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Response to DEP 246-0750 Comments 20210303An Equal Opportunity Employer M/F/V/H March 3, 2021 File No. 15.0166837.00 Northampton Conservation Commission City Hall 21O Main Street, Room 11 Northampton, MA 01060 Re: DEP File 246-0750, Response to MassDEP Comments Main Street Bridge Scour Protection Main Street Bridge over Mill River Leeds, MA Dear Northampton Conservation Commission, On behalf of the City of Northampton, we offer the following responses to comments dated February 23, 2021 and provided by MassDEP, Western Regional Office. We have annotated MassDEP comments below in blue text for the Six (6) comments issued. MassDEP Comments and GZA Responses [1] Work in the Mill River is subject to the Public Waterfront Act, MGL Chapter 91. Response to #1: GZA acknowledges the reviewers comment and intends to communicate with the MassDEP Waterways Program. [2] The Mill River at this location is considered a Cold Water Fishery Resource. Preventing sediment from entering the water and maintaining and/or increasing shading of the water column is important to protecting this valuable resource. Coldwater streams and rivers are critical habitat for a variety of fish including rare (American Brook Lamprey, Longnose Sucker, Lake Chub) and recreationally-important (Brook Trout) species. Response to #2: GZA acknowledges that the Mill River is considered a Cold Water Fishery Resource at the project location. The Applicant’s 2-phase water diversion plan allows for minimal disruption to river flow patterns. The proposed work in dry conditions in conjunction with the use of work area sumps and sediment filtering will greatly reduce the likelihood of sediment entering the water column during construction. Overall, the project is not anticipated to have a negative impact on Fisheries through phasing and avoidance measures. [3] Dewatering guidance will be provided to the parties. Response to #3: Please see in-line responses in the dewatering guidance document. March 3, 2021 File No. 15.0166837.00 Response to DEP Comments Page | 2 Proactive by Design [4] Please provide this reviewer the total amount of area below the high water mark where there will be a discharge of dredged or fill material subject to 314 CMR 9.00. The area below the high water mark is considered Waters of the United States within the Commonwealth and a discharge of dredged or fill material over 5,000 sq. ft. may require a 401 Water Quality Certificate application be submitted to MassDEP Western Regional Office per 314 CMR 9.04(1). Response to #4: The project impact area tables within the Narrative and Form 3 account for all of the proposed project impacts to area below the high water mark, including the area temporarily occupied by the water diversion coffer dams. The proposed project work areas include 2,494 ft2 of fill material and an additional 2,182 ft2 of temporarily dewatered work area. The total proposed area of disturbance below the high water mark for the project is therefore 4,676 ft2 which is shown within the Narrative and Form 3. [5] The narrative for compliance with the Riverfront standards references new development. Even as a limited project, the applicant must attempt to fully comply with the performance standards if possible. Since all the work is proposed within the inner 100, it would be impossible to comply with the performance standards, but it may be possible to comply with the redevelopment standards of 310 CMR 10.58(5) and the commission may require the NOI to be submitted through that regulatory pathway. Response to #5: The project location and scope of work require some activity within the RFA. To the extent practicable, the project has been designed to meet the majority of the performance standards of 310 CMR 10.58(4). The proposed impacts to Riverfront Area are associated with the excavation of uplands located on the center channel island and therefore represent conversion to an alternate resource area, Land Under Water Bodies and Waterways. No net loss of resource areas are proposed as part of this project. We do not believe that the redevelopment standards in 310 CMR 10.58(5) apply to the proposed project. However, we note that the area in question will be improved by providing increase high flow passage through the newly