Wetlands and Vegetative Buffers – filtering pollutants from runoff
UC Davis Plant Sciences , 2009
Atwell, R., Six, J.
We examined how well grass/forb vegetated strips filter E. coli, Cryptosporidium parvum, Giardia, and Salmonella from rangeland and irrigated pasture runoff at the UC Sierra Foothill Research and Extension Center. We applied cattle fecal pats to small runoff plots, and measured microbe load trapped in the filter during rainfall (rangeland) and irrigation (irrigated pasture) runoff. We examined filter strip widths of 0.1, 1.1, and 2.1 meters (yards). We found that annual rangelands and irrigated pastures retain the vast majority of the microbes deposited in cattle fecal pats. Over 90% of the microbe load was either retained in the fecal pat, dead, or filtered by the vegetation strip within 0.1 yard of the fecal pat. Each additional yard of filter strip removed 30 to 99.9% of the microbes that were mobilized more that 0.1 yard from the fecal pat.