HR: 0800h
AN: B41C-02    [Abstracts]
TI: Uncertainty Assessment for the Vegetated Filter Strip Performance with Respect to Manure- Borne Pathogens
AU: Pachepsky, Y A
EM: ypachepsky@anri.barc.usda.gov
AF: Environmental Microbial Safety Laboratory, USDA-ARS-BA-ANRI-EMSL , Bldg. 173, Rm. 203, BARC-EAST Powder Mill Road , Beltsville, MD 20705, United States
AU: * Guber, A K
EM: aguber@anri.barc.usda.gov
AF: Department of Environmental Sciences, University of California , A135 Bourns Hall , Riverside, CA 92521, United States
AU: Sadeghi, A M
AF: Hydrology and Remote Sensing Laboratory, 10300 baltimore avenue, bldg 007 BARC- WEST, room 211, Beltsville, MD 20705, United States
AU: Shelton, D M
AF: Environmental Microbial Safety Laboratory, USDA-ARS-BA-ANRI-EMSL , Bldg. 173, Rm. 203, BARC-EAST Powder Mill Road , Beltsville, MD 20705, United States
AB: Vegetated filter strips (VFS) separate fields and pastures from streams and other water bodies and can serve as barriers that prevent sediment and agricultural chemicals from entering waterways and spoiling them. Growing concern about the manure-borne pathogens as water pollutants defines the need to evaluate efficiency of VFSs with respect to pathogens. Selecting locations for the VFS placement can be done with the SWAT model allows for a comprehensive description of agricultural practices, and has proven to be efficient in applications to watershed with a substantial agricultural component. Functioning of VSF as barriers for manure-borne pathogens to the large extent depends on vegetation status, soil infiltration capacity in VFS, and rainfall intensity and duration. The effect of these factors on the pathogen breakthrough in VFS needs to be researched at the time scales smaller than the computation interval of one day that SWAT uses. The downscaling is necessary which creates an unavoidable uncertainty that cannot be ignored and has to be factored into the VFS efficiency estimates. We have developed the model STIR to simulate the overland transport and loss to infiltration of manure-borne pathogens in VFS. This model was used in Monte Carlo simulations in which the input parameters of vegetation, soil, rainfall, and pathogen load were drawn from probability distribution functions. The result of such simulations was also the probability distribution of the VFS efficiency. For the example of our experimental 6-m long VFS at the 20% slope, the VFS efficiency was less than 100% in 5% of cases, and less than 75% in 2.5% of cases. Relatively long high-intensity rainfalls, low hydraulic conductivities, high soil moisture contents before the rainfall, and high spread of surface water velocities were the main sources of the strip partial failure. Similar simulations can be done for any other VFS with site-specific soil and weather properties, and the results on terms of efficiency probabilities can be used in making decisions on VFS placement with respect to manure-borne pathogens.
DE: 0466 Modeling
DE: 0496 Water quality
DE: 1805 Computational hydrology
DE: 1838 Infiltration
DE: 1873 Uncertainty assessment (3275)
SC: Biogeosciences [B]
MN: 2007 Joint Assembly