More than 50 people crowded into the reading room at the West Tisbury Public Library on Saturday to hear Beth Lambert, river restoration program coordinator for the state Division of Ecological Restoration, discuss the state’s policy of dam destruction as a way of restoring natural stream ecology.
Ms. Lambert came to the Island at the private invitation of Prudy Burt, a member of the West Tisbury conservation commission who is concerned that methods — including dredging — now being considered to preserve the increasingly shallow Mill Pond would detrimentally affect the plant, fish and animal life in the pond and the brook that feeds it. Because she believes that the town should consider all options before proceeding, Ms. Burt asked Ms. Lambert to come to the Island to offer her alternative suggestion — removing the Mill Pond dam.
All across the state old dams are being demolished, Ms. Lambert said, because Massachusetts now requires that all dams be certified as to safety by a structural engineer. State funds are available for this purpose, she said. She also said 19-century dams have generally outlived their usefulness, and many — in addition to altering stream ecology — have become a danger to humans because of their dilapidation. As a result dam owners increasingly have been removing them.
“Dams prevent wildlife and fish from getting what they need in their life cycles,” she said. “Our rivers have been segmented by dams and that is deleterious.” An uninterrupted riparian corridor provides a good natural habitat for fish and wildlife, but dams change all this. Since today there is little need for dams to provide water power, and scientists have discovered their bad effect on fish and wildlife, there has been an increasingly active movement across the state to destroy them. “For example, warm water is created where there is a dam, Warm water does not contain as much oxygen as colder water and fish need oxygen,” Ms. Lambert said.
She said in the last year seven abandoned dams in the state have been removed. She showed a series of pictures of rich greenery that has grown in many of these areas now that the dams are gone.
The audience had questions for the speaker:
“Has a dam ever been removed when the waters it dammed flowed into a great pond?” She said she did not believe so.
“Does your group take care of the letter of intent required when there will be changes in a waterway and do you have funds for this?” Ms. Lambert replied that it did and that the cost of dam destruction can be as low as $70,000, or much higher.
“How would you deal with the landowners whose property edges the pond?” Also it was pointed out that there are six manmade ponds above the Mill Pond. She said it is always the dam owner’s own decision, and that usually when one is removed others see the good effects of the removal and follow suit.
Finally, the question was raised as to who owns the Mill Pond dam — the town, the state since it goes beneath a state road, the Martha’s Vineyard Garden Club that owns the original 19th-century mill structure for which the dam was built?
No one was able to answer that question.