Work starts on Coon Rapids Dam rehabilitation project

Work has started on the Coon Rapids Dam rehabilitation project.

The contractor, Edward Kraemer and Sons, Inc., is on site on the Anoka County side of the dam doing preliminary work, including testing and surveying, and has built a causeway from the dam to Dunn Island to move vehicles and equipment.

Under the two-year project timetable, work will take place on the Anoka County side of the dam this year, moving to the Hennepin County side in 2014.

Edward Kraemer and Sons, Inc, which is headquartered in Plain, Wis., but has a Minnesota office in Burnsville, was awarded the dam reconstruction contract in the amount of $10.804 million, according to Jason Boyle, state dam safety engineer, Minnesota Department of Natural Resources (DNR).

The company, which has been in business since 1911, has been the contractor on dam reconstruction projects in Onalaska, New Richmond and Chippewa Falls, all in Wisconsin, the firm’s website states.

A gravel road has also been created from 99th Avenue, just west of the Egret Boulevard entrance to the Coon Rapids Regional Park, through the regional park to the construction site at the dam, Boyle said.

Depending on the weather and water flow levels on the Mississippi River, the contractor hopes to start building the coffer dams in the next week, he said.

The coffer dams, which will be built above and below the dam, will divert the river to allow construction crews a dry place in which to do their job, according to Boyle.

The existing rubber dam will be removed and replaced with nine new steel gates.

A contract for the steel gates to be manufactured and delivered was awarded by the DNR last fall to the low bidder, Rodney Hunt Company, Orange, Mass. The contract totals $3.5 million.

The first delivery will be of the steel embedments that attach the gates to the concrete foundation, Boyle said.

But before the gates can be installed, a scour hole on the concrete apron downstream of the dam discovered in 2009, which resulted in the decision to replace the existing rubber gates at the dam, has to be repaired.

In fact, a new concrete apron will be built to replace the damaged apron, according to Boyle.

With the work on the Anoka County side, the walkway over the dam as well as the Anoka County boat launch have been closed for the year, Boyle said.

In fact, the walkway will remain closed until the entire project is completed next year, but the boat launch should be back open in 2014, he said.

And the water level in six-mile pool above the dam will remain at the summer level permanently, not only throughout the project’s construction period but in the years beyond once the project is completed, Boyle said.

The project is being funded by $16 million that was allocated in the 2011 state bonding bill approved by the Minnesota Legislature and signed by Gov. Mark Dayton.

With the contracts awarded for the new steel gates and the reconstruction work plus the $900,000 contract with Stanley Consultants, Minneapolis, to do the design and engineering, the project is within its budget, Boyle said.

“We are fairly comfortable with the budget,” he said.

“The late winter does not appear to have affected the project.”

Under a joint powers agreement with Three Rivers Park District, which owns and operates the Coon Rapids Dam, the DNR is solely responsible for the reconstruction of the dam.

The rehabilitation project is designed to make the dam a more effective barrier to the migration of invasive fish species, like Asian carp, as well as to extend the life of the dam.

Through the joint powers agreement, the DNR is responsible for the management of the dam as a fish barrier.

According to Stanley Consultants, the steel gates that would pass water over the top of dam would make the dam 99 percent effective as a barrier to invasive fish species.

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, NSP donated the dam and surrounding land on both sides of the river to the park district.

Anoka County now owns all the park property on the Anoka County side of the dam.

 

Peter Bodley is at peter.bodley@ecm-inc.com

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