DES putting cart before horse

An attorney and an engineering consultant, acting on behalf of the town, have told the New Hampshire Department of Environmental Services (DES), that KeySpan Energy Delivery and GEI Consultants, Inc. have failed to provide sufficient information about the coal tar disposal site on lower Liberty Hill Road to enable the agency to assess the alternative plans for addressing it.

While the Board of Selectmen have steadfastly insisted that DES require KeySpan to remove 100-percent of the contaminated materials from the site, in February DES issued a preliminary opinion approving a plan to remove 80-percent of the most contaminated materials from the site and contain the widely dispersed balance within a slurry wall and beneath an impermeable cap — "Remedial Action Alternative 5" (RAA5).

In correspondence submitted to DES yesterday attorney Jeffrey Meyers and McDonald Morrissey Associates, Inc. challenged the agency's preliminary decision as placing "the proverbial 'cart before the horse.'" In particular, they claimed that KeySpan and GEI failed to provide sufficient hydrologic data to support the conclusion that the wall and cap will prevent the remaining coal tar from contaminating ground and surface water in the future. Meyers noted that GEI conceded that its information was lacking when it stated that "prior to implementing the selected remedy, we propose to prepare a more rigorous groundwater model of the site to help evaluated and predict specific flow characteristics and to confirm the appropriate design for the slurry wall and cap."

Explaining that the wall and cap would resemble an upside down bucket, Meyers said that the bottom of the bucket would be open unless the slurry wall is anchored to an impermeable base, like the bedrock. KeySpan and GEI have proposed extending the slurry wall to a depth of 50 feet, well short of the bedrock. Depending upon precise groundwater flow analysis," Meyers continued, "these conditions may well allow for groundwater to pass under the wall, come into contact with contaminated soils and then transport contamination down gradient toward Jewett Brook."

McDonald Morrissey stressed that a thorough analysis of groundwater flows on the site could indicate that a pumping system would be required to prevent groundwater from passing under the slurry wall. A pumping system would increase the estimated cost of $8.7-million of RAA5. In approving RAA5, DES noted that it would cost $15.9-million to remove 100-percent of the contaminated materials and concluded that the additional expenditure of $7.2-million over the cost of RAA5 "would result in no appreciable reduction in risk to human health and would provide little or no benefit to the environment."

Meyers said that because a pumping system would add to the cost of RAA5 and narrow the cost differential between the two alternatives, DES "is in not in any position to assess the costs of the relative remedial actions which it must balance against the risks to human health and the environment." Moreover, a pumping system would represent an active treatment system at the site, as opposed to the passive containment system of the wall and cap, which would require KeySpan to assure sufficient funds to operate the pumping system and monitor the performance of the wall and cap for as long as necessary.

Insisting that DES defer its decision until KeySpan provides sufficient information, Meyers remarked "were the Lower Liberty Hill site an isolated industrial, then perhaps it may be appropriate for the Department to take a 'wait and see' approach: wait and see if KeySpan submits final designs that establish that the slurry wall will be an effective barrier; wait and see if KeySpan submits data demonstrating that it has completely identified the boundaries of the contamination; wait and see if an active pumping system is needed."

"But, he continued, "the Lower Liberty Hill site is not such an isolated area. It is indisputably residential and includes areas along the length of Jewett Brook that have been visited and used by numerous residents for many years. It is simply not appropriate to wait and see. . . . "

Connie Grant, who chairs the Board of Selectmen, said yesterday that the board was "very pleased and impressed" with the work of Meyers and McDonald Morrissey. "Getting them involved was definitely the right thing to do," she said. The board met with the attorney and consultants on Wednesday to approve the submission prepared on behalf of the town. Grant said that Meyers suggested that regardless of the course chosen by DES, the town should be represented throughout the design, implementation and operation of the plan to address the contamination at the site. "This is just the beginning of our relationship with Meyers and McDonald Morrissey," she said, adding that they would be engaged on an "as needed basis."

Selectmen Kevin Hayes, a civil engineer with experience of similar sites — including sites where a slurry walls were constructed — was equally impressed. "I think they have pointed out enough flaws in the process that DES will have to take a long, hard look at their preliminary opinion," he said. In particular, Hayes stressed the reservations McDonald Morrissey expressed about the proposed design of the slurry wall, with the risk that it would fail to contain the contamination as intended.

DES officials have indicated that after thoroughly reviewing the comments submitted in response to its preliminary opinion in favor of RAA5, it will issue a final decision within 60 days.