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2024.09.12 Staff Report.pdf September 12 2024 Staff Report To: Conservation Commission From: Sarah LaValley RE: Staff Report, September 12 2024 Commission Meeting 5:30 PM Request for Determination of Applicability to determine if septic system replacement is subject to the Wetlands Protection Act or Northampton Wetlands Ordinance. Angelo Vacchelli Estate. 412 Sylvester Rd, Map ID 28-002. CC-24-18 Application Overview: The application proposes construction of a septic system within buffer zone to BVW, in an area that is mown lawn and garden. The current septic system is not known and may be a cess pit. Confirmation of resource area boundaries is not requested. Consistency with WPA and Northampton Wetlands Ordinance, Staff Recommendation: 310 CMR 10.03 (3) specifies that a septic system constructed in accordance with Title V requirements is presumed to protect the eight interests of the WPA as long as it is set back at least 50 feet from BVW. This applies to discharge from the system only, and not to construction impacts. Wetland flags were no longer present onsite at the time of a staff visit, but are shown approximately to follow edge of lawn in the areas closest to the septic work, with which staff agrees. The Commission should discuss construction sequencing and excavated soil placement, and issue a negative determination by checking box 3. 5:45 PM Continuation - Notice of Intent for 12-unit cluster development, access road, pedestrian paths and related stormwater. Sovereign Builders, 8 View Ave/ 56 Northern Ave. Map 25C, parcels 012, 017. Record CC-24-6 Application Overview: The application proposes construction of 12 small single detached units and related stormwater and site improvements. An existing house is proposed to be demolished. Work is limited to work on just under 20% of the site; the remainder will continue to be undisturbed. The applicant proposes to place a conservation restriction on just over half of the property as part of the project. The site includes bank and land under water of a perennial stream that flows along the rear of the site adjacent to the rail trail, and associated riverfront and BVW. No bordering land subject to flooding, vernal pools, or other resource areas are present. Except for pedestrian trail work, no resource area alteration is proposed, all work is confined to buffer areas, much of which have been previously disturbed and degraded from prior residential uses and pas dumping. Trail work will result in 338 square feet of BVW work and restoration of approximately 151 square feet. The trail relocation also results in a disturbance of approximately 364 square feet of riverfront area and restoration of 241 square feet of riverfront area. Work will result in removal of 19 Norway spruce trees within buffer zone; and planting of a variety of native deciduous trees within buffer is proposed. September 12 2024 Staff Report 2 DEP Comments, File 246-0785 - Staff responses in italic [1] No mention is made of the perennial stream located on site. Based on aerial photos including LIDAR, this reviewer suggests that the MAHWL will be delineated per 310 CMR 10.58(2)(a)2.b. In some river reaches, the mean annual high-water line is represented by bankfull field indicators that occur above the first observable break in slope, or if no observable break in slope exists, by other bankfull field indicators. These river reaches are characterized by at least two of the following features: low gradient, meanders, oxbows, histosols, a low-flow channel, or poorly-defined or nonexistent banks. This reviewer opines that at least 2 of these factors are present. It is unknown if the location of the MAHWL and the 200 foot Riverfront Area might impact the project. [3] No information about the wetlands delineation appears to be included in the NOI Supplemental information and plans since the original filing reviewed by DEP to include riverfront delineation. On this site, banks are concurrent with the MAHWL in most locations. Where Bankfull field indicators were not found, the MAHWL was located by changes in slope, changes in vegetation, and stain lines [2] The narrative mentions that currently the informal trail connections between North Street and the bike path goes in part through BVW. Instead of retaining those pedestrian connections through BVW that is mentioned, possibly it should be considered how to discourage the use of the connections through that BVW. A Pedestrian connection to the rail trail is included in the application, which proposes to reroute the existing trail entirely onto the subject property. This relocation results in approximately 338 square feet of new wetland disturbance and restoration of approximately 151 square feet of existing trail currently within BVW. The trail relocation also results in a disturbance of approximately 364 square feet of riverfront area and restoration of approximately 241 square feet of riverfront area. This work is the only resource area alteration proposed as part of the overall project. [4] Has file number 246-0631 been issued a COC? This file number was issued in 2009 for a development that did not occur. The applicant should request an ‘invalid’ certificate of compliance. 