Public Notice Project Plans
The applicant proposes to modify Department of the Army (DA) Permit SWG-2013-00922 at Oil Dock (OD) 14 by dredging an additional 140,000 cubic yards (CY) of material to deepen and extend dredging thresholds within the existing dredge prism to new depth of minus (-) 60 feet mean lower low water (MLLW). The proposed activity will align with the CCSC IH authorized -60 feet MLLW. The 10.6-acre dredge prism includes all side slopes that would be dredged at a 3 horizontal to 1 vertical grade (3:1). The additional 140,000 CY of material would be dredged to achieve seamless transition between the basin and adjacent ship channel
Deepening the OD 14 basin requires structural upgrades for site stability and integrity. The applicant proposes to install an approximate 1,450-foot-long toe wall immediately in front of the existing bulkhead by driving 230 steel sheet piles and 80 (60-inch) steel pipe piles utilizing impact and/or vibratory impact methods dependent on in-situ soil material of the project area. The toe wall installation will occupy a total area of 14,301-square-foot and result in 540 CY of fill below the high tide line (HTL). To reinforce the toe wall, approximately 2,400 CY of cementitious fill will be placed between the toe wall and existing bulkhead. The cementitious fill will be placed in sleeve casings to predetermined target elevations. Sleeve casings will be removed once fill placement activities are completed. All proposed work will be performed via barge within the CCSC IH utilizing marine construction equipment. A designated staging area within the existing upland dock area will be utilized, as necessary, for equipment and materials necessary for the project.
Dredged material would be placed within any of the following designated dredge material placement areas (DMPAs): DMPA No. 1, Herbie Maurer DMPA, Rincon B West, DMPA Cell A-South Shore, DMPA Cell B-South Shore, Causeway Bird Island BUS, Horseshoe BUS, Elbow Corridor BUS, DMPA No. 6-Tule Lake, DMPA No. 8-Suntide, La Quinta DMPA No. 13, La Quinta DMPA No. 14, and Good Hope DMPA, or within an existing authorized beneficial use site (BUS). The designated DMPAs are privately held and located in existing uplands.
Following completion of the proposed project, maintenance dredging would occur approximately biennially over a period of 10 years. Maintenance dredging activities would either be performed by mechanical or hydraulic dredging with material deposited into one or more of the listed DMPAs above or qualifying BUS.
The permittee received authorization on 5 December 2014 for Permit SWG-2013-00922, to dredge a 10.6-acre basin to a total depth of -54 feet MLLW. Hydraulically dredged and mechanically excavated material, comprising approximately 675,000 CY, was to be placed within the following dredge material placement areas (DMPAs): Suntide DMPA, DMPA No. 6, Southshore DMPA Cell C and/or Cell B. Side slopes of the proposed basin were constructed at a 2:1 or 3:1 slope. Authorization also included a 200-foot-long by 100-foot-wide ship dock, 1,365-foot-long linear sheet pile bulkhead with six 13-foot by 9-foot mooring dolphins, two 150-foot-long by 4-foot-wide ship dock catwalks, and two 15-foot-wide by 21-foot-long by 9-foot-high breasting dolphins or two 96-inch steel monopoles along each catwalk for ship stabilization. Approximately 1,420 CY of articulated concrete block mat and/or riprap revetment encompassing approximately 0.55 acre was authorized for shoreline stabilization. The permit was subsequently modified on 19 November 2019 adding two additional mooring dolphins, one breasting structure, installing an additional 300 linear feet of bulkhead, expanding the dredging slip from 950 feet to 1,140 feet, adding 10 years for maintenance dredging, and installing approximately 430 CY of revetment that would encompass 0.4 acres. The dredge material will be placed within previously identified DMPAs. Approximately 127,000 CY of material would result from the initial dredge event. The current authorization for maintenance dredging expires on 31 December 2029.