Highland Pond Dam Removal

A dam removal project becomes an opportunity to improve the aquatic passage along Sawmill Brook and its tributaries and promote ecological uplift within a degraded stream corridor.

From its origin in Connecticut’s Higby Mountain, Sawmill Brook flows through Middletown to its confluence with the Mattabesset River. On its way, it had been dammed by a 12-foot-high dam. Constructed in 1875 for local water supply purposes, the dam created an 11-acre impoundment known as Highland Pond. Although the pond had become a prominent feature in what is now a 30-acre, wooded nature preserve, the dam was a barrier for migrating fish, such as alewife, blueback herring, and American eel.

Biohabitats worked with the Middlesex Land Trust, owners of the dam and nature preserve, and RiverWork to develop a design to remove the dam, restore fish passage, and enhance ecological function along the Sawmill Brook corridor. Biohabitats began by conducting a field assessment, which included wetland delineation and soil probing. Biohabitats performed hydrologic and hydraulic modeling to characterize the stream and floodplain, evaluate the potential movement of sediment in the impoundment, and quantify the effects of dam removal on migratory fish passage.

Biohabitats then crafted a design and supported permitting to restore ecological function to the riparian corridor while maintaining as much wetland value and complexity as possible. Relying on a mixture of engineered and passive processes, the solution integrated theories of Stage 0 restoration, added habitat complexity, and stabilize a portion of the impounded sediment and restored stream channel. It also took advantage of a local beaver population, allowing the beaver to actively restore the site and build ecological complexity through their activities. The dam was removed in the summer of 2025, restoring several miles of upstream aquatic habitat.