After eight years of trying, the state is still facing a roadblock to adding a fourth lane on the southern 20 miles of Interstate 93 — in the form of one brook in Windham that can’t get its chloride levels down.
Since the early 2000s, chloride levels in four brooks between Derry and Salem that exceed water quality standards have been a nuisance to the road widening project. The chloride issue needs to be resolved before construction crews are allowed to pave and mark a fourth lane on both the northbound and southbound corridors.
The chloride, which is harmful to aquatic life in high concentrations, is coming from road salt, primarily — road salt for I-93, road salt for other state roads, road salt for municipal roads and road salt for private roads and parking lots.
To fix the problem, a study was done to show how much less salt needed to be used in the areas that affect these brooks and tributaries. It led to a number of significant changes in the way state and town transportation departments de-iced their roads.
“They’re doing things that most private sectors are not yet doing, with the uses of technology, the training of their employees [and] the use of brine, which is liquid salt,” said Ted Diers, the watershed manager for the state Department of Environmental Services.
New efficiencies were found through what Diers describes as cutting-edge technology, including temperature sensors, GPS, computer tracking to eliminate waste and redundant salting and the use of pre-wetted salt.
Much of the private sector is on board, too, in large part due to a voluntary certification program called Green SnowPro created through 2013 legislation that trains commercial salt applicators to use salt more efficiently and gain liability protection. Diers says private lots are often over-salted out of an abundance of caution.
“There’s just such a fear of getting sued on a slip-and-fall case that most people use more salt than they need to to actually get the job done,” Diers said.
So far, more than 600 plow operators in the state have gone through the program.
These changes have helped save money and reach the salt load goals — but only for three of the four watersheds.
Best laid plans
For the past few years, the water quality tests for Dinsmore Brook in Windham — a water body that is now about 70 percent man-made with culverts and ditches beneath and around the highway and feeds into Cobbetts Pond — have shown little improvement. Diers says between the winters of 2014 and 2015, the test results appeared virtually unchanged. And while salt use in the area has been reduced by 25 to 30 percent according to Diers, it’s not close enough to the goal of essentially reducing total salt loads by 50 percent.
Right now, DOT Project Manager Wendy Johnson says the I-93 widening project is on track to be completed by 2020.
“What you’ll get in 2020 is a three-lane section that goes all the way from the Massachusetts border all the way up to Exit 5. And north of Exit 5 [to the I-293 split], the project they just started, that’s going to be four lanes,” Johnson said. “The question becomes, ‘When will we see four lanes [south of exit 5]?’”
The working group that is tasked with this issue has the help of academics from the University of New Hampshire and Plymouth State University, but it’s looking like they’ve exhausted every idea at this point.
“Everybody’s been doing their best, but our best just hasn’t been good enough yet,” Johnson said.
Johnson thinks this issue will likely not be resolved until after primary construction has concluded by 2020, and given how many government agencies and stakeholders have a hand in this project (DOT, DES, EPA, the U.S. Federal Highway Administration and the Army Corps of Engineers, to name a few), it may take years before the final eight feet is paved on each side.
For Dinsmore Brook at least, state officials are starting to think if it can’t reach the bar, maybe the bar needs to be moved.
“I think we need to take a look at what those values are and I think we need to take a look at how we’re estimating them,” Johnson said.
One way Diers is looking to adjust the salt load goal is by digging into historical data going back to the 1960s, in case that might help to move the baseline closer.
Though technically it’s the state that sets the exact water quality limits, Diers said, the EPA will need to be brought into the conversation to make sure the spirit of the Clean Water Act is adhered to. Whether there’s room to negotiate a different goal is an open question.
“Maybe that’s where we need to start. That’s the first question: Is there room to negotiate? Not that the environment is something that we should be negotiating over, but right now the … chlorides are definitely the issue,” Johnson said.
While environmentalists would not take kindly, generally speaking, to anything that seems to lower standards at the service of a major roadway development, Dinsmore may be an exception to the rule.
“It is a complicated and challenging problem because there are not a whole of options. It’s a very small watershed and a lot of it has a highway going through the middle of it,” Diers said.
Diers said the legal questions must be weighed against the science, which looks at how dangerous the water impairment is. And since the main concern around chlorides is the protection of aquatic life, it’s worth considering that the brook is apparently devoid of life, save for the few fish that manage to swim up the mouth from Cobbetts Pond. And there’s little hope the brook will ever be restored to its natural state with a more flourishing ecosystem at this point. The fact that much of the waterway is underground means there’s limited algae and plant growth, which means lack of food for fish or other forms of life.
“This is one of those [cases] that’s in this funny gray area where … [the] answers [are] not cut and dry,” Diers said.