As the Mississippi River rises dramatically following heavy rain, the St. Paul Downtown Airport is expected to close temporarily beginning Thursday afternoon.

The Metropolitan Airports Commission (MAC) announced Wednesday that its staff had begun erecting temporary sections of a floodwall around the airport. MAC spokeswoman Melissa Scovronski confirmed Thursday morning that the closure was expected to begin Thursday afternoon.

The floodwall will be built across Runway 14/32, which is the airport's primary and longest runway. MAC spokesman Patrick Hogan said that a total of 124 aircraft are based at the St. Paul Downtown Airport, which accommodates approximately 111,000 takeoffs and landings per year. By comparison, the Minneapolis-St. Paul airport recorded 432,395 takeoffs and landings last year. The MAC declined to provide a specific number of flights canceled as a result of this week's temporary closure.

The MAC said that the “threat to the airport is expected to pass quickly,” so it intends to close the airport entirely while the floodwall is constructed, rather than taking more long-term alternatives such as shortening a runway and repainting markings.

“We would need to close the runway two nights this week to repaint the runway markings to shorten the landing threshold when the floodwall is up and then close it again for two nights early next week to change the markings back when the floodwall is removed,” Gary Schmidt, director of reliever airports for the MAC, said in a statement. “Given the brief nature of the flood threat, it makes more sense in this instance simply to close the airport to flight operations for three or four days until the waters recede to safe levels.”

The MAC said that-assuming water levels drop as expected-it will begin removing sections of the floodwall on Monday and reopening at least Runway 14/32 to air traffic.

The floodwall was deployed once already this year when flood conditions occurred in March. That flood was more prolonged, and the wall was used to allow for limited flight operations.

The MAC owns and operates the Minneapolis-St. Paul International Airport and six smaller reliever airports within the metro area, including the St. Paul Downtown Airport.

Floodwaters from recent heavy rains have caused numerous problems in the metro area and around the state. The effects of the flooding prompted a visit by Governor Pawlenty to the hardest-hit towns in Minnesota, and thousands of commuters have experienced the headache of detours as highways have been closed and bridges have even collapsed as a result of the rising water.