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2020.10.08 Staff ReportConservation Commission Staff Report 1 October 8, 2020 To: Conservation Commission From: Sarah LaValley RE: Staff Report, October 8 2020 Commission Meeting 5:30 PM – Notice of Intent for construction of 3 new dwelling units, paved parking area, garage demolition, and related site improvements within buffer zone to bordering vegetated wetland. Pioneer Development LLC, 36 Hampden St, Map ID 38D-21. DEP File 246-746 Application Overview: The application proposes construction of a three-unit residential building within buffer zone to bordering vegetated wetland. An existing structure on the property will remain. Work will not extend further into the buffer zone than existing conditions. Additional work includes stormwater features, utilities, garage demolition, and driveway creation. DEP Comments: [1] MassGIS assessors data for property lines appear to be different than submitted. This is just a point of information. [2] The underground stormwater chambers are subject to UIC program requirements. https://www.mass.gov/underground-injection-control-uic Staff understanding that applicant is aware of these requirements [3] The same elevation datum should be used for the contour lines shown and the flood elevation from the FIRM and the FIS. Corrected on final plansets [4] Priority habitat of rare species is located here in very close proximity to the house, approximately 10 to 15 feet away. The priority habitat area needs to be overlaid on a plan. If any work is located within priority habitat, then a filing with NHESP is required under the MA Endangered Species Act. (MESA). The applicant has filed with NHESP. As of October 7, comments have not been received. If a comment letter is not provided in time for the hearing, the Commission should continue the hearing until October 22 to allow any comments to be included in the Order. Consistency with the Wetlands Protection Act and Northampton Wetlands Ordinance, Staff Recommendation: The project includes stormwater treatment measures, but proposes to discharge to the existing City of Northampton stormwater system, so is not subject to the Massachusetts Stormwater Standards pursuant to the wetlands permitting process. The Department of Public Works required that the standards be demonstrated to be met; treatment is increased and peak flows are reduced. Staff has no concerns with the BVW boundary as shown. The project is limited to the buffer zone. Floodplain exists onsite, but work is not proposed below floodplain elevations. The parcel is located within the Urban Residential B District, and all performance standards of the Ordinance that are over and above state law are waived except for the Protected Zone setback requirements. A reduced setback of 35 feet is permitted where ‘development Conservation Commission Staff Report 2 August 27, 2020 includes mitigation measures that will improve the existing condition of the wetlands or adjacent upland.’ If the Commission agrees this standard has been met, an Order of Conditions can be issued. The applicant provided a supplemental memo to demonstrate improvements through donation of the lower lot, within the floodplain, to the Massachusetts Audubon Society and increased stormwater treatment. Knotweed removal is also proposed. An additional reduced setback to 10-feet, allowable where an applicant provides extraordinary mitigation, replication, restoration or open space preservation measures, was not requested, and no work beyond the 35 foot buffer is proposed. Knotweed is pervasive on the slope as shown below, and staff has concern that mowing and seeding as proposed will not be sufficient to eradicate the invasive species, and that grass may not be an appropriate selection. The Commission should require a detailed control and planting plan be submitted that will include herbaceous native species beyond grasses to be reviewed and approved by the Commission prior to the preconstruction meeting. Discuss snow removal plans with the applicant, require a curb to prevent snow from being pushed into the buffer zone, and discuss whether limiting salt or sand may be beneficial Erosion control details propose silt sock; silt fencing may be necessary given the slope grade. Request for Certificate of Compliance, 115 Audubon Road, DEP File 246-0119 This Order of Conditions related to a stream crossing to access a single family home. As shown in the request materials, the stream crossing and driveway were constructed; with an open bottom as required, and no problems were evident. Staff noted on October 5 that the ‘existing stream crossing’ as shown on project plans was still in place, and the dilapidated wooden structure was creating scour and diverting the stream channel. The owner indicated that it was removed by hand, and staff recommends issuance of a certificate of compliance.