Moose Lake Star Gazette - Serving Carlton and Pine Counties Since 1895

By Natascha Watercott
Moose Lake Star-Gazette 

Rock arch rapids to be installed in Willow River

 


At the June 4 Willow River City Council meeting, Mike Peloquin, regional manager for the Ecological and Water Resources division of the Minnesota Department of Natural Resources (DNR), and Jason Boyle, DNR dam safety engineer, were present to discuss the DNR’s final decision to replace the city’s failed dam with a rock arch rapids design.

The Willow River dam, which is owned by the Minnesota DNR, was damaged during a large flooding event in the summer of 2016. As a result, the reservoir behind the dam was drained. The dam, installed in 1940, does not meet current dam safety standards and cannot be replaced as is; it would need to be redesigned. The city was presented with three options: build a new dam to replace the old one, install a rock arch rapids design, or restore the river to its natural, pre-dam state.

Peloquin discussed why the DNR ultimately chose the rock arch rapids design. “Construction costs [of the rock arch rapids], we’ve determined, are going to be less than the dam construction, and we’re going to essentially minimize and eliminate operational and maintenance expenses,” explained Peloquin.

He noted that one concern of many in the community was the restoration of the reservoir to pre-flood levels. He stated that the rock arch rapids would be able to do this at a much lower cost than constructing a new dam.

In his written report, Peloquin stated of the rock arch rapids, “The long term operational costs will be eliminated and maintenance costs will be lower than costs associated with maintaining the concrete spillway design dam.” This is because the rapids would essentially function like natural river rapids once installed.

“When you put this kind of a structure [the rock arch rapids] in, you’re not out there having to do routine inspections and maintenance and repair work, which can add up. The state of Minnesota owns 450 dams that we have to manage. We have about $114 million of repair work and we get about $1 million a year to repair and fix problems with dams. That’s a real big issue for us as we move forward and think about where is the money going to come from to operate and maintain these structures,” said Peloquin.

Other factors the DNR considered was that the rock arch rapids would improve the hydraulic capacity of the reservoir to pass flood flows, and the safety hazard of the hydraulic roller effect, which has been the cause of several drowning deaths in the past, would be eliminated.

There would also be ecological benefits as the rock arch rapids would restore fish passage to historical upstream habitats. Peloquin added that the design would still allow for recreational activities such as boating, fishing, waterfowl hunting, wild rice gathering and the annual ice fishing tournament as well as new opportunities for kayaking and canoeing at the rapids.

“We thought this was the best approach. We’ve done this in other areas of the state pretty successfully. It might take a little while to visualize what this might look like …there might be some other opportunities here that this type of a rock arch rapids dam will give you that the current dam doesn’t,” said Peloquin.

Boyle briefly discussed how the dam would be funded and what the current construction schedule looks like. Boyle explained that the Minnesota legislature had issued bonds in the 2017 Legislative Session for the project, so it will be funded. There is also a state disaster grant that they hope to utilize as well.

Boyle stated that the DNR is well into the engineering phase but have a ways to go. They still have to develop an engineering design and construction plans, conduct analyses and reviews necessary to secure permits, request bids and award contracts for construction activities.

The DNR hopes to have a 50 percent design completed in about a month. A preliminary design would be completed by September and the final design should be done by October with bid opening to be held in November. If everything stays on schedule, construction could start this winter.

Sewer gate valves damaged

The council also brought up they were recently made aware of two damaged gate valves. These valves are used to discharge water from the city’s sewer ponds; it was unclear what had caused the damage at that time. At the meeting, the council determined that at maximum, replacing the gate valves could cost as much as $32,000 and were unsure where they would get the money from.

As of this week, Vicki Whitehouse stated via phone that the city had been contacted by Homeland Security and Emergency Management (HSEM) which determined that the damage to the gate valves was related to the 2016 flooding event, and they would be paying 75 percent of the cost to replace the valves; Whitehouse stated that the repairs would likely be taking place this week. The council is still unsure where they will obtain funding for the other 25 percent; however, one possibility they are looking into is applying for a Minnesota DEED (Department of Employment and Economic Development) grant. They will receive more information about the status of the grant by the end of this month.

 

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