With spring flooding of the Mississippi River at St. Paul, Minn., all but certain, work crews from the Metropolitan Airports Commission today began deploying temporary sections of floodwall at St. Paul Downtown Airport (STP).
“Prior to developing the floodwall in 2009, flooding sometimes caused hundreds of thousands of dollars of damage and expense and closed St. Paul Downtown Airport for weeks at a time,” said MAC Executive Director Jeff Hamiel. “The floodwall is designed to protect the airport against a hundred-year flood, safeguarding infrastructure and minimizing operational impacts.”
This is the fourth time the floodwall has been deployed at the airport, having been erected once in 2009 and twice in 2010. The 9,532-foot dike includes 4,563 feet of permanently installed sheet pile wall, 3,595 feet of temporary, deployable wall and 1,374 feet of earthen levee. MAC staff can deploy temporary sections of the wall in about a week.
Portions of the wall along Bayfield Street and those crossing the airport’s two shortest runways, 13-31 and 9-27, will be erected first, leaving the longest, primary runway, 14-32, unaffected as long as possible. As the water rises, the MAC will close storm sewer gates to prevent river water from backing up onto the airport, and pumps will be activated to drain water that does collect there, according to airport officials.
If necessary, MAC also will install the deployable wall crossing the far southeastern end of 14-32, sealing off the airfield from the river. Barring unforeseen circumstances, Runway 14-32 will remain operational with the wall in place, but the landing threshold will be displaced, shortening the operational portion of runway pavement from 6,491’ to 5,341’. The two shorter runways already have been temporarily closed. The FAA will remove navigational aids located outside the floodwall to protect them from water damage. The wall will remain in place until the danger of flooding has passed.
St. Paul Downtown Airport has the only runway longer than 5,000 feet in the MAC reliever airport system. The airport primarily serves corporate aviation needs. In 2010, nearly 89,000 aircraft landings and takeoffs occurred there, making St. Paul Downtown the second busiest airport in the MAC’s six-airport reliever system and the third busiest airport in Minnesota.
For more information: MetroAirports.org