The Commonwealth of Massachusetts Executive Office of Energy and Environmental Affairs 100 Cambridge Street, Suite 900
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The Commonwealth of Massachusetts Executive Office of Energy and Environmental Affairs 100 Cambridge Street, Suite 900 Boston, MA 02114 Charles D. Baker GOVERNOR Karyn E. Polito LIEUTENANT GOVERNOR Tel: (617) 626-1000 Matthew A. Beaton Fax: (617) 626-1081 SECRETARY http://www.mass.gov/eea September 21, 2018 CERTIFICATE OF THE SECRETARY OF ENERGY AND ENVIRONMENTAL AFFAIRS ON THE NOTICE OF PROJECT CHANGE PROJECT NAME : New Harbor Electric Energy Company (HEEC) Cable Project PROJECT MUNICIPALITY : Boston PROJECT WATERSHED : Boston Harbor EEA NUMBER : 15746 PROJECT PROPONENT : Eversource Energy DATE NOTICED IN MONITOR : August 22, 2018 Pursuant to the Massachusetts Environmental Policy Act (MEPA) (M.G. L. c. 30, ss. 61-62I) and Section 11.06 of the MEPA regulations (301 CMR 11.00), I hereby determine that this project does not require an Environmental Impact Report (EIR). The purpose of the project is to ensure a reliable and uninterrupted power supply to the Massachusetts Water Resources Authority’s (MWRA) Deer Island Treatment Plant (DITP) and to facilitate the commencement of the Boston Harbor Deep Draft Navigation Improvement Project (BHDDNIP) to be undertaken by Army Corps of Engineers (ACOE) and the Massachusetts Port Authority (Massport) (EEA# 12958). The DITP treats wastewater generated by over 2 million residents in 43 communities and its uninterrupted operation is critical for maintaining the ecological health of the Commonwealth’s coastal waters. The BHDDNIP is necessary to maintain the important region-wide benefits of the Port of Boston’s maritime activity. Deepening the navigation channels will accommodate larger cargo vessels with deeper drafts that are increasingly used in the global transfer of goods. EEA# 15746 NPC Certificate September 21, 2018 Project Description The project includes the installation of an approximately 4.2-mile long 115-kiloVolt (kV) electric power cable on land and across Boston Harbor and the decommissioning and partial removal of the existing distribution line. The line serves as the primary electric supply facility for the DITP. When it was installed in 1990, an approximately 1,980-foot (ft) long section of cable in Reserved Channel was placed over an area of bedrock and was not buried to the intended depth. The shallow section of the cable will conflict with the planned dredging of Reserved Channel to -47 feet Mean Lower Low Water (MLLW) to be conducted as part of the BHDDNIP. In order to avoid conflicts with the BHDDNIP and potential future dredging projects, the new cable will be installed along a route that avoids key areas of navigation, including the navigation channel in the Reserved Channel, marine terminal and berths in the Reserved Channel associated with the Conley Terminal, a turning area east of the Reserved Channel and the President Roads anchorage area. It will be installed sufficiently below the main Federal Navigation Channel to accommodate the BHDDNIP and future deepening of the channel and expansion of the anchorage area. The cable will supply power to the DITP from the Eversource K Street substation in South Boston. A 7,814-ft (1.47 miles) long section of cable between the K Street substation and the eastern end of the MassPort’s Conley Container Terminal will be installed in a new trench with conduits and manholes. Approximately 2.73 miles of the cable will be located in the water. Two sections of the cable will be installed using Horizontal Directional Drilling (HDD): an approximately 2,505-ft long section of cable under the Federal Navigation Channel at a depth of -75 feet MLLW and a 975-ft long section at the eastern end of the route at Deer Island. Between the two segments installed by HDD, an approximately 2.12-mile long section of cable will be buried up to 10 feet below the bottom using a hydroplow. Pre-construction surveys identified the presence of Boston Blue Clay (BBC) along a 1,270- ft long segment of the route to be hydroplowed. A hydroplow cannot dig a trench of sufficient depth (8 to 10 feet deep) because of the stiffness of the BBC. The project includes the dredging of a 670-ft long and 93-ft wide area to remove BBC to allow the installation of the cable to a depth of 10 feet. According to the Notice of Project Change (NPC), the hydroplow will be used to dig a trench in the remaining 710- ft long section of the cable route through BBC to permit the burial of the cable to 8.5 feet below the bottom. Once the new cable is in operation, the existing cable will be drained of dielectric fluid and the cable core cleaned. An approximately 7,845-ft (1.49 miles) long