WINDHAM — A pump malfunction during a rainstorm Friday led to hundreds, perhaps thousands, of gallons of “dirty water” draining into Cobbetts Pond from the Interstate 93 construction site, a neighborhood group said.
The flow of brown storm water into the pond off Exit 3 was just one of many water quality violations that have occurred at the site since the highway-widening project began, especially in the last year, according to Cobbetts Pond resident Derek Monson.
Monson, a leader of the Cobbetts Pond Improvement Association, blames project contractors and the state departments of transportation and environmental services for not taking more action to prevent erosion.
Every time there’s a heavy rainfall, storm water also disrupts the water quality of the ecologically sensitive pond, Monson said. He is the vice president of water quality for the association, which he said represents more than 300 residents of Cobbetts Pond.
While Monson said the problems date back at least five years, there have been several instances in the past year when the contractor for that part of the 19-mile project, R.S. Audley of Bow, failed to take precautions, he said.
“It’s happened multiple times,” Monson said. “The bottom line is they (the contractor) are not doing what they need to do and the DES (Department of Environmental Services) is not doing anything about it.”
After similar problems with a previous company occurred five years ago, Monson said Cobbetts Pond representatives, state officials and construction officials began meeting on a weekly basis to monitor the work and prevent problems.
During that time, testing has shown water quality levels exceeded state standards whenever there is a heavy rain, Monson said. Although not contaminated, the “dirty water” is harmful to the pond’s aquatic life, he said.
That’s just one reason why the state’s Executive Council approved a $77,000 water quality grant for the Cobbetts Pond group last fall, he said.
The grant was awarded to the association to pay for the second phase of improvements around the pond to prevent runoff. The state had previously granted $80,000 to the association for a watershed restoration plan and an additional $100,000 for various projects.
But state officials said while it was difficult to prevent what happened Friday, there has not been a widespread problem with water quality in Cobbetts Pond.
A pump used to control rainwater broke during the storm, causing an undetermined amount of water to flow into the pond from a nearby brook, according to Conrad Skov, the Department of Transportation’s contract administrator for the I-93 project. Testing showed high turbidity levels that subsided by Friday evening, he said.
Skov and Rene Pelletier, assistant director of the DES water division, said there are times the pond’s water quality violates state standards because of heavy rain.
“It is a problem,” Skov said. “In this case, it’s not a lethal amount to most organisms.”
But the state and contractor do the best they can to avoid major trouble, which includes pumping storm water from the construction site, they said. Nearly two inches of rain fell during the storm Friday, Pelletier said.
“This is a very difficult site,” Skov said. “We have had these types of issues in the past as well.”
Skov and Pelletier praised Audley for its work to control storm water at the site. Efforts have included construction of a berm, Pelletier said.
“We believe they have done everything right,” Pelletier said.
Audley Chief Financial Officer Susan Harrington could not be reached yesterday for comment.