Extending the lifespan of vital water supply dams

New York City Dams

In 1842, New York City designed and constructed a system of dams and aqueducts known as the Croton Reservoir System—in operation ever since, this system provides about 10 percent of the city’s drinking water. In 1992, the City of New York proposed to rehabilitate the 100-year old structures and return them to modern operating condition. We were brought in to help.

We were first retained by the city to perform a feasibility study to upgrade 13 dams in the Croton Reservoir System to modern dam safety requirements—this included hydrologic and hydraulic analysis, geotechnical investigations and analysis, structural analyses, and visual and underwater inspections. For the next phase of the program, we provided analysis, design of rehabilitation measures, permitting and services during construction for Croton Falls Dam, Croton Falls Diverting Dam, Middle Branch Dam and New Croton Dam. We also worked on rehabilitating and anchoring the dams and spillways, reconstructing low-level outlets and gate houses, replacing sluice gates and valves, and implementing zebra mussel control features, and constructing a new intake tower.

With the rehabilitation complete, these dams will now be able to serve the community for another 50 to 100 years.