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Abstract: The Section 303(d) list submitted to and approved by EPA in 1998, identifies 281 river segments and 29 lakes in the Kansas-Lower Republican Basin as water quality impaired. Among the streams, excessive levels of fecal coliform bacteria caused the greatest number of impairments. Among the lakes, eutrophic conditions indicative of excessive algae production was the predominant cause of impairment. The pollutants limiting the use of Kansas-Lower Republican Basin streams include selenium, sulfate, dissolved oxygen depletion, ammonia, chloride, chlordane, zinc, nutrient oxygen demand, and sediment. Additional lake impairments were caused by atrazine, alachlor, dissolved oxygen depletion, pH, fecal coliform bacteria, siltation, and excessive aquatic plants. Each parameter causing impairment requires a TMDL. Tuttle Creek Lake on the southern edge of the Blue River Basin had TMDLs set for eutrophication, observed siltation and/or identified chronic turbidity that impacts development of a trophic state in the lake, and pesticide impairments by atrazine and alachlor herbicides. During 1997, the Blue River Compact, a joint group between Kansas and Nebraska created a monitoring plan to investigate the pesticide impairment issues in the basin and their contribution to the impairments reported in Tuttle Creek Lake. Funding for this monitoring project was obtained from the U. S. Environmental Protection Agency, Syngenta Crop Protection, Nebraska Department of Environmental Quality, Nebraska Department of Agriculture, Kansas Department of Agriculture, and Kansas State University. The designated uses of the Lake included primary contact recreation, food procurement, domestic water supply and expected aquatic life support. This paper will present monitoring results used to address the pesticide TMDLs for the Blue River Watershed and Tuttle Creek Reservoir.