STILLWATER, Minn. — The governors of Minnesota and Wisconsin have written a joint letter to President Obama urging him to quickly sign the legislation that clears the way for a new bridge over the St. Croix (KROY) River.

In a letter dated Tuesday, Republican Gov. Scott Walker of Wisconsin and DFL Gov. Mark Dayton of Minnesota say the two states have been working for decades to replace the current bridge, built in 1931.

An exemption from the Wild and Scenic Rivers Act passed the U.S. Senate in January and the House last week. That legislation was needed to advance the project.

An updated estimate from the Minnesota Department of Transportation pegs the project’s cost at about $626 million — down from an earlier projection of $633 million. With the president’s signature, construction of the bridge could start in 2014.