Blaine County Evaluation and Assessment of Nitrogen Sources  by J.B, Connolly, K.E. Lopez-Bernal and D.L. Shaffer

Agricultural sources are the largest nitrogen contributors to the Wood River Valley Watershed. The primary agricultural sources of nitrogen – fertilizer and cattle waste – are directly related to agricultural production. Currently there are approximately four times as many cattle in the watershed as there are people. Unlike human nitrogen contributions in residential areas, no economically feasible methods exist for capturing and treating the rangeland cattle waste that constitutes a significant portion of the watershed nitrogen load. Significant reductions in rangeland nitrogen loads from cattle waste must involve reducing the cattle density and related beef production in the watershed. . . The level of wastewater treatment is critical in determining the effects of continued development on nitrogen water quality. . . Monitoring of nitrogen concentrations in ground and surface water should be expanded. . . Elevated nitrogen concentrations in surface waters are likely to occur during the winter months as a result of seasonal variations and during storm events as a result of altered hydrologic dynamics that occur during storms. . .Nitrogen trading is an efficient, fair, and flexible policy tool that can be used to decrease nitrogen loads in order to meet nitrogen loading goals . . .In order to understand whether a nitrogen trading system would be environmentally beneficial and cost-effective for the Watershed, an economic analysis must be completed. . . Watershed residents and public officials are in a position to control whether the magnitude of the nitrogen load to the Big and Little Wood rivers increases or decreases in future years.