Mississippi River flooding this spring could cost the city of St. Paul $750,000.

The river has surpassed major flood stage — 17 feet — in downtown St. Paul, and is expected to reach 20 feet by early next week, according to National Weather Service predictions.

To hold back floodwaters, public works crews have worked through the night to build temporary levees and set up sewer pumps to divert water back into the river.

“One of the things that I’ve been reminded during this flood is that, unfortunately, St. Paul has done this many, many times,” Public Works Director Kathy Lantry said Tuesday morning, as she stood before a levee at Jackson Street and Kellogg Boulevard. “We have an incredible system and a lot of people who know exactly what to do during a flood.”

The state and federal governments may reimburse the city for mitigation costs, but it’s unclear at this point whether that will happen, said Mike Lovas, St. Paul emergency management department spokesman.

“We hope to be able to recoup costs, but the city is going to take all necessary and appropriate action regardless,” he said.

Flooding at Harriet Island Regional Park on Monday afternoon.

St. Paul has a permanent levee system that was installed after the record floods of April 1965. Building more concrete levees, rather than the temporary ones made of gravel and sand, could cost tens of millions of dollars, Lantry said.

While the river is expected to crest in coming days, Lantry said, the pace of snowmelt to the north and any additional precipitation could nullify that forecast. She said it will probably be two to four weeks before city officials decide it’s safe to remove the levees.

“It will be a ton of factors before we make that call,” Lantry said.