In 2006, the Iowa DNR identified 336 impaired water bodies in Iowa. The majority of these impairments are associated with elevated nutrient, sediment, or bacterial loads in streams and lakes. Poorly managed grazing of beef cattle in riparian areas may contribute to a reduction in quality of Midwest surface waters. However, research has shown that management practices that alter the timing, frequency, duration, and timing of grazing can reduce the impact of cattle on water sources.