Waterlevel & Dam

The waterlevel of Manchaug Pond is of utmost importance to the health of this lake ecosystem, the quality of life for year-round and seasonal residents and tourists, the safety of property and residences along the shoreline and downstream, and the maintenance of water in-lake and downstream flow feeding dependent fisheries, drinking water sources, water-dependent businesses. Key to maintaining the proper waterlevel is the Manchaug Pond Dam which is now owned, operated, and maintained by the Town of Sutton.

Frequently Asked Questions:

  • Who owns the Manchaug Pond Dam?   The Town of Sutton owns the dam while the Manchaug Pond Foundation holds the deed to the flow-rights of Douglas and Sutton.
  • Who operates and maintains and operates the dam?  The care and operation of the dam is executed by the dam owner monitoring daily and in accordance with the Order of Conditions issued to the town by the Sutton Conservation Commission citing the MassDEP Unilateral Administrative Order and actual historic rule curve levels.
  • What are  the waterlevel goals?
    • April 1st:  Achieve FULL. Refill of the lake from the winter drawdown occurs in February and March in order to bring the waterlevel to full or just above as required by Mass DEP (Massachusetts Department of Environmental Protection) and Mass Wildlife (Mass. Department of Fish and Wildlife) for healthy fisheries during spawning months.
    • Spring/Summer: Maintain FULL as much as possible for connectivity to coldwater fishery stream and healthy fisheries in coves, wetlands and along shore as required by Mass Wildlife. This is dependent on rainfall, evaporation and downstream conditions.
    • Early October: Winter DRAWDOWN begins.
    • Mid-Late January: Reach greatest low of drawdown.
    • Late January-Early February: End winter drawdown.
  • Will another flashboard be added to the dam spillway?  No, the current number of flashboards are for normal operation and to get us to “full.”
  • Who decides if the gate is open or closed?  The dam caretaker makes that determination. Many variables are considered from the weather forecast, to the presence/absence of snow cover in the watershed and ice cover on the lake, to runoff and saturated soils or lack of in the surrounding watershed, to conditions downstream at Stevens Pond and in the Mumford and Blackstone Rivers. Whatever the situation, you have a voice in the Manchaug Pond Foundation who works closely with the town. Waterlevel issues affect public safety, the health of the lake ecosystem, needs of shoreline properties, public access and recreation, flood prevention, drinking water wells and septic systems, control of invasive aquatic species, and more.
  • Why is the dam low-level gate open … or closed?  Possible reasons include winter lake-level drawdown, maintaining spring/summer season FULL, a rain or a storm event in the forecast, the low-level gate needs to be flushed, dam maintenance to be performed, or downstream work on the Steven’s Dam or a change in downstream water needs.
  • Is the dam safe? Yes, the dam undergoes regular inspections both informal as part of its daily operation and formal by an outside inspector as part of the requirements of the Massachusetts Office of Dam Safety (MassODS) and the Massachusetts Department of Transportation (MassDOT).
  • Who can I contact with a question or concern?  Ask it here! Manchaug Pond Foundation fields questions and concerns of the property owners and the user-community serving as the liaison with local and state regulating agencies.

What’s happening at the pond!

Manchaug Pond FoundationSave




~ September 8: Massachusetts Emergency Management Agency (MEMA) reports thatDue to four months of below normal rainfall, a Level 2 – Significant Drought has been declared in all seven regions of the Commonwealth – the Western, Connecticut River Valley, Central, Northeast, Southeast, Cape Cod, and Islands regions. The drought level remains unchanged from the previous month’s declaration.

At a Level 2 – Significant Drought, as outlined in the Massachusetts Drought Management Plan, conditions are becoming significantly dry and warrant detailed monitoring of drought conditions, close coordination among state and federal agencies, emphasis on water conservation, more stringent watering restrictions, and technical outreach and assistance for the affected municipalities.”
Tips for Saving Water: https://www.mass.gov/service-details/drought-basics-and-tips-for-saving-water

~ August 21: The Town of Sutton re-affirmed that the low-level gate is fully closed as it has been all season. No extra outflow.

Weds., August 19, 2020 outflow of the closed low-level gate of the Manchaug Pond Dam.

