Impact of a Constructed Low Water Stream Crossing, an Innovative BMP, on Microbial Water Quality of a Rangeland Pasture Stream
ASAE Annual International Meeting , 2003

Thurston-Enriquez, J.A.

The impact that livestock in pastures have on microbial water quality is poorly understood. A low water stream crossing (LWSC) was designed and constructed in the middle of a stream pasture segment to evaluate it’s effectiveness as a potential BMP and as an alternative to excluding livestock from streams with permanent fencing. The construction and application of the crossing is discussed. The stream segment was investigated for the presence of indicator microorganisms and protozoan parasites commonly associated with livestock. Stream samples and flow data were collected approximately twice per month during a period of 6 months. Water samples were assayed for total coliforms, Escherichia coli, Enterococcus, Giardia cysts, and Cryptosporidium oocysts. Concentrations of indicator organisms appear to exceed new recommended EPA guidelines for recreational contact for E. coli and Enterococcus. The presence of cattle in the studied pasture was the likely cause of increased concentrations of indicator microorganisms downstream of the cattle crossing.