NEWBURY — Selectmen are again under pressure to authorize removal of the 138-year-old Larkin Mill Dam.
At a recent meeting, Brad Chase of the state’s Division of Marine Fisheries urged the board to reconsider a previous stance it took against demolishing the dam as a way to improve the viability of migratory fish that rely on the fish passage located there. Selectmen had a lengthy discussion but took no immediate action.
In December 2011, town leaders voted against removing the dam, siding instead with public safety officials who thought the old dam could play a crucial role if a highway accident caused a spill into the Parker River. Interstate 95 crosses over the Parker River a couple hundred yards or so upstream from the dam.
Selectman Chuck Bear told his colleagues last Tuesday that the Fire and Water Departments have not changed their minds about the potential threat to public safety and the water supply that they feel comes with removal of the dam. But Chase contends the structure would “likely not” slow any leakage from the typical types of contaminant spills that occur on a highway.
Migratory diadromous fish — such as alewife, blueback herring, white perch, rainbow smelt, American eel, and sea lamprey — are a crucial part of the food chain upon which fishing fleets in this region depend. The fish runs of the six dams that make up the Parker River system play a key regional role in the sustainability of this marine population.
But according to Chase, impaired fish passage and degraded habitats are fostering the decline of runs of these types of fish in recent years. “Significant local stewardship and cooperative efforts among local, state and federal partners” are needed in order to stem this trend, he said.
Under state law, dam owners are required to maintain fish passages.
However, Chase said his organization is not interested in telling the town which course to follow. Rather, it prefers to work with property owners to find practical solutions for fish passage maintenance and improvements.
A 2007 study conducted by the Conservation Commission, in partnership with the Mass Riverways Program and the National Oceanic and Atmospheric Administration (NOAA), indicated significant degradation of the Larkin Mill Dam. A fish ladder that helps fish migrate around the dam has been at least partly blocked by debris, the dam study found.
It looked at the feasibility and costs of four alternatives: doing nothing ($0); replacing the dam ($645,000); partly removing it (at least $275,000); and fully removing it (at least $340,000).
“Our opinion is that dam removal is the most feasible option for that site,” Chase told selectmen.
When the board asked if there might be any resources available through Marine Fisheries to simply repair the fish ladder, Chase said his crew can handle work on small dams, but a larger project such as the dam on Larkin Road — which may need reconstruction if it isn’t removed — would be more than they could provide.
Selectman Geoff Walker inquired about new technologies that would employ natural materials for the fishway. But Chase said although these types of fishway utilize natural resources, they are still “very much engineered structures” that don’t come cheap.
In the past year Marine Fisheries has undertaken an effort to improve the fish runs of the Parker River system. The organization hired new staff at its Gloucester facility that have rebuilt failed fishway weirs at the Wollen Mill Dam in Newbury and Snuff Mill Dam in Byfield. Culvert weir repair below the Wollen Mill Dam has been funded and contracted, with work slated to begin in the upcoming year. A two-year river herring habitat assessment at the Pentucket Pond in Georgetown is ongoing.
Concern over fish that spawn in the river has been growing in recent years. In the 1970s, some 38,000 river herring passed up the river to spawning grounds; in recent years, the numbers have dwindled to fewer than 1,000.
But a dwindling fish population is not the only concern associated with the aging dam. The impact of a dam failure would be felt at all downstream locations, which include some residential areas and the Parker River waterfront around the Route 1A bridge.
Last April the old Larkin-Morrill Building adjacent to the dam was razed because it had become an attractive nuisance susceptible to teen partying and vandalism.