The Massachusetts Emergency Management Agency reports today: Due to above normal temperatures throughout July and early August and more than three months of below normal rainfall, Energy and Environmental Affairs (EEA) Secretary Kathleen Theoharides declared a Level 2 – Significant Drought in all seven regions of the Commonwealth – the Western, Connecticut River Valley, Central, Northeast, Southeast, Cape Cod, and Islands regions.” Link to Full Report.

~ August 17: The low-level gate remains closed as it has been all summer.  The visible flow is, by design of the gate itself, a required 1/2 inch minimum outflow to support healthy fisheries downstream as required by the Commonwealth of Massachusetts.

~ August: This summer’ significant drought conditions – little to no precipitation, no inflow from the watershed, and evaporation with the sunny and hot weather – is causing the waterlevel to drop.

~ June 1: The waterlevel remains at full. Thank you to the dam caretaker as he adjusts for rainfall and dry times.

~ April 13: The significant rainfall and runoff from the watershed has brought the lake to full. With continued flow coming in and rain in the forecast, the dam low-level gate will be opened to prevent flooding.

~ April 7: The dam owner reports with rain in the forecast, the waterlevel is expected to reach the full mark by Monday.

~ April 1: Waterlevel is nearing full, having made considerable gains over the week/weekend. Recent precipitation and subsequent watershed runoff are resulting in significant gains.  Coming into March with no ice or snow cover, and drought conditions made for a slower refill process.  Low-level gate remains closed.

~ March 6: The winter drawdown period comes to an end with open water and no ice on the lake. The low level gate is closed and flashboards are in for the refill process this month. Everyone living and working around the lake need to be aware of rising water levels and take the necessary safety precautions. This is also a good time to clean waterfront areas of litter, rake up and remove leaves so they do not decompose in the lake, and remove invasive aquatic plants from shoreline areas.

~ August 1: 
The waterlevel has remained constant through these summer months. 

~January-February: The dam low-level gate remains open as winter low are achieved and snowmelt, rain, and watershed runoff are captured.

Gate is open 100%.  Expectation is with no to little precipitation the lake can be lowered fast for drawdown to resume. High water downstream in the Mumford River is being monitored but Stevens is handling Manchaug’s outflow.

    Aerial View of Manchaug Pond Dam – November 2018

    Winter Lake-level Drawdown & Refill


    Winter Drawdown:

    October:  The annual drawdown of the waterlevel begins about Columbus Day or the first week of October reaching its lowest point in January-February. This is a gradual drawdown with timing to allow for amphibians, reptiles and other aquatic organisms to move to deeper water before ice formation and substrate freezing and to provide fall recreational opportunities.

    Lake Refill:

    March-April: Lake refill must be achieved by April 1st to provide a stable pool elevation and habitat for spring spawning and connectivity with the watershed in-flowing cold water fishery stream.*


    Flood Control:

    The lower winter waterlevel provides storage capacity for runoff from unusually high precipitation and snow-melt events.

    Dam Maintenance:

    With the upstream face of the dam exposed during drawdown, inspection and maintenance can be performed as needed which would include re-pointing and facing of the stone and concrete face.

    Invasive Species Control:

    Since 1990, the Manchaug Pond Foundation and its parent organization, the Manchaug Pond Association, has worked with the dam owner to employ lake-level drawdown as the best option for controlling aquatic invasive species.  2018 both the Sutton and Douglas Conservation Commissions issued Order of Conditions  (DEP file numbers 303-0866 and 143-0956) which mandates drawdown and other physical/mechanical means of management as the first-line of defense in the control of invasives.

    Lycott Environmental’s Lee Lyman, a pioneer in the management of ecological systems, first recommended tweeking the timing of our annual drawdown to both protect native species and to knock down unwanted invasives populations.   Providing the weather conditions are conducive, it makes a difference.

    Drawdown allows for the desiccation, freezing, and physical disruption of plants, roots, and seed beds around the shoreline. In addition to reducing the growth of non-native invasive weeds such as Fanwort and Variable Milfoil, Manchaug Pond Foundation notes successful control of Asian Clam at the state public access boat ramp.   A look at Manchaug Pond’s bathymetry  shows how lake-level drawdown can be an effective method for aiding in the management of aquatic vegetation in the shallow shoreline areas of lakes and ponds.

