Wisconsin heavy rainfall; MMSD's effort to prevent sewer overflows

MMSD's effort to prevent sewer overflows

The Deep Tunnel is at 77% capacity due to heavy rain, prompting MMSD to ask residents to limit water usage to prevent overflows and basement backups.

MILWAUKEE - The Milwaukee Metropolitan Sewerage District (MMSD) is urging residents to limit their water use, to prevent sewer overflows.

Preventing sewer overflows

What we know:

Right now, the Deep Tunnel is at 77% capacity, totaling 331 million gallons of waste water, waiting to be treated. With more rain in the forecast, and an already saturated ground, MMSD is asking people to help limit stresses on the wastewater treatment system.

Flooding at Currie Park

"We’re not saying don’t take a shower, don’t use a bathroom, please do. Try to use less water in other parts of your life," said MMSD spokesperson Bill Graffin. "The more water we keep out of the sewer system, that’s water that can’t become an overflow or a basement backup or problem for someone else."

Heavy rain Tuesday, Wednesday

Dig deeper:

Some of the heaviest rainfall Tuesday night and Wednesday morning fell on the city’s north side, causing localized flooding in low lying areas and streets, stranding some drivers – including some who tried to drive through the high floodwaters. The Milwaukee Fire Department says it received about 50 calls for help relating to submerged cars in the city.

FREE DOWNLOAD: Get breaking news alerts in the FOX LOCAL Mobile app for iOS or Android

By Wednesday morning, much of the street flooding had subsided, as storm sewers had a chance to catch up, or were unclogged. But evidence of the rainfall could be seen on area waterways and watersheds.

A portion of Currie Park Golf Course in Wauwatosa was underwater, as the Menomonee River swelled. Downstream, at Hart Park, the USGS water gauge showed the river rose roughly five feet in 12 hours.

Flooding at Currie Park

MMSD sanitary sewers are, in large part, separate from storm sewers. But during heavy rainfall events, water takes the path of least resistance, and finds its way through cracks into the sanitary sewers, causing water treatment system to be put under greater pressure.

What they're saying:

"The ground is extremely saturated, there’s a ton of water that ends up leaking into cracks in sewer pipes, that doesn’t need to be there," Graffin said.

MMSD said it is also investigating five possible sanitary sewer overflows, following intense rains Monday, in the northern half of MMSD’s service area, including Bayside, River Hills and Milwaukee.

SIGN UP TODAY: Get daily headlines, breaking news emails from FOX6 News

"We need to go out and check those with our crews," said Graffin, "just to determine whether an overflow occurred, or not."

Flooding at Currie Park