By Anna Jauhola
The dam on Lake Bronson is No. 1 on the list of dams that need to be replaced or repaired in the state of Minnesota. Funding is the problem. The current request to completely reconstruct the 83-year-old structure is almost $18 million.
During a visit to Thief River Falls on Thursday, Sept. 5, members of the state’s Capital Investment Division – casually known as the state bonding committee – heard from the Minnesota Department of Natural Resources and Kittson County officials. Jason Boyle, state dam safety engineer, said the state owns two high hazard dams – Lake Bronson and the dam at New London. The condition of the dam at Lake Bronson is poor.
“That means, if the dam fails or is misoperated, it would probably cause loss of life,” Boyle said. “It has nothing to do with the actual condition of the dam. It only has to do with the high hazard (designation). They typically store a lot of water and are pretty tall.”
According to a handout Boyle gave to committee members, Lake Bronson’s dam is 35 feet high and over 2,000 feet long. The concrete spillway is 60 feet wide. His report states the dam has terrible seepage problems, which have been temporarily fixed using relief wells, but “if seepage is not controlled it can lead to failure.” He also stated the dam’s “spillway is too small to safely pass a large flood.”
Lake Bronson’s dam has been on the list for many years, as had New London’s dam, which was funded and rebuilt about 10 years ago, Boyle said.
Kittson County Engineer Kelly Bengtson showed the committee members a map to illustrate how a devastating failure would affect the town of Lake Bronson and its residents – as well as people living along the river in between. He also said the impacts further downstream include extreme damage in the city of Hallock, including water possibly breaching Highway 75, not to mention all the homes near and along the river in between on all three branches.
Rep. Mary Murphy, DFL-Hermantown, is chair of the House Capital Investment Committee and attended the meeting. She asked why the dam’s condition hadn’t raised enough alarm bells in prior years to be funded.
Boyle said the DNR received some funding in 2008 to repair the gates on Lake Bronson’s dam and have engineers develop a design for a new dam. At that time, the design estimate would have cost about $10 million. However, that plan was only for modification of the dam, not for a complete rebuild.
“But that was not able to be funded,” Boyle said. “We’ve done everything we can to keep the dam as safe as we can until it gets fixed.”
When asked how much the New London dam cost, Boyle said that project was approximately $3.5 million, noting that dam is in the middle of town.
“Where there’s lots of people,” Murphy said.
“There’s much smaller flows at New London to deal with,” Boyle replied.
Murphy asked whether the money could come from DNR’s appropriations rather than from the safety fund. Boyle said that safety bonding funds are the primary source of funding for repairs and removal of state-owned dams.
Currently, with new engineering specs, the DNR is requesting $18 million to rebuild the dam at Lake Bronson. Lance Crandall, with DNR Parks and Trails, spent five years operating the Lake Bronson dam.
“There’s no way we’d be able to manage to and put our operating money toward that project,” Crandall said.
Having managed that dam, Crandall added the biggest challenge with the structure occurs with spring runoff.
“With this dam, you have to have people on site to adjust the three gates on the dam,” he said. “So all that water from the watershed is funneled through those three small gates. The biggest challenge we have is spring runoff. If it’s fast, like what happened to us in 2006, all that water came in at one time. We can only open the gate so high and we can only let out so much water.”
In that situation, he added, they built emergency levees along each side of the dam outlet to ensure the water did not cross the road and wash out the dam. In the worst case scenario, he said, should something like that happen, the dam can’t handle it and it will fail.
“There are a significant number of farm homes that are not too far from the north, south and middle branches of the Two Rivers,” said Theresia Gillie, Kittson County commissioner. “So it’s quite a big concern.”
Bengtson said County State Aid Highway 28 runs over top of the dam and the county maintains the bridge, which is the worst in the county. He said it’s rated at 53, which is well below standards and is eligible for state aid funding to replace it. He shared some statistics about the dam with committee members, including that it is not wide enough for vehicles to pass on it and has a posted load restriction of 68,000 pounds.
Boyle said the $18 million request will also include some funding for a handful of other high-hazard, city-owned dams that qualify for cost-share from the state, including one at Norway Lake by the city of Pine Lake and one at Pelican Rapids.
He said preliminary designs for Lake Bronson’s dam should be completed this year using funding from 2012 dam safety bonding. And construction would be completed by fall 2022, should funding be approved in the next legislative session.
“I want to emphasize we’re doing everything we can to keep (Lake Bronson dam) safe until we can get it rebuilt,” Boyle said. “We have an emergency action plan, an operation maintenance plan and spring communications are really good between the county, city, watershed district and the state.”
The Minnesota State Legislature reconvenes in February at which time the Capital Investment Committee members will discuss bonding for projects, including the Lake Bronson dam.
By Anna Jauhola