Lac La Belle spans 1,154 acres in the City of Oconomowoc, located approximately 30 miles west of Milwaukee. The community and area stakeholders — including the Village of Lac La Belle, Town of Oconomowoc and Lac La Belle Lake Management District — had been rallying for an updated boat launch for some time, with the goal of incorporating upgrades to the launch with neighboring City Beach Park to improve site flow, safety, accessibility, and stormwater management.

MSA worked with the City in applying for a Recreational Boating Facilities Grant (RBF) from the Wisconsin DNR to help offset the overall project costs. Project site improvements include a new expanded and renovated asphalt parking lot, underground stormwater, rain garden, retaining wall and railing, general site grading and demolition, boat launch expansion, repair to existing launches, pier improvements, site lighting and electrical and site restoration.

One challenge of the existing launch is its relatively low elevation. In this case, the floodplain line directly bisects the parking lot, making it inaccessible during high-water events and requiring new stormwater collection and storage practices to achieve stormwater BMP compliance. The site also currently slopes toward the lake, meaning that all runoff and associated Total Suspended Solids (TSS) is funneled directly into Lac La Belle. MSA designed a variety of boat launch upgrades to address these challenges and more, including utilizing fill to raise the elevation of the shoreline area, constructing three new wetland/sediment basin areas, and re-grading the site to drain into those new collection systems rather than into the lake.

The site also needed a new system to collect, store and treat stormwater and lake water during high-water events, so MSA stormwater engineers and hydraulic modelers determined the right size and elevation for a new underground storage system. Constructed of large-diameter corrugated metal piping that is welded together, the 8,750 cubic feet of underground storage will be placed so that when the lake level rises, water backs up into the drainage system where it is stored until the lake recedes — after which, it is slowly released over hours of time — allowing sediments to settle out and reducing any adverse impacts of a quick release (shoreline erosion that would have occurred due to site modifications) without mitigation practices in place.

Site work is underway at the Lac La Belle Boat Launch and MSA is also assisting with the dredging of Lac La Belle Marina to improve capacity. The project is anticipated to be complete and open for use in May of 2025, much to the delight of local residents, stakeholders, and boating enthusiasts.