Construction will begin in May on projects to treat the storm-water runoff that pollutes Bare Hill Pond, according to the Bare Hill Pond Watershed Management Committee. Runoff carries phosphorous and other pollutants, contributing to the weed growth that threatens the pond’s survival, Pond Committee Chairman Bruce Leicher explained at a public forum on March 18. Phosphorous is a particular problem because, as a fertilizer, it promotes rampant growth of the three main problem weeds in the pond—water chestnut, milfoil, and fanwort.
The committee’s goal is simple, Leicher stated: to get Bare Hill Pond off the state’s list of endangered ponds, where it has been since 1999. “Everything that enters into the watershed eventually enters the pond,” Leicher told the small but attentive audience in Volunteers Hall. According to Pond Committee documents, the pond could become a weed-choked marsh in less than a century, 10 times faster than the natural transition of pond to marsh, if the polluted runoff and invasive weeds are left unchecked.
The Pond Committee has put together a $975,050 storm-water management program, with approximately two thirds of the money coming from federal funds administered through the Massachusetts Department of Environmental Protection (DEP). The local share of the costs will be drawn from a variety of resources. Community Preservation Committee funds were approved at the 2009 Annual Town Meeting. The Department of Public Works already spends a portion of its budget on runoff-related issues, and the town can credit these costs toward its share of the project, under state and federal guidelines. Likewise, Harvard can claim credit for volunteer efforts, including water chestnut pulls and professional services, at a set hourly rate.
For each major drainage area around Bare Hill Pond, the committee asked the design firm Horsley Witten to develop a treatment project suited to the terrain and volume of runoff. Proposed solutions range from dry swales that capture runoff to bioretention systems that create an artificial wetland with carefully chosen plantings over a gravel base. In each case, vegetation absorbs the fertilizer components in the storm water, preventing them from entering the pond, while soil and gravel filter out other pollutants.
Committee member Bill Johnson identified the eight areas that have been targeted for treatment to deal with runoff. The worst area, Johnson said, was the north shore near Route 111 and Pond Road, where rain washes road salt and lawn fertilizer into the pond.
Besides storm-water runoff, another major problem is the phosphorous already held in the peat layer on the pond bottom. Johnson described a three-year pilot program, with grant financing, to excavate the all-too-fertile peat in the beach area. Johnson expressed the hope that the peat, which tests have shown to be free of harmful contaminates, could be marketed as a garden soil supplement. Its sale could help to finance peat removal from other areas of the pond bottom.
Weed control on Bare Hill Pond remains a knotty problem on which opinions differ. Dr. Jeff Harris, a longtime observer of the pond, recalled in a conversation with the Press, “We nearly lost the pond in the 1960s. Herbicide treatments saved it.” Harris, who is a medical doctor and a former member of the Board of Health, expressed doubts about the effectiveness of drawdowns in eradicating the invasive plant species, saying that some are winter-hardy in this climate zone.
Abutters on Lake Shirley, in Lunenburg, have taken a different approach to weed control, according to Joanna Bilotta, president of the Lake Shirley Improvement Corporation. Bilotta said that yearly drawdowns of about 6 feet had been helpful in combating fanwort but ineffective against milfoil. As a result, the private group returned to the use of herbicides three years ago. Through their annual dues of $300, corporation members cover costs of $30,000 to $70,000 per year for treatments of copper sulfate to control algae and an herbicide to combat milfoil. Costs vary with the acreage treated.