Marshfield-03
Marshfield, South River
42.093107, -70.700388
Technical Specifications
Basic Properties
- Type
- Flap Gate
- Material
- Wood
- Geometry
- Rectangular
- Status
- Inactive
- Number of Gates
- 1
Operator & Management
- Operator Type
- PUBLIC
- Operator
- Town of Marshfield DPW
- Purpose
- Flood Protection
Dimensions & Elevations
- Dimensions
- 4.167ft diameter, 4.167ft height
Culvert Details
- Restriction Type
- Roadway
- Geometry
- Circular
- Material
- Concrete
- Number of Pipes
- 1
- Dimensions
- 2.5ft diameter
- Comments
- Culvert under Rt139 / River side has large stand of narrow leaf cattail / large tide-gate system on the upstream side of Rt.140
2024 Field Survey Results
Comprehensive field assessment conducted in 2024Physical Conditions Assessment
Channel Conditions
- Channel Alteration
- Limited (<133 ft/acre)
- Channel Constriction
- Wider than channel_
- Channel Erosion
- Moderate (10-60% of bank)
- Sediment Deposits
- None
Blockages & Issues
- Debris Blockages
- None
- Evidence of Overtopping
- No
Transect Measurements
50 Yards
- Open Water
- 0
- Salt Marsh
- 0
- Brackish
- 0
- Freshwater
- 0
- Ditch
- 0
- Unvegetated
- 0
150 Yards
- Open Water
- 0
- Salt Marsh
- 0
- Brackish
- 0
- Freshwater
- 0
- Ditch
- 0
- Unvegetated
- 0
300 Yards
- Open Water
- 0
- Salt Marsh
- 0
- Brackish
- 0
- Freshwater
- 0
- Ditch
- 0
- Unvegetated
- 0
Ecological Assessment
Habitat Observations
- Crab Burrow Intensity
- None
- Ponding Depressions
- None
- Phragmites Present
- Severe (>60%)
- Ecological Impairment
- Moderate
Invasive Species
- Upstream Invasive Species
- Yes
- Downstream Invasive Species
- Yes
- Invasive Species Notes
- Upstream is monoculture of phragmites
- Additional Comments (2024)
- Upstream channel width and dense phragmites upstream indicate moderate constriction. Downstream end is freshwater wetland with mix of phragmites and cattails so tidal exchange salinity maybe already be limited on the incoming tide. Previous analysis indicated that enlarging culvert is infeasible and tide gate is already managed fully open due to flapper being broken.
Historical Records
Environmental Data
- Invasive Species
- Yes
- Invasive Comments
- Phragmites
- Restoration Comments
- Flap has rusted off within vault, culvert is now open. DER investigated with Town and Jason Burtner back in 2012. Recent sewer line installation in Ocean Street limits opportunities for increasing culvert size. Examination of LiDAR and tide data suggests little risk of leaving flap off. DER has tide and Lidar analysis for site.
- Upstream Area
- Salt Marsh: 5-10 acres
Notes & Comments
- Operation Plan
- No
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