When torrential rains hit Pittsburgh’s West End in 2018, the Saw Mill Run surged with more force than the neighborhood had seen in years. Within eight hours, more than four inches of rain funneled down the steep watershed into a narrow urban channel.
The storm did not just test the system – it critically damaged portions of the Saw Mill Run local flood-protection project, a 4,717-foot channel built by the U.S. Army Corps of Engineers Pittsburgh District (USACE) in 2000 to defend thousands of residents and commuters just across the river from downtown Pittsburgh.
By the time the 2018 stormwaters receded, the channel had suffered several structural damages, and the storm exacerbated existing erosion, leaving areas of the local flood-protection project vulnerable to further damage.
“The high flows washed out the exposed bank material beneath the revetment, creating a void,” said Krista Kutzner, the local flood-protection project’s construction manager. “The concrete revetment collapsed under its own weight or broke off, washing out the toe of the bank. After the 2018 storm, any rain event just continuously washed away material because it was exposed and couldn’t withstand the flows.”
In the upstream work area, a massive scour hole – roughly ten feet deep – had formed below the drop structure.
“There was a huge hydraulic jump during rain events that continuously scoured out that hole,” said Kutzner. “It was even beginning to undercut the wall below Route 51. That area was slowly degrading over time, but the 2018 storm accelerated everything.”
Left unrepaired, this damage threatened the structural stability of the revetment, gravity walls, soldier pile and lagging walls, and other elements that give the channel its protective capability.
However, since the local flood-protection project’s construction was federally authorized, it can receive federal assistance under Public Law (PL) 84-99. Under PL84-99, communities can request USACE to provide rehabilitation assistance for flood risk-management projects damaged by storm events.
“Congress authorized the funding for the Corps of Engineers to build it, and in the case of local flood-protection projects, they are turned over to the sponsor to maintain after USACE completes construction,” said Al Coglio, the district’s chief of emergency management and PL84-99 program manager. “If the project is kept in good working condition, and our inspections show it’s at least minimally acceptable, and then if high water or a flood causes damage, USACE can go in and repair those damages.”
In the case of Saw Mill Run, the district evaluated multiple repair strategies, including restoring the original concrete revetment and using high-performance turf reinforcement matting. Ultimately, the district decided to revive the channel to pre-storm conditions, ensuring it can withstand future floods.
The sponsor, the city of Pittsburgh, shares the project cost with USACE at a rate of 31.5 to 68.5 percent, respectively. USACE awarded a contract for the work to Gale Construction Company in February.
The federally-funded portion of the repair totaled $637,000, with the project delivering an estimated 20-to-1 benefit-to-cost ratio – meaning every dollar spent returns 20 dollars in avoided flood damage.
However, property damage would not be the only concern if the local flood-protection project’s channel was left unfixed – regional mobility would also see direct impacts.
“The project protects the community from flooding, but additionally, Route 51 runs right past the project,” said Coglio. “Any failure of that channel would cause a traffic nightmare for anyone living south of the city.”
The Saw Mill Run local flood-protection project is one of 84 local flood-protection projects within the Pittsburgh District.
Major construction on the Saw Mill Run channel repairs is complete, with follow-on work transitioning into routine maintenance. What remains is a strengthened system designed to withstand the sudden, forceful storms that characterize Saw Mill Run’s steep watershed.
The restored channel doesn’t just represent concrete, engineering, and cost-effective federal investment – it represents peace of mind. Because of the Saw Mill Run and local flood-protection projects like it, communities are safer, more resilient, and better prepared for the next storm.
“Small projects can have big impacts, and this project is an excellent example of how federal partnerships can benefit local communities,” said Patrick Moore, a project manager with the Pittsburgh District. “By partnering with the district, the city of Pittsburgh can complete this project without increasing costs to taxpayers, and the district can continue reducing flood risk for the people of West End.”