segment of the cable will be removed, corresponding to the length of the cable located within the proposed dredge footprint of the BHDDNIP in the Reserved Channel and the Federal Navigation Channel and an additional 500-ft buffer east of the Navigation Channel. The cable will be pulled out of the sediment using a crane and wench; additional methods such as jetting or mechanical dredging may be used if necessary to remove overburden covering the cable. The remaining 2.3-mile long section of the cable will be capped and abandoned in place. Project Change The project purpose and general design are unchanged since the filing of the Environmental Notification Form (ENF). The NPC described changes to the cable route and installation procedures and 2 EEA# 15746 NPC Certificate September 21, 2018 provided a detailed description of the cable removal process; the revisions are reflected in the project description above. The changes to the cable installation methods include: Repositioning of the HDD entry and exit holes at Deer Island, resulting in a longer HDD segment that will avoid impacts to Bank and Coastal Beach and reduce the length of cable installed by hydroplow to 195 feet; Change to the HDD method that will minimize the release of drilling fluid at the seaward end of the drill segment that occurs each time it bores through the bottom sediments (“punch out”). The drill will stop below the bottom of the harbor for each of the reaming runs and will punch out only once to complete the final reaming run; The hydroplow route has been slightly modified to accommodate a series of straight-line pulls of the cable rather than an arc geometry. Straight line pulls require fewer placements of barge anchors, which will minimize impacts to benthic habitat. The change to a straight-line pull across the eelgrass bed will reduce the length of the cable route through the eelgrass bed from 830 feet proposed in the ENF to 405 feet and reduce overall eelgrass impacts from 5,810 sf to 2,835 sf; Removing BBC along a 560-ft long section of the hydroplow route by dredging a 670 ft by 93 ft area with 5:1 side slopes and a 9-ft wide bottom to a depth of 12 feet (15,250 cy of BBC material). The 5:1 side slopes will minimize amount of dredge material that can fall back into the excavation and the 9-ft wide trench width is necessary to ensure safe conditions for divers working in the trench. The trench will be filled with sand so that the hydroplow can bury the cable through this area to the desired depth of 10 feet; and, Changing the burial depth of the cable to 8.5 feet in a 710-ft long section of the route where the presence of BBC will limit the effectiveness of the hydroplow. This burial depth will provide sufficient cover to protect the cable and avoid impacts associated with dredging the BBC as described above. The NPC provided a detailed description of the cable removal process which is summarized above. As noted in the NPC, the Proponent must remove the cable within the Reserved Channel and the Federal Navigation Channel to avoid conflicts with proposed or future navigational dredging projects. After it is drained and cleaned, the cable will be removed starting at the western end of the Reserved Channel. The cable will be exposed and cut; the end of the cable that will be abandoned in place will be capped and reburied. Recovery of the cable will continue in an easterly direction, with the cable lifted onto a barge as it is removed. At the eastern end of the cable section to be removed, the end that will be abandoned in place will be capped and buried. Sediment excavated from above the cable will be side- cast and returned to the trench when the cable is removed. Compared to the ENF, the overall impacts to Land Under Ocean (LUO) will increase from 3.36 acres to 7.99 acres, as follows: Impacts to LUO from the hydroplow will decrease from 2.96 acres to 1.8 acres; Eelgrass impacts will decrease from 0.13 acres to 0.07 acres; Dredging of BBC will increase impacts to LUO by 1.43 acres; Impacts to Coastal Beach will be eliminated (0.05 acres proposed in the ENF); Impacts to Coastal Bank will be eliminated (0.01 acres proposed in the ENF); and, Cable removal will impact 4.47 acres of LUO. 3 EEA# 15746 NPC Certificate September 21, 2018 According to the NPC, the dredged material may be disposed of at the Massachusetts Bay Disposal Site (MBDS), a treatment and processing facility in New Jersey or at an upland location The MEPA Regulations at 301 CMR 11.10 include criteria for Insignificance which provides guidance in determining whether a change in a project might significantly increase environmental consequences and informs a determination regarding whether additional MEPA review is warranted in the form of an EIR or Supplemental EIR.