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    Winter drawdown allows for the desiccation, freezing and physical disruption of plants, roots, and seed beds around the shoreline.
    Manchaug Pond has two non-native submerged invasive weeds, Fanwort and Variable Milfoil. Winter Drawdown decreases these plants as well as successful control of an infestation of Asian Clam at the public access boat ramp lauch area.


    Purpose:Manchaug Pond Foundation

    While the waters of Manchaug Pond Reservoir are no longer needed in the manufacturing processes of downstream textile mills, today the importance of the 380 acre reservoir and its dam are no less important and are found to be farther reaching:

    • provides required minimum, continual flow in the Mumford River supporting aquatic species;
    • supplies storage capacity to attenuate flooding concerns on-lake and downstream;
    • provides and enhances fisheries and wetlands;
    • ensures connectivity with in-flowing coldwater fishery streams;
    • allows year-round recreational opportunities benefiting tourism;
    • provides higher quality of life in this corner of the Blackstone Valley and Commonwealth.

    Overall Structure & Construction

    Manchaug Pond Foundation Waterlevel & Dam

    2010 Aerial of Dam with Torrey Road at crest.

    Originally constructed in 1836 by downstream textile mill owners, its primary purpose was to impound the pond creating a reservoir to provide the mills with a continuous flow through the year.  In 1960, extensive improvements were made which included widening and raising the dam crest, constructing the downstream earthen embankment, replacing the overflow spillway, expanding the low-level outlet, and accommodating Torrey Road.

    Today, Manchaug Pond Dam stretches 330 feet long, 28 feet high, and 36 feet wide with Torrey Road at its crest and sits in the town of Sutton, Massachusetts, U.S.A. at Latitude 42.09048 N   Longitude 71.76630 W. The upstream side of the dam is a stepped-face stone-masonry wall made up of large stone blocks with joints mortared with concrete. The downstream slope is a grass/vegetation covered earth slope constructed in 1960’s.

    • Manchaug Pond Foundation Dam

      Dam viewed from Holt Road




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      Upstream side made of stone-masonry


    • Looking south toward low-level gate




    • Earthen downstream side




    The overflow spillway was constructed in 1960 when extensive improvement were made to the dam.
    Primarily a reinforced- concrete box culvert, it extends from the upstream side through the center of the day to the downstream side measuring approximately 10 feet. wide by 9.35 feet high.

    2016: On February, 26th, new flashboards installed made of thick, red oak. Two flashboards were significantly damaged by a beaver in 2015.

    • Manchaug Pond Foundation Waterlevel & Dam

      Spillway with cage on upstream side

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      Spillway/culvert box opening with flashboards.

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      Culvert box of spillway as seen from upstream

    • dam flashboards

      Water flow over spillway flashboards

    Low-level Gate

    The low-level outlet is comprised of a hand-operated gate which opens to a 2 ft. by 2ft. stone conduit through the dam structure enlarging to a 2-ft. by 3-ft. high reinforced-concrete outlet on the downstream side of the earthen embankment, added during the 1960 construction.

    Operation & Maintenance:

    Visual inspections of the dam are made with daily water surface elevations and precipitation levels recorded and necessary adjustments made to the low-level gate and flashboards/stoplogs in compliance with the Conservation Commission and Mass DEP orders.

    Annual maintenance includes cutting of the grass-covered earthen embankment twice a year. Re-pointing with concrete of the upstream stepped-face’s stone-masonry wall is done as needed. In compliance with Massachusetts Office of Dam Safety regulations, a Phase I Inspection/Evaluation is conducted every other year by an outside engineering firm.

    In 2006 the low-level gate mechanism was replaced with steel construction and the operator’s platform renovated.

    Repairs to the spillway box culvert were made in the years 2005, 2008, 2009, and 2013.

    2016 new flashboards/stoplogs installed.

    2006  Repairs to low-level gate
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    • Order of Conditions. Page 10-g #32, Town of Sutton Conservation Commission. October 15, 2018
    • Optimum Rule Curve approved by Sutton Conservation Commission in 2018 and utilized by Town of Sutton in operation of the dam.
    • Unilateral Administrative Order (UAO),  Massachusetts Department of Environmental Protection (MADEP), April 21, 2009.
    • Order of Conditions, Town of Sutton Conservation Commission March 18, 2009.
    • Drawdown Performance Standards for the Protection of Fish and Wildlife Resources. Approved September 23, 2002, Massachusetts Division of Fisheries & Wildlife.