Lexington Old Reservoir Dam Rehabilitation

Weston & Sampson provided design, permitting, bidding, and construction services for the rehabilitation of significant hazard Old Reservoir Dam in Lexington, Massachusetts.

Our team provided Phase I inspections and Phase II evaluation for the dam and prepared the Emergency Action Plan (EAP) and Operations and Maintenance Plan. We provided site topographic survey, LLO investigations, hydrologic/hydraulic analyses, wetland delineation, geotechnical explorations, geotechnical slope and seepage stability analyses, and structural evaluations. The design plans included the removal of trees, flattening of the dam slopes, raising the dam crest, installation of a mineral filter at the downstream toe, installation of a new manhole for the existing LLO, protection of existing wetlands and wetland replication, installation of a pedestrian path on the dam crest, and planting of new trees. The rehabilitation was successfully implemented in a tight schedule during the summer break of the nearby school.