- Class III - Low Hazard dams
- H&H analyses and modeling
- Dam rehabilitation, bridge repair, and dredging design
- Permitting
- Construction phase services
Challenge
A significant rainfall event caused overtopping and severely damaged the Club’s access road bridge abutments and Lower Pond Dam embankment.
Solution
GZA conducted hydrologic and hydraulic modeling of the watershed and site (Upper Pond Dam, Lower Pond Dam, and roadway culvert). Based on the results of its HEC-HMS modeling, GZA recommended that both dams be classified as Class III – Low Hazard structures with associated Spillway Design Storms (SDS) equal to the 100-year event. GZA also recommended and was subsequently retained to complete the design and permitting to rehabilitate both dams, dredge both ponds, and repair the bridge abutments at the Lower Pond Dam.
Permitting included Dam Safety Permit, Joint Application for Freshwater Wetlands (GP#1 for bridge and GP#18 for dam rehabilitation) and Flood Hazard Area Individual Permit for the dredging work, Soil Erosion and Sediment Control Plan Certification and Water Lowering Permit.
Benefit
GZA’s swift response to the emergent conditions caused by the storm not only allowed critical repairs to be made to the site’s access road, but also brought the dams into compliance with the state’s dam safety standards.