Cooper Lake Dam and West Dike Rehabilitation

Nestled amid woodlands, Cooper Lake Dam is an earthen embankment dam 460-ft long and 45-ft high that impounds a 3,700 acre-foot reservoir, the primary water supply source for Kingston, N.Y. The city’s water department hired Schnabel to design the rehabilitation of its dam, west dike, and water intake to comply with dam safety regulations and restore full water supply source operability and low-level outlet control.

Working with our subconsultant CDM Smith and the city’s stakeholders, we developed a comprehensive rehabilitation design to construct operational and safety improvements to the dam and its related structures. This included evaluating alternatives to address spillway capacity, embankment slope stability, and inoperable water supply and outlet works system components, as well as an underwater investigation of the existing raw water intake and low-level outlet. The improvements will facilitate compliance with New York State regulations for achieving spillway capacity and stability requirements. They also factor in long-term water supply planning elements, including a new water supply intake tower and a dam raising for future additional water supply storage.

A system safe-yield model was developed and used to support design and construction decisions. As part of the design development, we worked with the owner to develop a comprehensive project risk management plan, which included developing a baseline project risk register prior to detailed design work. The objective was to identify, evaluate, assess, prioritize, and plan responses for potential project risks. These included project life-cycle risks spanning from initial permitting and alternatives evaluation, through design development and construction, and, ultimately, to future operations and maintenance.