| Title: | Escherichia coli release from streambed to water column during baseflow periods: A modeling study |
| Authors: | Park, Y., Y. Pachepsky, E.-M. Hong, D. Shelton and C. Coppock |
| Year: | 2017 |
| Journal: | Journal of Environmental Quality |
| Volume (Issue): | 46(1) |
| Pages: | 219-226 |
| Article ID: | |
| DOI: | 10.2134/jeq2016.03.0114 |
| URL (non-DOI journals): | |
| Model: | SWAT |
| Broad Application Category: | pollutant only |
| Primary Application Category: | pathogen fate and transport |
| Secondary Application Category: | in-stream and/or channel processes |
| Watershed Description: | 60.8 km^2 Little Love Creek, located in Franklin County in Southern Pennsylvania, U.S. |
| Calibration Summary: | |
| Validation Summary: | |
| General Comments: | |
| Abstract: | Streambed sediments can harbor large Escherichia coli
populations that are released into the water column during
high-flow events. Few studies have been conducted on the rates
of E. coli transfer from streambed sediment to water column
in low-flow conditions in natural streams. The aim of this work
was to apply the watershed-scale model SWAT (Soil and Water
Assessment Tool) to a natural stream to evaluate the need to
account for the E. coli release from streambed sediments during
baseflow periods and to compare the results of simulating
such a release by assuming predominantly passive transport,
driven by groundwater influx, against simulations assuming
predominantly active transport of random or chemotaxis-driven
bacteria movement. Escherichia coli concentrations in water
during baseflow periods were substantially underestimated
when E. coli release from the streambed was attributed only to
streambed sediment resuspension. When considered in addition
to the release due to sediment resuspension at high flows, the
active and passive release assumptions provided 42 and 4%
improvement, respectively, in the RMSE of logarithms of E. coli
concentrations. Estimated E. coli fluxes to water column during
the baseflow periods from June to November ranged from 3.3 ´
105 colony-forming units (CFU) m−2 d−1 in the game land area to
1.4 ´ 106 CFU m−2 d−1 in the mixed pasture and cropland. Results
demonstrate that release of E. coli from streambed sediments
during baseflow periods is substantial and that water column E.
coli concentrations are dependent on not only land management
practices but also on in-stream processes. |
| Language: | English |
| Keywords: | |