Conservation Commission Minutes 01/05/2016
CONSERVATION COMMISSION/INLAND WETLANDS
AND WATERCOURSES AGENCY MINUTES
JANUARY 5, 2016
REGULAR MEETING
I. CALL TO ORDER
Margery Winters, Chairperson, opened the Regular Meeting of the Conservation Commission at 7:30 p.m. in the Main Meeting Room at the Town Offices. Other members and alternates in attendance were Charles Haldeman, Andrew O’Connor, Jim Morrison, Donna Beinstein, and Donald Rieger. Also present were Michael Glidden, Assistant Town Planner; Janis Prifti, Commission Clerk; and other interested parties.
II. ROLL CALL
1. Appointment of Alternates
Chairperson Winters seated Commissioner Haldeman for Darren Cunningham and Commissioner Beinstein for the vacancy.
III. APPLICATIONS
1. Administrative Approvals
None.
2. Discussion and Possible Action:
a. CONTINUED FROM 12/15/2015: Application #15-48 of John M. Lightfoot, Applicant; Nancy Onken, Owner; for the construction of an addition to the existing residence on the property located at 35 Lucy Way (Assessor's Map H13, Block 109, Lot 023). Zone R-80. (received 12/01/2015; decision must be rendered by 02/04/2016)
Application #15-48 was read into the record.
The Applicant’s Engineer and Land Surveyor, John Paul Garcia, noted that Town comments received a short while ago seemed agreeable. The Engineer proposed building an addition (shown in yellow) north of the existing house (shown in brown}; the area behind the house is presently graded and the area where the addition would go is relatively rough; and stormwater would be handled by tying the front part to the existing retention pond with a level spreader in back.
The Engineer noted that the Town comments requested reducing the amount of grading on the retaining wall side; the Engineer and Contractor had discussed that idea and preferred angling it back to the west from the wall to slope better with the intent to remain 20 feet from the wetland; they would use modular block geogrid with reinforcement every 2 courses for the retaining wall. The Engineer indicated while an erosion control plan was provided, no landscaping plan was provided because no landscaping was proposed – the Owner would like to have a grass area with a geogrid under the slope and allow the area to revert back to native vegetation, including scrub, bull briar, and white pine. The Commissioners noted the landscaping plan was suggested by the Commission as it is a good practice at the edge of a wetland to have a properly vegetated buffer of selected plants to protect the wetland from the activities of civilization uphill from the area. The Commissioners added that it is likely invasive plants will be introduced to the area when the soil is disturbed for grading. The Engineer believed the 2 to 3-foot area for the retaining wall, built up on a pad of stone with about 2 layers of geograde and geotextile about 6 blocks high and dirt on top with nothing below it, would disturb as little area as possible. The Commissioners asked for clarification of how the wall would be built and how much regrading would be done. The Engineer indicated the regrading would be above the retaining wall, and not below, and would be about the width of a 30-inch bucket; they would dig about 1 to 1 ½-feet deep depositing a layer of 1 ¼-inch crushed stone and then build the wall on that stone and fill behind it on the uphill side.
Regarding the retaining wall height, Town Staff noted for a wall higher than 4 feet a professional engineering plan is required under the State Building Code and deferred to the professional engineer who would have to certify the correct height and extent of the wall ends. Town Staff suggested they consider about a 4-foot high wall (approximate location shown on the topo map by the pink line) at elevation 106 which seemed reasonable for grading to work while limiting the amount of disturbance and doubling the amount of separation from mapped wetland soils to 22 feet rather than what was shown on the original plan; the silt fence would be tightened to the edge of the retaining wall with the footing drain and trenched roof leader outlet being the only disturbance beyond the retaining wall, which would cut grading almost in half.
The Commissioners asked if water running off the retaining wall would drop down. The Engineer responded the majority of site water would be directed to the roof leaders to the spreader or front detention pond and there should be no sheet flow over the wall, like a waterfall; because the wall is porous block material, any water falling behind the wall will filter through the wall and not over the top. Town Staff noted the wall block manufacturer specifies backfill and distance; and if the wall were higher than 4 feet, the Applicant would have to devise a drainage plan that could be tied into the footing drain. The Engineer added that as the water drains through the porous wall there are visible wet spots on the wall and no hydrostatic buildup behind the wall. Regarding whether the manufacturer recommends running a compactor over the ground, the Engineer confirmed they would do that behind the wall, but 1 ¼-inch crushed stone under the wall would not be compactible, which is what is generally used; although the contractor may decide to run a compactor over the stone on its flat wall bed – the compactor could be walked down or machine-swung over on a chain – the wall would likely be completed prior to beginning work on the foundation.
