September storm exposes weak points in Pittsburgh’s aging water system | The Homepage

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First photo: Sewage sprays out of a manhole in Four Mile Run during flooding on Sept. 3. Still image from video taken by Justin Macey. Second photo: Floodwaters at the corner of Saline and Acorn streets in The Run begin to recede as the severe storms that swept through Pittsburgh on Sept. 3 tapered off. Photo by Justin Macey

By Ziggy Edwards and Ray Gerard for Junction Coalition

On the evening of Sept. 3, a series of thunderstorms drenched Greenfield, Greater Hazelwood, and neighborhoods in the 31st Ward. August had brought near-record rainfall to Pittsburgh, so the storm itself did not surprise residents. The flooding it caused throughout the area did.

The Run had its first flood since September 2021. The Run has experienced 11 major flood events in the past 17 years. Other neighborhoods, like Hazelwood, saw flooding in new areas.

A flood of data from The Run

Mon Water Project Director Annie Quinn observed conditions in The Run and quickly created an online survey to gather details on how this storm affected the M-29 watershed. A watershed is a land area that channels water to rivers, lakes or oceans. People who experienced the storm can fill out the survey to report whether their homes flooded and describe other effects of the storm.

Several Run residents who completed the survey reported water in their basements along with a sewage smell, and stormwater flowing down Saline Street that looked higher than in other flood events.

Luckily, Pittsburgh Water had monitoring equipment in The Run. They installed it last year to gauge the effectiveness of repairs on the M-29 outfall into the Monongahela River that ALCOSAN completed in 2022. Pittsburgh Water planned to remove the equipment at the end of August, but it was still in place on the day of the flood.

According to Pittsburgh Water Community Relations Manager Holly Bomba the equipment included monitors in the sewer system, as well as a surface-level one located near Boundary Street. That monitor was supposed to record the height of street flooding at five-minute intervals.

“The collected data is in the process of being reviewed for quality assurance by the project team,” Ms. Bomba wrote on Sept. 11. She added that “some flow monitoring equipment may have gone out of service during the rainfall event due to the severe flow conditions, which is not atypical during extreme storm events.”

One rain gauge at Magee Rec Center measured 1.3 inches of rainfall in 15 minutes, she wrote. Across the M-29 sewershed and Four Mile Run watershed, the total rainfall from 6:30 to 9:30 p.m. was roughly 2.5 to 3.1 inches. In some areas, the rainfall event met the criteria to be classified as a 100-year storm.

Ms. Quinn said on Sept. 14 that this latest flood points to system failures that still need to be fixed. The question that had been unanswered was whether the work on the M-29 overflow outfall had boosted its capacity during heavy storms, and if it was enough.

“The Sept. 3 storm proved it was not enough. The branched nature of the system still hits a pinch point in The Run and the amount of flow above the neighborhood is beyond the system’s capacity,” she said.

She added that infrastructure failures happened across the board. “Manholes popped near St. John’s Church, on Four Mile Run Road by the playground, and at Saline Street both before and after the bowl of the flood zone. What makes that significant is that those are three completely different branches of the M-29 sewer pipes. Every branch, from Greenfield and Squirrel Hill South, from Oakland and the universities, to the Parkway, flowed out of the system in The Run.”

This should not be a surprise. At a May 14 stakeholder meeting hosted by Pittsburgh Water, Wet Weather Program Manager Tony Igwe acknowledged to members of Junction Coalition that the M-29 outflow restoration would not be enough to alleviate flooding in the neighborhood.

Hazelwood reports new flooding

Residents in Hazelwood reported flooded basements and flooding along Hazelwood and Second avenues.

Ms. Bomba attended the Sept. 8 Hazelwood community meeting to discuss sewer lining and water main work planned in Hazelwood.

“When we opened the floor for questions, and with the storm event being so timely, we had quite a few observations of water near catch basins and on the roadways,” she said. “Second Avenue was mentioned and, in general, we’ve had many people reaching out after that storm to flag areas that don’t normally see flooding.”

Calls to complete shelved project

Pittsburgh Water has so far spent $8.9 million on the design and planning of the 4 Mile Run Stormwater Improvement Plan. The authority had earmarked $42.65 million total for the project. Design is 90% complete. But without consulting or notifying the public, Pittsburgh Water’s Board of Directors canceled the project in late 2024. Their decision is not included in any of the Board’s public meeting minutes. The project page on Pittsburgh Water’s website currently states, “The construction of a stormwater only pipeline will help to alleviate flooding and basement backups and will convey stormwater from The Run neighborhood to the Monongahela River. Pittsburgh Water plans to initiate the design of this project in 2023.”

“Following the Sept. 3 storm, I think we can all agree that the outfall in Hazelwood did not end up inadvertently fixing the flooding problem in The Run,” District 5 City Councilor Barb Warwick wrote on Sept. 12. “It’s time for Pittsburgh Water to re-institute the funding they cut from the Four Mile Run Stormwater Project and deliver the flood mitigation Run residents were promised.”

She added that the solution must also include PennDOT and address the runoff from the Parkway, which, in addition to the sewage overflow, is a major contributor to flooding.

The watershed plan was to be constructed in tandem with the controversial, now-canceled Mon-Oakland Connector. This was a publicly paid-for, privately controlled road slated to run through the Panther Hollow neighborhood, the Junction Hollow trail in Schenley Park, and The Run. Its purpose was to connect Oakland universities with the Hazelwood Green development site.

Residents vehemently opposed the Mon-Oakland Connector and built a multi-community coalition to fight it. Former Mayor Ed Gainey canceled the project in 2022. Of immediate concern at that time was that Pittsburgh Water would nix the flood control plan, in spite of promises that they would complete it “no matter what,” as stated in a 2020 meeting in The Run.

The project’s extended limbo is unacceptable to Ms. Quinn.

“This is an environmental injustice, and solutions need to be put into place immediately,” she said.

Share your flood experience by completing the Mon Water Project’s survey about the Sept. 3 storm at tinyurl.com/MWP-flooding-survey-2026.

Ziggy Edwards is a citizen journalist who lives in Four Mile Run and proofreads every issue of The Homepage.

Ray Gerard is a citizen journalist and photographer in Greenfield.

Junction Coalition is a grassroots organization comprising residents of Four Mile Run and surrounding communities.