South Strabane to address Manifold Road flooding
South Strabane Township plans to apply for Local Share Account money to pay for a stormwater improvement project behind Manifold Road.
The “stream bank restoration project” will address a flooding issue that’s been occurring in the 700 block of Manifold, according to township manager Brandon Stanick.
The creek that floods regularly – an unnamed tributary of Chartiers Creek – sits between Manifold Road and the development at Old Mill Boulevard that includes Hobby Lobby and Field & Stream.
“It’s apparent that there has not been any type of past improvements made to the creek,” Stanick said. “I’m not sure if we’ve had to close the road, but it’s to the point where the fire department is responding because people’s homes are flooding.”
The project will focus on 1,600 feet – 800 on either side – of the creek bank, starting with the southern end of the SMS Group property and north to Berry Road. Sarah Boyce of Widmer Engineering, who’s working with the township on the project, said the banks of the creek are too steep.
“That causes erosion when the water gets high and moves fast,” she said. “It causes the banks to collapse or undercut.”
Boyce said the project will stabilize those banks by “reconfiguring them,” reducing the potential for erosion. She said the state Department of Environmental Protection has deemed the creek “impaired.”
“They say there’s too much sediment in the stream that’s causing environmental issues,” she said. “This is one of those projects that will benefit the township as a whole.”
The project is expected to cost about $800,000. Stanick said he doesn’t expect to get the full $800,000 from LSA, but that the township will seek grants from other entities, as well. The deadline for the LSA grant application is Sept. 25.
“This is a long-term project,” Stanick said. “We’re just starting by securing funding sources. If we get LSA funding, we’re not going to stop there.”
In addition to flooded homes, the SMS Group, a technical services company at 750 Manifold Road, has experienced a lot of flood damage from the creek. The company made an agreement with the township earlier this year that it would invest in upgrades to the stormwater system in that area, if the township takes over ownership and maintenance of those upgrades.
SMS Group’s plan is to put in storm drainage parallel to the road and to install additional inlets and storm pipes, according to a project engineer overseeing the project.
Stanick said the township’s bank stabilization project will “check a lot of boxes,” since it also will contribute to requirements the township needs to meet for its Municipal Separate Storm Sewer System (MS4) permit – a five-year permit that will need to be renewed in 2023.
Sediment removal falls under one of six best practices in the permit’s pollution reduction plan, Stanick said.
“The pollution we’re talking about is mainly sediment and the discharge of unnatural substances into the stream,” he said. “This is where the MS4 permit becomes tangible – where you can actually see the improvements.”
Stanick said the bank stabilization project is expected to prevent about 71,800 pounds per year of sediment entering the stream. That number, he said, represents 20% of the township’s “required load reduction” for the MS4 permit renewal in 2023. He said the township supervisors will discuss during budget season different proposed projects to meet the other 80% of the required sediment reduction for the permit.