposed water quality criteria

Abstract

To address the problem of excessive nutrients in US waters, the Environmental Protection Agency is developing water quality criteria for four types of waterbodies and 14 ecoregions. In this article we focus on total nitrogen and total phosphorus criteria for rivers and streams. A review of 300 streams draining small forested watersheds finds that nutrient concentrations often exceed EPA's proposed criteria. More detailed nutrient concentration patterns were evaluated for eight unmanaged research forested watersheds, three of which would have failed EPA criteria and been identified as impaired. Finer-scale tools would more precisely reflect water quality patterns and make the nutrient criteria rational, physically achievable, and biologically relevant.