05035-012 Clear Lake Watershed Final Report

Clear Lake, Iowa's third largest natural lake, is located in Cerro Gordo County in north-central Iowa. The lake is a premier natural resource and popular recreational destination in north central Iowa, providing more than $40 million dollars annually to the local economy. Despite the lake's already strong recreational use, water quality concerns have not allowed the lake to reach its full recreational potential. Clear Lake is listed on Iowa's 2004 303(d) Impaired Waters List due to excessive levels of phosphorus, bacteria, and turbidity. Urban storm water runoff from the 8,600 acre watershed is a significant contributor to Clear Lake's impairment. There are over 68 storm water outlet points in the Clear Lake watershed that allow untreated urban runoff to empty directly into Clear Lake. Local governments have been very active in installing storm water Best Management Practices (BMPs) at as many of the outlets that current funding allows. To date, 11 of the 68 sites (16%) have been protected. These improvements have been very effective in reducing contaminants in the storm water runoff, but the remaining outlets still need protection. The first phase of this grant request is for an investigation of 10 storm water outlet sites to determine the most cost effective BMP for each site. The second phase of the grant request is to implement the BMPs deemed most cost effective at 5 of the 10 sites investigated. The grant request addresses one of the main priorities of the Iowa Watershed Improvement Grant: storm water runoff.