Salisbury-01A

Salisbury, Town Creek

42.830882, -70.866953

Dimensions: 4ft diameter, 5ft height
Condition: Good
Comments: Each tide gate was installed in a concrete box culvert with approximate dimensions of 4' by 5'. Both culverts were installed in conjunction with the tide gates in 2013 and appeared to be in good condition with no signs of deterioration.

Comprehensive field assessment conducted in 2024

Upstream Invasive Species: Yes
Downstream Invasive Species: Yes
Invasive Species Notes: Near mono culture of phragmites on both up and downstream side. Narrow bands of low marsh on upstream side.
Additional Comments (2024): Tide gate is actively managed. Remote operation does not work so gated are manually closed by DPW. Gates are typically left open at 12 in. Opening appears to be too small and is ponding flow on both sides of tide gate. Restriction of incoming tide ponds flow on downstream side due to lost storage. Small bands of low marsh exist on upstream side but improved drainage may help restore marsh community. Openings are 4x5 ft boxes only left at 12 so plenty of room for improvement without redesign. Fixing telemetry data may increase operation adjustments as well. Coordination with Hudson’s boat yard will be needed to not flood yard and is limiting factor in management.

Legacy data from previous surveys and documentation

Invasive Species: Yes
Restoration Status: Unknown
Invasive Comments: Upstream area was predominately comprised of phragmites.
Restoration Comments: Large upstream area has strong restoration potential if a balance can be struck between upstream flood protection of Route 1 businesses.

General Comments: Site is located on the Old Eastern Marsh Trail bike path to the west of route 1. The site is accessible by parking at the Enpro services parking lot and walking to the north for approximately 1/4 mile.
Operation Plan: Yes
Operation Comments: The primary purpose of the tide gates was flood protection of upstream areas (e.g., Route 1 and associated businesses). There were water level sensors installed on posts with solar panels on the upstream and downstream portion of the berm. These monitoring stations were potentially logging life data via cellular modems and transmitting to the Town DPW to alert staff to close the tide gates in advance of a storm or when water levels reach a certain threshold.
Gate Comments: There were two identical tide gates at the site. Salisbury-01A was located to the north and Salisbury-01B was located to the south on the downstream side of the bike path berm. Both tide gates were metal combination sluice / flap gates (i.e., they could adjusted upwards or downward via a manual gear to enable full tidal flow or no tidal flow). Both tide gates appeared to be in good condition. The valve stem for each tide gate was visible via a clear marked PVC pipe, thus enabling a user to know the exact level of adjustment. At the time of the site visit, the tide gates were adjusted open 1’ and had a range of up to 3’.

Elevation Comments: Staining could not be evaluated on the upstream or downstream ends of the culverts – a gently sloping riprap embankment was present, so measuredowns and corresponding LiDAR spot elevations would not be able to be correlated. There were staff gauges installed on the upstream and downstream sides of the berm (datum and measurement units unknown). It appeared that the mean high water mark on the upstream side was approximately “12” and “20” on the downstream side. The invert of the tide gates was obtainable. The below lists the measuredown taken from the tide gate headwall to the invert corresponding top of headwall LiDAR elevation (NAVD88 datum). 1) TG Inv (D/S): Top of HW El (D/S) = 4.19’; Inv Measuredown = 7.00’; TG Inv = 7.74’ – 12.2 = -2.81’
External Data Comments: US ACOE CENAE-R-2011-1402 Permit with Draft Operation and Maintenance Plan (signed) 5.10.2012 US ACOE CENAE-R-2011-1402 Modification 10.31.2014 Chapter 91 License W12-3660 Application 8.6.2012 Chapter 91 License W12-3660 License No. 13350 10.3.2012 MA DEP 401 WQC X250782 7.16.2012 (Permits) MA DEP 401 WQC X250782 Amendment 1 NAE-2012-1402 X251806 5.6.2014 (Permits) MA BUAR Comment Letter 12.29.2011 (Other)