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2024.09.26 Staff Report September 26 202 4 Staff Report To: Conservation Commission From: Sarah LaValley RE: Staff Report, September 26 2024 Commission Meeting 5:30 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. The only resource area alteration proposed is limited to pedestrian trail work. All other site 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. 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 September 26 202 4 Staff Report 2 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 and plans 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 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 September 26 202 4 Staff Report 3 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, accompanied by restoration of 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 the work within BVW can be allowed under 310 CMR 10.55 (4)(c) as an alteration that is less than 500 sf in area. Work related to walking and multiuse trails designed for nonmotorized use are also a separate exception under the Ordinance. Comments have referenced 2007 discussion of vernal pools during the Commission’s consideration of a project at that time. A follow-up study in 2008 confirmed that depressions onsite do not meet vernal pool criteria. The project is subject to the DEP stormwater standards. The submitted stormwater checklist and drainage report detail compliance with the standards and calculations A stormwater permit from the Northampton DPW, which applies standards equal to or exceeding the MA stormwater standards through the City Stormwater Ordinance, has been issued. The hearing was continued to allow the applicant to address some calculations, elevations and plan details. Plan revisions will necessitate an amended stormwater permit prior to any work. DPW’s engineering review of the revisions noted that the HydroCAD model was updated to address the the inverts and dimensions of the detention and infiltration basins with the plan set, that depth to ESHGW has been corrected, HSG used in both the recharge and infiltration basins matches the soils group per the USGS and is consistent with the test pits and mounding analysis. HSG B is used in analyses since that is the majority of the soil within the development area. Infiltration rate used for analysis is more conservative for recharge requirements and infiltration, so is acceptable, mounding analysis is not an issue, and an impermeable barrier proposed will prevent potential breakout at lower slope elevations into the wetland. 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 that are intended 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 the applicant did not seek any exemptions for work in degraded area by proposing to comply with all performance standards. Though no such work is proposed, and no further reduction is requested by the applicant, the 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. While not necessary since no work is proposed within 35 feet of resource area, 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. 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 September 26 202 4 Staff Report 4 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. 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. Planting and trail work to be completed prior to or concurrently with other site work 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 5:50 PM Notice of Intent for open-sided pavilion, driveway and walkway construction within bordering land subject to flooding (Mill River). Grow Food Northampton. 140 Meadow St, Map ID 22B-011. Application Overview: The application proposes to modify an existing shed buildings within its original footprint, and construct an adjacent open air pavilion on wood posts with stone surfacing below. The one-way gravel drive to the North of the proposed pavilion will be widened to better accommodate parallel parking, and gravel walkways will be added. The project also proposes to replace the existing entry sign and repaint the existing information sign. Work will take place within bordering land subject to flooding to the Mill River. DEP Comments, File Number 246 -0789 None. Consistency with WPA and Northampton Wetlands Ordinance, Staff Recommendation: The pavilion will result in a loss of 26.5 cf (about the size of a refrigerator) of flood storage. No compensatory storage is proposed due to the flat topography of the site. The Commission should discuss whether there is any possibility of making the existing shed flow-through to create additional flood storage. If the Commission can find the work will not contribute to extent and level of floods, an Order of Conditions can be issued. September 26 202 4 Staff Report 5 Rocky Hill Road Emergency Certification Application Overview: DPW requests emergency authorization for an urgent need to repair two outfall locations on Rocky Hill Road in the vicinity of the Hampshire County Jail. The proposed work includes the installation of two drainage structures, resetting of two existing outfalls with stilling basins, and repair of the sidewalk. The proposed site improvements are attached. Direct impacts to wetlands are 20 sf of temporary land under water impacts and less than 5 sf of BVW impacts. Work is proposed to begin September 30. Staff Recommendation: Staff agrees with DPW's assessment that this work is necessary to prevent a full roadway failure. The piped system underneath Route 66 that outlets to resource areas has a very steep pitch, which exacerbates impacts of flows during storms and creates erosive conditions. The work proposed will create a drop system underneath the roadway to reduce the slope and force of flows. This is a similar problem and solution to the work at the rail trail at Adare Place, though that was a much larger project in scope. Work within resource areas is quite limited, and includes areas already disturbed with riprap; most work will occur underneath the road. The sidewalk repair could be considered more than is necessary 'to abate the emergency,' but the sidewalk already exists, and there would be no resource area benefits created by separating that work from the emergency work, and would increase costs. Staff recommends issuing an emergency certification to allow the work as proposed, including all construction- related conditions of Orders of Conditions.