Dennis-01

Dennis, Unnamed channel

41.671382, -70.168454

Dimensions: 1.5ft diameter
Condition: Good
Comments: The corrugated metal circular culvert pipe appeared to be in good condition; no evidence of deformation or deterioration was observed. The culvert had recently been repaired on the downstream end with a pipe saddle where it was joined to the tide gate. The conveyance capacity of the upstream end of the culvert was partially occluded (i.e. the bottom 4") by live mussels in the channel. The wooden bulkhead on the upstream and downstream ends of the restriction appeared to have recently been repaired and/or replaced and was in good condition.

Legacy data from previous surveys and documentation

Invasive Species: Yes
Restoration Status: Not Applicable
Invasive Comments: The upstream impoundment was mainly comprised of high marsh and was fringed with phragmites. Upland vegetation was also observed directly to the south of the upstream culvert opening.
Restoration Comments: It appeared that the site would be a candidate for restoration; however, a potentially low lying barn and field was observed to the west of the restriction.

General Comments: The site was easily accessible and was located directly off of Wheatfield Lane. There was a small public parking area where Cove Road transitions to Wheatfield Lane; the site was located approx. 200 feet to the west of the parking area on Wheatfield Lane.
Operation Comments: It appeared that the intended operational purpose of the tide gate was for upstream flood protection.
Gate Comments: The circular metal flap gate was located on the downstream end of the culvert and appeared to be in good condition. It appeared that the tide gate had recently been repaired as evidence by new “shiny” bolts installed at the connection point. The tide gate appeared to be operable for its full range of motion. The tide gate was mounted slightly loosely to the mouth of the culvert, but did not appear to be at risk of falling off.

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) = 0.59’; Inv Measuredown = 8.5’; TG Inv = 0.59 - 8.5’ = -7.91’ 2) Upstream Tidal Influence: Top of headwall LiDAR Elevation = 0.59’; Staining Measuredown = 6.3’; U/S Tidal influence = 0.59 - 6.3 = -5.71’. 3) Downstream Tidal Influence: Top of headwall LiDAR elevation = 0.59’; Staining Measuredown = 5.25’; D/S Tidal Influence = .59’ – 5.25’ = -4.66’
Other Comments: An abundance of live mussels was observed within the channel at the upstream end of the culvert.