Fate and Transport of E. coli in Cedar Creek Watershed, Texas
2009 Reno, Nevada, June 21 - June 24, 2009 , 2009

Reema, Padia, Israel David, Parker, Bailey, Sullivan, R. Karthikeyan, Saqib, Mukhtar

Presence of E. coli is recognized as an important indicator of fecal contamination leading to impairment of a water body. Apart from point and non-point sources, in-situ re-growth is believed to be a considerable source of E. coli in many cases. There is a need to identify, characterize, and quantify E. coli loads from various sources in a watershed. To understand re-growth phenomenon better, the fate of E. coli needs to be monitored under different environmental factors such as temperature, moisture content and pH. Wildlife and range cattle manure samples have been collected and analyzed for their E. coli content using EPA recommended Method 1603. Growth and die-off rates at different temperatures (0°C, 10°C, 25°C, and 50°C), moisture conditions (0%, 5%, 25%, 50%, 75% dry-basis) and pH (acidic, alkaline and basic) are being monitored. The concentrations measured within and among different temperatures over a period of 7 days showed highly variable counts. Potential E. coli loads calculated will then be incorporated in a newly developed model called Spatially Explicit Load Enrichment Calculation Tool (SELECT) to predict E. coli loads resulting from various identified sources in Cedar creek watershed of south central Texas. Findings of this research will aid in Watershed Protection Plan (WPP) development and Total Maximum Daily Load (TMDL) development to address impairment from point and non-point source pollution of E. coli in the State of Texas. The results and findings of our study will be discussed in this paper.