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LYME CONSERVATION COMMISSION
Joint meeting with the Recreation Commission
Minutes - November 5, 2007
PRESENT: Matt Stevens, Dick Jones, Vicki May, James Graham, Adair Mulligan, Conservation Commission
Dina Cutting, Simon Carr, Bob Couture, Pete Mulvihill, Kathleen Henriques, Steve Small, Recreation Committee
Public: Ross McIntyre, Scott Rodi, Jack Elliott, Brian Cook, Stuart and Elizabeth Lopez, Breck and Kim Taylor, Jules and Rob McCutcheon, Thea and Susan Valence, Horace Henriques, Judy Barker, Keith Wilson, Tom Turkington, Don Metz, Rod Finley, Sandy Kelsey, Scott Steffey, Peter McGowan, Rick and Liz Bradley, Ellen Mulvihill, Norm and Beverly Wakely, Tom Morrissey, Patricia Reynolds, Charles Ragan, Dan Lynch, Hebe Quinton.
Copies of the Conservation Commission’s trail guides to town conservation properties and other information were offered to the public in attendance.
Chairman Matt Stevens opened the joint meeting at 7:40 pm, asking that the CC and the Rec Commission look for common goals rather than focusing on differences. He stated that the CC is aware and sympathetic with concerns at the beach and ball field. He briefly summarized the CC’s efforts to date, installing two flow devices in the beaver dams in Clay Brook, a 12" pipe in the upper dam and a 10" pipe in the lower dam. This week, Matt said that beaver management expert Skip Lisle would install another pipe in the lower dam which should create a better draw. Matt said that it appears that the flow devices have worked as intended. Simon Carr asked Rod Finley to make a presentation. Adair Mulligan noted that the CC had turned to Rod several years ago to investigate whether, at high water, Trout Brook might
create a flood chute into Clay Brook and bypass Post Pond, which could have serious consequences for water quality in the pond. She recalled that Rod had concluded that the berm created by Route 10 would prevent flood waters from causing Trout Brook to relocate.
Rod presented his new survey of the area, which included the ball field, tennis courts, beach, and boat access area. The mark of 3.0 feet on the gage installed by the CC is 496.0' above mean sea level. The soccer field surface is about one foot to 20 inches above the water level of the pond. His crew measured into the pond to the 494' level, about 20 feet from the edge of the pond. He concluded that if the water level drops one foot on the gage, the beach gains 10 feet of dry space. Rod offered his conclusions:
1. There are poor soils on the ball field site. This was an alder swamp that was graded to create the playing field. The soils are Binghamville silt loams, the same soils as at Dartmouth’s Chase Field, which have forced the college to invest in sand-based drainage. They are characterized by poor infiltration and percolation and have little granular material.
2. The surface of the playing field is poorly drained. The field is not properly crowned, and currently slopes northwest to southeast, toward the drainage area near the boat access. A proper crown could be put on the field after it is raised, although because a baseball field is usually crowned differently than a soccer field, a compromise must be worked out that works for both soccer and baseball. The soil does not have internal drainage, and is compacted. Rod pointed out that on July 4, the town parks 300-400 cars on the field, which he said is not a good practice. Even use of the field during play compacts the field.
3. Capillary action within the soils creates additional problems. The pond water affects groundwater in the area. The groundwater elevation is slightly higher in the field than in the pond. Any adjustment in the pond level affects soil in the fields through capillary action, which Rod explained.
Rod noted that Jim Jenks, in building the tennis courts, raised them 2-3 feet above the pond level, and they have performed very well. He advised that for the playing field, the town should build up the field and lower the pond. A two foot elevation difference is needed between the water level and the surface of the field, so that subdrains could be put in at 18" and have daylight. Alternatively, the town could leave the pond where it is and build the field up a foot further, which would be more expensive.
Matt asked if there is a restrictive layer in the soil. Rod answered that the soil on the field at present is entirely a restrictive layer, and that it is the type of soil where a septic system could not be built without modification. Dick Jones asked if the field needs to be crowned and drained. Rod said that it does, because the water does not seep into the ground. He said that while he has not tested the percolation rate at this site, he has tested it at Dartmouth’s field, which has the same soils, and they perc at a rate of 1/16 inch per hour. One inch of rain takes 16 hours to percolate in. He recommended using a large bulldozer to strip the topsoil to the subsoil, rototill or otherwise stir up the subsoil, and apply 6-15 inches of a mix of 70% sand and 30%
peat before spreading the topsoil back over and reseeding it. Asked about aerating the surface now, Rod said that it would do no good if no other improvements are made in the drainage, because the surface is uneven, but it would be a good maintenance practice in the future after the field is reworked.
Pete Mulvihill asked about the beach. Rod laid out two options: lower the pond to get the beach back, or keep the pond at the 3.0 level and expand the beach, which he felt was not a good option because the soils behind the beach would remain wet. He advised against raising the whole beach area, which would involve bringing in material and raising the structures and could require a permit. Dina reported that the state allows beach replenishment every six years, and that the town currently has the largest beach that is permitted.
