PITTSFIELD -- Heavy rains overnight on June 26-27 resulted in high stormwater flows into the city's sewer plant, necessitating an emergency procedure to divert water into nearby fields, Mayor Daniel L. Bianchi said Thursday.
A gate at the entrance to the plant off Holmes Road had to be shut down, the mayor said, which caused the stormwater and wastewater mixture to back up onto nearby open land.
"This was not an extraordinary event," Bianchi said. "This is something that can happen two or three times a year, after heavy rains or sometimes when the snow melts in the spring."
The purpose of the response, he said, is to halt or reduce untreated water flows directly through the wastewater plant into the Housatonic River.
"From time to time, the plant can only handle so much stormwater and wastewater," he said.
Afterward, city crews "then go out and clean up the fields," the mayor said. "That has been done."
Bianchi said plant officials have been in contact with the state Department of Environmental Protection about the incident.
DEP spokesman Ed Coletta said the city notified the agency as required, but that was done through a voicemail on a Friday (June 27), but the state official did not receive the notice until the following Monday.
The DEP has visited the plant site, including about 400 square feet of field affected when the plant was bypassed, and is continuing to review the incident, which occurred in the timeframe of 2 to 3 a.m., Coletta said.
"We will review what happened with city officials and try to determine what will prevent it from happening in the future," he said.
Some untreated wastewater apparently reached the Housatonic, Coletta said, but the swollen, fast-moving river would have helped to quickly dilute any effects.
"This is something that happens quite often at facilities like this," Coletta said.
Asked about possible fines for the city, he said "it is way too premature" to determine whether any are justified.
In recent years, the city has undertaken steps to map leaks and weak pipe connections that allow stormwater and groundwater to flow into the sewer lines. Planning included a $300,000 study to measure the inflow problem, which showed significant infiltration into the lines.
An overall plan for addressing the problems was then developed. One phase of the work was a $600,000 drainage system rehabilitation project that involved cement lining and epoxy sealing manhole walls that were leaking and replacing manhole covers.
Sewer line replacement in areas of greatest concern also was planned.
Commissioner of Public Utilities Bruce Collingwood was out of the office Thursday and could not be reached for an update on the anti-infiltration projects.
To reach Jim Therrien:
or (413) 496-6247.
On Twitter: @BE_therrien