Technical Abstract: This study examined the effectiveness of surface impoundments for mitigating water quality downstream of a dairy operation. Two small, mixed land use watersheds (~1000 ha) were studied over a three year period. Each watershed incorporates management with grazed winter wheat pastures and native rangeland, but one was further impacted by effluent from a small (~350 head) dairy operation. Three surface impoundments positioned sequentially on each watershed drainage were sampled. Water samples were collected monthly from the inlet and outlet of each surface impoundment, as well as a location 0.5 km upstream from the first impoundment (i.e., source inlet). The samples were analyzed for nitrate-nitrogen (NO3-N), water-soluble phosphorus (WSP), bioavailable phosphorus (BAP), fecal and total coliforms (FC and TC), and heterotrophic bacteria (HC) counts. Expected results will provide insight on 1) comparison in nutrient and pathogen levels between a grazed watershed and a watershed with grazing and effluent contributions from a dairy operation, and 2) the effectiveness of surface impoundments for mitigating the impact of effluents in a watershed. Implications of such a study can lead to efficient and cost-effective methods to enhance downstream water quality while also providing habitat for wildlife.