A Review of Stormwater Quality Data for Salt Lake County, Utah

Salt Lake County (SLCo), Salt Lake City (SLC) and Utah department of Transportation (UDOT) have been permitted under the Municipal Phase I National Pollutant Discharge Elimination System (NPDES) program since 1995. Stormwater runoff monitoring and wet and dry weather screenings have been conducted since 1992 on nine outfall locations located throughout Salt Lake County. A total of 13 storm events have been sampled up to 1999. Annual pollutant loads and event mean concentrations (EMC) were calculated for total suspended solids (TSS), trace metals, total phosphorus, and biological oxygen demand for three primary landuse types residential, transportation, and commercial/industrial. Annual pollutant loads for transportation and commercial/industrial la nduses were determined to be the greatest contributor to all major pollutants. EMCs for all six major pollutants were found to fall within the range of values reported by several municipalities across the country with a similar climate type. The calculat ed EMCs also compared reasonably with the National Urban Runoff Program (NURP) data for Salt Lake County.