About this Project

Tobyhanna Dam No. 2 is an earthfill embankment dam located in Tobyhanna State Park, owned by the Pennsylvania Department of Conservation and Natural Resources (DCNR). The dam spans 860 feet in length and stands 18 feet high, including a 62-foot spillway. Initially constructed in the 1950s, the dam is now undergoing a complete replacement to meet modern safety standards and withstand the Probable Maximum Flood (PMF). The project includes raising the dam’s height, replacing the spillway, and implementing infrastructure improvements to protect downstream communities and enhance recreational use.

AEG’s scope included:

• Site Reconnaissance: AEG prepared a Site Reconnaissance Report summarizing background research and field observations of the existing embankment and surrounding areas.
• Geotechnical Investigation: AEG performed subsurface exploration, coordinated drilling operations, and conducted in-house laboratory testing to evaluate embankment stability and seepage risks. These findings were compiled in the Final Geotechnical Engineering Report (FGER), which included recommendations for armoring the dam breast and spillway channel walls.
• Geophysical Analysis: Electrical Resistivity Imaging (ERI) and Spontaneous Potential (SP) methods were used to assess material variability, saturation, and seepage potential.
• Environmental Services: AEG completed wetland identification and delineation, prepared a wetland investigation report, and supported environmental permitting efforts.

The US Army Corps of Engineers will scan the lakebed for unexploded ordnance due to the site’s history as a military testing ground.

AEG’s technical expertise is helping DCNR deliver a safe, cost-effective, and environmentally responsible solution for one of Pennsylvania’s high-hazard dams.