Lake Bronson dam plan revealed, explained publicly

By Anna Jauhola
Officials shared the first glimpse of the new dam to be constructed at Lake Bronson State Park during a public meeting on Tuesday, June 13. The labyrinth weir design will drastically change the landscape we are used to, but for the better, according to DNR, dam and engineering officials.
Major concerns from the public included how and if fishing numbers will rebound, how construction will affect not only tourism numbers but also the local economy, and whether the current dam can be saved in some capacity for historic preservation. About 30 people attended the meeting, which was held in the auditorium at Kittson Central School in Hallock.
Stacy Smith, a development consultant for DNR Parks and Trails, has been working with Barr Engineering and explained the new design. The labyrinth weir will be built 250 feet to the south of the current dam and the spillway will be about 120 feet across – double the size of the current dam. The new road will be two lanes, allowing for traffic to pass on the bridge. The walking path will be slightly higher than the road on the east side as before, and will be separated from the road by railings, allowing for more observation for foot traffic.
The dam will sit on native soil, rather than backfill, which was used to create the existing dam. This weir does not require gates as water naturally flows over the top of the sawtooth-looking structure to flow down the spillway and into the channel below.
“With that element, we know there’ll be change in the way people recreate on the lake and will have a chance to access the areas adjacent to the dam for fishing,” she said.
There will be a device around the east side of the weir called a debris boom that will not only block major debris from going over the weir, but also alert boaters to the weir’s location.
They anticipate construction to begin in spring 2024 and last between 18 and 24 months. The project is currently at 90 percent design and they have yet to obtain all permitting before they can bid the project. Jason Boyle, DNR dam safety engineer, said he expects the project to go out for bid this fall.
The major process they are handling now is the Environmental Assessment Worksheet (EAW), which is the main component needed to apply for permitting. When that is complete, there will be a 30-day comment period for the public.
Smith said the process is lengthy, but necessary to ensure safety for the project during construction and once it’s complete.
“We also have federal and state regulatory processes we have to include,” Smith said. “We are coordinating with the Army Corps of Engineers and the State Historic Preservation office. Because (the dam) is a WPA era structure, we are making sure that all the work we’re doing in the removal and replacement fit within the standards of what that historic district requires us to do.”
The Lake Bronson dam was built through the Works Progress Admini-stration and Civilian Conservation Corps in 1937. The dam created a reservoir to provide freshwater to downstream residents in Hallock as the river had become stagnant due to severe drought.
Following the main presentations, DNR staff was originally going to meet in an open house setting in the band room. The audience asked if they could have an open comment period instead as they wanted to hear everyone’s questions and concerns, and the DNR’s answers. The format changed and everyone stayed in the auditorium.
FISHING and
RESTOCKING
This dam replacement project will require a nearly-full drawdown of the lake so there is only a minimal flow channel of the Two Rivers on the lakebed. The current dam structure will remain in place during construction of the new dam, which will allow for the continued flow of the river. This means the fish population will suffer a large die-off, but Matt Skoog, DNR area fisheries supervisor, is optimistic that some of the fish will migrate upstream as they have seen natural reproduction in recent years. He did say that migration will likely be minimal.
“So we expect a significant amount of mortality due to the reduced water volume and habitat loss and dissolved oxygen reduction,” Skoog said.
Although they hope for natural migration and reproduction, Skoog said their plan to repopulate the lake post-construction will be stocking and monitoring the population until it is restored. Pan fish will be trapped and transferred from other locations, while walleyes and bass will be brought in from regional hatcheries.
During the question and answer session, several people noted the 1991 drawdown of the lake severely reduced the quality of fishing at Lake Bronson for years. They drained the lake that year to repair the dam and address the seepage issues. One person said they felt the DNR didn’t do a good job of following up on monitoring fish population after restocking the lake.
“It feels insufficient what you’re showing us on the screen to get back to the quality and quantity we’re at today,” said Preston Dagen, member of the Lake Bronson Cabin Owners Association. “You’re literally taking a generation of people, cabin owners and others, out of that fishery. And that feels insufficient.”
Skoog agreed, “Lake Bronson is an excellent fishery,” and acknowledged the drawdown in 1991 caused issues.
“We’re going to start earlier and more frequently to make sure we are on top of the dissolved oxygen concentration through the wintertime so we’re not creating winterkill conditions that are likely to cause black bullhead populations to explode,” Skoog added.
Bobby Schmiedeberg, of Lake Bronson, said he hopes they won’t stock northerns as they ate any walleye stocked in the lake last time, and there are plenty northern in the lake now.
Skoog said he doesn’t foresee them stocking northern pike, considering they can withstand harsher conditions better than any other fish in the lake.
Ben Bergey, northwest regional manager of Minnesota State Parks and Trails, emphasized the DNR’s commitment to retaining the lake as a quality fishery.