Dina distributed to the CC copies of a resolution by the Recreation Committee that called for lowering the targeted water level of Post Pond to 2.0 feet or lower from its current level of 2.5 to 3.0 feet. Dick pointed out that the CC revisits the pond water level management policy in March of each year in preparation for ice-out. He reminded everyone that the 3.0 level on the gage is what the Dam Bureau at NH Department of Environmental Services (DES) determined to be the normal mean high water level, that defines the limit of the state property under the pond. During the summer, he said, the pond fluctuated around 2.5 feet, and higher after a rain. Now it is at 2.9 feet. The water level goes up 2/10" to 3/10" after each rain, and takes a day to max out after a
storm. Simon advised taking an on-going record of gage levels and rainfall. Matt agreed, and said that there is time before changes in the policy must be made. Vicki May pointed out that the CC had chosen the 3.0 level because this is the level identified by the state, but that if a different number could be found that all could live with, that could be considered. Dina said she recognized that the Conservation Commission’s charge is to advocate for conservation in the town, but that the town would lose the beach if changes were not made.
Adair pointed out that Lyme’s new Natural Resources Inventory points to 2.5 feet as an ideal upper limit for the wetland vegetation at the Chaffee Sanctuary, and that the report strongly advises against fluctuating water levels. James Graham noted that the two castor master pipes currently functioning in the two beaver dams were set to maintain the water level at 2.5-3.0 feet, and they have functioned as intended. Dina said that this works unless it rains. Bob Couture said that if the water level is kept at 2.5 feet, there is not enough room to accommodate a rainstorm. Dick reminded everyone that Trout Brook drains a very large watershed above the pond, and that both the pipe diameter and head affect the drainage through the castor master pipes. He said that after
the first pipe was put in the lower dam, the beavers moved to the upper dam, so a larger pipe was put there.
Dina suggested changing the water level to a lower level. Matt said that the CC is already making an effort to lower the level further, by adding a third pipe in the lower dam. He warned that the town should not assume that the water level can be completely controlled in times of storms without an engineered flood control dam, which would not be practical for this site. He said that the CC might be willing to consider breaching, which upsets the system, if significant ecological integrity could be maintained. He said that a legally defensible reasoning must be behind the selection of any water level so that it is not arbitrary. Dina replied that any water above the mean high water level is considered flooding. James reminded that state law requires the water level to be
at least 3.0 to permit breaching of the dam. Matt added that the CC is already attempting to manage the level of the pond between 2.5 and 3.0 feet. The part of the beach that is below the 3.0 water level is state property, not town property.
Pete said that since Rod’s plan for field improvements requires a specific water level, the town should not be concerned about legal liability. James said that Normandeau Associates’ study recommended a level of 2.0 to 2.5 feet. Dick warned that setting the level of the beaver pipes is a matter of trial and error. Vicki added that use of pipes was essential because if the dams are completely removed, they will be rebuilt by the beavers. Pete said he did not think the pipes would solve the problem. Dick said that Skip Lisle, the town’s consulting beaver expert, had advised that if changes were made gradually to the dams, the beavers would learn to live with them, but that if sudden changes are made, the beavers would build new dams and thwart the
efforts. Matt said that if the pipes are set between2.0 and 2.5 feet, the CC can exercise what limited control is possible, but a massive breach of the dams would not be contemplated, as this would be contrary to the CC’s mission. However, efforts at limited breaching could continue as before. Dick offered that there is no way to regulate the water level to keep it within an inch of a desired target.
Matt reminded everyone that the purpose of the meeting is to figure out a compromise that is in keeping with the charges of both the Recreation Committee and the Conservation Commission. Vicki recalled that the CC had initially set the target water level at 2.0, but changed it after the state identified 3.0 as the proper level. Dick noted that since this occurred, the town now has a Natural Resources Inventory that was not available last March when the issue was discussed at town meeting. Now, a professional recommendation is available on the water level. Matt said that this allows the CC to use a lower water level, but he hopes to avoid constant manipulation of the dams, and that the point of using the castor master pipes is to avoid having to breach the dams.
Pete Mulvihill asked about trapping the beavers. Matt said that this would need to be done constantly. James said that trapping goes against the purpose of establishing the Chaffee Sanctuary, and that it would put the town on unsafe legal ground, since federal funds were provided to purchase the land for the sanctuary. Adair added that there is a biological reason why trapping will be ineffective. She said that the conversation would be much different if the situation was in Dorchester, far from the Connecticut River, but because Post Pond is a very short distance up Clay Brook from the Connecticut, which has a strong beaver population, there is potential for constant dispersal from the river to the Chaffee Sanctuary, with its excellent beaver habitat. She added that
many mammals, such as coyotes, respond to such control efforts by increasing their fecundity and producing more embryos, so that control efforts can actually backfire by encouraging more reproduction. Dina said the population of beavers has exploded beyond historic levels. James asked how many beavers there were. No one seemed to know.
