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2020.04.23 Staff Report Conservation Commission Staff Report 1 April 23, 2020 To: Conservation Commission From: Sarah LaValley RE: Staff Report, April 23, 2020 Commission Meeting 5:30 PM –Continuation: Notice of Intent for bridge replacement – I91 over US Route 5 and B&M Railroad, and widening of Mount Tom Road/US 5. Work proposed within bordering vegetated wetland and bordering land subject to flooding (CT River). MassDOT, roadway rights of way. Application Overview: The application proposes replacement of both northbound I91 bridges over Route 5 and the railroad, and improvements to Route 5: addition of turning lanes at the highway on-ramps, bike lanes on both sides, and a sidewalk on US5 westbound. Resource area impacts are temporary BVW impacts during construction, permanent BVW alteration within existing mown area, and filling within floodplain. 174 sf of permanent BVW impacts are proposed to be mitigated through creation of a replacement wetland of 215 sf. Stormwater will be mitigated through construction of a new bioretention area. Deep sump catchbasins are also proposed to increase treatment. Increases in alteration to BLSF were identified following the initial submittal, and flood storage creation is increased as a result. DEP Comments: Staff note – these were reviewed and discussed during the January hearing but are provided for reference. Additional information and revised plans have been submitted to demonstrate compliance with the WPA and address concerns, and the applicant will provide a presentation during the hearing. [1] The commission should review the filing fee. There are three activities proposed and each activity is its own fee. Comment noted. We will coordinate with the Conservation Commission to for guidance. Staff note: An additional filing fee has since been provided [2] Since the DEP regional office will be issuing the 401 WQC, the Department recommends that the commission keep the NOI hearing open until it has been issued. It also appears this work is subject to MEPA, per 301 CMR11.03(3)(b)1.d. MassDEP cannot issue the 401 WQC until the Secretary has issued the Certificate. The applicant should contact the MEPA office for guidance. The WQC application will be submitted the week of 1/20/20. An ENF is being prepared and will be submitted to the MEPA office in Late January. Staff note: NOI hearings are generally continued until WQC permits are issued to ensure consistency between them, but this is not a legal requirement. An Order can be issued that includes the WQC conditions by reference. [3] Since this area only has priority habitat, it is not subject to 310 CMR 10.59, the estimated habitat of rare wildlife species section of the regulations. Conservation Commission Staff Report 2 April 23, 2020 Thank you for the clarification. Please note that Consultation has already occurred with NHESP. NHESP indicated that, “the Division has visited the site and conducted a botanical survey on June 27th. There were no rare plants found during the visit. Based on the findings, no further review is required.” (Refer to NOI Attachment E – Agency Correspondence – for e-mail, D. Paulson to R. Natario, dated 8/7/2018). Staff note: NHESP issued a ‘no-take’ determination letter with a condition to complete a survey noted above. Since this has already been satisfied, there are no NHESP conditions to include in the Order of Conditions. [4] It has been a few years since the BVW and IVW was delineated. To help ensure that conservation commissions have sufficient expertise available to address specific issues regarding an applicant’s filing, M.G.L. c. 44, section 53g gives Commissions authority to charge a fee for the employment of outside consultants that allow for the use of the fee to ensure that they have the necessary information for them to make a decision pursuant to the Wetlands Protection Act, M.G.L. c. 131, sec. 40 and 310 CMR 10.00. Comment noted. Staff note: Staff advised the applicant that wetland flags will need to be replaced to allow for confirmation of resource areas as part of the NOI review. There are no flags currently present in the field. This is especially important for areas where BVW and buffer zone alteration is proposed. The applicant has requested that the flagging be conditioned as part of the work. [4a] Please review the wetlands status of the plants. Data sheets shows sugar maple as a FACW and it should be FACU. The data sheets include several occurrences of Acer saccharinum (silver maple) with a correct indicator status of FACW; Acer saccharum (sugar maple) does not appear on the data sheets. [5] 310 CMR 10.24(7)(c) only applies to coastal resource areas. Likely the applicant meant to refer to 310 CMR 10.53(3)(f). Maintenance and improvement of existing public roadways, but limited to widening less than a single lane, adding shoulders, correcting substandard intersections, and improving inadequate drainage systems. Thank you for the correction; agreed. [6] The Commission may require that a replication checklist and a monitoring report be submitted per the Massachusetts Inland Wetland Replication Guidelines (https://www.mass.gov/media/1523011) should BVW alterations be warranted (i.e., unavoidable) and permitted. Comment noted. Please note that in addition, the existing BVW area that will be temporarily