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LAND USE AND SEASONAL EFFECTS ON URBAN STORMWATER RUNOFF MICROORGANISM CONCENTRATIONS
Citation:
Selvakumar*, A AND M Borst*. LAND USE AND SEASONAL EFFECTS ON URBAN STORMWATER RUNOFF MICROORGANISM CONCENTRATIONS. Presented at World Water and Environmental Resources Congress 2004, Salt Lake City, UT, June 27 - July 01, 2004.
Impact/Purpose:
To inform the public
Description:
Stormwater samples collected from storm sewers draining small municipal separate storm sewer systems shown to be free of cross connections within an urban watershed dominated by a single land use were analyzed for pathogens (Pseudomonas aeruginosa and Staphylococcus aureus) and indicator organisms (total coliforms, fecal coliforms, fecal streptococci, enterococci, and E. coli). The samples were collected from three land-use designations (high-density residential, low-density residential and landscaped commercial) in all four seasons. Flow-weighted samples were collected using automatic samplers connected to flow meters. Rain gauges in the drainage basin recorded the event while the flow meter recorded flow velocity, water level, pH, dissolved oxygen, conductivity, and temperature of the runoff. The concentrations of microorganisms in the stormwater runoff were found to be similar to, but less variable than, those reported in the National Pollutant Discharge Elimination System (NPDES) database (Pitt et al., 2003a). Organism concentrations from high-density residential areas were higher than those associated with low-density residential and landscaped commercial areas. Concentrations of organisms were significantly affected by the season during which the samples were collected. The lowest concentrations were observed during winter. The results will help watershed managers target BMPs or treatments to land uses having higher runoff loads having greater impact on lowering the total load to receiving water.