In a story published Oct. 13, “Mill Brook summer data points to deadly temperature spikes,” The Times reported on the results of the third year of summer temperature monitoring along the Mill Brook, part of a study of the Mill Brook watershed. In sections where the brook’s flow is slowed to a crawl by dams and obstructions, water temperatures spiked above 85° in three locations, and on one day in 2015, the stream warmed to 97°.
For the Island’s native brook trout, one of nature’s most beautiful fish, temperatures above 82° result in immediate death, according to state trout biologist Steve Hurley. The fact that brook trout are resilient and survive in cold-water pockets of the brook provides little comfort.
The attendant decline in the American eel and herring populations that once swam up the brook in large numbers are part of an overall decline witnessed along the East Coast. Mill Brook has a role to play in reversing that trend, but that will depend on the policies set by the residents of West Tisbury, who are chiefly responsible for the Mill Brook watershed.
The dams that block the flow of the Mill Brook have outlived their purpose. The mills ceased operation more than a century ago, but the dams have not ceased to harm the brook. This is not a new notion.
In 1833, Dr. Jerome V.C. Smith published the “Natural History of the Fishes of Massachusetts,” the first comprehensive study of fish in state waters. As the industrial revolution gained steam, Dr. Smith was disturbed by what he saw occurring in brooks across the state. He found one bright spot. Despite the recent passage of a law that penalized illegal netting by a 50-cent fine, writing about trout almost two centuries ago, he said, “Factories and sawmills have done their part towards the work of extermination, and the destructive net bids fair to do the rest. But though much diminished from these causes, there are more or less waters all over this state, and particularly in Plymouth county, and Barnstable county on Cape Cod, where the fish live and thrive in the undisturbed possession of their element. In no place, however, do we remember to have seen them in such abundance as in Duke’s county, upon Martha’s Vineyard … It was here in the month of November last, and of course in their spawning time, while returning home from a ramble among the heaths and hills of Chilmark and Tisbury, that crossing the principal brook of the island, our attention was attracted towards the agitated state of the waters, and never do we recollect so fully to have realized the expression of its being ‘alive with fish,’ as on this occasion.”
What would Dr. Smith say were he to return to that brook 183 years later in November? To this point, Prudy Burt and a small energetic group want to restore Mill Brook to its natural state. The Nature Conservancy (TNC), which has an office on Martha’s Vineyard, and the Vineyard Conservation Society, two organizations that support that effort, have been content to lead from behind. It is time for these well-respected environmental organizations to speak more publicly about the science and environmental policy that underpin a nationwide effort to remove obsolete dams, and speak directly to those who see beauty and not environmental harm in the impoundments.
In a recent Letter to the Editor published in the Vineyard Gazette, Margot McClellan of West Tisbury described a campaign by the Friends of the Mill Pond and the West Tisbury historic district commission to fund the installation of a marker on a boulder beside the pond that “will highlight the importance of the West Tisbury Mill Pond through the centuries.”
“The plaque will recount how, in early days, the Wampanoags ground corn at a gristmill powered by the Mill Brook’s waters, formerly known as the Mill River,” Ms. McClellan said. “It will relate how, in the 19th century, a dam was built that created today’s pond and provided stronger power for a mill that would produce woolen yarn from Vineyard sheep … ”
The dam and the pond that powered it were essential to the West Tisbury economy. But it takes environmental blinders to ignore the devastating effect it has had on the natural ecology.
“Today’s Mill Pond is and has always been important for children learning to fish, for turtles and wild ducks, for playful otters and regal swans, and for those humans who seek tranquility in nature,” supporters of the plaque state.
That statement does not give credit to our children and the quality of their environmental education, or their ability to recognize that Mill Pond is an artificial impoundment populated by invasive swans that displace native waterfowl. If we truly want to provide for those who “seek tranquility in nature,” we ought to remove the dams and restore the natural environment as it existed.