FPA performed the inspection, design and preparation of plans, specifications and permit documents to rehabilitate this Class I, High Hazard cyclopean concrete gravity dam with a maximum height of 39 feet and an overall length of approximately 490 feet according to NJDEP Dam Safety Standards N.J.A.C. 7:20. An H & H analysis was performed and the spillway inadequacy was addressed by raising the top of dam to provide additional flood storage and prevent overtopping. This was accomplished by constructing new retaining walls with a New Jersey Barrier face on top of the dam and on the approach embankments with a top of wall elevation that provides 1-foot of freeboard over the Spillway Design Storm, which is the Probable Maximum Precipitation event. A fourteen-foot wide paved road (Split Rock Road) traverses the eighteen foot wide crest of the dam. A 50 foot wide uncontrolled overflow spillway is traversed by a two span bridge. The existing deteriorated roadway section over the dam and on the approaches was completely removed and a new pavement section was constructed. Re-grading of the roadway and the installation of new roadway drainage structures (pipe, inlets and scuppers on the dam) were designed to improve drainage of the roadway. The design improvements included concrete spall and crack repairs, stone wall repair/reconstruction, eroded earthen embankments restoration, riprap stone slope protection construction for erosion control, road reconstruction and other miscellaneous repairs. The project also included applying for an NJDEP Dam Safety permit and Soil Erosion and Sediment Control Certificate
FPA had previously performed the Regular Inspection of Split Rock Reservoir Dam in 2007 and 2010. consisting of a the visual inspection of the dam and appurtenances, as well as completion of the Visual Inspection Checklist in accordance with the NJDEP Bureau of Dam Safety and Flood Control Guidelines. FPA also performed a Stability Analysis for the dam for the Spillway Design Storm. FPA provided construction engineering, including office support and full-time inspection, for construction.