Dane County Awards $3.25 Million Contract for Yahara Chain of Lakes Sediment Removal Project

December 30, 2019
Ariana Vruwink, (608) 267-8823
County Executive

Project is Part of 11 Mile Sediment Removal Initiative for Flood Mitigation

Today, County Executive Joe Parisi announced that Dredgit Corporation will be awarded the contract to begin the first phase of Dane County’s Yahara Chain of Lakes Sediment Removal Project. This first phase will take place between Lakes Monona and Waubesa. The contract totals about $3.25 million and will further the County’s initiative to improve water flow, flood storage capacity, and fish and wildlife habitat in the Yahara Lakes.

“As climate change rains continue to impact our area, Dane County is committed to mitigating future flooding risks and increasing the flow of water through the Yahara Chain of Lakes,” said County Executive Joe Parisi. “We are excited to award this contract and work on this project in 2020. In the new year, we will also begin to form our own sediment removal crew to accelerate future phases of this initiative.”

The County’s multi-year sediment removal project in the Yahara Lakes will take place in five phases, with each phase carried out as Dane County secures permitting. At the site of this first phase, the County hopes to remove between two to three feet of sediment about 50 feet wide and approximately 1.5 miles long.

Water currently comes into the Yahara Chain of Lakes faster than it goes out—taking two inches of rain over two weeks to leave the Yahara Lakes system. The efficient movement of water downstream can be undermined by sediment loading. While sediment movement is a naturally occurring process, accumulation of sediment in the Yahara River and Lakes is greatly increased by human activity, including urban development. It is estimated that over 8.5 million pounds of sediment enter the Yahara River and Lakes each year from urban runoff.

The type of sediment removal that will take place between Lakes Monona and Waubesa is comparable to the County’s “Suck the Muck” initiative. Nearly a month after historic rainfall in the late summer of 2018, water levels on Lake Monona were 8 inches higher than Lake Waubesa. Sediment removal in this location could improve water quality, habitat, navigation, and the rate at which water leaves the Yahara Lakes in the wake of heavy rains.

In addition to this investment, County Executive Parisi is also including money in his 2020 budget to create a brand new sediment removal crew and purchase the equipment needed for the County to do its own hydraulic sediment removal. This will ensure for years to come that Dane County has the equipment and staff expertise in-house to manage work demands created by the new realities that pose unique challenges to a quickly growing area with diverse water resources.

The 2020 budget includes $5 million to purchase equipment needed for sediment removal work and the staff to carry out the job. This adds 4 new positions dedicated to Yahara Chain of Lakes sediment removal work in the Land and Water Resources Department. The County hopes this investment will accelerate its work to increase capacity and water flow in the Yahara Lakes.

The $3,249,500 contract between Dredgit Corporation and Dane County was approved during the County Board’s final meeting in 2019. Permits have been secured and the project is expected to start in the spring of 2020. Specific project timelines are being prepared by the contractor and the schedule will be posted in the near future on the Dane County Land and Water Resources website.