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2020.02.27 Staff Report.pdf Conservation Commission Staff Report 1 February 27, 2020 To: Conservation Commission From: Sarah LaValley RE: Staff Report, February 27 2020 Commission Meeting 5:30 PM – Notice of Intent for construction of a 4-story office building, parking lot, utility and stormwater management. Work proposed within bordering land subject to flooding (CT River) and buffer zone to bordering vegetated wetland. Northwood Development. 15 Atwood Drive, Map ID 39-043. Application Overview: The Commission issued an Order of Conditions in 2013 for demolition of the Clarion (since completed), and construction of an office building, hotel, restaurant, and associated utility, stormwater and sitework. In June 2017, the Commission issued an amended Order for a shifted site layout, elimination of the hotel and restaurant, and replacement with two commercial buildings, with related parking lot and stormwater. One of the buildings was constructed, and the stormwtaer system partially constructed. The Order expired in late 2017, and this NOI represents an application to construct the second building, install plantings as required in the original Order and by the stormwater and planning board permits, and complete the stormwater system, including work to address concerns about water retention and overall functionality. DEP Comments: [1] What is the current status of compliance with the previous Orders on the site? [2] Plans should state which elevation datum is being used. The NOI narrative states all elevations are based on NGVD29 but that should also be on the plans if not already there. [3] The commission should review the filing fee. Each activity is its own fee. [4]All stormwater BMP’s must be designed, constructed, operated and maintained per the Stormwater Handbook, Volume 2, Chapter 2. The simplest thing to do is to cut and paste the relevant pages of the Handbook into the Stormwater Report and use that to describe compliance. [5] The MASTEP web site is no longer available for review of alternative BMPs. MassDEP suggests that a comparable alternative resource that may be considered to demonstrate compliance with TSS removal may be found at the following link: https://www.nj.gov/dep/stormwater/treatment.html Consistency with the Wetlands Protection Act and Northampton Wetlands Ordinance: Staff communicated several questions and concerns about the application, please see below. Responses have not been provided, and will be needed in order to ensure compliance with performance and stormwater standards. The Section 1 introduction indicates that the amended Order of Conditions lapsed in August 2019. Please note that it actually expired on November 14, 2017. Amendments cannot extend Orders, as noted in that permit. Conservation Commission Staff Report 2 February 27, 2020 Please clarify what Table 4-1, BLSF Existing and Proposed, represents. As we discussed, utilizing accumulated flood storage capacity from the project as a whole, including the demolition of the Clarion is fine if necessary to meet performance standards, but the figures do not match those presented as part of that review. Function of the infiltration basins will need to be restored through excavation of existing soils, these have been holding water consistently Please address DEP's file number notification comments, and confirm that DEP was provided the revised submittal The engineered soil mix has changed from the mix that was originally presented. Please explain Both the overall totals and number of species of shrubs and trees have decreased from the 2017 preconstruction plans. These will need to match the planset approved by the Planning Board, and the stormwater permit, which is still valid. The planting plan for the native habitat feature is different than the original submittal, please explain proposes shifts in species and locations If provisions specific to the bioretention area plantings were not included in the O&M for the project, please provide for review inclusion in the Order of Conditions. Permit drawings refer to bioretention basins as detention basins. Please correct for consistency on construction drawings. Staff Recommendations: If questions and concerns have not been addressed, the hearing must be continued to ensure that all standards are met. If additional material is provided to demonstrate compliance with performance standards, including BLSF calculations, functionality of the stormwater system and compliance with previous plansets that are still valid as part of other permits, an Order of Conditions can be issued. Include standard conditions, all additional conditions from the 2017 amended Order, and additional suggested conditions: After one year from the date of the Order, an assessment of the northerly wetland to ensure it is receiving parking lot drainage sufficient so as not to have become dewatered Retention of a project engineer to oversee construction, with weekly reports submitted to the Commission during construction Engineered soil mixes utilized as part of the stormwater system must be tested by an independent lab to confirm required components, results provided to DPW and Commission If raingarden surface material is proposed to be retained and not excavated, a sample from raingarden must be tested by an independent lab to confirm required components, results provided to DPW and Commission. If not found to meet DEP requiments, it must be excavated and the material replaced. After one year from the date of the Order, an analysis of the functionality of the raingardens and infiltration basins, stamped by a professional engineer of record in the commonwealth of Massachusetts, must be submitted to the DPW and the Commission.