by Mandy Moran Froemming
Three Rivers Park District and the Minnesota Department of Natural Resources have finalized a joint powers agreement to move forward on the refurbishment of the Coon Rapids Dam.
The upgrades will enable the dam to serve as a barrier against invasive aquatic species, in particular stopping Asian carp from moving up the Mississippi River into northern Minnesota waters.
In 2011, the Minnesota Legislature provided $16 million to the DNR to modify the dam for use as a fish barrier. The dam has been owned and operated by Three Rivers Parks District for the past 40 years.
The agreement approved Thursday, Jan. 19 by the park district’s board of directors allows the DNR to take control of the construction of the project.
“Upgrading the Coon Rapids Dam is among our most effective options for preventing the movement of Asian carp upstream and into our lakes,” said DNR Commissioner Tom Landwehr. “This project is vital.”
Landwehr is expected to soon sign off on the agreement between the DNR and the park district.
Stanley Consultants, working for the park district, last year presented a plan to repair the dam at an estimated $16 million. The firm was hired by the park district to evaluate the effectiveness of the dam to keep invasive fish species, like Asian carp, from moving upstream.
Under the Stanley proposal, which is being used to guide the design for refurbishing the dam, the rubber gates presently in place at the dam would be replaced with hydraulic or pneumatic gates that pass water over the top.
That would be an ideal fish barrier and would make the dam 99 percent effective to invasive fish species, Marty Weber, an engineer with Stanley Consultants, told the Coon Rapids Regional Dam Commission last year when the plan was presented.
The commission had been set up by the 2010 Minnesota Legislature to make recommendations on a repair project and also the future ownership of the dam.
The design and engineering will follow the proposal made by Stanley, according to Dale Homuth, manager of conservation assistance and regulation for the DNR.
The DNR is ready to go out for bids on the design in the coming weeks.
While residents along the Mississippi River will not likely see any construction impacts this summer, the DNR is still looking to raise the pool above the dam.
“We’re still trying to raise the pool level yet this winter to get a better barrier in place,” said Homuth.
It has been recently reported that DNA from the invasive silver carp has been found above the Coon Rapids Dam. Asian carp are known to be able to travel up to 10 feet in the air, which means keeping as much distance between the recreational pool and the river below the dam is the first step to keeping the fish from actually moving upstream, said Homuth. Right now there is plenty of separation between those water levels, but that could change once the snow melts.
“Even though there is evidence of silver carp DNA above the dam we still think it is an extremely important structure,” said Homuth.
He added the DNR would be lucky to get construction underway by this fall. Homuth said a major challenge of the project will be holding those pool levels up during the construction phase.
Once upgrades to the dam are complete, the six mile recreational pool above the dam will be required to remain at its higher summer level year-round, instead of being lowered in the fall for the winter months, then raised again in the spring.
This would prevent fish species from breaching the dam during high water flows in the spring or in the event of a flood.
In addition to improving the dam as an effective barrier against invasive species, the project will also repair a scour hole found in the concrete apron of the dam during a routine inspection in 2010. The upgrades proposed by Stanley and the commission recommended to the Legislature to be funded through state bonds has an estimated 50-year lifespan.
According to the park district, the project is estimated to be complete in the fall of 2014.
“Fishing, boating and water recreation are critical components of Minnesota’s economy and central to our way of life in this state,” said Larry Blackstad, chairman of the Three Rivers Park District Board of Directors. “This project is an example of government agencies working together to solve problems.”
There are no plans to change the recreational opportunities provided by the dam.
“The walkway across the dam and the fishing deck will be preserved, so it will continue to be a recreational amenity for the communities on both sides of the river,” said Marilynn Corcoran, a commissioner with the Three Rivers Park District.
The Coon Rapids Dam was built in 1913 by Northern States Power (NSP) Co. to generate hydroelectric power. When power generation stopped in the 1960s, the power company donated the dam and surrounding land on both sides of the river to the park district.
To date, the future ownership of the dam has not been addressed by the legislature. While Three Rivers Parks District has made it clean it no longer wants to own and operate the dam, DNR Commissioner Tom Landwher has said in the past the state agency is not interested in taking over ownership or operations of the dam.
Mandy Moran Froemming is at email@example.com