Conservation Practice Effects On Water Quality In the Cheney Lake Watershed.

Water quality in Cheney Lake, the primary water supply for Wichita, KS, is impaired from excess sediment and phosphorus, which have promoted algal blooms and resulted in foul taste and odor.  Over the past 12 years, federal, state, and local funding has encouraged conservation practice implementation in Cheney Lake Watershed as part of a source-water protection plan.  The objectives of this study were to determine the impact of reduced tillage, terraces, and conservation reserve program on sediment and P loading to Cheney Lake.  Water quality impacts of the conservation practices were simulated with the Soil and Water Assessment Tool (SWAT) accounting for temporal and spatial variations in conservation practice implementation. Modeling results indicate that reduced tillage had the largest impact on sediment load reductions, however it did not reduce P loading to the reservoir.  Terraces implementation and CRP reduced P loading, but reductions were minimal (3 and 1% respectively) due to placement of the conservation practices.  This data suggests that voluntary conversion to no-till and reduced till is an effective method at reducing sediment losses, however other conservation practices are necessary to reduce P losses.