NORTH MANKATO — Making clear that they didn’t agree with it and aren’t sure how they’ll pay for it, members of the North Mankato City Council consented Monday to a federal demand that the city undertake a potentially costly study of its levee and flood wall along the Minnesota River.

“If we don’t sign the letter, we’re putting lower North Mankato at risk of not having FEMA’s flood protection,” Mayor Gary Zellmer said.

The Federal Emergency Management Agency sent a letter in January giving the city just 90 days to agree to recertify the flood protection system or face the prospect of having lower elevation neighborhoods listed as high-risk areas for flooding. That would force home-buyers to purchase flood insurance at a cost of several hundred dollars.

When North Mankato sought estimates of the cost of the recertification, ballpark estimates came in at $120,000 to $240,000. Mankato, which has even more flood wall and levee to inspect, and Blue Earth County, which is responsible for the levee in the Le Hillier area, also are facing the same mandate.

The local governments typically would have relied on the U.S. Army Corps of Engineers to inspect the flood system at a relatively small local cost, but that probably isn’t an option because of an amendment inserted in a federal water bill by Sen. Craig Thomas, a Wyoming Republican, in 2000. The amendment requires governments to use private sector firms rather than the Corps whenever possible.

The high cost of certifying the soundness of the levee doesn’t come from the work involved but from the liability insurance that a private engineering firm would need to purchase to cover the firm’s exposure to lawsuits should the levee fail, Zellmer said.

The city turned to Congressman Tim Walz for help, and Walz’s staff is working to persuade FEMA and the Corps to find a more affordable solution, City Administrator Wendell Sande said.

“That’s part of the problem — you have two federal agencies handling different parts of the same issue,” Sande said.

But with the 90-day deadline of April 14, the council was running out of time.

“My guess is we’re not going to get resolution out of Washington in two years,” Zellmer said.

The next question, if FEMA isn’t persuaded to change its requirement, is how to pay for it, he said. The city also wants to know how often the expensive recertification process might be required.

“If this is going to be an ongoing thing, we’re going to need a source of revenue,” Zellmer said, mentioning the possibility of a levee levy.

Councilwoman Diane Norland said the city needs to find some allies among other cities and counties with flood-control projects to boost its influence in Washington.

“It’s not only a problem for us, it’s a problem for all people in flood plains,” Norland said.

Zellmer said FEMA is undermining any flood of opposition by sending out the letters sporadically over a period of time.

“Unfortunately, they’re picking us off one at a time,” he said.

Norland also suggested that Walz — along with being asked to help with the immediate problem — be urged to try to strip the Thomas amendment from federal law.

“That’s ridiculous,” she said of the privatization requirement.