WESTFIELD – The Conservation Commission voted Thursday night to deny a state Department of Transportation application to construct a stormwater detention basin on East Main Street.
The DOT applied last July to the Conservation Commission to install a detention basin alongside Route 20 to improve the quality of stormwater being discharged into the Westfield River. DOT engineers presented details of the project to construct a detention basin to replace an existing drainage swale created in 2006 during construction of the Army and Air Force National Guard bridges connecting East Main and Springfield streets.
The current drainage system collects stormwater for four acres of pavement, or impervious surface, at the intersection of East Main Street (Route 20) and Little River Road (Route 187) and the entrance to the Home Depot store.
That water is currently discharged from a 36-inch pipe and runs through the swale into the Westfield River.
The state has initiated a program to improve water quality throughout the Commonwealth and the DOT is focusing on stormwater issues with the goal of improving the quality of stormwater being discharged into rivers and ponds.
The state, in its application to the commission, proposed to create the detention basin with baffles at the end of the swale to slow the velocity of stormwater, which will allow sediment to settle out of the water before it is discharged into the river. The detention basin would have several “chambers” to collect sediment and an overflow pipe terminating at the river.
The Conservation Commission denied that permit because it felt that the proposed detention basin system is actually less effective than the present swale in removing suspended solids from the stormwater.
Conservation Coordinator Karen Leigh said this morning that the DOT’s project collects “less total suspended solids than what’s there today.”
“Why replace something that is getting 70 percent removal (of the suspended solids) with something that would only get 50 percent?” Leigh asked.
“The commission asked for additional information, for the DOT to consider other options,” Leigh said, “but the applicant asked for a decision that night and did not want to look at alternatives, so the commission voted to deny the application.”
