Meeting Minutes

Agenda Item #1. Introductions

Mr. Sobel convened the meeting at 6:37 PM. He then asked if, due to the lack of attendance, the members of the public would prefer to proceed with the meeting as planned or continue their informal discussions with the technical staff. Mr. Quenzell commented that although he feels he is fairly informed, he would like to hear about the projects and results of this effort. It was decided that Mr. Aker would give his presentation on the Air Force Center for Environmental Excellence’s (AFCEE) preferred alternative, but that the other scheduled presentations would not be given.

Mr. Sobel asked the panel members to introduce themselves. Mr. Marchessault introduced himself as the Remedial Project Manager (RPM) from the United States Environmental Protection Agency (EPA), and explained that the EPA provides the oversight for AFCEE’s cleanup effort. Mr. Goydas introduced himself as a wellfield design manager with Jacobs Engineering Group and Mr. Karson introduced himself as a community involvement specialist with the Air Force.

Mr. Karson then stated that the treatment systems being installed in the Briarwood neighborhood will be operational on June 17, 1999, and the effected roads, which will be open to traffic by June 24, 1999, will be re-paved shortly thereafter. He reported that additional work will be done on Ashumet Pond this summer when a barge will be on the pond to collect more water samples. Mr. Karson stated that tonight’s presentation will pertain to future work the Air Force is proposing to do along Hooppole Road.

Agenda Item #2. Storm Drain 5 (SD-5) South/Trichloroethylene (TCE) Plume Treatment Alternatives

Mr. Aker displayed a map of the SD-5 South and the TCE plumes and stated that the goal of tonight’s meeting is to present AFCEE’s preferred approach for these plumes. He noted that this is a Time Critical Removal Action.

Alternative 1

Mr. Aker stated that the preferred alternative, Alternative 1, involves pumping extracted contaminated groundwater to the existing Sandwich Road treatment facility. He noted that one advantage of Alternative 1 is that the treatment and discharge systems already exist and include sufficient pipeline capacity for additional wells and flow. Another advantage is that access and permission for construction along existing roads should not delay the construction – most of the access issues have been resolved. Mr. Aker then reported that AFCEE is considering implementing trenchless technology to lay the pipeline, which would be less disruptive to the neighborhood and could possibly provide long-term benefits. He then noted that on-base treatment would minimize any inconvenience to the neighbors during construction and operations.

Mr. Aker then noted that a disadvantage associated with Alternative 1 is that it requires the installation of approximately 6000 feet of piping up Hooppole Road and along Back Road. Also, the installation of the wells for this, or for any of the proposed alternatives, would require that Hooppole Road be closed for six weeks, with an additional three to four weeks with only one lane open.

Alternative 2

Mr. Aker stated that Alternative 2 includes two extraction wells on Hooppole Road. The contamination would be piped along Hooppole Road to a treatment system located in a nearby conservation area.

Mr. Aker noted the advantages of Alternative 2 as follows: it requires a shorter pipe run, approximately 2800 feet; the utilization of trenchless technology would be considered; and in the event that something unexpected is found, future treatment capacity could be provided by modifying the treatment system.

Mr. Aker then stated that a disadvantage associated with this alternative is that there would be construction on Conservation Commission lands, which would require approval from the Town of Mashpee and the State Legislature – this could delay startup of the system. He noted that delaying the startup of the system is a concern because the TCE plume is moving very quickly in this area. Mr. Aker also said that the above-ground treatment plant associated with Alternative 2 would be in a community setting and this alternative would involve a lot of clearing. He stated that Alternative 2 is more costly than the other alternatives, and the addition of pretreatment would require a new phase of access, design, and construction. Traffic would be disrupted for six weeks while the wells are being installed, with an additional one to two weeks with only one lane open.

Alternative 3

Mr. Aker explained that Alternative 3 involves the installation of two treatment facilities in the middle of Hooppole Road. He displayed a slide of a vaulted ETR system. Mr. Aker then reviewed the advantages for this alternative. He stated that there would be minimal piping runs because the pipes and the extraction wells would be located in the vaults. The treatment systems would be located in the middle of the road and therefore, clearing of brush would not be required.

Mr. Aker then reviewed the disadvantages of Alternative 3. He stated that the system would be constructed in the neighborhood. He also stated that in addition to the road being closed for six weeks to install the wells, Hooppole Road, between Highland Avenue and Hillside Avenue, would be closed for eight to ten weeks. He noted that, especially during startup, O&M crews would frequently be "in the middle of the road" performing various tests and maintenance on the systems. Mr. Aker also noted that, if it were necessary, it would be much more difficult to pretreat the water with this alternative. Another disadvantage is that the system configuration requires near-field reinjection, which could result in a lot more clean water being pumped than the Air Force would like. Mr. Aker stated that if there were a need to treat additional contamination that might be found as a result of the pond investigation, it would be very difficult to modify this alternative to treat those higher flows.