impacted (primarily Wetland 1) will be improved because the restoration will result in removal of trash and invasive plant species. Staff note: Staff requested additional construction details about the wetland restoration/creation area. Construction methods are critical to ensure that the artificial wetland is viable. These have since been provided. [7] One cannot model stormwater without confirming actual soil type. Per Volume 3 Chapter 1 of the stormwater handbook, a Competent Soils Professional conducts a site visit to verify soil conditions on the site. Please see Table 2.3.1. The commission needs good soils information at the locations of the bioretention areas. Agreed. The Web Soil Survey conducted for the Stormwater Report section of the NOI showed a dominant HSG of B in soils present in the project area. The Geotech performed at the 25% submittal Conservation Commission Staff Report 3 April 23, 2020 shows that there is adequate vertical separation between bottom of the bioretention cell and seasonal high groundwater. Additionally, soil test pits at the proposed bioretention areas are being arranged and are expected to be conducted in early February 2020. Staff note: The hearing should be continued to allow the Commission to review the test pit details, and accommodate any design changes necessary if soil types or groundwater elevation will not allow for the amount of infiltration planned. [8] Section 2.3.4 RUNOFF COEFFICIENTS appears to use inadequate coefficients. Because the project area is not that large, correct numbers should be used. Please find the attached page from the Massachusetts DEP Hydrology Handbook showing runoff coefficient values. We have used the coefficient values of 0.95 and 0.35 for pavement and grassed areas, respectively. These values are considered the highest suggested values in the handbook, and therefore utilizing these values allows for a conservative sizing of the of stormwater BMP design. [8a] One cannot take additional TSS removal credit for a catch basin that discharges into a bioretention area. For drainage areas 1 and 11 worksheets, total TSS removal for a bioretention area can only be 90% as that includes the required pre-treatment. Cannot take any double credit. Agreed, we will revise the worksheets. Staff note: The Commission will need to ensure that the TSS removal requirement is met once the worksheets have been revised. [8b] The applicant should provide information to the commission on the actual number of times catch basins were cleaned in this area on I-91 in recent years. • According to MassDOT Annual Report (link below), Catch Basins are inspected annually and cleaned and maintain ANI (As Needed per Inspection). Report does not indicate any specifics for I-91 Catch Basins. However, District 2 staff report that the catch basins on I-91 were inspected in the summer of 2019. • The link for the Mass DOT MS4 General Permit Annual Report 15 is as follows: https://www.mass.gov/files/documents/2019/04/16/dot-hwy_NPDES_annual_rpt_2017- 18.pdf?_ga=2.54156008.1797597181.1574177612-1892217036.1574177612 [9] Please note that an exfiltrating bioretention area provides groundwater recharge. To receive TSS removal credit, all stormwater BMP’s must be designed, constructed, operated and maintained per the Stormwater Handbook, Volume 2, Chapter 2. Please cut and paste bioretention BMP into the stormwater report. Please review pages 23 to 35 from Volume 2 Chapter 2 of the Stormwater Handbook. • Agreed; exfiltrating bioretention areas are designed so that following treatment by the bioretention area the stormwater may recharge the groundwater supply. A six-inch (6”) underdrain will be proposed to both bioretention areas. The bioretention areas have been designed to the guidelines provided in the Massachusetts Stormwater Handbook. The Stormwater Report of the NOI will be revised to reflect the language stated in the Stormwater Handbook. • The I-91 bioretention area does not have a sediment forebay proposed due to spatial constraints. The TSS removal sheet will be changed to reflect the absence of a forebay pretreatment measure. Consistency with the Wetlands Protection Act and Northampton Wetlands Ordinance: As a MassDOT project, work is not subject to the Wetlands Ordinance. The application includes a narrative, beginning on page 6, regarding compliance with all applicable performance standards of the Act. The Commission should note that work includes additional fill Conservation Commission Staff Report 4 April 23, 2020 within the highest floodplain elevations, but this is compensated for by additional excavation within lower elevations. Staff Recommendation: Issue an Order of Conditions with standard conditions, and additional conditions regarding the replication area: An annual report, in accordance with the Massachusetts Inland Wetland Replication Guidelines, shall be provided to the Commission by November 30 of each year, for the first three growing seasons. The report shall contain all elements required in monitoring the wetland replacement area, and shall detail how and to what extend the replacement area meets the General Performance Standards and the Wetland Replication Plan in the NOI. If non- compliance with any Performance Standards or the Replication Plan is documented, the report shall include a draft “corrective plan of action.” Prior to the issuance of a certificate of compliance, the applicant shall demonstrate that at least 75% of the surface of each replacement area has been re-established with indigenous wetlands plants. The Commission shall be given 48 hours notice prior to the beginning of construction of each wetlands replication areas, to allow for discussion of requirements and to ensure compliance with all special conditions. Any future alterations of areas shown on NOI plans as Wetland Replication Areas, except as may be required to maintain them in restored or mitigated condition, are prohibited. Additional allowable activities are removal of species listed on the Massachusetts Prohibited Plant list and planting of native species. 