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. The Manchaug Pond Foundation holds the deed to the flow-rights of Douglas and Sutton. Both entities work together, the Manchaug Pond Foundation in an advisory role, in the interest of the waterlevel and benefit of the lake, neighboring properties, and down stream safety.
- Who operates and maintains the dam? The operation and care of the dam is executed by the dam owner monitoring daily and in accordance with the Order of Conditions issued 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.
- Mid-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.
Winter drawdown allows for the desiccation, freezing and physical disruption of plants, roots, and seed beds around the shoreline.
Winter Lake-level Drawdown & Refill
WHEN?
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.*
WHY?
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.
Winter drawdown keeps non-native exotic invasive species in check.
Manchaug Pond has three invasive species affected:
- Asian Clam
- Fanwort
- Variable Milfoil
- Curly Pondweed
Asian Clam infestation was localized at the public access boat ramp but in 2024 was observed in the Mumford River beyond the dam.
Fanwort and Variable Milfoil,two submerged invasive plants, were first documented in 1990 and have spread throughout the pond by motorboat usage.
See our Invasive Weed Watcher page to learn more.
THE DAM
Purpose
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
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.
Dam viewed from Holt Road
Upstream side made of stone-masonry
Looking south toward low-level gate
Earthen downstream side
Spillway
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.
Spillway with cage on upstream side
Spillway/culvert box opening with flashboards.
Culvert box of spillway as seen from upstream
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
Sources:
- Order of Conditions. Page 10-g #32, Town of Sutton Conservation Commission. October 15, 2018. Extension secured by Manchaug Pond Foundation
- 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.