What is causing flooding in Sioux Falls?

SIOUX FALLS, S.D. - Hundreds of people are working in Sioux Falls to make sure everyone is safe during the flooding event much of the area has dealt with this week. Mayor Paul TenHaken is asking for people's patience as they work to resolve issues.

One of those issues is how full the storm drainage system is right now. Workers are having to pump water over the levee system and into the river that way. The city had to bring in more pumps to even make this happen.

Sioux Falls Public Works Director, Mark Cotter, said Thursday morning they will have to pump water for at least the next 48 hours. The fact that there's still snow on the ground combined with the amount of rain Sioux Falls received has really caused much of the flooding. The snowpack is causing issues. In a typical year, we will get snow, then it will melt, then we will get more and it will melt again. That just hasn't happened this winter though.

"In some of these areas that normally free drain when there's no ice and snow that's in the ditches, and the drainage channels, they would just normally just pass under the roads," Cotter said. That's not able to happen and it's causing a backup.

There was so much flooding near 41st Street and Louise Avenue because the storm drainage system in the area is full. Normally, gravity would take it down to the river but it's too full, so crews are manually pumping it over the levee system.

Another concern for the public works department is the waste water system and how full it is. It's running at twice its normal capacity.

Cotter is asking residents to limit water use in the Sioux Falls area because of this. They're asking to limit use through Friday. People can do that by limiting shower time, waiting to do laundry or waiting to do dishes.

The waste water system is partly so full because people are pumping water from their basements into the system. That means they're pumping it into the shower, which then goes into the waste water system. Homeowners need to be draining it into the street out of their home so it can go into the drainage system.

If you get in a situation where you think waste water is exceeding the piping limits and you have a sewer backup, then call 605-367-8198 and someone with the city will help you. There were two homes on the north end of Sioux Falls that dealt with this situation Wednesday.

Todd Heitkamp, who is the meteorologist in charge for the National Weather Service in Sioux Falls, said once the city gets past this flooding event, it's not over. There is a lot of water from the north, like Watertown, that has to come down the Big Sioux River. He said it's going to be a long spring for that reason, and this is going to be something the city has to keep in mind.

"A gradual warming process to allow that water to slowly get into the system and get out of the system as quickly as possible," he said. "We can't let our guard down. We still have a good month ahead of us."

He said hopefully mother nature will cooperate and allow that gradual warming process to happen.