The Pompton Dam is a Class I, High Hazard Dam, constructed in 1908, is a 290 foot long, 30 foot high arched concrete gravity dam, located on the Ramapo River and is considered part of the Wanaque Reservoir system. With a drainage area of 160 square miles, the on-site treatment plant supplies up to 210 MGD of drinking water to surrounding communities. A grouted boulder wall was constructed during previous emergency repairs to the left abutment of Pompton Dam by the Army Corps of Engineers. Additional repairs included the construction of a sand bag diversion wall which directed flow from the left abutment to the spillway. These improvements were temporary in nature and a permanent repair was required. FPA was later retained by the North Jersey District Water Supply Commission for a new reinforced concrete retaining wall with soil/rock anchors to replace the existing grouted boulder wall on the left abutment of the dam.
FPA was retained by the North Jersey Water Supply Commission to perform a Formal Inspection of the Pompton Lake Dam and appurtenant structures which included the visual inspection, review of all instrumentation data, and review of the hydrologic, hydraulic and stability analyses in accordance with the Bureau of Dam Safety’s Guidelines.
FPA’s scope of services also included performing an updated Stability Analysis of the dam and appurtenant structures.