Engineer presents Lake Road bridge replacement plan; commission receives application and flags environmental constraints

Howard Farmer, a professional engineer with Jacobson Associates, presented design drawings and a construction timeline for application permit 26‑2 — replacement of bridge number 001007 on Lake Road over Chain Road — at the April 7 Andover commission meeting.

Farmer described the existing structure as a 14‑foot span corrugated metal pipe arch with an 8.25‑foot rise and a perched outlet, and said downstream wing walls and parapets show “100% section loss” in places. The proposed replacement is a pre‑cast reinforced concrete three‑sided frame set on cast‑in‑place footings poured on rock, with cast‑in‑place wing walls, head walls, a bridge rail and upgraded roadside barriers. Farmer said the new opening would be roughly 28 feet to meet the applicable bank‑full span requirement and to reduce velocities in large storms.

“The existing downstream wall is a little disturbing,” Farmer said, describing visible masonry deterioration and bedrock at the outlet. He added that the design includes riparian shelves and a locally natural stream bottom where the channel is disturbed to improve aquatic passage. Farmer said the structure was hydraulically sized to meet the DOT drainage manual for a 100‑year storm and that roadside barriers will be improved to current standards.

Farmer also explained erosion controls and construction sequencing: contractors would install two smaller bypass pipes through the existing barrel, place upstream and downstream sandbag cofferdams, dewater the work area and install the pre‑cast frame. He said the project is a state‑local bridge program award covering 50% of total cost and estimated a construction window of June–October 2027 with bidding late 2026 or early 2027.

On environmental review, Farmer said the team will pursue an Army Corps nationwide permit and that a 401 water‑quality certification is in place for the nationwide permits the project would use. He reported outreach to the state historic preservation office (no concerns), to US Fish and Wildlife (noting a bat and a butterfly) and to four tribes (no response). Farmer said Connecticut Inland Fisheries recommended a seasonal restriction barring in‑stream work or cofferdam installation in April, May and June; he said he would revise the drawings and permit notes to reflect that timing restriction.

Commissioners asked detailed questions about staging, easements, access for nearby residents, erosion control, and the potential for sediment to travel downstream during dewatering. Farmer said he would add contractor guidance, erosion‑control notes and a photo with handling instructions for wood turtles — which commissioners said have been observed in the brook — and would resubmit revised drawings a week before the next meeting.

The commission formally received application 26‑2; no final approval was taken at the meeting. Commissioners asked staff to seek input from the town herpetologist and from zoning staff, and to confirm whether a wetlands agent will provide on‑site review during construction. The application will return for formal action after the commission receives revised drawings and any agent comments.