Crailsheim Water Quality Improvement Pond

Okabena Lake, in Worthington, Minnesota, is plagued by excess phosphorus and sediment loading that causes harmful algae blooms and poor water clarity. Excess nutrients and sediment contribute to the impaired status of the lake, occasional objectionable odors, reduced recreational use, lack of aquatic plants and less diverse aquatic life. The lake has both regional and local importance. It is identified as a high priority in county, watershed, and Missouri River Watershed CWMP plans. The Sunset Bay sub-watershed is a significant contributor of non-point source phosphorus pollution to Okabena Lake. This project will treat water flowing from this largely agricultural sub-watershed by constructing a 15-acre sedimentation reduction and water quality treatment pond on Independent School District (ISD) 518's property. When completed, the project will remove 327 pounds of phosphorus annually achieving 11% of the TMDL reduction goal for non-point source phosphorus. Current water management plans identify the need for storage practices like this that will provide high value TSS and TP reductions. Project partners include the OOWD, Nobles SWCD, City of Worthington and ISD 518. The project's primary goal is maximizing total phosphorus removals while providing cost-effective life-cycle treatment. Secondary goals include water retention in 2 year and 10 year frequency storm events leading to downstream floodplain reduction and sediment retention. This project will also enhance educational opportunities, protect the floodplain from development, and provide new and enhanced aquatic and terrestrial habitat. The OOWD has already completed and paid for a project feasibility report, preliminary design, and approval/land rights coordination necessary for construction.