Estimated Costs

Mr. Aker reported that Alternative 1 costs $4.7 million, Alternative 2 costs $6.0 million, and Alternative 3 costs $5.0 million. These estimates include design, modeling, drilling, construction and equipment, site restoration, startup, and O&M for approximately six months. Mr. Aker displayed a slide that summarized the alternatives and included factors such as: initial cost, relative lifecycle costs, design flexibility, existing pretreatment, pretreatment flexibility, pipeline flexibility, impacts during construction, and traffic disruption. He then reviewed the schedule summary. He noted that the timelines shown are durations and not hard-and-fast dates.

Agenda Item #3. Questions and Answers

Mr. Quenzell asked if the timeline in the summary holds true for all three options. Mr. Aker replied that this is correct. Mr. Quenzell then asked if there was a significant difference in blocking the flow from one option to another. Mr. Aker replied that all three options involve different variations of extraction and reinjection technology; however, the systems are essentially the same. Mr. Quenzell asked if the timeline for installing pipes to go back to the treatment system at the base would be the same for installing reinjection wells. Mr. Aker replied that Alternative 3 would take slightly longer to implement, but for the most part the alternatives are comparable in that sense.

Mr. Lewis, a resident of Hooppole Road and representative of the Briarwood Association, introduced himself. He noted that the Briarwood Association’s annual meeting is scheduled for next month and he would like to provide accurate information at that meeting. He asked if, from a cleanup capability standpoint, the technology is more optimistic with Alternative 1. Mr. Aker replied that high levels of cleanup would be achieved with any of the three alternatives. He added that an advantage of Alternative 1 is that the treatment system already exists. He also said that, in terms of cleanup, Alternative 3 is just as good as the other two alternatives, if not better.

Mr. Lewis asked if, with Alternative 1, the portion of Hooppole Road from Hillside Road to Highland Road would be closed. Mr. Aker replied that this is correct. Mr. Lewis said that last year he had requested that, when the Air Force reached the construction portion of the process, the construction at the two sites on Hooppole Road not be done simultaneously. He explained that there would be "mass confusion" since Hooppole Road is the only way to get in and out of the Briarwood community. He then asked, if Alternative 1 is selected, whether Hooppole Road would be closed all the way to Back Road at any one time. Mr. Aker replied that the construction will occur in sections, relative to the amount of trenching or directional drilling that could be done in one day. Mr. Lewis asked if it is correct that there could be two lanes open at the upper end of Hooppole Road. Mr. Aker replied that this is correct.

Mr. Lewis asked when the Air Force will reach a decision on which alternative will be implemented. Mr. Marchessault replied that Alternative 1 is being presented tonight in the hope of getting approval from the community. He stated that an attempt is being made to acquire regulator concurrence on the design by tomorrow, in order to meet the schedule of installing the system by January 2000. He noted that this information was presented at the June 9, 1999 Joint Process Action Team (JPAT) meeting and there was no opposition to the preferred alternative. Mr. Lewis asked if it is correct that which alternative is presented to the Selectmen depends on the result of the regulatory approval. Mr. Marchessault replied that this is correct.

Mr. Quenzell asked if the obstruction on Hooppole Road that is associated with Alternative 1 would vary depending on how the pipe is installed. Mr. Aker replied that the obstruction would vary according to how the utilities are laid out on the road. Mr. Quenzell asked if the Alternative 2 facility that would be constructed in the conservation land would be similar to the facility at the Quashnet system. Mr. Aker replied that it would be similar, possibly a little bigger.

Mr. Lewis asked if at this meeting there would be any discussion regarding additional drilling in Johns Pond. Mr. Marchessault replied that additional meetings will be scheduled in the future to discuss the activities occurring in Ashumet Pond and Johns Pond. Mr. Lewis asked if those meetings would be scheduled within the next few months. Mr. Marchessesault replied that they would. He added that the EPA and AFCEE are working with the United States Geological Survey (USGS), which is currently installing vapor diffusion samplers in Ashumet Pond. Those samples will be analyzed the first week in July 1999, and results will be available soon thereafter. Mr. Lewis stated that, in order to be fair to the Briarwood residents, given that Briarwood Beach might be used for access, he would like to be notified when there are more details regarding additional drilling at Johns Pond. He asked if this request is reasonable. Mr. Marchessault said that Mr. Lewis’s request is reasonable.

