Action on authorized lake levels urged
Calling the vote a "no-brainer," Madison's Commission on the Environment voted unanimously on a resolution to bring the city, county and state together to better manage the lakes in the Yahara watershed for the onset of flooding.
The resolution asks the Wisconsin Department of Natural Resources to relook at authorized lake levels for Mendota, the county to relook at summer minimum and maximum levels for the lake and both agencies as well as the National Weather Service and the cities of Madison, Monona and Middleton to establish flood levels for the chain of lakes -- Mendota, Monona, Waubesa and Kegonsa -- beginning south of the Yahara River.
This is not the first time the city has requested action on the lakes from the DNR, but the council member who proposed the resolution, Ald. Michael Schumacher, said record rainfall and flooding this year highlighted the problems of the lake system. That along with this resolution would prevent the DNR from saying "we didn't know" if another storm caused further damage, he said.
According to city engineer Larry Nelson, the last year that lake levels were set was nearly 30 years ago in 1979, and since then, the frequency of such high-intensity storms as the ones the state experienced in June have increased significantly.
Add in high lake levels after record snowfalls, and a particularly damaging situation for the Yahara lakes was created this year, he said.
"We knew that we had 100 inches of snowfall that was going to come down, and yet we had the same orders," he said. "We didn't have any flexibility to actually think ourselves through how we were going to handle this, and we got clobbered."
Peter Cannon, a member of the Madison Audubon Society, added that the increased urban nature of Dane County has also meant that water moves into the lakes faster, making flexibility in managing the system more important.
"I would argue that the '79 levels were too high," he said. "What has changed since is that we've become a lot more urban. Every new roof, every new parking lot, every new driveway, every new city street puts water into the lake quicker."
Schumacher said Lake Mendota is important to look at first because it serves as a storage tank for letting water into the other lakes in the system, which are managed by tributaries of the Yahara River as well as dams. In particular, the tributary between Monona and Waubesa has been obstructed by increased sediment over the years, slowing the flow down to a trickle and preventing Mendota from releasing the needed amount of water into Monona.
This has had a particularly drastic effect on the Cherokee Marsh, located on the north side of Madison in Schumacher's district. According to conservation manager Russ Hefty, increased water in Lake Mendota has hastened the erosion of the marsh, which began to break off in large chunks in the 1800s after the first dam was installed at Tenney Park. The "general consensus," he said, is that Lake Mendota is 5.5 feet above where it would be without the dam, backing up into the marsh and widening the Yahara River within the marsh an average of seven feet per year between 1980 and 2007.
"Basically we have an unsustainable situation," he said. "Even under 'normal' conditions, without all the flooding that we have, we'd have wetland losses."
Lower lake levels, he said, would help more wetland plants grow, providing a buffer against erosion and catching the sediment that has been filtering down to Monona. More plants would also help preserve the marsh, which in many places is only tethered to the ground by plant roots, he added.
File photo
The Yahara River in Tenney Park is shown in late June with high water from the rain and flooding that pounded the area that month.
