The Fourmile Creek Watershed is a 76,600 acre watershed (HUC 10 – #0710000801) consisting of urban and agriculture communities. The watershed’s northernmost reaches are located in Boone and Story Counties and include portions of the cities of Sheldahl and Slater. The largest area of the watershed is located in Polk County and encompasses the cities of Pleasant Hill, Ankeny, Altoona, Alleman, Elkhart, and Des Moines.
Fourmile Creek and its tributaries run for over 40 miles, beginning in northern Polk County and eventually joining with the Des Moines River in southern Polk County. Resource concerns seen in and along the creek include high bacteria levels, excess nutrients (nitrogen and phosphorus), and erosion. A Watershed Management Authority (WMA) was formed to try and address these concerns. A watershed management plan was completed by Snyder and Associates and will be used to improve the watershed and address the environmental concerns.