20 years of Measured Changes in the Shenandoah River Quality

Presentations: PowerPoint Author(s): Wayne Webb Soil and Water Conservation Director Board member of the Friends of the Shenandoah River Lord Fairfax Soil and Water Conservation District Friends of Shenandoah River Clarke County, Virginia

Abstract: Nitrogen and phosphorus concentrations in the Shenandoah River have been reduced in the past 20 years at stream flows of less than 1 cubic foot per second per square mile (cfsm). Ortho phosphorus has been reduced through the entire flow range. Total nitrogen (TN) and total phosphorus (TP) concentrations at stream flows above 2 cfsm are the same or higher. Loads of TN and TP to Chesapeake Bay are directly related to stream flow. The 8-day flood on the Susquehanna River in September 2011 delivered more TN and TP to the Bay than 2 years of Shenandoah River flow.