Winchester MA North Reservoir Dam

Weston & Sampson conducted a comprehensive evaluation and rehabilitation design for North Reservoir Dam to address safety risks, regulatory compliance, and long-term water supply reliability for the Town of Winchester.

North Reservoir Dam is a 780-foot-long, 25-foot-tall high hazard potential earth embankment dam owned and operated by the Town of Winchester. Built around 1875, it continues to serve as the town’s water supply. For nearly a decade, the town has engaged Weston & Sampson for dam inspections and rehabilitations. Most recently, Weston & Sampson conducted a preliminary study and engineering evaluation of the dam, including hydraulic and hydrologic analyses, soil borings, monitoring wells, test pits, dive inspections, structural and geotechnical assessments. The study identified inadequate factors of safety due to loose sands susceptible to liquefaction and lateral spreading. Hazardous materials were also suspected, prompting Weston & Sampson’s Licensed Site Professional to perform a site visit and oversee test pitting to estimate debris volume and evaluate disposal options. Weston & Sampson then provided rehabilitation design and permitting services to bring the dam into compliance, including embankment improvements, structural upgrades, drainage features, and wetland replication.