Lefferts Pond Dam Reconstruction

Chittenden, Vermont

The Lefferts Pond Dam Rehabilitation project involved the renovation of a 130-year-old earthen, concrete spillway dam owned by the USDA Forest Service. The dam is located at a popular recreational destination. The goal was to rehabilitate the East and West Dams to meet modern dam safety standards and maintain the historic look of the structures. The constructed project consists of a low-maintenance earthen and concrete dam, concrete spillway, pedestrian bridge, and rehabilitated step-pool structure.

Unexpected deterioration of existing structural components was encountered during construction. A solution was designed while construction was under way, keeping the project on budget. Regulatory bodies required construction activities to take place without lowering the level of the 75-acre pond. The contractor constructed a temporary bladder dam of maximum size (11 ft high) to safely retain water.

The design for replacing the stone walls, which made up the downstream abutments, involved building a new concrete wall behind the original abutments and using anchors to mechanically connect cobblestone facing to the new concrete walls. To maintain the historic character of the dam and contain costs, existing cobblestones were reused on the facing of the piers and pedestrian bridge.