5:30 PM – Continuation: Notice of Intent for parking lot expansion and related stormwater work within buffer zone to bordering vegetated wetland. 26 Carlon Drive, Northampton Fire Department, Map ID 24B-086 Applicant: Northampton Central Services Application Overview: The application proposes to expand the parking lot at the fire headquarters to the rear of the existing lot into an existing lawn and vegetated area. A solar canopy, refueling station, and battery backup are also proposed. The work is proposed to include 14,345 sf of buffer zone disturbance, primarily conversion of lawn to pavement. Stormwater from the additional impervious area is proposed to be mitigated through construction of a new detention basin. The work required site plan approval from the Planning Board, which was approved in December. Stormwater review was also conducted by DPW as part of this process. DEP Comments: Please refer to December 23 2019 Tighe and Bond ‘Response to DEP Comments’ for DEP and staff comments and applicant responses. (Note - These were reviewed and discussed at the January hearing but are attached for reference.) Consistency with the Wetlands Protection Act and Northampton Wetlands Ordinance: As noted by staff in comments, test pits indicated potential wetland indicators in soils shown as upland areas, and full wetland data sheets and test pits were not included in the application. These have since been provided, indicating that hydrology did not demonstrate wetland conditions within the top 12” of soil, but that a predominance of wetland indicator plants and a change in topography were used to classify the area pursuant to 310 CMR 10.55(2)(c)(1). The applicant notes that the test pit data also indicates perching rather than high groundwater, in response to concerns about potential flooding. Conservation Commission Staff Report 5 April 23, 2020 The Protected Zone in the HB zone is reduced to 10 feet, and most other provisions of the Ordinance do not apply in this district. However, development must still ‘include mitigation measures that will improve the existing conditions of the wetland or adjacent upland.’ Planting capacity is limited due to the proposed solar canopy, but the Commission should discuss how this standard is being met. The project includes design changes made to address the ‘higher potential pollutant load’ of the parking lot and addition of a treatment unit to meet the Stormwater Standards. Revised calculations have been completed using accepted rainfall data. Staff Recommendation: Discuss how the standard to improve the wetland and upland is being met. Discuss operation and maintenance plans with the applicant, since these will be critical to ensure functionality of the stormwater system and protect the wetland, and require notification of street sweeping and other critical activities within the Order. If these concerns are met, an Order with standard conditions can be issued. 6:00PM – Continuation: Notice of Intent under the Northampton Wetlands Ordinance for construction of a new 3-story apartment building and related siteand utility work within wetland resource areas and buffer zones. Dewey Court Properties LLC, 34 Dewey Court,Map ID 31D-217 Application Overview: The application proposes construction of a 3-story building containing 15 residential units in a 7,100 sf footprint, including a pedestrian pathway crossing of the wetland, landscaping and raingardens, and replacement of a sanitary sewer line that is likely accepting surface drainage. The resource areas are not jurisdictional under the WPA, and only the local Ordinance applies. The Commission previously confirmed the wetland boundaries with an Order of Resource Area Delineation. Consistency with the Northampton Wetlands Ordinance: The applicant has provided an assessment memo of compliance with the local Ordinance (attached for reference). The area is within the Urban Residential C zoning district. The Protected Zone within this zone is reduced to 35 feet, and 337-10 B waives any of the Performance Standards of the Ordinance that are over and above state law with the exception of this Protected Zone. Utility work within the Protected Zone to repair the sewer is allowed as a Limited Project. The size of the wetland may increase once the sewer repair is complete. Staff Recommendation: Issue an Order of Conditions with standard conditions. Require that the pedestrian crossing be elevated on piers at least 12” above the wetland surface. Discuss details of shed demolition within the Protected Zone and drain line replacement with the applicant and add additional conditions for these portions of the project if necessary.