Williams Lake Dam Rehabilitation
York, Pa.
Merit Award
Sent by: Gannett Fleming
Owner: The York Water Co.
Main design company: Gannett Fleming
General contractor: Kinsley Construction
The dam was built in 1912 to support fire protection, drinking water and manufacturing needs. Its rehabilitation was made necessary by flood regulations that required an exponential increase in the dam’s designed capacity. The new flood regulations require the dam to handle a probable peak flood of more than 107,000 cubic feet per second, a huge increase in its capacity.
York Water took the opportunity to improve other elements, including the original spillway’s lack of underground drainage, the foundation of the central wall on undisturbed soil rather than bedrock, and an aging bridge and swing gate system. A labyrinth weir constructed on a roller compacted concrete gravity section is founded on bedrock and is designed to handle significantly higher discharge capacities than the original dam. Other upgrades include an outlet valve tower and advanced leak management features. These improvements respected the historic elements of the dam, including the original concrete wall core, which was excavated and confirmed to be intact and structurally sound.
The $40 million project was completed in 22 months, on budget and on schedule.
