The official floodplain in Sioux Falls is shrinking. That’s because a project to update levees in the city is complete, so FEMA officials are changing flood maps. Five years ago city leaders advanced the federal government millions of local tax dollars to accelerate the project. Since then, federal officials have reimbursed the city, and the project is a split among local, state, and federal money.
A study in the 1990s showed levees along waterways in Sioux Falls were five feet lower than necessary to protect property from a major flood event. Local planners collaborated with the US Army Corps of Engineers and FEMA to design a three-phase plan. After more than a decade, the project is finished. Workers raised the spillway and levees, upgraded a diversion dam and added a confluence dam to regulate water flow.
Kermit Staggers is a longtime member of the Sioux Falls City Council.
“We made a wise decision 14 years ago to go with the higher levees, because now it’s estimated with the 2016 flood map 500 properties will remain in the floodplain. But before that, we had 2,200 properties in the floodplain,” Staggers says.
People who have mortgages on property that’s part of a floodplain are forced to buy flood insurance. A smaller area at risk of flooding means some of those homeowners can opt out of flood insurance if they choose.
On the commercial side, Public Works Director Mark Cotter says developers consider infilling open spaces in town instead of sprawling along the edge of Sioux Falls.
“All the infrastructure is essentially there, but they know that if they were to move forward before the maps were updated they would have had to significantly raise that land to get future buildings out of the floodplain,” Cotter says. “[That] didn’t make economic sense, so there’s a lot of that type of development that is just waiting.”
Builders have to wait one more year before the classifications change. Sean McNabb is a risk map analyst with the Federal Emergency Management Agency. He says officials updating the maps need time for appeals to resolve challenger.
“Right now the best estimate that’s out there is that we’ll have the maps effective in the community in late 2016, and essentially at that time that would be all the changes that you would see where the community would begin using the maps for new development,” McNabb says.
The levee system upgrades cost about $65 million. Federal money covered three-quarters of it. The city and state split the remaining 25 percent.