Veering from common practice in most communities, the Groton Board of Health took an unusual step last week and voted to ban the burial of all wood-waste material following an outbreak of sinkholes in backyards across town.
Local health officials say the ban is needed in order to prevent potential problems with decaying buried wood, which has collapsed driveways in some cases and which also poses safety risks. State regulations prohibit developers from burying stumps and other wood waste but allow local property owners to bury stumps at their discretion. The Groton initiative, which went into effect immediately following Monday's vote, bans such burials altogether.
Board of Health chairman Jason Weber said his own driveway buckled in spots and then collapsed last year, creating cavities as deep as 8 feet in places as a result of a sinkhole, as such a depression is typically called.
"It cost $2,000 to $3,000 to fully remediate," he stated in an e-mail, adding: "The homeowner who wants to bury a stump in their backyard may not be aware of the sinkhole it can create. Also, they may forget to mention it to the property owner they sell their property to."
Other area communities also have reported occasional problems with sinkholes resulting from old "stump dumps," but the issue does not appear to be as pervasive or as prevalent as is currently the case in Groton, where the town has faced dozens of sinkhole problems in the past few years, according to Weber.
None of those towns have pushed a total ban on wood burials.
Richard Day, Chelmsford's health director, said there was a "serious problem" with a sinkhole in the town some years ago, when a number of stumps were buried in a yard, which caused a nearby stream to divert into the homeowner's septic system.
"The septic system basically blew out and was running down the hill," he said.
Evan Bolansky, the community development director in Chelmsford, said the town falls back on the state regulations, which allow wood-waste burial by homeowners but not by developers. The Planning Board typically requires all wood waste to be transported off-site when issuing an order of conditions, he said.
Day said the majority of communities, including Chelmsford, don't like to see any wood-waste materials buried.
"Most towns do have some restrictions," he said. "They don't want to see organic matter buried because they do create voids, and those voids become a problem" as the material rots.
Darren MacCaughey, director of environmental services in Westford, said stump burying is an intermittent problem, especially in older developments where less-stringent practices were in place when they were built.
"With older subdivisions, every now and then you run into an old stump dump," MacCaughey said. "We see maybe one or two a year, when we are doing testing."
If towns don't have any regulations in place, they invariably fall back on state regulations, said Joseph Ferson, a spokesman for the state Department of Environmental Protection. But the environmental agency encourages residents not to bury any wood-waste materials, he said.
Ferson said he wasn't aware of any serious accidents or injuries resulting from sinkholes in the state.
"Nationally, you will hear of a child falling into a sinkhole" from time to time, he said.
David Hamilton, principal of Burlington-based Capstone Properties, a commercial developer, said his company hires a contractor to compost stumps and other wood-waste material and then usually sells the material for a small profit or scatters the material into the woods somewhere. Though sinkholes are a problem in Massachusetts, the state doesn't have the same problems as Florida or California, where roadways and housing lots have been known to cave in because of soil and plate shifting, he said.
"Given a choice between burying a stump and grinding it, I would choose grinding it," Hamilton said. "You do at least get some money for it."
In Groton, some residents have dealt with the sinkhole problem creatively.
Tendrils of ornamental grass protrude up from the indentation in John Carver's backyard. Mulch, scattered around the small semicircle, provides a blackened carpet for the plants in the "rain garden," but it once was an ugly sinkhole.
"I've got a saucer-shaped area that looks like it's there by design," said Carver, describing how the cavity acts like a drainage funnel for rain water. "It's kind of cool."
Carver said his house was built in 1990, but the sinkholes didn't emerge until about five years ago. He noted that disposing of wood waste to an off-site location, as required under state law, is often costly and inconvenient for a developer, making burial a tempting proposition. His yard is home to three depressions, the largest being 20 feet in diameter and a foot in depth.
And the cavities are getting deeper each year, he said. Filling them with a combination of materials, such as compost and fill, has been his way of dealing with the problem.
At this point, Carver said, he has no legal recourse because he doesn't even know how to track down the builder.
"In many cases, the developer is long gone before these things start to rot away."