Tags Posts tagged with "Mill Brook"

Mill Brook

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From its headwaters alongside North Road in Chilmark, the Mill Brook drains a significant portion of West Tisbury. — File photo by Tony Omer

West Tisbury selectmen waded back into the muddy waters of the Mill Pond debate last Wednesday and appointed all but one of the applicants to a new Mill Brook watershed study committee at their meeting on May 29.

With dredging the Mill Pond sidelined by a vote at annual town meeting on April 8, on April 16 selectmen agreed to form a seven-member committee to oversee a watershed study and to draft a watershed management plan by the 2016 annual town meeting.

Voters at town meeting agreed to add $15,000 to $15,000 appropriated in 2012 to study the watershed.

“The new committee will finalize the scope of a new RFP to study the watershed and will draft a watershed management plan based on the study,” selectman and selectmen’s representative Cynthia Mitchell told The Times on Wednesday. “I expect this to be a two-year process.”

Ms. Mitchell was appointed committee chairman pro-tem.

Also appointed were conservation commission member Prudy Burt; emergency management director John Christensen; Tim Boland, executive director of the Polly Hill Arboretum; Chuck Hodgkinson, a West Tisbury resident who is the Chilmark conservation agent; Sue Hruby, a member of the town’s capital improvement and energy committees; former conservation commission and Mill Pond committee member Rez Williams; and watershed riparian landowners Selena Roman and Nancy Huntington.

Bill Wilcox, retired Martha’s Vineyard Commission water resources planner was the only applicant not appointed. A proposal he and West Tisbury engineer and watershed researcher Kent Healy submitted to the selectmen to conduct their own watershed study was cited as the reason. That proposal is expected to be addressed by the new committee, according to selectman Richard Knabel.

The question of whether to dredge the Mill Pond, and the cost associated with that project, has roiled the town’s political waters for several years. There are those who want to maintain the man-made pond and its placid vista. Others want to remove the dam used to create the pond and allow the stream to return to its natural state, a change they say would enhance the spawning habitat of native fish, including herring, white perch, and eels, and allow free passage of brook trout.

A Mill Pond Committee was formed to pursue the dredging issue in 2009, and a group called the Friends of the Mill Pond, closely aligned with the committee, raised $20,000 in pledges this year from private donors for dredging. That committee is now on hiatus pending the results of the new committee’s work, according to Ms. Mitchell.

The new committee will meet for the first time at 5 pm on Tuesday, June, 10, at the West Tisbury library.

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The Mill Pond is part of the Mill Brook system. — File photo by Ralph Stewart

State fisheries manager says high water temperatures are a barrier to survival.

In a presentation Sunday on the fisheries ecology of Mill Brook, Division of Fisheries and Wildlife (DFW) Southeast District fisheries manager Steve Hurley described a complex ecosystem in which wild brook trout and other native species struggle to survive. Mr. Hurley presented the results of a water temperature study that revealed readings that at the height of the summer could prove lethal to trout.

2013-mill-brook-stream-temperatures.jpgAccording to the study, which regularly measured water temperatures at nine locations along the Mill Brook system during the summer months and continuously from July 18-20, the temperatures are dangerously high, at temperatures at which brook trout have been eliminated from the lower stretches of Mill Brook.

For example, one graph Mr. Hurley offered showed that temperatures below Roth Pond averaged 78 degrees Fahrenheit in July, and reached as high as 92 degrees at midday on July 19, 2013. Above Priester’s Pond, where there are still wild brook trout, the temperatures also reached the high 80s (see related chart).

Brook trout are a cold water species that require temperatures between 33 and 53 degrees for egg development, spawn optimally at 51 degrees, and grow best at 59 degrees. Ten degrees higher than this is the upper limit for the survival of the brook trout population.

“If these fish are there at all, they’re hanging on to the last bits of habitat,” said Mr. Hurley, a trout biologist, during the presentation. “When the water is revealed to the sun, it’s easy for the temperature to reach lethal limits.”

2013-lower-mill-brook-temperatures.jpgThe 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. Hurley placed significant blame on dams, of which there are more than 2,645 in Massachusetts, 10 along Mill Brook.

“If you have a dam that’s no longer in operation,” he said, “consider breaching it and letting the stream return to its natural form.”

About 60 Islanders attended the two hour presentation at the Public Safety Building in West Tisbury, during which Mr. Hurley also addressed a 2012 fish census and the history of the Mill Brook system.

1955 mill brook tisbury 08051955 letter to nelson bryant.jpgMr. Hurley noted that the water temperature study was completed almost 70 years after his predecessors in the Massachusetts Fish and Game Division highlighted similar issues in a letter dated August 8, 1955, in which they recommended a temperature study to Nelson S. Bryant, Sr., a selectman then, in response to a request for help to maintain the brook system “suitable for maximum trout utilization.”

The unnamed aquatic biologist wrote, “One undesirable feature of the system, as I saw it, is that the series of ponds (Priester’s Pond, etc.) in the upper system, must cause considerable warming up of the water … No doubt small spring brooks or spring holes will always carry over some trout, but large quantities of suitable cold water is vital for maximum trout utilization and survival.”

2013-upper-mill-brooks-stream-temperatures.jpgHe added, “I would strongly urge, possibly with the help of the Rod and Gun Club, to take water temperatures in Priester’s, Mill Pond and Mill Brook during August. Both surface and bottom temperatures should be taken. I think Howard Andrews, secretary of the Rod and Gun Club, still has a Max-Min. thermometer of ours, which could be used.”

Click here for an accompanying “Wild Side” column on the Mill Brook talk