The Commissioners asked what the plan would be for staging equipment. The Applicant confirmed all machinery would enter from the opposite end of the building and the retaining wall would be put in utilizing a safer mini-excavator with a less than 6-foot footprint on tracks with light ground pressure. The Applicant added that a larger excavator would be used to dig out the hillside for other pieces and for septic system repair. The Commissioners discussed putting the retaining wall in first given the huge slope and need to protect the wetlands; the Engineer agreed the retaining wall should go in first as it provides a better working platform given the large slope. The Commissioners indicated a well-thought out process is required. Town Staff reconfirmed under the State Building Code as part of the building permit process that any retaining wall above 4 feet in height requires a professionally engineered plan be submitted to the Town; and the building official will review the details and decide if the proposed manufacturer/specifications will work, or request further information or changes in relation to the proposed addition and steep slope. Town Staff also requested that the retaining wall be installed first, and that a revised formalized grading plan be submitted to the Town for issuance of the building permit – and Staff will report back to the Commission on their status. The Commissioners noted the need to have a map on record showing the correct grading, rather than the extensive grading shown on the previously submitted map. The Engineer confirmed that a footer between the wall and wetlands would not be needed with the wall about a bucket wide.
Regarding vegetation, the Engineer confirmed native vegetation would be behind the wall and mowed lawn above the wall. Around wall corners, the Commissioners preferred a redesign providing a native vegetation landmark buffer at the wetland edge; the Engineer confirmed that would be included in their plan redesign. The Applicant confirmed the goal to have as little mowed grass as possible and indicated there are no invasives, e.g., multiflora rose, Japanese barberry, or Guatemala. The Commissioners noted their need to focus on the activities of residents of this property over the long term and suggested a plan for the small strip of disturbance near the wall; the Engineer agreed to include that in their revised submitted plan. Regarding utilizing either certified weed-free hay bales or wood chips, the Engineer noted there are no trees coming down to provide wood chips, and they would use hay bales, but it is hard to find certified weed-free hay bales. The Commissioners requested and the Engineer agreed to submit a plan to utilize certified weed-free hay bales – the Commissioners noted many towns in Massachusetts require them and could potentially provide information on a source. The Commissioners noted in the drawing the potential of stacking hay bales or using 2 rows; the Engineer explained that would be done for reinforcement if there was a lot of water coming off the hillside, but there is no indication of that with no erosion issues anticipated on this stable site.
Regarding Special Condition #1, “Limits of wetland soils shall be delineated by a soil scientist before commencement of site work.”, Town Staff noted the Contractor agreed to that at the last meeting and would like the field marked in order to indicate to the excavators and contractors the area protected so that dirt and runoff are not entering the wetlands.
Commissioner Morrison made a motion that the Conservation Commission finds this is a regulated activity because the proposed activities are within the Upland Review Area.
Commissioner O’Connor seconded the motion, and it was passed unanimously.
Commissioner Morrison made a motion that this is not a significant activity because of the erosion controls in place and the pre-construction planning that has been done to minimize erosion and the setback of all the work from the actual wetlands themselves; it appears there should not be any impact to the wetlands based on the proposed Application.
Commissioner O’Connor seconded the motion, and it was passed unanimously.
Commissioner Morrison made a motion to approve Application #15-48 with the Special Conditions and Standard Conditions in the 12/31/2015 Staff Report and with the change in the plan that the retaining wall be installed prior to building construction downslope of the new building approximately 22 feet from the wetland; that any disturbed areas on the downslope side of the retaining wall will be replanted with native plants; that a new revised grading plan will be submitted to the Town prior to issuance of the Building Permit; that the vegetative buffer be generally along the wetland edge requiring submission to the Town of a Landscaping Plan, as described in Special Condition #7 that, “The final landscaping plan shall be provided to Town Staff by the Agent and discussed with the Chairperson whether the plan is appropriate; no building permit shall be issued until such time as the landscaping plan is approved.”; that the Soil Scientist will visit the site and delineate the inland wetland soils on the property and determine appropriate planting materials and planting method to enhance the buffer area and incorporated in the revised grading plan; and assuring either use of certified weed-free hay or an approved alternative.
Commissioner O’Connor seconded the motion, and it was passed unanimously.
3. Receipt of New Applications
None.
IV. GENERAL COMMISSION BUSINESS
1. Correspondence
a. Eversource Energy: maintenance activities on selected electric rights-of-way, 2016
Town Staff indicated Eversource has provided notification of clearing along their rights of way and will contact them and, if possible, walk the areas of work with them and bring any concerns with photos to the Commission’s attention. Town Staff noted this falls under Docket 34, where the Commission is procedurally notified and can provide comments on areas of concern. The Commissioners suggested reminding them that where the line crosses the Red Trail at the top of West Mountain there are some plants of special concern; Bill Morehead has cataloged some of those plants.
a. DEEP: 2015 Legislation and Regulation Advisory
Town Staff indicated the report provides items that have been approved or failed.
2. Commission Education/Workshop
Town Staff noted that the new Director of Planning plans to provide extra training for Commissioners in the future at the time of regularly scheduled meetings; and this item will remain on the regular Agenda.
Regarding chemicals used near drainage areas, as well as training for related Staff, Tom Roy was unable to attend this meeting and Town Staff will meet as soon as possible with Parks and Rec for a response to requested information.
APPROVAL OF MINUTES of the December 15, 2015 regular meeting
Chairperson Winters accepted the December 15, 2015 minutes, as written.
V. ADJOURNMENT
Commissioner O’Connor made a motion to adjourn the meeting at 8:15 p.m.
Commissioner Haldeman seconded the motion, and it was passed unanimously.