created stream channel, and increase in the area of Land Under Waterbodies and Waterways on the Site, an increase in volume for BLSF on Site, a decrease in scour in and around Span 3, and the use of native seed mix and live stakes as part of the post-construction bank stabilization. [6] It should be noted that riprap or gabion baskets provide no benefit to the interests of the Act. Within the riverfront areas, short and long-term stream bank stabilization should incorporate bioengineering with natural materials such as vegetated geogrids, fiber rolls, live stakes and tree revetments in lieu of the use of hard structures such as rip rap, gabion baskets or retaining walls. Geotextile fabric should not be considered for moving water as experience has shown it becomes exposed and can dislodge over time. Response to #6: This is a scour remediation project intended to both protect vulnerable infrastructure and improve the capacity of the structure to convey high flows. The project is required to maintain structural adequacy of the dry laid masonry arch bridge. Currently scour is undermining the bridge footings and will lead to eventual failure. Riprap and not gabion is proposed as a scour countermeasure. Nearly all of the riprap is proposed below the MAHW elevation and is expected to quickly become infilled and covered by natural stream bed material; therefore, becoming restoration in-place. Also, the riprap is specified to have gravel packed voids to mimic the natural channel. A small area of riprap is proposed above March 3, 2021 File No. 15.0166837.00 Response to DEP Comments Page | 3 Proactive by Design MAHW elevation at the edge of the span 2 culvert which is necessary to tie into existing grade just outside of the culvert. Bioengineering with natural materials and live stakes is also specified in the proposed span 2 approaches where design conditions allowed. No geotextile fabric is proposed where there is risk of dislodgement due to flowing water. Thank you for the opportunity to clarify the project elements and jurisdictional activities. We trust that our responses adequately address the questions and comments that MassDEP provided. We look forward to working with the Commission to discussing the project further with the Commission. Sincerely, GZA GeoEnvironmental, Inc. Joseph Rogers, PWS, CESSWI Daniel M. Nitzsche, CPESC, CESSWI, SE Project Manager Senior Consultant Cc: MassDEP-WERO Charles D. Baker Governor Karyn E. Polito Lieutenant Governor Matthew A. Beaton Secretary Martin Suuberg Commissioner This information is available in alternate format. Call Michelle Waters-Ekanem, Diversity Director, at 617-292-5751. TTY# MassRelay Service 1-800-439-2370 MassDEP Website: www.mass.gov/dep Printed on Recycled Paper Western Region-Bureau of Water Resources-Wetlands Program Minimum Information and Documentation for Dewatering Plans The Massachusetts Department of Environmental Protection’s (hereinafter “the Department”) Western Region Wetlands Program has determined that a set of site plans and attached information submitted for its review does not clearly demonstrate that proposed activities “will contribute to the protection of the interests identified” in the Massachusetts Wetlands Protection Act, MGL Chapter 131, Section 40 (and similarly that such plans do not clearly demonstrate that the project will prevent “adverse impacts” to the “Aquatic Ecosystem” associated with “Waters of the United States within the Commonwealth”, each as defined at 314 CMR 9.02). Therefore, please review the below criteria and either modify such plans accordingly where pertinent, or contact the Environmental Analyst assigned to your project to further discuss possible changes. Any request to modify any of the below minimum requirements should be submitted to the Department in writing, and should include justifications. Approval to modify will be provided by the Department in writing, and solely at its discretion. 