Mr. Rizzotto, a property owner in the area, commented that he feels disappointed. He said that he thinks many people who have followed these issues wonder if any of these meetings really count for anything. He stated that he thinks that the military has tried to do nothing, through denying things, proposing more testing, or suggesting that letting "this" vaporize into the air is the best solution. He mentioned that a recent study of air quality determined that pollution on Cape Cod is 100 times the federal standard, which reminded him of the Air Force’s solution at one time, to let more "things" just go off into the air. Mr. Rizzotto said that everyone is listening to what seems to be a simplistic approach. He remarked that he feels there are very few wells to treat the contaminants with this new set of alternatives, and there were many more wells with the earlier alternatives. He said that it seems to him that the EPA has forced the military back into agreeing to two wells, which seems to be a minimal approach.

Mr. Rizzotto stated that at previous meetings there were discussions about impacts on the water table, such as drawdown, which was not mentioned tonight. He noted that it appears to him that Alternatives 1 and 2 would take water out of one location and, in one case move it over a mile, and in the other case, move it over another mile – he said that he wonders if there would be simultaneous reinjection. He also asked if the pipelines are two-way pipelines that would return the treated water to its original location, or if the water would be relocated, which could potentially drawdown the water table. Mr. Rizzotto reiterated that these issues were major concerns at previous meetings, and they were not even mentioned tonight.

Mr. Aker replied that approximately 400,000 to 500,000 gallons of water per day (gpd) are entering the pond, and these alternatives would require pumping 90 gallons per minute (gpm) from the SD-5 plume, and 70 gpm from the TCE plume. He commented that this is a small amount of water compared to the amount that is passing through the system, and it will virtually have no effect on the pond itself.

Mr. Rizzotto questioned whether this reinforces his implication that initially the military wanted to do nothing and now it is doing very little. He went on to say that according to Mr. Aker, however, very little of the water is being treated, so most of it is being allowed to pass the treatment wells. He asked if it is true that doing almost nothing is very close to doing nothing. Mr. Aker disagreed and said that the TCE plume is very small and narrow. Mr. Rizzotto interjected and said that he is referring to the SD-5 plume. He then commented that it does not appear that the two wells are anywhere near the TCE plume, rather they are "up in the middle" near the main plume. Mr. Aker replied that the recirculating wells will be removing the mass and "this" well, located within the SD-5 plume, will capture virtually everything coming down from "here." He stated that what remains "here" will discharge to the pond, but nearly all the mass will be captured by "these three wells."

Mr. Rizzotto commented that there is an inconsistency. He explained that Mr. Aker is indicating that very little water will be treated, therefore having very little effect on the flow. He questioned how everything can be captured yet, a lot can be missed.

Mr. Goydas from Jacobs Engineering Group explained that ecological thresholds have long been a concern, remain a concern, and are considered during the design process. Mr. Sobel noted that Mr. Goydas is responding to Mr. Rizzotto’s question about the impact on the water table. He then explained that ecological thresholds are particular standards that have been established for impacts on different elements of the ecology, including the water table. Mr. Goydas stated that basically the ecological thresholds include maintaining water levels and not changing the type of water that flows through these surface water bodies. He reported that the SD-5 South system, which includes the two wells currently being installed and a new well being proposed along Hooppole Road, will capture 99% of what is upgradient of the distal wells. The TCE system will capture 100% of the mass that is upgradient of the distal wells. Mr. Goydas explained that the amount of impacted water is infinitesimal relative to the amount of water that flows through Johns Pond. He stated that Johns Pond is a large water body and approximately 580,000 cubic feet of water flow through the pond on a daily basis. Approximately 90 gpm will be extracted for the SD-5 South plume and 70 gpm for the TCE plume. These are relatively small flow rates; however, the systems are still very efficient.

Mr. Rizzotto asked if 99% efficiency refers to the total flow in the plume or the efficiency of whatever is being extracted from the well. Mr. Goydas replied that treatment is 99.99% efficient – in terms of the hydraulic performance of the well, 99% of the flow that crosses through the plume will be captured. He added that, essentially, any mass that is upgradient of these wells will be captured. He also noted that the below-ground portions of all of the alternatives being discussed tonight are nearly identical, in that they are all 99% to 100% efficient.

Mr. Rizzotto asked if it is correct that 99% of the pollutant in the "slot" of the SD-5 South plume would be captured. Mr. Goydas clarified that this is upgradient of the wells, and added that Mr. Rizzotto’s statement is, however, correct. Mr. Sobel explained that Mr. Goydas is making the point that this is "upgradient" because there is some contamination that has already passed where the wells will be located. Mr. Goydas agreed that this is correct and added that, as a result of the decision criteria process in 1997, it was agreed that the SD-5 system would be from Hooppole Road to the north, and an attempt would not be made to address what is downgradient of Hooppole Road. He explained that the SD-5 system is designed from Hooppole Road and up into the body of the plume, and the TCE system includes one well along Hooppole Road.

