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2021.09.23 Staff Report.pdf Conservation Commission Staff Report 1 September 23, 2021 To: Conservation Commission From: Sarah LaValley RE: Staff Report, September 23, 2021 Commission Meeting 5:30 PM, Notice of Intent for headwall replacement within land under water and BVW, Sylvester Rd, and new guardrail Sylvester, Chesterfield & Kennedy Rds, Arch St. Northampton DPW. Application Overview: The application proposes several items at various roadway locations: • Replacement of two deteriorated headwalls at a Sylvester Road culvert crossing, and installation of 140 lf of guardrail above the inlet. All work will be done from the roadway. Two trees will be removed. Work will include temporary impacts as noted on page 6 of the application, and 13 sf of permanent land under water impacts from the extended headwall. Work is planned for low or no- flow conditions, but a coffer dam and bypass pumping will be used if there is flow. • Installation of safety guardrail in two locations on Sylvester Road, within riverfront, and buffer zone. Work will also occur in BLSF but will not decrease flood storage due to the guardrail elevation. • Installation of safety guardrail in two locations on Kennedy Road, within buffer zone to BVW and intermittent stream bank • Installation of 975 lf of safety guardrail on Arch Street, within buffer zone to BVW and bank, and riverfront area DEP Comments: [1] The crossing on Sylvester Road has been surveyed and information on the crossing can be found at https://naacc.org/naacc_display_crossing.cfm?aqId=74199 Noted, DPW staff conducted the assessment [2] Guidance on dewatering will be provided in the file number email notification. The applicant should review the current ACOE General Permit regarding extensions to existing stream crossings. The applicant should be aware of any requirements of the General Permit. However, the crossing is not being replaced, so the stream crossing standards pursuant to the Wetlands Protection Act do not apply. [3] The commission should review the minor exempt activities as they apply to buffer zone or Riverfront area found at 310 CMR 10.02(2)(b)2. for the remainder of the proposed work and determine if any of the activity is exempt. None of the proposed work qualifies as an exempt activities [4] For any regulated activity that is located in jurisdiction and also within estimated habitat of rare wildlife species, the commission must keep the NOI hearing open until NHESP has issued its determination. NHESP has issued a ‘no-take’ determination, with no conditions required to be included in the Order. [5] For any work in Riverfront that is not exempt, an improvement over existing conditions is required. Acceptable improvements include, but are not limited to: 1) Significant net reduction of impervious surfaces; 2) Planting of indigenous plant species; 3) Providing stormwater management demonstrably in excess of what is required per 310 CMR 10.05(6)(k) through (q); 4) Removal and proper disposal of noxious but otherwise legally located materials. Conservation Commission Staff Report 2 September 23, 2021 Staff agrees. The Commission should discuss improvements, such as tree replacement or other plantings. Additionally, milling mulch is proposed to be installed below the guardrails, with crushed stone between the pavement edge and mulch. The Commission should discuss whether it is possible to reduce or eliminate these surface impacts. Consistency with the WPA and Northampton Wetlands Ordinance; Staff Recommendations: A brief alternatives analysis and description of how alterations associated with the work are minimized is included on page 9 of the application. The Commission should discuss the items noted above to determine if impacts can be further minimized, and issue an Order with standard conditions once they have been addressed. 5:45 PM, Notice of Intent for greenhouse building, parking, bike path, stormwater management and related site improvements, and mitigation of three degraded riverfront areas (CT River). Green Delta Holdings, 60 Damon Rd, Parcel 18-009. Application Overview: The Commission issued an Order of Conditions in 2012 for demolition and removal of the Lane Asphalt Batching Plant, including the plant, outbuildings, operational equipment, and a stockpile yard, and construction of 3 new commercial buildings, a boathouse, boat ramp and dock, parking, and stormwater and service utilities. The Order was for the full site, including the boathouse and dock (constructed), and the business park on a private parcel (not constructed). Overall stormwater for the project was permitted as a whole, and mitigation and restoration required to meet performance standards also applied to all parcels. That Order has expired and cannot be amended; this NOI proposes a modified building design, stormwater, and the riverfront mitigation that was required for the dock and other roverfront work already done. DEP Comments: [1] Were HSG Soils group as well as depth to seasonal high ground water confirmed previously? [2] One cannot use manufacturers specifications when using alternative BMP’s for determining TSS removal. 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. [3] The commission should require a specific timeline for when any improvement or restoration/mitigation must be done. Staff agrees, the Order should include a condition that restoration and mitigation be begun prior to or concurrently with work on the rest of the site. DPW also had the following comments regarding the stormwater, to which a response has not yet been provided. These items will need to be addressed prior to the close of the hearing or included as conditions, and a condition added that an amended stormwater permit be required prior to the start of work. 1) The revised plans and drainage calculations should be stamped by a Professional Engineer registered in the Commonwealth of Massachusetts. 2) The submission should document how the proposed revised project continues to meet the Massachusetts Stormwater Management Standards. The proposed changes include construction of an infiltration trench to receive flow from a building, however recharge calculations have not been submitted demonstrating how the project meets the recharge standard. Please note that the Stormwater Permit included a condition that the recharge calculations be revised to reflect the correct increased area of impervious. The recharge calculations may not have been accurately revised in the past, so the total area of impervious should be calculated at this time and provide recharge calculations based on the revised increase in impervious. The percent of impervious that is directed to recharge must also be calculated to Conservation Commission Staff Report 3 September 23, 2021 show that at least 65% of the impervious area is directed to recharge in accordance with the guidance in the Mass Stormwater Handbook Volume 3. 3) The proposed plans include existing areas of compacted gravel to be "loam and seed." Additional details and specifications must be provided in the plans showing how the compacted gravel areas will be converted to vegetation. Consistency with the WPA and Northampton Wetlands Ordinance; Staff Recommendations: Work was previously permitted, and will take place in this phase only in previously disturbed buffer zones. Work in riverfront is limited to restoration and mitigation, and is necessary to bring the full project into compliance with the previously issued Order. Once stormwater standards and other details have been addressed, an Order with standard conditions can be issued. A requirement for assessment of the riverfront mitigation areas, and replacement of any plantings not surviving should be added The application indicates that a diverse planting mix will be added in mitigation areas, but a planting plan is not included and notes include only a conservation mix. The Commission should discuss whether any additional tree or understory plantings should be added, and a detailed sequencing and construction plan for converting the disturbed areas to pervious, vegetated surfaces should be discussed and required. Erosion control for the mitigation areas is not shown on project plans, but should be added since soil will be destabilized during mitigation. Include the following relevant special conditions from the previous Order: 34. The Stormwater O&M must specify an appropriate snow-storage location. 35. Future alterations areas shown on NOI plans as Wetland Replication Area and Riverfront Mitigation Areas, except as may be required to maintain them in restored or mitigated condition, are prohibited. Allowable activities include removal of species listed on the Massachusetts Prohibited Plant list and planting of native species. 36. Vista pruning for safety adjacent to the ramp and access road is allowed without further Conservation Commission review. Cutting within other resource areas or buffers is not allowed 6:00 PM, Notice of Intent for construction of two single family homes and shared driveway in buffer zone to BVW. Mary Cadorette, Cardinal Way, Parcel 36-245. The applicant has requested a continuation until October 28 at 5:30 PM