River Watch

The Delaware River Basin Commission and the Pennsylvania Emergency Management Agency are concluding an educational initiative in the River Towns and beyond that will give flood mitigation projects a competitive edge for FEMA funding.

 

Following a similar program in the Upper Delaware, the three-year Middle Delaware Flood Mitigation Assistance Program, which ended March 1, has offered a series of events for government staff and others involved in planning, conservation, floodplain management, and emergency management across five Pennsylvania counties, including Bucks. Information from the events is available on the basin commission’s website.

 

The commission also hired a consultant to help select municipalities prepare the documentation FEMA requires to show that a project’s flood-risk reduction justifies its cost, says Avery Lentini, a community engagement specialist with the commission.

 

“The goal of this is really to help increase the capacity of local municipalities to be competitive for grants from FEMA,” Lentini says, “so that they can proactively prepare for disasters instead of just reacting to them after they’ve happened.”

The Delaware River Joint Toll Bridge Commission authorized nearly $2 million for engineering studies to evaluate the structural integrity of heavy-duty bolts that connect critical joints on six bridges.

 

Since the bolts are often shielded by other bridge components, making them difficult or impossible to inspect, the firms will use ultrasonic testing, which employs high-frequency sound waves.

 

The testing was scheduled after inspectors last year discovered a “severely deteriorated” steel pin at risk of failure on the toll-free New Hope-Lambertville Bridge. The bridge is one of twenty river crossings managed by the commission and one of the commission’s four pin-connected truss bridges. It was temporarily closed while the pin was removed and replaced, says Joe Donnelly, the commission’s deputy executive director of communications.

 

The commission will conduct ultrasonic testing this spring on six bridges with structural pins, including, in the River Towns, the New Hope-Lambertville Toll Bridge (on Route 202) and the Lumberville–Raven Rock Pedestrian BridgeMost of the commission’s bridges do not use structural pins.

 

The commission said the testing will establish a baseline for comparison in future years. Contracts were awarded to Pennoni Associates, based in King of Prussia, Pennsylvania, and Modjeski and Masters, based in Mechanicsburg, Pennsylvania.

Summer flooding in the Delaware River Basin is expected to occur more often and become more severe in the second half of this century as the climate warms, according to a 2025 study conducted by hydrologist Matthew Cooper.

 

According to the study, winter flooding would occur less often as warming temperatures reduce snowpack and nearly eliminate rain-on-snow events. But when winter floods do occur, the study found, they would look more like summer floods—driven by heavier rainfall, less snow, and greater flood synchronization, a phenomenon that occurs when upstream and downstream floodwaters combine to create more severe flooding.

 

“We were interested in this region specifically because of the historical occurrence of both rain-on-snow flooding and tropical storm-driven summer floods, both of which are expected to change,” says Cooper, who conducted the study, part of a U.S. Department of Energy research program, while working as a postdoctoral research associate at Pacific Northwest National Laboratory, in Richland, Washington. “The core finding is that warming fundamentally changes the seasonality of flood risk in the basin.”