Prior Lake Outlet Channel Realignment/Wetland Restoration

Estimated Timeline: December 2018-November 2021 Estimated Cost: Feasibility Study: $22,000

The Prior Lake Outlet Channel was constructed in 1983 to assist with localized flooding in the City of Shakopee. The system was replaced once in 2010, and then received damage in 2014 after record-breaking rainfalls. In 2010, the outlet structure war replaced. The Prior Lake Outlet Channel was damaged in 2014 after the area saw record rainfall. The 2014 storm damaged the Prior Lake Outlet Channel, knocked over trees, damaged culverts, and caused bank erosion. Waters downstream, such as Dean Lake, have since been receiving additional pollutant loads.

The Prior Lake Outlet Channel Realignment and Wetland Restoration project included a feasibility study to determine the potential water quality benefits to Dean Lake that would result from the restoration of the Prior Lake Outlet Channel. The restoration included altering the realignment (creating meanders) and restoration of the channel and constructing a flow-through wetland complex to slow the flow of water. Funds were also used to construct identified activities and best management practices (BMPs) to reduce total phosphorus (TP) and total suspended solids (TSS) that will benefit water quality in Dean Lake and, ultimately, the Minnesota River, from increased stormwater runoff draining to the channel from new development in the area.

The project was completed in November 2021 and received watershed-based implementation funding from the Minnesota Board of Water and Soil Resources (BWSR). The project feasibility study verified the estimated load reductions of 30-50 pound of TP annually and 75,000-100,000 pounds of TSS annually. Channel restoration and wetland construction provided additional capacity and control structures. Project partners at the Prior Lake-Spring Lake Watershed District have created several resources detailing the Prior Lake Outlet Channel and this project here.

 

Prior Lake Outlet Channel Realignment/Wetland Restoration Workplan

Wetland Conservation Act Notice of Application 

Concept Plan #1

LMRWD Technical Review - 99% Plans (dated May 6, 2020)