The Carlisle Mosquito Online

Friday, January 7, 2000


Farmer fears impact of planned Chelmsford wells

Cranberry Bog farmer Mark Duffy gave the Chelmsford Conservation Commission and representatives of the Chelmsford Water District some stern statistics to factor into existing calculations on the likely impact of a proposed well field upstream of Carlisle's bog. The public hearing he addressed on December 21 was considering an application from the privately-run Chelmsford water district to locate six wells with a cumulative daily pumping capacity of 350,000 gallons in the Chelmsford portion of the Cranberry Bog Reservation. After listening intently for over an hour as the Chelmsford ConsCom quizzed water district managers on their proposal for solving water supply problems in South Chelmsford, Duffy requested time to explain the nature and extent of his irrigation requirements at the cranberry farm.

Pegging his average daily water consumption at 337,000 gallons, the farmer declared that, due to their shallow root system, his mature plants needed water two to three times a week, while new cuttings have to be irrigated daily. He identified two periods of peak demand during late fall and into the winter. An early fall frost means that the bog must be flooded temporarily to preserve the vulnerable crop. As winter settles in following the wet harvest, the plants themselves must be protected from a hard freeze. Therefore, when a frigid spell is forecast, the bog is again inundated; a protective sheet of ice is allowed to form over the plants, and subsequently the water is lowered to prevent their drowning under the icy shield. A warm spell that melts the ice may force this process to be repeated to reestablish protection.

Apparently impressed at the implied arithmetic, commission member John Smeldane asked Duffy, "When the water district takes 350,000 gallons [from the watershed] and you take 337,000 gallons, what happens then?" Duffy replied, "Unfortunately, during the permitting process [involving the state Department of Environmental Protection] no mention whatever was made of what the bog is taking."

A look at a map of the Cranberry Bog Reservation shows the Heart Pond wetland system upon which the bog depends. It originates at the pond itself in South Chelmsford, whence River Meadow Brook flows southeasterly toward the cranberry farm. Damming of the stream as it reaches the bog has formed two holding ponds or impoundments that back up into Chelmsford and supply a major portion of the bog's water. The level of the water in the lower stream and its associated wetland is therefore affected by water storage and withdrawal from the impoundments.

Water rights

Duffy reminded his listeners that the bog operation has spanned more than a century and that its historic water rights were confirmed as part of the 1986 sale of the property to the two towns. He assured them that he has maintained these "registered rights" to take up to 357,000 gallons of water a day from the system, taking precedence over all other usages.

Explaining that although he is able to manage the water level in the impoundments so as to meet his normal requirements, the ponds do not assure sufficient water in times of severe drought or weather emergency. It is only then, and as a last resort, that he "pulls the boards" at Heart Pond for an additional supply. Duffy pointed out that the modern farming methods implemented over the past eight years of his stewardship have reduced the bog's water use significantly.

Given his dependence on a reliable supply of water in the ponds, Duffy expressed concern that figures used in the water districts's permitting documents call for 70 to 100 percent of the well water to come from the major holding area. If in the future he were often forced to look to Heart Pond to replace water pumped by the district wells, he feared, from past experience, that pond abutters would react negatively.

During the previous questioning of representatives from the water district chair David McLachlan had raised the matter of the effect the wells might have on the Cranberry Bog and asked, "In your calculations, do you care what he [Duffy] does?" The reply from the district spokesman George Allen was that the DEP's analysis suggested a positive answer, but when pushed further, he and his colleagues admitted that they were not hydrogeologists. McLachlan then advised, "The district is going to have to build a relationship with Mr. Duffy, and from my experience, he's a pretty reasonable person to deal with."

A number of issues

Other questions posed during the hearing raised a number of issues that the conservation commissioners appeared to want to see resolved before making any decisions on the well project. For starters, they brought up the question of whether more wells were really needed, and if so, if they had to be located on the land bought for open space conservation and recreation. It was noted that a new water treatment plant now nearing completion could more than equal the amount of water to be taken from the proposed Barnes Terrace wells and might solve the problem until other proposed wells could come on line. One member even suggested that buying water from Lowell, as was done in last summer's drought, might be cheaper in the long run.

Finally, the district's calculations concerning water level and environmental impacts received the closest scrutiny. Members focused on Allen's predictions, which were based on the performance of test wells, that water levels would recover sufficiently on a cycle of 12 hours pumping and 12 hours resting. His assertion rested on rebound tests showing 77 to 90 percent recovery after seven days of steady withdrawal. Unconvinced, commissioner Smeldane posited a 90 percent recovery on day one, a 90 percent recovery from that level on day two, a similar recovery from the new level on day three, etc., concluding, "Eventually, you will run dry." He was also dubious because the recharge figures involved the combined rebound performance of surface water and groundwater. "The pertinent question is what the effect will be on the surface water alone," he insisted.

It was at that point that McLachlan opened the discussion to a brief period of audience reaction, most of which was taken up by Duffy's presentation. Tricia Smith, one of three Carlisle Conservation Commission members present noted the apparent lack of a "watershed budget" for the entire system, indicating that there was no evidence of it in the Notice of Intent.

The hearing will be continued as the sole agenda item at 7:30 p.m. on January 18 at the Chelmsford Town Hall.

2000 The Carlisle Mosquito