Finding ways to reduce the sticker price on an $820 million flood protection project won't be easy, Minot aldermen learned Wednesday.
The Minot City Council, meeting in committee session with project engineers, discussed project features and potential areas of cost savings, which will depend on what type of project and risk level the city can accept.
Cutting the protection level nearly in half would save only 10 to 20 percent, said Jason Westbrock with Barr Engineering.
Jill Schramm/MDN • Dikes run along the Souris River between the Third Street viaduct and a monument dedicating the rechannelization project in the 1970s.
Engineers designed the project to 27,400 cubic feet per second at the direction of the state, city and county. That level would have protected the region last summer. The biggest expense is in constructing flood control features. Levees and floodways are a quarter of the cost of the project.
Minot's share of the overall project is about $543 million.
"We have to get that to a number that we can afford to pay," Dean Frantsvog, council president, said. "Right now, that number is really a number that's difficult to work with. We need to explore every avenue to get that number to a cost that protects our citizens and at the same time is a manageable number."
Frantsvog added that the city will need to know how much money it has to work with in order to proceed.
Mayor Curt Zimbelman estimated the city could receive as much as $100 million in federal hazard mitigation funds, but other federal funding will be hard to obtain. On a positive note, the state has been supportive and has set a precedent in agreeing to assist Fargo with its flood control, Zimbelman said.
The mayor noted that the $820 million preliminary design is a good starting point.
"We needed to look at what would handle the 2011 flood, and this is the cost," he said. "We needed to know that number."
Now the city will have to decide whether to scale back and take more risk, he said.
Engineers presented information on ways to save money that included:
- Reducing the 2.25 miles of flood walls, which are two to five times the cost of levees.
- Modify the 16 pump stations designed to handle water unable to drain naturally into the river because of dikes.
- Reduce the size of river closure structures, which would create the need to use the Maple and 27th Street diversions more frequently than during a 100-year flood event.
- Eliminate certain project features in isolated areas.
- Lower the level of the dikes and assume more risk of flooding.
- Concede the loss of certain transportation routes during flood periods.
Engineers have not done an analysis to determine how much could be saved with any of these options.
Westbrock said reducing the protection level to 15,000 cfs would allow lowering the levees by five feet, with cost savings of about $82 million to $164 million. Lowering the protection level would not change the footprint of the dike system, though.
Ryan Ackerman with Ackerman-Estvold Engineering said the design reflects the job that engineers were tasked with, but changes in Souris River management can influence the scope of design needed to accomplish the same effect.
"There's other ways to do the project, but again, this was one that we can say credibly will work against an event very similar to 2011," Ackerman said.
Engineers also presented a timeline that put flood protection in place in 11 to 12 years. The planning stage is expected to last five years, depending on the complexity of environmental and permitting issues. Bidding and construction could take another six years. How fast construction occurs will depend on availability of funding and contractors.