Concord dredging subgroup revises proposal after $5 million cost estimate

Chris Dennaro, who opened the meeting of the Town of Concord dredging work group, said members would review and finalize a dredging proposal and the related cost estimate. The group examined technical language, maps and access points, and debated how to present sampling and permitting needs.

The meeting focused on a new cost estimate Delia presented: "what we're looking at from this cost estimate is a 5,000,000, base bid for the 35,000 yards," a figure several participants described as higher than prior assumptions and one that will need to be reflected in the proposal. Members discussed a 10 percent "design escalation" line item Delia said addresses early‑stage uncertainty rather than a formal contingency, and they debated whether to seek additional contractor quotes or to reissue procurement documents (an RFQ) to obtain updated pricing.

The group identified several technical clarifications to the draft proposal. Members agreed to: correct and replace an inaccurate map image with higher‑resolution parcel boundaries; explicitly note Commonwealth Avenue and Giroux access points (and to label the Bruce Freeman Rail Trail consistently); reword the dredge‑slope description to state that "slopes in the dredged area will be gradual"; and add a short illustrative photo or diagram for a stepped‑pool/riffle system to explain fish passage concepts. On sampling, Delia said chemical testing will be required for permitting and disposal decisions and that chemical results are valid for three years.

Participants debated ecological and resilience claims. Bruce stated, "Dredging has no impact on resilience," and members generally concluded language claiming resilience benefits should be removed or hedged as "marginal" or "inconclusive." The committee also discussed whether the proposal should recommend ADA‑compliant access improvements at Commonwealth Avenue and Giroux; members agreed to include access improvements as part of the broader proposal while clarifying that dredging alone does not create ADA access.

Contract‑specific details were also discussed. Members noted prior bids from Charter and newer estimates from Sumco/Sunco; participants said procurement rules require reissuing an RFQ for price work above the town threshold and that Charter’s prior quote can’t simply be treated as an RFI response. The group also discussed erosion‑control approaches and the contractor recommendation to use geotubes; Delia noted one contractor’s view that geotubes are more expensive up front but may reduce long‑term maintenance costs.

Action items assigned during the meeting included: Paul will add the Commonwealth Avenue access language and provide the CPA application number; Delia will rework wording on slopes, sampling, and greenhouse‑gas language; the subgroup will seek clarification on the two Northfield monitoring wells and follow up with DOT contacts; and members will make tracked‑change edits to the draft document. The subgroup set a follow‑up meeting to finalize edits and prepare a proposal for the task force, with a 3:00 p.m. Monday meeting proposed in the chat.

With no public comment, Dennaro closed the meeting at 07:18. The dredging subgroup will present updated materials and the cost estimate to the larger task force for its recommendation to the Town of Concord.