Near the source of the Mill Brook along North Road in Roth Woodlands, an earthen berm and two small, misplaced culverts prevent brook trout and endangered American brook lampreys from reaching their upstream breeding grounds. Last Friday, the Massachusetts Environmental Trust (MET) sought to restore Mill Brook to a more natural state by awarding the Sheriff’s Meadow Foundation — which owns and maintains Roth Woodlands — $40,000 to complete the design and permitting of a replacement culvert.
“We want to be the best stewards of this land,” Foundation Executive Director Adam Moore said in a telephone conversation with The Times. “And that includes the Mill Brook, and the brook trout and lamprey.”
As it is now, the two corrugated-steel culverts are both too small to allow brook trout passage, and placed too high above the streambed. The berm acts like a dam, creating a buildup of water that lacks plant cover and reaches temperatures which are dangerously high for the threatened brook species.
“This is a demonstration project, and we want it to be a model for other landowners,” Mr. Moore said. “We want other landowners to see this and restore the Mill Brook on their properties, too.”
The Mill Brook begins in Chilmark, passes through several artificial impoundments in West Tisbury, such as Mill Pond, and streams into Tisbury Great Pond. A combination of dams and changes made for agricultural purposes have altered the ecosystem, limiting habitat for brook trout that were once in abundance on the Island. An important factor in the decrease of the population is water temperature, which has increased, in part because of a reduction in the wetland plant life that shields streams and ponds from excessive solar heating.
Mr. Moore says the grant will cover the design and permitting of a much better concrete box culvert, but that further funding will be necessary for the culvert’s construction. The foundation’s application for a $75,000 grant from the National Fish and Wildlife Foundation, which would have covered the cost of construction, was rejected.
“But we’ll apply again,” Mr. Moore said. “We found out within 30 seconds that we had won the MET grant but not the other one. It’s actually better this way, to get the design and permitting first, and then apply again next May.”
The foundation also received $7,500 from the Daniels Wildlife Trust in April, and prior funding from the commonwealth, for the initial culvert design.
“The commonwealth has been very supportive,” Mr. Moore said. “The Massachusetts Department of Ecological Restoration has also committed $20,000 for Mill Brook restoration, but we might not get to use that directly.”
The MET grant was part of $480,568 awarded statewide to 12 projects that protect and restore rivers, watersheds, and wildlife, according to a press release from the Massachusetts Executive Office of Energy and Environmental Affairs.
“The Environmental Trust has been investing in the waters of Massachusetts for over 25 years,” said Lieutenant Governor Karyn Polito in the press release. “Our coastal regions and rivers are just some of the natural resources that make Massachusetts such a great place to live and visit, and these grants will continue to improve these incredible resources.”
In September 2012, a team led by Steve Hurley, southeast district fisheries manager for the state Division of Fisheries and Wildlife, conducted a survey of Mill Brook at multiple locations to officially document the existence of wild brook trout.
In an official “Fisheries sampling report on Mill Brook and tributaries – West Tisbury,” dated September 18, 2012, Mr. Hurley described what his team found.
“A total of eight fish species were sampled in Mill Brook and two small tributaries (Witch Brook and an un-named tributary to Priester’s Pond). Reproducing wild brook trout were found in the upper reaches of Mill Brook and in the Witch Brook tributary as well as in an un-named tributary to Priester’s Pond. A single adult (apparently wild) brook trout was captured below a small impoundment (Berresford’s Pond) on the river. No brook trout were found in the sampling area below Old Mill Pond and above the Town Cove section of Tisbury Great Pond.”
In addition, Mr. Hurley reported, “Large numbers of American eels were captured in the lowest site surveyed on the river below the first dam (Old Mill Pond) above the brackish Tisbury Great Pond. American eel, anadromous and marine species have ready access to the Tisbury Great Pond during periodic man-made and natural openings of the pond to the sea but the openings may not coincide with peak migration times for elvers. American eels were present at the majority of sites sampled but abundance appears to be reduced compared to a brook with unimpeded access to marine waters. Passage of eels and other fishes may be impeded by the numerous dams along the main stem of Mill Brook.”
Brook trout historically thrived in rivers and streams stretching from Maine to Georgia. The presence of brook trout in a watershed is considered an indicator that water quality is excellent. Declining brook trout populations can provide an early warning that the health of an entire stream, lake, or river is at risk, according to fisheries managers.
In his report, Mr. Hurley noted the observations of Dr. Jerome V.C. Smith, a medical doctor and former mayor of Boston, who, referring in 1833 to the brook trout of Mill Brook, remarked:
“In no place, however, do we remember to have seen them in such abundance as in Dukes 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 water, and never do we recollect so fully to have realized the expression of its being ‘alive with fish’ as on this occasion.”
Mr. Hurley noted the modern challenges, including climate change, that now face the descendents of those brook trout. “Wild brook trout populations are persisting in Mill Brook watershed where suitable cold water habitat exists but their access to tidal areas is blocked by the numerous dams and barriers which do not allow the anadromous life history variant known locally as ‘salters’ or in Smiths early 1800s as ‘sea trout.’ The small stream coldwater habitats of Mill Brook are a habitat at risk due to climate change.
“Mill Brook has been highly modified with the presence of numerous impoundments that warm the waters of the brook, trap sediment, increase habitat fragmentation and reduce fish passage.”
The brook that feeds Mill Pond, the man-made water body next to the former town police station, is at the heart of a town tussle. One group would like to see the dam maintained and the pond dredged to maintain its historic scenic appeal. Another would like to see the watershed area returned to its natural pre-pond state.
In March, West Tisbury began a yearlong study of the West Tisbury Mill Brook watershed. The study will include data collection from specific sites to measure rainfall, and to analyze nutrients and chemicals in the water, and water quality. The study will monitor water sources, diversions, and withdrawals, water flow and temperatures, and will record seasonal weather impacts and the impact of existing and potential sources of threats on the health of the watershed.
The study is under the management of ESS Group, an environmental consulting and engineering services company, and is the result of sometimes contentious discussions over almost 10 years concerning the condition of Mill Pond and whether the pond should be dredged to maintain its scenic value or whether the dam that creates the pond should be removed to allow parts of the watershed to return to a natural state.