When it rains in Chicago, it floods in the South Side's Chatham neighborhood — and research has been under way for years to investigate the causes of that flooding and ways to relieve it.

Now, a new app developed by researchers at the University of Chicago is connecting the Chatham community to warn and report about flooding. The brand-new technology is years in the making.

People living in Chatham deal with more flooding than anyone else in Chicago.

Cars end up submerged underwater, and people are seen walking through floodwaters up to their waists. It often looks like video one would see after a hurricane.

"The average flood experience for a homeowner who's lived in their home for 10 years is 6% flood risk," said Nedra Sims Fears, executive director of the Greater Chatham Initiative. "In Chatham, it's 64%."

Fears grew up in Chatham and now she leads the Greater Chatham Initiative. Why is flooding such an issue in the neighborhood? Fears said that is the "billion-dollar question."

It is also a question research teams are working to answer and to address with solutions — especially with a changing climate bringing more extreme weather, and more rain.

The "Water On My Block" app is the result of the latest effort to make a difference in Chatham. The app provides reporting resources and data to help neighborhood residents understand and communicate about flooding events in real-time.

"The main functionality is being able to see real-time where there's flooding in their neighborhood," said Kelly Wagman, a fourth-year Ph.D. candidate at the University of Chicago, who designed the app along with other U of C students.

Wagman provided a preview of the app on Thursday before it officially launches this weekend. 

"This is really state-of-the-art," said Fears. "Most neighborhoods don't have flood alert apps."

Wagman explained that the app was also created with privacy in mind.

"It doesn't pinpoint any particular house just because we want to really sensitive to people's privacy," she said.

People can report flooding in real time, see where floods are happening, and immediately file reports with the city and their alderman. Users also provide data for those studying flooding in Chatham and working to learn how to prevent it.

"Their instruments are not able to see things like basement flooding, but that is a really important component of flooding," Wagman said.

The goal is eventually to bring Chatham a step closer to solving flooding.

"An app can't solve flooding, but we are hoping it can bring resources to help solve flooding," said Wagman.

"We can stop guessing and start knowing," added Fears.

Also on Chatham on Thursday, Dr. Max Berkelhammer of the University of Illinois Chicago instructed 12 preselected volunteer citizen scientists on how to install rain gauges on their property and report rainfall for 45 days beginning Tuesday of next week, April 15.

Soil gauges will be placed in residents' front yards to measure the rain. The Greater Chatham Initiative will upload the rain data collected by the neighbors into the Community Collaborative Rain, Hail & Snow Network, or CoCoRaHS.

Residents on Thursday were also urged to combat flooding by having a tree planted on the parkway in front of their property — which the city will take care of with a call to 311.

An event to launch the "Water On My Block" app kicks off this coming Saturday in Chatham.