Bob Couture asked if a change in the water level could be made before April 1. James said that he hoped it would occur next week when the pipe goes in. Charles Ragan said he thought that the decisions should be made by the Recreation Committee and the Conservation Commission, not by the town. He read from a 1972 Lyme Recreation Committee report that noted frustration about the water level at the beach following rainstorms. Bob said that he thought all could live with 2.0 feet with fluctuations. Matt said that the CC has no problem trying to get more water through the dam, but was not ready for a motion. One member of the CC could not attend, and a second member has recently resigned. Adair invited those present to consider volunteering to serve on the CC. Rod said he
thought that 2.0 feet would work, and bring the beach back while the field would not have to be raised too much. If the pond comes up from that level, it would not raise the water in the field immediately.
Chairman Stevens invited questions and comments from the public. Breck Taylor asked how much time would be needed after the new pipe is installed for the water level to stabilize under normal weather conditions. Matt said it might take up to five days. Breck asked if another pipe would be installed if this one does not work. Matt said the CC would consider this based on Skip Lisle’s guidance, but that funds would have to be found. Dick explained that the CC had played with the water level when the last pipe was installed to ensure that it would function as desired. James added that the current pipes are working for the level at which they were set. Dina asked if the new pipe could be 16" in diameter, and asked why a 12" pipe was being discussed. Adair
said that the CC would need to check with Skip to be sure that a 16" pipe would not cause such a radical change that the beavers would abandon that dam and build another one. James agreed that the balance is delicate. Pete said he is not optimistic about the pipes. Adair pointed out that the town hired Skip Lisle because his approach has been successful elsewhere. Someone asked whether the beaver population would get to the point where the CC felt a need to control the population because the beavers were ruining the wildlife habitat. Adair said that the river system is dynamic, and that all types of habitat have different values.
Don Metz asked why the CC could not select 1.0 as the optimum water level. Vicki pointed out that 1.0 was likely too low – resulting in unfavorable pond conditions. James said that there is mixed information on how to maintain the dams, and it is not a matter of the CC being unwilling to accommodate the recreation activities. Dick said that the CC is restricted by state statute. If the water level is above mean high water (3.0), the pond is flooding private property, and the law clearly allows the CC to breach the dam to prevent this, but it is not clear in the law what can be done when the water level is below 3.0. He added that there is a difference between tearing out a dam and putting in a pipe.
Tom Turkington said that he did not previously realize what effort the CC had put in to the issue, and hoped that most people would be happy with the 2.0 level. Tom Morrissey said that the Recreation Committee had pushed the Conservation Commission to pick a lower number, and he asked the Recreation Committee to commit to improving the field and preventing parking on it. Simon said that such a decision would have to be made a town meeting because of the expenditure involved. Pete said that the Recreation Committee would be reluctant to advise people to drive on a newly rebuilt field. Rod agreed that this would be a bad practice. Dina said that if tax money is spent on the field, she hoped that the Independence Day Committee would find new parking.
The CC turned to other agenda items and the Recreation Committee and members of the public left the meeting. Minutes of the October meeting were approved on a motion by Dick seconded by James. The resignation of Mimi Weinstein was accepted with regrets, on a motion by Dick seconded by Vicki. Members agreed that the visit to evaluate Jim Poage’s land amounted to a favor for Jim and the Upper Valley Land Trust. James and Matt (and Adair if possible) will visit the property, but it was agreed that this does not mean that the CC will take over an easement in the future.
People are continuing to park under the trees on the west end of Lyme Common near the school, which could kill the trees. James has spoken to the principal who has asked his staff not to park there, and the parking ended for a while but has resumed. Dick advised that because there is not enough parking in the school lot for the school staff, the selectmen are reluctant to try to enforce the parking ordinance there. It was agreed that James and Matt will put up a sign that will obstruct the parking, and alert Bill LaBombard in advance. An alternative is to put notes on the windshields of cars parked in the wrong place. Some of the culprits might be from out of town and using the area as a park and ride lot. Agreed to table the discussion of trails until the next meeting.
Matt invited ideas for the annual report. Dick advised starting with last year’s draft. Topics to include: snowshoe walk, Trails Day, action on the beaver pipes in Clay Brook and Skip Lisle’s educational program, site visits, tree planting, Tree City status, and the Natural Resources Inventory. Adair will prepare an article for the Church News focusing on hiking safety during deer season, hypothermia, and the new castor master.
Returning to the initial discussion, Dick noted that DES considers breaching the beaver dams constitutes harassing the beavers, but installation of beaver pipes does not. The law says that it is permissible to breach a beaver dam if it is flooding private property (over 3.0 feet) but that it is not legal to breach a dam if the water level is not over 3.0.
Meeting adjourned 9:41 pm.
Respectfully submitted, Adair Mulligan, Secretary pro-tem
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