Three members of the Army Corps of Engineers addressed a town hall meeting Thursday evening in Cranberry Township regarding mitigation of flooding along two creeks in the township.
Project team leader Jen Cristobal and engineers John Sourbeer and Alex Nupp presented computer models they had prepared demonstrating various flood control measures for Sage Run and Riverside Drive.
Cristobal said the Sage Run study area is within the Horse Creek watershed that flows from the headwaters near Seneca to the Allegheny River.
Cristobal said that was a 50-year flood, and the data from that event was readily available, including a high water mark.
She said the modeling was developed using computer software “informed by topography. She said the problem areas had been surveyed by Corps employees.
The approximately 30 people who attended Thursday’s gathering in the township building were shown slides representing the 2019 flooding and progressive slides showing how various mitigation efforts would impact future flood events.
Sourbeer showed Lower Two Mile Run and the areas where flooding currently occurs. He suggested removing an abandoned stone arch bridge and adding a raised embankment between the existing culverts and the Deep Hollow Road Bridge.
Sourbeer said options included widening the stream and dredging it to make the channel deeper.
Cristobal said the purpose of the meeting was to solicit comments from the residents. Township resident Ed Barrett Jr. suggested that the creation of retention ponds up stream might help divert some of the water flow.
Cristobal said it is one thing to create the ponds and another to maintain them.
“Maintaining the ponds and dredging would be the responsibility of the local municipality,” said Cristobal.
Former PennDOT district manager Michael Deibert said that maintaining areas around the bridge would not be PennDOT’s responsibility. He produced a study that had been completed in the 1980s, and that study was given to the township.
Cristobal said no construction estimates were involved in this study.
“This study will help us understand how to move forward,” she said. No cost estimates were presented at the meeting, and Cristobal said grants are available for flood mitigation projects.
The target date for the completion of the study is this fall.