Beyond the Breach: How communities are learning to rebuild after historic flooding
PORTLAND TOWNSHIP, Wis. (WKBT) — One year ago, historic rainfall devastated parts of southeastern Minnesota and Western Wisconsin. Now some officials are wondering if there could be better ways to protect their communities for the next time.
The Coon Creek Watershed spans more than 90,000 acres across portions of La Crosse, Monroe and Vernon Counties. In that area, there are 14 dams that were designed specifically for flood control. But at the peak of last year’s flood, some of the dams couldn’t keep up, which is leading some officials to consider other options.
As the sun rose, residents were salvaging what they could. It’s around that time that Bob Micheel got the first phone call.
“One of the landowners said his dam is gone,” said Micheel, director for the Monroe County Land Conservation Department.
Coon Creek 29. It’s located on Nashville Avenue, in the township of Portland. Built in the early 60’s, the Korn Dam is 39 feet tall.
“When it gave away, it was devastating,” Micheel said.
This dam is designed to handle 5.4″ rain over a 6 hour period. Areas of Monroe and Vernon Counties saw 12 inches to nearly 13 inches of rain during the storm event, according to the National Weather Service of La Crosse.
“What really is the issue is the intensity of the rain events,” Micheel said.
“It was record-breaking rain,” said John Wetenkamp, a service hydrologist with the National Weather Service of La Crosse.
An initial line of storms in the early evening contributed to the problem.
“Then overnight the rain just continued to fall in those same areas resulting in the extreme flooding,” Wetenkamp said.
Steep terrain and wet soil conditions created rapid runoff.
“And the intense rainfall rates that really increased the flash flooding risks,” Wetenkamp said.
As Micheel explains, the water goes through a pipe at the base of the structure. But if there is too much water pooling behind the dam, until it comes over the top and runs down the auxiliary spillway, which happened at Coon Creek 29.
“During that storm event, you’d be standing in about 6 inches of water,” said Micheel, at the top of the dam.
The slope eroded away, kicking out debris downstream.
“Ultimately that town road blew out. No one could go down through here,” Micheel said.
At first, the dam held back until it breached.
“And then all of a sudden [water] races down the valley floor 15 feet high,” Micheel said.
In all, there were three dams that breached and three that were damaged, according to the Monroe County Land Conservation Department. Eight had water go over the top of the dam.
“That is being repaired as we speak,” said Gary Flock, referring to the Coon Creek 24 dam.
In October, Micheel met with residents from the township of Portland to talk about what needed to be done.
“The consensus of the townspeople was to go ahead with these repairs,” said Flock, the chair for the township’s board.
When the water rushed down, it moved foundations, blew out bridges and eroded river banks. The price tag for this little township was hefty.
“Real cost was over $1.15 million,” Flock said.
He said that’s over twice the annual budget. But the residents decided the cost is worth it.
“It affects a lot of folks downstream. It’s for the safety and well being of the residents of Portland and also our neighboring counties,” Flock said.
The dams that had more minor damage were fixed this year. While the structures that breached will be stabilized and debris cleared away, major repair work will have to hold off, for now. Right now the question is: What if there was a better way to rebuild?
“There’s a lot of opinions on that,” Flock said.
While these dams were meant to last, they couldn’t withstand this storm. Micheel and other officials have proposed looking at the whole picture of the watershed.
“The last one was in the 50’s- 1958 to be exact,” Micheel said.
He’s hoping a new watershed study with funding from the Natural Resource Conservation Service will provide insight into how to rebuild– and not just the dams because this area is not what it used to be.
“There’s more building, more roads,” Micheel said.
Farming has changed.
“Today we’re rotating farms,” Micheel said.
More people using the valleys for camping, opening businesses and building homes.
“And as far as flood risk, we’re putting people at risk if we allow that to happen,” Micheel said.
And, we need to prepare for more extreme rain events. Part of what will be considered is the effect climate change will have on the region.
“Something’s going on. Things are changing,” Micheel said.
Maybe the way we’ve been building dams to control flooding needs to change, as well.
“We’re never going to design to the storm events that are occurring now,” Micheel said.
Instead, we need to be prepared for the future of flooding, which is what the study intends to do.
Micheel said he is supposed to hear any day now about the funding for the watershed study. If it gets funded, it would take anywhere from two to three years to complete. Then they’ll be able to determine the total cost, feasibility and best way to rebuild.
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