An engineer’s perspective

MANAWA – Representatives from Cedar Corporation, the City of Manawa’s engineering firm, gave a public presentation about the dam as well as the feasibility analysis for future construction on May 28.
Brendan Strelow, the community infrastructure consultant at Cedar Corporation, started the presentation going over the pond’s details and the historic rainfall that made the dam breach.
The Mill Pond is 180 acres with 4.9 miles of shoreline at an approximate depth of 12 feet.
The July 5 storms produced 5.7 inches of rain in a matter of four hours which caused stress to the northern shoreline causing the dam to break away from the shore and failing.
Recently a project to stabilize the shore, as it was continuing to erode, was just finished, with the help of a grant through the U.S. Department of Agriculture which covered 75 percent of the cost.

The dam saw repairs in the late seventies, mid-nineties and in 2012, said Joe Pingel, a resource engineer with Cedar Corporation.
Pingel went over what the repairs were, as well as noting all of the cracks and degradation not only from the flooding but from the natural wear and tear or deterioration of the dam over time.
“Repair of the dam is simply not feasible, a complete replacement of the dam is therefore recommended,” Pingel said.
The options that are being discussed at the city level were also brought up, with the options being remove the dam entirely, build the dam as a spillway or build the dam as a hydroelectric.
The cost is the biggest factor, without help from the state or federal level, through grants the city may not be able to generate the funds needed for reconstruction.
The removal of the dam is $700,000, a cost that is included in each quote due to the fact that it will need to happen no matter what. The cost for the spillway came in at $8.4 million and the cost of a hydroelectric dam came in at just over $13 million.
It is notable to mention that these are estimates, and it is likely that the bidding process for this dam will be highly competitive.
Strelow said that at the time of the dam breach the city had committed itself to various projects around Manawa leaving little range for funding an expensive project such as this.
The city submitted a request to the Joint Finance Committee in Madison to be added to the next state budget, results of which the city won’t hear back until July.
“If that doesn’t come through, it’s going to take a mixed bag and a lot of different funding sources to get this done,” Strelow said.
There are grants out there to apply for that if granted will cover only portions of the cost to rebuild not entire costs.
The desire of the city and township is to rebuild the dam, so they are continuing to look at all avenues for funding and should funding become available, hypothetically speaking, then there are still lengthy time lines for finishing the project.
Pingel said the design portion of the project could take six months to complete, to ensure the design is in compliance with local ordinances and state laws, as well as adhering to Federal Emergency Management Agency (FEMA) and Department of Natural Resources specifications.
This process is to obtain a permit to start the construction process; the design stage is not complete until all the necessary permits are obtained.
Pingel said he estimates the time of design, permitting and bidding to take about 18 months, with about nine to twelve months for construction to complete, making the total project length to take an estimated two to three years to finish.
If the city and township agree to continue with the hydroelectricity, there are additional regulations and processes with that would need to be completed with the Federal Energy Regulation Commission (FERC).
Pingel emphasized throughout the meeting that this should be a 100-year decision, with a lot of factors that will have to be weighed and taken into consideration.
Pingel said Cedar Corporation has worked on a number of dams, including repair and a few reconstruction projects.
“In the current dynamics of things there’s not a lot of brand new dams going in across Wisconsin, but we do have a significant amount of experience with flood studies and structural engineering,” Pingel said.
He said in the last ten years there have been 28 dam failures in Wisconsin, saying that the grant program is highly competitive.
For now, the City of Manawa is awaiting a response from the state; the next steps won’t be decided until that decision comes down in July.