Marshfield-01A

Marshfield, Green Harbor

42.089930, -70.645111

Dimensions: 4ft diameter, 3ft height
Condition: Good
Comments: Both culverts appeared to be in good condition. The upstream wingwall was in good condition, but appeared to be starting to slightly separate from the headwall.

Comprehensive field assessment conducted in 2024

Upstream Invasive Species: Yes
Downstream Invasive Species: Yes
Invasive Species Notes: Phragmites on fringe and starting to creep into high marsh.
Additional Comments (2024): Tide gate submerged on incoming tide. Not all factors could be completely assessed, however lack of low marsh community, severity of ponding and lack of sediment exchange indicate tidal restriction is present.

Legacy data from previous surveys and documentation

Invasive Species: Yes
Restoration Status: In-Progress
Invasive Comments: Upstream marsh was comprised of a mixture of low and high marsh with fringing phragmites.
Restoration Comments: "Assessing Alternatives for Reducing Flooding within Green Harbor River Estuarine System through the Optimization of the Tide Gates Located on Dyke Road" received funding from CZM's coastal resilience grant program in 2017 to evaluate modifications to the culvert and tide gate structure on Dyke Road under existing and future sea level rise conditions to address flooding issues and enhance ecological resources by improving tidal flow and flood storage capacity within the Green Harbor River estuary. USACE, NOAA, CZM correspondence in May 2021 indicates special conditions of the pursuant permit have not been met.

General Comments: Site is located directly off of Town pier Road and easily accessible. Note that Jason Burtner can provide permitting drawings and other relevant files and site information to further flesh out attributes. Permitted together with Marshfield 02 tide gates.
Operation Plan: No
Operation Comments: Self-regulating tide gate installed to enable expanded upstream tidal exchange will still providing flood protection.
Gate Comments: There were two tide gates installed at this location. A metal self-regulating tide (SRT) gate was installed to the west (Marshfield-01A) and a metal flap gate was installed to the east (Marshfield-01B). The self-regulating tide gate was in fair condition and was inoperable; the bottom float which allows the tide gate to open was missing. As a result, it appeared that the gate was currently operating as a flap gate and limiting upstream tidal exchange. A hand operated winch and strap had been installed to operate the SRT and the strap was weathered. Additionally, the SRT’s breather was clogged with debris and some leakage was observed around the flange connection to the headwall. The metal flap gate appeared to be in good condition and operable.

Elevation Comments: See "General Comments". Invert elevation and extent of downstream tidal influence can be located on permitted plans to be uploaded. Staining was not apparent on the upstream headwall (i.e., it was higher), so extent of upstream tidal influence could not be assessed.
External Data Comments: US ACOE NAE-2004-3126 Green Harbor Tide Gates Permit Application 10.2.2002 US ACOE NAE-2004-3126 Green Harbor Tide Gates Permit 12.3.2004 US ACOE NAE-2004-3126 Green Harbor Tide Gates Operation and Maintenance Plan 12.3.2004 Nekton, Inc. Green Harbor Tide Gate Report 8.10.2003 (Other)