1. Prepare or modify a dewatering plan, which shall minimally include identification of techniques for bypass of water around the area of alteration; and separately, identification of techniques for treatment of residual water (“seepage water”) within the area of alteration. All such plans shall completely segregate bypass water from residual water. This dewatering plan shall include: Identification of any regulatory “time-of-year” (“TOY”) restrictions governing the proposed work [from the US Army Corps of Engineers “General Permit- Commonwealth of Massachusetts” (“MGP”); any Massachusetts Natural Heritage and Endangered Species Program directive; and any presumptive directions offered by the Massachusetts Division of Fisheries and Wildlife]. The Department will require adherence to TOY restrictions unless the applicant demonstrates that compliance with them is not practicable; THERE IS NO TOY RESTRICTION BUT THE CONTRACTOR IS NOTIFIED THE WATER LEVEL VARIES SEASONALLY AND HAS BEEN DIRECTED TO EVALUATE THE WATER ELEVATION AT THE TIME OF WORK. WE ANTICIPATE THE PROJECT WILL BID IN THE SPRING AND WORK COMMENCE IN THE SUMMER WHEN WATER LEVEL IS LOW. 2 Identification of any “Cold-water Fishery” (as defined at 310 CMR 10.04 and 314 CMR 9.02) within the subject reach where work is proposed, by reference to the Massachusetts Division of Fisheries and Wildlife “Coldwater Fishery Resources Index” (See http://www.mass.gov/dfwele/dfw/fisheries/conservation/cfr/watershed_index.htm); MILL RIVER IS IDENTIFIED AS A COLD WATER FISHERY ON THE WEBSITE Use of temporary flume pipes to bypass flowing water in small rivers and intermittent streams, when flowing, and upstream and downstream temporary dams to isolate the work area and protect it from backwatering. Flume pipes shall be equipped with anti- seep collars where they pass through temporary dams, and fish screens on their upstream inverts. Flume pipes shall be sized to adequately handle at least a two-year storm event; NOT APPLICABLE Use of cofferdams to isolate the area of alteration from flowing water in larger rivers, and in reservoirs, lakes, and ponds; REQUIRED IN CONTRACTOR DESIGN WITHIN PROPOSED WORK AREA SHOWN IN SUBMITTED PLAN SET Use of pumps and hose lines to dewater standing water held behind cofferdams, and to dewater residual water and leaked water in isolated work areas. The rating, type, and location of all pumps and the intake and discharge positions of all hoses shall be identified and located on the site plans; REQUIRED IN CONTRACTOR DESIGN Use of appropriate energy dissipaters and erosion and sedimentation control best management practices at the discharge orifices of all bypass flume pipes and pump hoses; REQUIRED BY SPECIAL PROVISIONS AND IN CONTRACTOR’S DESIGN. EROSION CONTROL SHOWN ON DESIGN PLANS Treatment of pumped residual water prior to discharge back to resource areas. Techniques such as filter bags, frac tanks, and stilling basins shall be analyzed and specifically proposed; REQUIRED IN THE SPECIAL PROVISIONS TO BE INCLUDED IN THE CONTRACTOR’S DESIGN Salvage of sessile aquatic organisms (vertebrates, crayfish, freshwater mussels, etc.) stranded during dewatering; THIS IS A RECOMMENDED BEST MANAGEMENT PRACTICE THAT IS NOT CURRENTLY LISTED IN THE DESIGN PLANS. WORK AT SPANS 1 AND 2 ARE LIKELY TO OCCUR UNDER NATURALLY DRY CONDIIONS. DEWATERING MEASURES WILL BE INSTALLED TO PREVENT FLOODING OF THE WORK AREA DURING HIGH FLOW EVENTS. NO ORGANISMS ARE ANTICIPAED TO BE PRESENT WITHIN THIS INITIAL WORK AREA. THE INSTALLATION OF THE COFFER DAM AT SPAN 3 WILL ALLOW THE SMALL WORK AREA TO SLOWLY DRAIN AND REDUCE THE LIKELYHOOD OF AQUATIC ORGANISMS GETTING TRAPPED. SALVAGE IS A RECOMMENDED BEST MANAGEMENT PRACTICE, BUT IS NOT CALLED OUT SPECIFICALLY ON THE PLAN SET. WE RECOMMEND WORKING 3 WITH THE COMMISSION TO ADDRESS ANY SPECIFIC ON SITE REQUIREMENTS THROUGH THE ORDER OF CONDITIONS. THERE ARE NO KNOWN SPECIES OF SPECIAL CONCERN PRESENT WITHIN THE WORK AREA. Structural and nonstructural best management practices to separate stormwater from the area of alteration during work and while the site is unstable; ACKNOWLEDGED Assurance that the substrate of the area of alteration is stable prior to the reestablishment of flow within it. ACKNOWLEDGED The Department advises that dewatering plans be designed according to Stream Simulation: An Ecological Approach to Providing Passage for Aquatic Organisms at Road Crossings (USDA Forest Service-National Technology and development Program 0877 1801-SDTDC, May 2008) (available at http://www.nae.usace.army.mil/reg/Stream/USFS_StreamSimulationManual.pdf ). This document is very useful, even for projects not located in flowing streams.