Mill Street - Modification Request
National Grid proposes a temporary substation yard on 0 & 14 Mill Street with equipment pads, access drives, stormwater controls and restoration measures; the yard will remain until load transfer to Hillside No. 66 (estimated ~2029).
AI summary
National Grid proposes a temporary substation yard at 0 & 14 Mill Street to replace the Amesbury No. 5 Substation while load is transferred to an upgraded Hillside No. 66 Substation (anticipated ~2029). The project includes equipment pads, a transformer containment unit, underground cable connections, crushed‑stone access and equipment areas, an 8‑ft security fence, and stormwater controls (deep‑sump catch basin and a 35 ft × 15 ft drywell); work lies within the Powwow River Riverfront Area and 100‑foot buffer. A Notice of Intent was filed in September 2025 and the Amesbury Conservation Commission issued an Order of Conditions after review.
Gallery
Project details
What is proposed
Massachusetts Electric Company (National Grid) proposes to construct a temporary substation yard on two parcels at 0 & 14 Mill Street to serve as the primary Amesbury substation while the Hillside No. 66 Substation is upgraded. The installation includes substation equipment and pads, a transformer containment unit, underground cable connections with protective steel plating, crushed‑stone equipment and access areas, and site security (8‑ft chain‑link fence with an additional 1‑ft of barbed wire and gated access).
Where and how big
The project occupies two National Grid parcels (Assessor’s Map 53, Lots 121 and 123) totaling about 1.67 acres, located east of Mill Street/Mill Street Extension and adjacent to the Powwow River. The applicant reports a post‑construction impervious area of roughly 5,593 square feet. Work and staging areas are shown inside an approximately mapped Limit‑of‑Work that lies within the 200‑foot Riverfront Area and the 100‑foot Buffer Zone to Bank; NOI/plan materials quantify Riverfront Area alterations (16,350 sf permanent; 11,980 sf temporary, with specific areas inside the 0–100 ft and 100–200 ft bands provided in the filing).
Stormwater, erosion controls and access
Permit drawings and a Stormwater Management Report (Simpson Gumpertz & Heger) propose erosion and sediment controls (filter tube, inlet protection, catch basin filter bags, stabilized construction entrance, designated stockpile locations) and a stormwater system sized to meet the Massachusetts Stormwater Management Standards to the extent practicable for a temporary facility. Runoff from the yard is routed via a collection trench, a deep‑sump catch basin and drain manhole to a 35 ft × 15 ft drywell; the report calculates a required recharge volume of about 280 cubic feet and indicates the drywell provides roughly 800 cubic feet of storage. HydroCAD/SCS methodology was used to compare pre‑ and post‑development peak flows and to size the proposed controls.
Access and equipment areas are shown surfaced with compacted/gravel and crushed stone; steel plating is specified where underground cable protection is required. The plans include notes requiring maintenance of erosion controls, weekly inspections, and sediment controls after rainfall events.
Landscaping, restoration and temporary nature
The drawings include an upland ROW restoration plan and a planting schedule (evergreen shrubs/trees such as Juniperus virginiana and Ilex opaca specified as 10–12 ft B&B), topsoil and seeding details (6 in. topsoil and native upland/ROW seed mixes), and planting/mulch/staking notes. National Grid’s filing states the temporary substation will be removed once load transfer to Hillside No. 66 is complete (applicant estimate: by ~2029) and that installed materials will be removed and the area restored to pre‑construction herbaceous conditions in accordance with the restoration plan.
Special considerations
Resource areas: The entire project locus lies within the Powwow River’s Riverfront Area; parts of the work are within the 100‑foot Buffer Zone to Bank. The NOI and supporting materials include resource delineation data, Riverfront impact calculations, and an alternatives/BMP analysis addressing constraints.
Floodplain: FEMA mapping shows portions of the right‑of‑way and nearby areas in Zone AE (BFE ≈ 10.8 NAVD88) and other portions in Zone X; plans and details reference these conditions and include grading and drainage notes accordingly.
Temporary vs. permanent design choices: the applicant evaluated larger infiltration BMPs (infiltration basins/trenches or a larger drywell) but limited disturbances within the Riverfront Area given the facility’s temporary function; the chosen suite of BMPs balances treatment/recharge requirements with the project’s temporary scope and resource impacts, per the Stormwater Management Report.
Status
A Notice of Intent was submitted September 15, 2025 and abutters were notified; the Conservation Commission held a public hearing (posted) and issued an Order of Conditions for the proposed work. Permit drawings and a Stormwater Management Report were prepared for City review by Simpson Gumpertz & Heger; environmental permitting and NOI preparation were completed by LEC Environmental Consultants on behalf of National Grid. The applicant indicates the temporary yard will be removed and the site restored after the Hillside No. 66 Substation is operational (anticipated around 2029).
Discussion at meetings
- AMENDAll right. Can we have a voice vote on an amendment that right now is up to 15 monitoring reports.
- APPROVESo moved.
- CONTINUEDo I have a vote to continue this until our December 9th administrative meeting that is a selection of the environmental monitor?
- OTHERI will make that motion to waive the peer review.
- APPROVEI'm prepared to entertain a motion to approve the NOI subject to the extra conditions that have been laid out by our agent and expanded on a little bit by Commissioner McCarthy.
- OTHERI'll entertain a motion to close the hearing on this NOI.
- CONTINUEMotion to continue the hearing on this NOI until our November meeting.
- CONTINUEI move to continue this until our November meeting (later withdrawn) ... I withdraw that motion. I propose a new motion to convene at the 10/20 to review and select a peer reviewer so we can expedite approval of this project.
Documents on file
