MADISON, Wis. — A task force is developing recommendations on how a southern Wisconsin county should prevent future flooding after torrential rains last summer caused lakes to spill over, prompting evacuations.
A study released this month identified strategies for Dane County to lower flood levels in the Yahara chain of lakes, which include Lakes Mendota and Monona. The task force assembled by the county's Board of Supervisors is reviewing the report and plans to present recommendations to county officials by April 1, Wisconsin Public Radio reported.
Dane County budgeted more than $18 million this year to go toward flood mitigation projects. The move comes after then-Gov. Scott Walker declared a state of emergency in the county in August, when flooding drenched streets and damaged homes.
The new report identified two types of lake management strategies: adaptation and mitigation. Adaptation strategies reduce flood vulnerability without changing fundamental problems, while mitigation addresses the underlying issues.
"Fundamentally, what the report says is that in order to reduce future flooding, we need to improve flow in the system," said Sharon Corrigan, who chairs the county's board. "Because our lake system is very flat, water that comes into the system, stays in the system, even if we have everything opened up wide."
Two mitigation strategies, dredging and pumping, were identified in the report as the most effective. Dredging would remove excess sediment and material from the Yahara River. Pumping would reroute water from the lake chain to another body of water, such as Badfish Creek near Cooksville. Using the two methods together could lower flood levels by 7 to 21 inches (18 to 53 centimeters), according to the report.
The option has its setbacks, including that dredging could affect historical artifacts.
The adaptation strategies include lowering the level of Lake Mendota by a foot, and removing all dams from the lakes chain.
The task force will seek public comment before making recommendations.