TideGateway

Scituate-01A

Scituate, Scituate Harbor

42.186309, -70.725321

Technical Specifications

Basic Properties

Type
Flap Gate
Material
Metal
Control
Manual Gear
Condition
Poor
Geometry
Circular
Status
Active
Number of Gates
1

Operator & Management

Operator Type
PUBLIC
Operator
Town of Scituate
Purpose
Flood Protection

Dimensions & Elevations

Dimensions
2ft diameter
Invert Elevation
-0.3 NAVD88
Tidal Influence
Upstream: 3.77 NAVD88, Downstream: 5.24 NAVD88

Culvert Details

Restriction Type
Roadway
Geometry
Circular
Material
Concrete
Number of Pipes
1
Dimensions
1.5ft diameter
Condition
Fair
Comments
The reinforced concrete pipe was in fair condition. It appeared that the mouth of the pipe was beginning to separate from the weir wall on the upstream side of the restriction. In addition, erosion was observed around the upstream concrete weir, presumably from stormwater runoff from the adjacent road, tidal influence, or some combination thereof. Erosion was also observed around the downstream headwall. The downstream headwall was in poor condition and appeared to "leaning" towards the channel towards the top, indicating mobilization of soils behind it. Additionally, spalling of the headwall was observed.

2024 Field Survey Results

Comprehensive field assessment conducted in 2024

Physical Conditions Assessment

Channel Conditions

Channel Alteration
Moderate (133-398 ft/acre)
Channel Constriction
Narrower than channel
Channel Erosion
Severe (>60% of bank)
Sediment Deposits
Limited (<10% of channel width)

Blockages & Issues

Debris Blockages
None
Evidence of Overtopping
Yes

Transect Measurements

50 Yards

Open Water
0
Salt Marsh
175
Brackish
32
Freshwater
0
Ditch
4
Unvegetated
0

150 Yards

Open Water
0
Salt Marsh
134
Brackish
53
Freshwater
0
Ditch
4
Unvegetated
0

300 Yards

Open Water
0
Salt Marsh
86
Brackish
41
Freshwater
0
Ditch
4
Unvegetated
10

Ecological Assessment

Habitat Observations

Crab Burrow Intensity
Limited (<10% banks are densely
Ponding Depressions
Limited(<10% of marsh platform
Phragmites Present
Limited (<10%)
Ecological Impairment
Moderate

Invasive Species

Upstream Invasive Species
Yes
Downstream Invasive Species
No
Invasive Species Notes
Phragmites on fringe
Additional Comments (2024)
Lack of low marsh community, early indicators of phragmites encroachment, apparent and apparent lack of sediment exchange supports observations of a moderate tidal restriction.

Historical Records

Legacy data from previous surveys and documentation

Environmental Data

Invasive Species
Yes
Restoration Status
Unknown
Invasive Comments
The impoundment was comprised primarily of high marsh and was fringed by phragmites.
Restoration Comments
Houses were observed around the marsh; however, they appeared to be elevated.
Upstream Area
Salt Marsh: 5-10 acres

Notes & Comments

General Comments
Site is located directly adjacent to Kent Street (busy road). The downstream side is located to the east and the upstream side is located to the west.
Operation Plan
No
Operation Comments
Upstream sluice boards put in seasonally to impound water in marsh for ice skating. It appeared that the downstream tide gate was installed for the sole purpose of flood protection.
Gate Comments
There were two tidal control structures at the site. A metal flap gate was installed on the downstream portion of the culvert and a concrete weir with wooden stop logs was installed on the upstream portion. The downstream metal flap gate was in poor condition. It was rusted open approximately 3 to 4 inches, the bolts affixing it to the concrete headwall were corroded, and it appeared that someone had attempted to remove the tide gate as evidenced by loosened nuts (i.e., the nuts had been backed off the bolts). The upstream concrete weir and wooden stop logs appeared to be in good condition.
Elevation Comments
Staining was apparent on the upstream (U/S) and downstream (D/S) ends of the headwall (HW) so approximate extent of U/S and D/S tidal influence was able to be assessed in addition to tide gate (TG) invert elevations. The below lists measuredowns taken with a surveyors rod and corresponding top of headwall LiDAR elevations (NAVD88 datum). 1) TG Inv (D/S tide gate): Top of HW El (D/S) = 6.53’; Inv Measuredown = 6.83’; TG Inv = 6.53’ – 6.83 = -0.30’ 2) Upstream Tidal Influence: Top of headwall LiDAR Elevation = 4.43’; Staining Measuredown = 0.66’; U/S Tidal influence = 4.43 – 0.66 = 3.77’. 3) Downstream Tidal Influence: Top of headwall LiDAR elevation = 6.53’; Staining Measuredown = 1.29’; D/S Tidal Influence = 6.53’ – 1.29’ = 5.24’
Other Comments
Upstream saltmarsh appears to be impacted by septic systems and corn field
© 2025 Massachusetts Bays Program. Monitoring tidegates across Massachusetts.