Sandwich-02
Sandwich, Sagamore Marsh
41.774607, -70.520671
Technical Specifications
Basic Properties
- Type
- Tide Gate
- Material
- —
- Control
- Electric Actuator
- Condition
- —
- Geometry
- —
- Status
- Active
- Number of Gates
- 0
Operator & Management
- Operator Type
- PUBLIC
- Operator
- Owned by DCR, managed by ACOE
- Permits
- —
- Purpose
- —
Dimensions & Elevations
- Dimensions
- —
- Invert Elevation
- —
- Installation Date
- 2001
- Tidal Influence
- —
Culvert Details
- Restriction Type
- —
- Geometry
- —
- Material
- —
- Bottom Material
- —
- Number of Pipes
- 0
- Dimensions
- —
- Condition
- —
- Comments
- —
Salt Marsh Field Assessment Results
Comprehensive field assessment dataPhysical Conditions Assessment
Channel Conditions
- Channel Alteration and Ditching
- Severe (>398 ft/acre)
- Channel Constriction
- Narrower than channel
- Channel Erosion
- None
- Sediment Deposits
- None
Blockages
- Debris Blockages
- Moderate (10-60% of opening)
- Evidence of Overtopping
- No
Ecological Assessment
Habitat Observations
- Ecological Impairment due to Tide Gate
- Limited
- Crab Burrow Intensity
- None
- Ponding and Die-off Depressions
- None
- Phragmites Present
- Limited (<10%)
Invasive Species
- Upstream Invasive Species
- Yes
- Downstream Invasive Species
- No
- Invasive Species Notes
- Phragmites limited to patches along top of channel bank. Further up in actual marsh, phragmites is limited to upland border
General Comments
Creek has been channelized, straightened and had its banks reinforced with boulders all the way to the next constriction, a culvert about 250 ft upstream. Reinforcement has eliminated possibility of salt marsh along bank, debris buildup indicate slight constriction of flow. Area upstream of second culvert also had an armored bank for about 700 ft upstream. Scour hole in front of culvert again indicates slight constriction. Upstream marsh has large sections of low marsh with phragmites limited to upland fringe. Increasing tidal exchange may improve marsh community? Confirm with BH.Habitat Transects
First Transect (50 yards upstream of tide gate)
Second Transect (150 yards upstream of tide gate)
Third Transect (300 yards upstream of tide gate)
Restoration Potential
Assessment
- Salt Marsh Impairment due to Tidal Restriction
- Moderate
- Potential Extent of Marsh Restoration
- Moderate
- Implementation Feasibility
- High
- Restoration Priority
- High
- Recommended Improvement Type
- O&M and Infrastructure
Notes
Site shows moderate salt marsh impairment due to restricted tidal flow. Replacement with self-regulating tide gate could restore approximately 5-8 acres of degraded marsh habitat. Good access for construction equipment. Regional coordination completed with town DPW and conservation commission.Historical Records
Environmental Data
- Invasive Species
- Yes
- Restoration Status
- —
- Invasive Comments
- —
- Restoration Comments
- The Sagamore Marsh restoration project is one of the largest wetland restoration projects ever undertaken in New England. Tidal flushing of the Sagamore Marsh was restricted in the mid 1930s when the Cape Cod Canal was widened and deepened, creating a fresh and brackish water system. A 48-inch diameter culvert was constructed as part of the Canal reconstruction to drain runoff from the marsh into the Canal. This culvert proved inadequate to provide sufficient tidal flushing to maintain the salt marsh. Various alternatives were examined to restore the salt marsh. The one that provides the maximum project benefit called for replacing the 48-inch culvert with two 6-foot high by 6-foot wide reinforced concrete box culverts under each road, installing electric sluice gates, deepening the man-made channel and widening the channel from 4-feet to 12-feet.
- Upstream Area
- —
Notes & Comments
- General Comments
- —
- Operation Plan
- —
- Operation Comments
- Gates have never been fully opened. Concessions to listed four-toed salamander prevented full gate opening and complete restoration. Salamanders are now delisted, however US ACOE is working with DCR on a MOU before gate adjustments can be made.
- Gate Comments
- Culverts and automated tide gate were installed in 2001.
- Elevation Comments
- —
- Visit Comments
- —
- Other Comments
- The Sagamore Marsh Project was under the direction of the U.S. Army Corps of Engineers and the Massachusetts Executive Office of Environmental Affairs. The National Marine Fisheries Service, U.S. Fish and Wildlife Service, and the EPA provided expert scientific analyses in support of this ecological restoration project. Project : Sagamore Marsh Tide gates that run under the Canal North Access Road, these were constructed through a Corps partnership agreement to restore Sagamore marsh. Constructed finished in April 2001 Waterbody : Sagamore Marsh/Cape Cod Canal Owner: This project was constructed by The Corps and is located on Corps Property. Permittee: There is no federal permit for the project. Maintenance and Operation Plan: It is attached Responsible Party for maintenance and operation: MA DCR Gate type: 2x electric sluice gates
- External Data Comments
- US ACOE Sagamore Marsh Operation and Management Plan September 2012 US ACOE Sagamore Marsh Project Cooperation Agreement 9.22.1999 (Other)
Part of the Massachusetts Bays Program© 2026 Massachusetts Bays Program. Monitoring tidegates across Massachusetts.