The Carlisle Mosquito Online

Friday, March 30, 2001


Selectmen reverse Greenough dam decision

A tightly reasoned presentation by conservation commissioner Jo Rita Jordan has swayed the currently cost-averse board of selectmen to let the town decide the fate of the Greenough Pond. On March 13, they agreed to reinstate an article on the Warrant for the May 14 Town Meeting that requests $13,050 for an engineering study of the Greenough Dam. The dam is a 70-year-old man-made structure that holds back the flow of Pages Brook to form the largest open-water pond in Carlisle and to enrich extensive wetlands upstream.

Backed by color slides, Jordan pointed out that the pond, with its lovely vistas and varied wildlife habitat, was the main reason the town voted to acquire the Greenough Land in 1973. Today it is one of the most utilized parcels for hiking, snowshoeing, birding and other outdoor recreation. On the strictly practical side, she noted that its wetlands help fill the aquifers that feed both private and possible future town wells. The pond recharges the water table in the O'Rourke Farm area, which is considered a prime candidate for a future municipal well.

Dam integrity threatened

But why the hurry to effect repairs at a time when the town is facing so many other pressing problems? That has been the concern of both the selectmen and the finance committee as they considered the commission's request. Jordan and her colleagues replied that the town is facing an emergency. The roots of about 50 sizable trees are threatening the integrity of the earthen dam, and more serious, water is beginning to erode the side of the spillways"the first step to a breach." The state dam inspector has urged an immediate engineering study leading to timely repairs. From a fiscal standpoint, Jordan warned that repairs following a breach could be far more expensive than timely preventive measures.

In answer to previous finance committee questions concerning the option of decommissioning the dam (and therefore the pond), Jordan was more specific about the probable costs involved in that scenario, as well as in waiting for the dam to go out on its own. Major expenses would arise from clearly delineated Department of Environmental Protection (DEP) policies. Decommissioning would have to start with environmental impact studies and testing of pond sediments for pollutants. It would proceed with probable sediment-disposal costs and wetland replication of damaged or destroyed upstream wetlands. In its assessment, the state would also have to consider possible impact on Billerica's water supply and on area groundwater levels, plus the destruction of habitat for rare and endangered species.

Conservation administrator Sylvia Willard has consulted officials from the town of Plymouth, which is decommissioning a one-acre pond where asbestos was found in the sediments. Disposal alone is costing $150,000, and the total tab for the job is expected to reach $350,000. Greenough Pond covers approximately 20 acres

On the other hand, Jordan observed, if the town authorizes the study and the resulting design plans are in place, the DEP would help oversee the project, and the town would be eligible to apply for state grants to help defray the costs of the repairs. Conservation commissioner Carolyn Kiely has already enlisted the help of state senator Susan Fargo, who has promised to recommend including money for repair of the dam in the state budget. However, that cannot go forward until Town Meeting results are known.

State criteria

Replying to sharp questioning from selectman Vivian Chaput about the $13,050 price tag for the study alone, Jordan referred her to Robert Stevens, head of the engineering firm chosen from a field of five on the basis of both low cost and compliance with DEP requirements. He informed the board that, to meet state criteria, he must include plans not only for repair of the 300-foot earthen dam, but study the hydrology and hydraulics of the pond in relation to the spillways, give detailed specifications for upgrading those structures and prepare a maintenance guide to prevent future problems.

Although the selectmen, like the commissioners and a number of abutters and other interested citizens in attendance, were concerned about what is down the road financially, they also wanted to preserve an irreplaceable conservation and recreation resource. Apparently convinced that the commissioners had done their homework, the selectmen agreed to reinstate the Warrant article when they take up last minute changes on March 27.

2001 The Carlisle Mosquito