Mr. Rizzotto asked how the SD-5 system compares in efficiency, above or below Hooppole Road, to systems that were proposed two or three years ago, which included six to eight wells. Mr. Goydas replied that there are two main differences. He explained that the SD-5 decision was based on mass removal because at that time it was not known whether all of the plume discharged to the pond. He reported that the SD-5 system essentially becomes a hydraulic capture or containment, and noted that it is capturing more mass than was initially indicated in the SD-5 decision. He also said that the understanding of the plume has changed slightly and therefore it is predicted that the SD-5 system will remediate the plume more quickly – this prediction will be borne out in monitoring data. Mr. Goydas said that in terms of meeting the original intent of the decision, this arrangement of wells meets or exceeds the goals for the SD-5 decision.

Mr. Quenzell asked if the flow of the plume into the pond would be halted once the extraction and reinjection wells are installed and operational. Mr. Goydas displayed a slide of the capture zones for the proposed wells. He explained that there are three color-coded areas for the SD-5 plume: dark blue, light blue, and green, which represent the flow paths, or the zones that these wells will capture. He then identified the location of the northernmost well, the central well, and the southernmost well. He stated that any water that would normally flow through this cross-sectional area is either captured by the northern well, the central well, or the southernmost well. Upgradient of Hooppole Road, 99% to100% of the mass that is in the SD-5 plume will be captured by one of these three wells. Mr. Goydas stated that as part of this decision, it was agreed that what is downgradient will not be addressed; rather, it will continue to migrate and discharge. He stated that for the TCE plume, shown in purple on the map, the actual flow rate through the plume is approximately 45 gpm, and the Air Force is proposing to pump 70 gpm. He commented that this is a relatively conservative, robust design, and added that anything that is enveloped by the purple lines on the map will flow to the well. Mr. Goydas reiterated that the flow of any contamination past that point is being held and what is downgradient will continue to migrate and discharge.

Mr. Quenzell asked if these results are projected. Mr. Goydas replied that they are. He explained that these are the results of the groundwater flow model and are based on the best understanding of the aquifer hydraulics, the pond relationship to the aquifer, and the physical geometry of the plume.

Mr. Rizzotto referred to the map of the well locations and asked if the "little circles" in the roads are wells. Mr. Goydas identified the two currently installed wells, and the schematic locations for the TCE plume and the SD-5 plume wells. Mr. Rizzotto inquired about another well scheme on the map. Mr. Goydas explained that this is the Sandwich Road component of the CS-10 plume response decision. Mr. Rizzotto asked why this scheme requires so many wells in such close proximity. Mr. Goydas explained that there are two primary reasons for the distribution of wells along Sandwich Road relative to Johns Pond. The Sandwich Road plume is three to four times the thickness of the SD-5 plume; it is more than 200 feet thick and down to a depth of 275 feet below ground surface. He also reported that 820 gpm is being pumped, which is at or above the threshold for flux through Ashumet Pond. He explained that the wells cannot be separated because that would result in too much drawdown – the wells have to be placed closer together to dissipate the stress. Mr. Goydas summarized that the two primary differences between the CS-10 Sandwich Road system and the SD-5 South system are the physical geometry of the CS-10 Sandwich Road system, and its physical proximity relative to Ashumet Pond. He noted that with the amount of water being pumped it is important to be critical of how the water is extracted and how it is reinjected.

Mr. Lewis asked if Mr. Goydas could comment on the success of the SD-5 North system. Mr. Goydas reported that the SD-5 north system was put on line in August/September 1997. He explained that this system was designed as a cut-off fence along the base boundary, and has essentially met that goal. He stated that the influent concentrations are relatively low and the effluent is non-detect. Mr. Goydas also noted that a clean zone has been established downgradient of the fence, which indicates that the system is performing.

Mr. Miller asked if Mr. Goydas could elaborate on the travel time between the top of the SD-5 South plume and when it reaches Johns Pond. Mr. Goydas stated that the proposal for these wells is about three to five years – this timeline will need to be verified through field monitoring. He stated that the travel times range from 1.5 feet to several feet per day, especially near the isthmus between Johns and Ashumet Pond where the plume is moving very fast. If the plume is cut off and there is a recharge of rainwater, 1.5 to 2 feet of clean water per day gets back-filled behind the SD-5 South plume, and the plume continues to migrate down to Hooppole Road. He noted that the fast travel time of the plume has been incorporated in the evaluation process.

Agenda Item #4. Adjourn

Mr. Sobel noted that the technical staff are available to answer any additional questions people may have. He thanked everyone for attending and adjourned the meeting at 7:25 PM.