SHREWSBURY – Work began this week on a series of repairs to a “high hazard” dam off Prospect Street in Shrewsbury.
Known as the Rawson Hill Brook Floodwater Retardation Dam, the structure is classified as “high hazard” under a federal rating system due to its potential to cause loss of life or serious damage to homes, buildings, utilities, highways or railroads if it were to fail.
Contacted on Thursday, however, Shrewsbury Director of Public Works Jeff Howland emphasized that there is nothing necessarily wrong with the dam.
“There’s no issues with the dam itself,” he told the Community Advocate.
“It’s [just] time for an upgrade,” he added.
The dam impounds flow along the Rawson Hill Brook, which is a tributary of the Cold Harbor Brook.
It’s located at the bottom of Prospect Street near the intersection of Prospect and Reservoir streets, close to I-290.
Officials, including Shrewsbury Selectman John Lebeaux, Town Manager Kevin Mizikar and Howland were among those joining Congressman Jim McGovern at a groundbreaking event on Tuesday celebrating the start of repair work.
“This rehab is very important – very essential to Shrewsbury and to the folks who live down there in that neighborhood,” Lebeaux said during a Board of Selectmen meeting later on Tuesday.
The dam is scheduled to get approximately $2.3 million in upgrades funded through the United States Department of Agriculture’s Natural Resources Conservation Service (NRCS) and the state Department of Conservation and Recreation’s (DCR) Office of Dam Safety.
The dam is owned and operated by the DCR. It was constructed in 1963 as one of 10 floodwater retaining dams built by the NRCS in the Sudbury-Assabet-Concord River Watershed.
“These 10 structures are the silent protectors for the SuAsCo watershed communities,” said NRCS state conservationist Dan Wright in a press release.
According to that press release, land use changes upstream have increased the quantity of stormwater runoff in the watershed.
The dam will be upgraded to meet current dam safety standards. The upgrades will increase both public safety and climate change resiliency while extending the dam’s service life by 50 years, according to the NRCS.
As part of the project, a portion of the dam will be lowered to construct a 190-foot wide stepped roller-compacted concrete auxiliary spillway on the dam’s embankment. The top of the dam, meanwhile, will be raised by roughly six inches to accommodate for extra stormwater runoff.
Wright said the dam provides about $172,100 in average flood damage reduction benefits for the Rawson Hill Brook watershed.
“[The dam] has served us very well,” Lebeaux said.
Work on the dam is expected to be completed by late September.