Friday, June 2, 2006
Coventry Woods water supply to be evaluated
What is involved in a Department of Environmental Protection (DEP) go-ahead for testing wells to serve 41 units of proposed housing in Coventry Woods? What are the possible impacts on nearby wetlands? And most important, how reliable will the resulting data be? These are a few of the questions the Conservation Commission is about to tackle following a May 18 hearing on the 40B developer's request for approval of a water supply development plan.
Donald Provencher of Merrimack, New Hampshire mounted a map showing five test wells, with one located about ten feet from a wetland. He explained that the area will need to be leveled sufficiently to keep the drill rig and its supporting truck stable, but as many trees as possible will be saved. The access road will cross over an existing culvert, which will be protected by metal plates. Once the test is successfully completed, gravel paths will run from well to well, and the area will be seeded.
Turning to the specifics of the test, Provencher said the DEP calls for a flow rate of 9,000 gallons per day for drinking water. The 48-hour test run will involve at least 10,000 gallons per day. "We are not trying to get enough water for irrigation," he added. Estimating that they may have to go down 300 to 400 feet, he described a casing to be drilled adjacent to the well pipe to carry water and drilling materials to the surface, whence it will be directed to a pit designed to handle 43,000 gallons per day. Once the particulates have settled, the remaining clean water can be removed.
The commissioners soon launched into a drumbeat of questions about the logistics of the test. Chairman Tom Schultz asked why the test site was so close to the wetland and what would the pumping of 10,000 gallons a day do to the wetland itself? The answer: since a 300 to 400 foot well would not tap the same aquifer as the resource area, there should be no problem.
Commissioner Tricia Smith asked if the test team is proposing any technique to determine whether the withdrawal rate is adversely affecting the wetland. The answer: the crew has equipment that can measure the water table, not only as the pumping is going on but for a considerable period thereafter.
Smith continued, "You say you are not going to have irrigation, but how can you monitor that rule once the new owners take over? The answer: the prohibition against watering will probably be written into the deeds. The commissioners were clearly dubious about the effectiveness of such instructions in the long run, and suggested that an iron-clad enforcement mechanism will be needed.
Commissioner Roy Watson then inquired, "What do you plan to do with the tailings [the water and silt] going into the large pit?" The answer: the water will go into the wetland and the solids into the center of the parcel.
At this point abutter Mike Epstein was recognized from the audience. Informing Provencher and the commissioners that the abutters' organization will be monitoring their own wells both during and after the test, he asked if the company would be checking them and, if so, when and how. There was some conversation about whether ConsCom should be given permission to monitor, but the question remained open, and Smith returned to the matter of what should be done with the discharge. A suggestion that it be allowed to flow into an intermittent stream along Concord Street appeared to be reasonable until it turned out that the stream flowed into Epstein's lot.
With the discharge, well monitoring, and the status of two certified and two certifiable vernal pools still very much in question, Schultz continued the hearing to 9 p.m., June 9.
© 2006 The