By Doug Ireland
---- — State transportation officials say progress is being made to resolve water quality issues in towns along the Interstate 93 corridor, but more needs to be done.
To help tackle the problem, the state Department of Environmental Services is offering $2.2 million in grants to help protect drinking water in several Southern New Hampshire towns.
The towns include Salem, Windham, Londonderry and Derry, according to Holly Green, a DES grant coordinator.
The towns are already working together to reduce the salt used to melt ice and snow on roadways, avoiding contamination of waterways along the I-93 corridor, Derry Public Works director Michael Fowler said.
Use of road salt and stormwater runoff have been linked to water quality problems in the decades since the highway was built.
Department of Transportation Commissioner Christopher Clement and Sen. James Rausch, R-Derry, chairman of the Senate Transportation Committee, said at a transportation forum in Derry that more funding is need to finish the $770 million project to widen I-93 between Salem and Manchester.
As construction continues, cutting back on the amount of road salt on the highway remains a top priority, Rausch said.
“We have been trying to mitigate the salt use for some time,” he said. “One of the biggest problems where there is a problem is Cobbetts Pond.”
But an even bigger priority is reducing the amount used on local roads and on private property, especially parking lots, Rausch said.
Small amounts of salt used to melt ice on blacktop and sidewalks can contribute to a much larger contamination problem.
“We do have to control how much salt is put down in the parking lot if we really want to solve the water issue,” Rausch said.
Runoff from parking lots is contaminating local waters, he said,
A bill sponsored by Rep. John O’Connor, R-Derry, to limit the liability of business owners and others who use road salt has been stalled in committee, Rausch said.
Rausch and Clement said the DOT is capitalizing on the use of “best management” practices to reduce the amount of salt used.
Those practices include use of specially calibrated spreaders to ensure salt is properly dispersed and limiting the environmental impact, they said.
They also include the use of liquid brine on roadways before storms, Raush said. Snow and ice melt, with minimal impact on the environment, he said.
Fowler said Derry and other towns in I-93 corridor have received grants to help minimize salt use on roads. The towns receive 80 percent reimbursement from the state, he said.
These grants are not specifically targeted toward improving drinking water such as those announced by the DES on Friday, he said.
Green said the grants now being offered by the DES allow towns and land trusts to protect drinking water through the purchase of conservation easements. The grants cover 25 percent of the cost.
Derry was recently able to purchase three $185,000 dump trucks through the salt reduction program, Fowler said. The town has been able to cut its salt use from an average of 3,800 tons per winter to 3,500 tons, he said.
Derek Monson, member of the Cobbetts Pond Improvement Association, said road salt has had a tremendous impact on water quality in Dinsmore Brook. The brook feeds Cobbetts Pond, where the most significant problem is reduced levels of dissolved oxygen — affecting the pond’s ecosystem.
Storm runoff is the biggest problem at Cobbetts, he said. His group received a $77,000 state grant last fall to help control runoff, he said.
Heavy rain in March 2010 led to a major runoff problem at Cobbetts and Dinsmore when a detention pond overflowed. The problem was linked to the I-93 construction.