The Whites Mill Pond Dam was built as a part of the historic Whites Mill complex in Winchendon, MA. The dam consists of an earthen embankment with a dry-laid stone masonry downstream wall. The dam has been considered in Poor condition primarily due to concerns about seepage and stability. The new owners of the site proposed to breach the dam to eliminate the risk and restore the upstream river channel to its natural condition, creating more than 25 acres of wet meadow and other wetlands in the former impoundment area. This plan was intended to benefit both the public safety and the ecology of the North Branch of the Millers River.
GZA inspected the dam and created site plans that defined topography, bathymetry, and regulatory resource areas in and around the pond. GZA also modeled the hydrology and hydraulics of the river system, including assessment of post-breach flow depths and velocities for fish passage. GZA designed a breach configuration to match the expected natural river characteristics based on adjacent channel morphology. A wide overbank area was specified, and streambank stabilization was provided in-part via coir logs. An in-stream sediment management plan was developed assuming return of natural sediment transport and channel formation.
GZA presented its findings and proposed designs to the community in public meetings and at permit hearings. Permitting efforts included seeking authorization through or from the Massachusetts Environmental Protection Act (MEPA) process, the MA Wetlands Protection Act, Chapter 253 Dam Safety program, Chapter 91 Waterways program, Section 401 of the Clean Waters Act, and Section 404 of CWA.
After an extensive process, all permits were obtained. The project received grant funding under the Massachusetts EOEEA Dams and Seawalls Program.