Restoration Spotlight: Lake Poygan Breakwall Phase 2 Construction

Article was originally published in Winnebago County Land and Water Conservation Department 2020 Annual Report.
Written by Melanie Leet, Resource Conservationist, Winnebago County

For anyone traveling by boat this summer near the mouth of the Wolf River where it outlets into Lake Poygan, you likely noticed the second phase of a very large offshore breakwall project in construction. The second phase of the Lake Poygan Breakwall was built which included two breakwall structures totaling 2,269 ft. The first phase of the project was installed in 2016 and included one structure that is 1,170 ft in length. This breakwall was then monitored for three years to determine how much it would settle into the lake bottom. Minimal settling occurred during this monitoring period, so the second phase was designed in 2019 and included two more breakwall segments. These two segments were constructed by barge over the summer of 2020, a lengthy process due to the fact that all the materials needed to be barged onsite from the other side of Lake Poygan.

Typically offshore breakwalls are built on the ice over winter, but due to the unstable ice conditions at the mouth of the Wolf River, it was determined these breakwalls would need to be constructed by barge. Because of the extent of this project, it would not have been possible without the partnership between many groups including the Lake Poygan Sportsmen’s Club, the Wisconsin Department of Natural Resources, Ducks Unlimited, and the Winnebago County Land & Water Conservation Dept. Winnebago County LWCD provided the design for this phase of the project and construction supervision in conjunction with Ducks Unlimited.

An estimated 600 acres of wetland have been lost from this site since 1941. Once all phases are complete, these breakwalls will create 540 acres of new wetland and protect the existing wetlands from further wind and wave action which will reduce the amount of sediment resuspension. Regeneration of vegetation in these protected areas will encourage improved fisheries and wildlife use of the acreage behind the breakwalls. Monitoring of the vegetation and fish populations in these areas was conducted previous to construction and will be conducted post construction to evaluate the effectiveness of these breakwalls. The next phase of the project will take place after the three years of monitoring has been completed and after funding is attained.

Questions? Please contact the Winnebago County Land and Water Conservation Department: https://www.co.winnebago.wi.us/lwcd

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