“People care about fish. We know and appreciate that. Matt and fisheries are well aware of this project and the DNR has to get it right,” Bergey said.
TOURISM and
THE ECONOMY
A DNR document shared prior to the meeting indicated very limited access within Lake Bronson State Park during construction, which caused locals concern. The document stated the picnic area by the beach would be closed, there would be no access to the lake at all, bike trails would be closed and camping would be restricted.
Tim Williamson, Lake Bronson State Park manager, said none of that is accurate.
“The picnic area won’t be closed. Some of it might be, but not the shelters,” Williamson said. “Certain segments of the bike trail will be closed, like over the dam. A large part of the picnic area will be open throughout construction.”
Williamson said they don’t know what camping will look like in 2024 yet, but they do not anticipate closing all campgrounds by any means. He said during the project, he and his staff plan to work on upgrades in the Two Rivers Campground and at the island campsite, as well as clearing major debris from the lake bottom.
Bergey added the document was also inaccurate stating people will not have access to the lakebed or able to observe the dam construction.
“You’ll be able to walk along it. Of course we’ll keep people out of places where it’s softer or dangerous,” Bergey said. “We’ve talked about safety being a priority. There will be areas we’ll close for access onto the lake. It’s going to be soft, posing some sort of safety risk.”
They plan to keep as much of the park open as they can, including near the construction zone from the lakebed so people can observe the process. The road above the dam will be closed to all non-construction traffic. That distance will depend on the contractor’s staging. There will be limits, he said, as to how close people can get, but he acknowledged watching construction is an activity in itself.
Bergey and Williamson said the main entrance to the park will remain open and all main areas will still be accessible, with only the section of CSAH 28 over the dam being closed.
Bergey said the DNR will be working on a marketing plan to promote the park, and Williamson and his staff will be providing more programming at the park, which has been limited in recent years. He added that while the large construction crews will help offset some of the lost tourism, he understands it will not totally offset it.
“We are committed to keep Lake Bronson tourists coming,” he said.
SAVING THE DAM
The current dam is listed on the National Register of Historic Places as a WPA era project. Cindy Adams, director of the Kittson County Museum in Lake Bronson, asked whether that could partially be saved. Boyle said they looked at that option early in the project, but all engineers have continually said leaving the structure would pose a safety risk.
The current dam was deemed unsafe in 1978 and has presented seepage issues from artesian, or underground water, pressure for decades. In 1991, the DNR installed relief wells to help relieve that pressure. However, the relief has faded over time, Boyle said. While new dam gates in 2008 improved dam operation significantly, the state restudied the dam in 2015 and deemed it still in poor condition.
“Wouldn’t that new dam relieve pressure off the old dam?” Adams asked.
Smith reiterated that native soil has much more strength than fill, which is the foundation for the current dam. It wouldn’t be as easy as filling in the current dam foundation with rock and fill as that will continue to pose a seepage problem.
To solve the seepage issue, Barr Engineering’s design includes an 85-foot deep cutoff wall, which will span the embankments from either side of the labyrinth weir along the bike path. The contractor will dig a 3-foot wide trench about 85 feet deep and mix bentonite and cement with the soil to “create a relatively impermeable barrier,” Boyle said. “Originally the plan was to go up to 120 feet, but through analysis they determined 80-some feet should be enough of a barrier to take seepage out of the equation.”
Smith said again they have looked for ways to incorporate the dam as a historical site with the existing spillway, but every answer comes back to safety concerns.
“Jason (Boyle) mentioned the artesian pressure, that’s where the water is coming from the ground, and it’s also water pressure from the basin,” Smith said. “It’s important to make sure the cutoff wall goes in.”
She said the current dam has been identified as the weakest point in the construction area as it was either severed or never existed prior to the current dam’s construction.
“In order for us to create the safest project possible, our engineers recommended that we not allow that existing structure to stay in place,” Smith said.
Adams followed up, asking whether the State Historic Preservation Office (SHPO) has been kept in the loop about the project. Smith said SHPO is aware of the project, but the DNR is working official channels through the process. When DNR completes the Environmental Review Worksheet (EAW), they will submit it to the U.S. Army Corps of Engineers who will then share it with SHPO.
“The EAW process takes the lead, then the historic properties report follows that EAW process,” Smith said.
The plans call for creating a parking pad in the approximate location of the current dam, and include a walking path leading down to the river channel. This area may include historic markers explaining the original dam’s history and significance.
DNR staff acknowledged there will be growing pains associated with this project as construction could last up to two years. However, they stressed the new structure will provide a higher level of safety for everyone who lives in and visits the area.
Everyone can keep up to date with information on the Lake Bronson State Park website at dnr.state. mn.us/state_parks/lake-bronson-dam-replacement-project.html.