Concord subcommittee reviews three dam‑removal schemes; asks for 30% design and fisheries expertise

The Warner’s Pond Dam Removal Subcommittee met by Zoom on Aug. 7, 2024, to review three draft dam‑removal schemes and to compile questions and images to bring to the full Warner’s Pond Task Force on Aug. 13.

The subgroup’s primary work was a walk‑through of schematic overlays on aerial imagery showing existing conditions (Route 2, Commonwealth Avenue, Laws Brook, the Bruce Freeman Trail, MCI property and Giroux Park) and two identified public access points. The presenter asked members to flag where maps should show current access points and to note a roughly four‑acre ‘‘deep pond’’ area cited in prior studies as a question to be resolved by the 30% design package.

Members focused on three technical uncertainties: (1) the post‑removal channel route and depth, (2) how sediment will move and settle once the impoundment is removed, and (3) fish‑passage and seasonal temperature effects. One participant cited USGS flow variability, noting summer flows may be as low as about 4 cubic feet per second while higher seasonal flows can be much larger, and warned that the channel’s final position could change with storm events.

The group discussed management approaches ranging from a minimal‑intervention option (no dredging, minimal boardwalk and viewing access) to scenarios that include dredging limited areas for a swim hole or formalized boat launches. The subgroup heard a caution from an ecological restoration presenter (Mass Audubon) that mechanical dredging is often costly and may fail to achieve a sustainable channel compared with allowing the river to re‑establish its course; members agreed dredging should be considered only for targeted features and not assumed across the whole channel.

Recreation and liability were raised: informal fishing currently occurs at the dam and the subgroup asked the town to consider designing safer, formal fishing/viewing points if access is preserved. The group also discussed trail connections to permit a partial circumnavigation of the pond by linking the Bruce Freeman Trail, Jerome/Giroux park areas and town land, while noting property line and easement questions that will require follow‑up.

The subcommittee approved the prior meeting minutes (Jeff Collins moved; Liz Morrison Howe seconded) with several ‘aye’ votes recorded and one abstention noted. No formal decisions were taken on which removal scheme to advance; members agreed to assemble precedent images, mark outstanding technical questions on the drawings, and request the 30% design deliverables (hydrology/bathymetry, renderings and fishery data) before finalizing a recommended scheme.

In public comment, Anna Feldwick (343 Commonwealth Ave.) urged the task force to invite Brad Chase, identified as a fish‑passage expert on another dam removal project, and suggested a year‑long lowered‑water trial using the dam’s boards or the 24‑inch outlet pipe to observe channel formation and sediment behavior before full removal. Carlin Reed, a finance committee liaison speaking personally, warned that limits on where dredged material can be placed (a disposal site north of the Bruce Freeman Rail Trail with constrained fill heights) will restrict how much material could be legally and practically dredged.

The subgroup will present the three schemes, annotated questions and selected precedent images to the full Warner’s Pond Task Force at its Aug. 13 meeting, and will determine whether additional subgroup meetings are needed after that feedback. No formal adoption of a plan occurred at this meeting.