5} Per the WPA Stormwater Standards, the new impervious area is considered new development and therefore requires full compliance with the stormwater standards. Revisions to the stormwater drainage report since DEP’s review fully meet all standards [6] An infiltration basin can only receive up to 80% TSS removal no matter how much pre- treatment is proposed. Noted. The 80% TSS removal standard is met. [7] In order to comply with Stormwater Standard #8, the commission should review if there is a need for construction period sediment basins, due to mostly HSG D soils as well as whether or not the project needs to be phased such that the entirety of the buffer zone is not cleared of all September 12 2024 Staff Report 3 vegetation at the same time. The commission needs to confirm there is at least 2 feet of separation between the bottom of the basin to the seasonal high ground water. Construction period basins will be addressed in SWPPP, address in conditions to require SWPPP submittal [8] MassDEP created the stormwater handbook in 2008 to assist all commissions in understanding the stormwater management regulations. Volume 2 Chapter 2 of the Handbook lists all approved BMPs including their design, construction, operations and maintenance. This reviewer recommends that the applicant cut and paste from that handbook, into the stormwater report, the section(s) dealing with each BMP and that the maintenance requirements shown in the handbook be included in the stormwater report. As a reminder, a log book must be kept and made available for commission or MassDEP review upon request subsequent to the COC being issued. This item should be discussed at the hearing as this requirement is frequently not met by an owner. Noted, address in O&M condition Consistency with WPA and Northampton Wetlands Ordinance The majority of the work is a buffer zone only project and as such, does not have associated WPA performance standards. The only resource area work proposed is 338 square feet of new wetland disturbance and restoration of approximately 151 square feet of existing trail currently within BVW. The trail relocation also results in a disturbance of approximately 364 square feet of riverfront area and restoration of approximately 241 square feet of riverfront area. This work qualifies within riverfront as a minor project under 310 CMR 10.02(2)(b)(1)a, and within BVW can be allowed under 310 CMR 10.55 (4)(c) as a <500 sf in area alteration. The project is subject to the DEP stormwater standards. A stormwater permit from the Northampton DPW, which applies standards equal to or exceeding the MA stormwater standards, has been issued. Recent plan revisions have resulted in elimination of recharge from one of the infiltration basins that was not resolved at the time of this report. The Commission should discuss compliance with this standard and clarify recharge calculations and LC-501 with the applicant. The Ordinance creates Performance Standards stricter than C131 and its 310CMR regulations, and establishes a Protected Zone adjacent to resource areas. In the URB zone, the Protected Zone is 35 feet, where development includes mitigation measures that will improve the existing condition of the wetlands or adjacent upland. The applicant proposes to meet this standard by native and climate-resilient tree plantings to add to plant diversity and create wildlife values in the buffer zone. Much of the 0-35 foot Protected Zone area also qualifies are previously degraded or developed. Though no such work is proposed, and no further reduction is requested by the applicant, Protected Zone may further be reduced to 10 feet “at the discretion of the Conservation Commission if the applicant provides extraordinary mitigation, replication, restoration or open space preservation measures.” the applicant proposes to permanently protect more than half of the site through a permanent conservation restriction to be held by the City so the Commission may find that this standard is met. The Commission should also note that much of the area outside the 35-foot Protected Zone is already degraded or developed. Work related to walking September 12 2024 Staff Report 4 and multiuse trails designed for nonmotorized use are a separate exception under the Ordinance. Staff Recommendation: The project does not propose any resource area disturbance aside from that related to pedestrian trail work. It will result in the permanent protection of more than half of the site, and a permanent no-disturb area for all areas within the 35-foot protected zone. The drainage report demonstrates full compliance with the 10 stormwater management standards; standards that would not need to be met for a development of the same area or larger in the same location if it were made up of four single family homes. If questions regarding calculations of the recharge stormwater standard have been addressed, an Order of Conditions can be issued. Suggested conditions: Stamped revised full planset, including detail sheets, submitted prior to preconstruction meeting Submittal and approval of SWPPP Subject to required local approvals, the applicant shall donate a permanent Conservation Restriction on that portion of land shown as ‘Proposed Conservation Restriction’ on plansheet CR-01. Prior to the preconstruction meeting, the applicant shall execute a purchase and sale agreement for the donation. The applicant shall work with the City to submit a restriction for state approval and endorsement. Assessment of plantings following two growing seasons to be submitted concurrent with request for certificate of compliance. Any plants dead or diseased to be replaced at that time. Permanent markers installed at 35-foot Protected Zone Stormwater permit amendment to be obtained prior to preconstruction meeting Include all conditions specified in DPW stormater permit Consider invasive species removal within resource areas; numerous invasives are present