Upcoming levee projects among the most expensive
The COVID-19 pandemic hasn’t stopped progress on the $16 million levee recertification project, city and Lycoming County officials say.
Expect the next phases to cost $11 million, including repair and replacement of relief wells, cross pipe drainage systems and concrete walls along Lycoming Creek, said Jon Sander, city engineer.
“We are working in conjunction with the county to get the levee up to Federal Emergency Management Agency and Army Corps standards,” Mayor Derek Slaughter said.
“Additionally,” he said, “we appreciate and are grateful for the federal support we are receiving through this project as well.”
Relief wells are discharge points releasing water that would put stress on the earthen dike. Their repair and replacement is priced at $2.1 million, Sander said.
“They prevent instability and failure of the earthen levee system,” he said.
Funding is secured for the wells after the county was successful in getting a $1 million grant through Gov. Tom Wolf’s office of budget and the commissioners agreed to budget $1.2 million toward the project, said Shannon Rossman, executive director of the county planning department.
The cross pipe repair is estimated at $1.4 million. These are pipes that discharge water from the dry side to the river and Lycoming Creek.
“They have flap-gate systems,” Sander said.
The gates close when water becomes high, so water does not flow backwards into the city or municipality, he said.
The final section for repair is deficient concrete I-walls, which are in place along both banks of Lycoming Creek, upstream of Memorial Avenue.
“They are too low to contain a 100-year flood, plus freeboard, due to being designed using older design standards,” Sander said.
“Freeboard,” which is defined as “wiggle room,” is measured from the top of the calculated 100-year water surface elevation to the top of the concrete floodwall.
“It’s a built-in factor for safety,” Sander said.
The concrete I-walls have to be made stronger and more flexible, he said.
Inspecting engineers discovered that the piling thickness is inadequate to resist the bending stress that would happen when the concrete wall is loaded during a flood, he said.
“Failure would not occur, but there are numerical safety factors that would likely not be met,” he said.
Sander noted how this portion of the project is more complex due to the technical aspects of the location. He specified the problem is where High Street becomes Lycoming Creek Road.
“That bridge,” he said. “They are going to have to reconstruct the bridge, I think, to tie the T-wall into the bridge.”
Additionally, the engineers may have to look at designing the project to raise the floodwall under the structure close or possibly put it into the structural beams that carry the bridge, Sander said.
“They could extend the wall into the beams and waterproof the beams,” he said.
That will require some traffic considerations and involve the state Department of Transportation, he said.
“We’re looking at a tremendous amount of coordination,” he said.
The U.S. Economic Development Administration awarded $5.6 million toward the project, Rossman said.
South Williamsport has four relief wells targeted for replacement with funding likely in grant for flood-mitigation with the county, said Steven W. Cappelli, borough manager.
Loyalsock Township’s portion of the system is recertified with the Army Corps of Engineers, said Bill Burdett, township manager.
An application for a $1 million to $1.5 million H20 flood-mitigation grant was submitted to the state Department of Community and Economic Development in April, but COVID-19 led to delayed notice of the award. The county expects to hear how much they are getting in September, Rossman said.