Water Resources Research Act Program

Details for Project ID 2016SD260B

Evaluating E. coli particle attachment and the impact on transport during high flows.

Institute: South Dakota
Year Established: 2016 Start Date: 2016-03-01 End Date: 2017-02-28
Total Federal Funds: $23,172 Total Non-Federal Funds: $46,343

Principal Investigators: Rachel McDaniel, Bruce Bleakley

Abstract: Nearly 70% of the streams in South Dakota are impaired or threatened of becoming impaired. The most common cause of impairment is bacteria, including E. coli. Recreational waters, such as the Big Sioux River, are a concern for public health as high E. coli concentrations are indicators of fecal pollution. The goal of this study is to evaluate E. coli attachment to particles of different sizes and estimate the impact of attachment on E. coli transport in streams during high flows. This will provide additional information about how the bacteria are being transported within stream environments, the load contribution of each particle size, and an initial estimate of transport distance based on the particle size. Skunk Creek is a major contributor of bacterial pollution to the Big Sioux River, and was therefore selected as the study site. Six high flow events will be monitored for 5 hours with samples collected every 30 minutes. E. coli concentrations will be measured and analyzed for attachment to particles of different sizes. Loads will be calculated to assess the peak transport times of total E. coli, unattached E. coli, and E. coli attached to different particle sizes. High flow events have been shown to resuspend bacteria from bottom sediments; therefore, the bed shear stress will be compared with the E. coli concentrations associated with different particle sizes. This will provide insight into the force required to resuspend bacteria attached to different sized particles. The transport distance for each particle size will be estimated with information calculated by Stoke’s Law. This will provide information about how many bacteria are being transported over what distance. The ability to better predict movement of E. coli and associated pathogenic microorganisms is of continuing interest and importance to public health authorities, microbiologists and engineers. It will help confirm efficacy of practices to control entry of these bacteria into surface waters, and help devise future methodologies to better accomplish control.