Shenandoah River Accumulated Wastewater Ratio

De facto wastewater reuse from Waste Water Treatment Facilities (WWTF) has the potential to be a significant contributor of Endocrine Disrupting Chemicals. An ArcGIS model of WWTFs, NHDPlus Version 2 stream networks (USGS and EPA 2012), and gage stations across the Shenandoah River watershed was created to calculate accumulated wastewater ratio. Virginia Pollutant Discharge Elimination System (VPDES) discharge facilities, VPDES outfall locations, and stream gages were spatially joined to the nearest river segment. Waste Water inputs from VPDES outfall locations were summarized by river segment COMIDs (Common identifier). All VPDES wastewater discharge facility locations were verified with VPDES outfall locations and United States Environmental Protection Agency (EPA) Facility Registry Service's facilities. WWTFs were categorized as industrial or municipal based on the type of permit they were granted. Accumulated wastewater and accumulated wastewater ratio were calculated using a python script. Maximum facility-capacity permitted wastewater discharge and 2015 average-annual wastewater discharge were used to calculate accumulated wastewater ratios for mean-annual and mean-August streamflow conditions.