Crews began tearing out the concrete spillway at the South Natick Dam the week of July 14, removing a structure that has blocked migratory fish on the Charles River for decades.
The milestone comes more than three years after the Natick Select Board voted 4-to-1 in November 2022 to remove the spillway and restore the river. The Charles flows from Natick through Newton, and CRWA's watershed analysis found that removal would connect long stretches of the river and improve ecosystems downstream.
"We plan to re-deploy them after the dam is removed to compare water quality before and after dam removal," Carly Sherman of the Charles River Watershed Association wrote in a July 15 update, referring to monitors the organization recovered from above and below the dam on June 17.
A dam past its purpose
The South Natick Dam is an earthen dam with a concrete spillway, originally a mill dam rebuilt in 1934 after a 1929 flood destroyed the previous structure. The Massachusetts Office of Dam Safety classified it as a high-hazard structure in "poor condition." It generated no power, provided no flood control, and blocked fish passage, according to CRWA.
CRWA flagged the dam as a priority for removal in its Watershed Restoration Plan, finding that taking it out would improve public safety, connect the river, and protect surrounding ecosystems.
What's happening on site
Water levels in the impoundment were drawn down the week of July 7 by opening sluice gates (underwater openings in the dam). Photos published by the Natick Report on July 9 showed sediment flowing downriver and mucky floodplains exposed above the dam site. Herons were spotted flocking to the former spillway area.
The spillway removal is part of the Town of Natick's larger Charles River Park Improvements project, which also aims to preserve mature trees along the riverbank, reduce heat-island effects, and mitigate flooding.
Water quality tracking
Sherman said CRWA recovered water quality monitors placed upstream and downstream of the dam on Wednesday, June 17, and will redeploy them after removal is complete to measure changes in the river's condition.
How to follow the project
CRWA is hosting drop-in office hours at the Bacon Free Library, 58 Eliot St., Natick, on three upcoming Fridays from 10 a.m. to noon. Residents can also review project details and sign up for updates at natickma.gov/2134.
Upcoming dates:
- Friday, July 31, 10 a.m.–noon — CRWA office hours, Bacon Free Library; guest Adrienne Dunk of GZA on project permitting
- Friday, August 14, 10 a.m.–noon — CRWA office hours, Bacon Free Library
- Friday, August 28, 10 a.m.–noon — CRWA office hours, Bacon Free Library
