A.01 SOW _nav 4-20-2021.pdf

Statement of Work FY21 Savannah Inner Harbor Maintenance Dredging

The Savannah Inner Harbor Contract provides construction services, including furnishing personnel, transportation, mobilization and demobilization, equipment and materials required in connection with maintenance dredging. This contract is traditionally performed with a hydraulic cutterhead dredge and the duration is expected to be one year from Notice to Proceed. Up to four million cubic yards of maintenance material is expected to be removed from the inner harbor.

The work is located in the deep draft Savannah Harbor navigation project in Georgia.

The Savannah Harbor project is located on the border of Georgia and South Carolina (SC) in Chatham County. The Savannah Inner Harbor channel’s existing project depth is -42.0 ft. MLLW and 500 ft. wide to the upper end of Kings Island Turning Basin: -36.0

ft. MLLW and 400 ft. wide to the upper end of Argyle Island Turning Basin; and -30.0 ft.

MLLW and 200 ft. wide to the upper limit of the project. Refer to Table 1 for the Savannah Inner Harbor stationing and depths which include current depths and post- SHEP depths.

The Savannah Inner Harbor channel is undergoing a deepening project (SHEP) from stations 0+000 to 103+000 and Kings Island Turning Basin. The project also includes the construction of channel wideners which will also be required dredging for this project. The deepening is scheduled to be completed in December 2021.

Savannah Harbor’s Kings Island Turning Basin (KITB) is the primary turning basin for large civilian and military ships, lying adjacent to the Georgia Ports Authority docks.

KITB requires dredging twice a year to allow the loaded ships to freely turn when using the port. Approximately 1.6 million cubic yards of maintenance material is removed from the KITB annually.

Current project and advance maintenance depths authorized for Savannah Inner Harbor are below. The Inner Harbor is expected to undergo a deepening which will alter the project depth by -5 ft. MLLW. Deepening of portions of the Savannah Inner Harbor may be completed during this contract and required maintenance dredging depth may be adjusted accordingly.

Other contractor(s) may be working for the Savannah District on the Savannah Harbor, to include confined upland dredged material containment areas and designated staging areas. If such work occurs, the contractors shall coordinate activities under the direction of the Contracting Officer.

All material dredged from the Savannah Inner Harbor shall be placed in upland confined disposal areas adjacent to the Savannah River, with DMCA-12A receiving the majority of the maintenance material. Savannah confined upland disposal areas DMCAs 12A, 13A, 13B and Jones Oysterbed Island are owned by local sponsor Georgia Department of Transportation. Disposal areas DMCAs 14A and 14B are owned by the Joint Project Office of the Georgia and South Carolina Port Authorities and portions of DMCAs 2A

Formatted: Font color: Auto and Jones/Oysterbed are owned by the Georgia Department of Transportation and the US Fish and Wildlife Service, and DMCA 1N is owned entirely by the US Fish and Wildlife Service. The Federal Government holds existing easements on all confined upland disposal areas in the Savannah Harbor except DMCA 1N which has a Memorandum of Understanding.

Environmental windows limit the timing of dredging in the Savannah Inner Harbor. The environmental windows in Savannah include a Striped Bass spawning window (2 weeks within the 1 April through 15 May timeframe) which limits the amount and timing of dredging above station 63+250 (River Mile 12), and a dissolved oxygen window (approximately July 1 through September 30). An environmental window also exists for sturgeon between 1 May and 30 October annually, no dredging is allowed above station 105+500, cutterhead dredging below 105+500 during those months will monitored for sturgeon take.

Certain reaches of O&M sediments may contain cadmium (Cd) in levels significant enough to harm foraging avian species in the DMCAs. Therefore, O&M sediments in those reaches will be tested by the Government prior to dredging. If Cd is found in those sediments equal to or greater than 4 mg/kg, then options will be exercised that include disposal of the sediments in specific DMCAs under special handling conditions.

Obstructions are objects or materials in the channel/dredging prism template and side slopes which are unknown to exist when encountered by the dredge or identified by pre and post hydrographic surveys, and monthly condition surveys. Obstructions are objects which cannot be removed by a hydraulic pipeline dredge. The Contractor may encounter obstructions during dredging operations and must remove the objects or materials to provide the required section as shown on the cross-section plates. If the Contractor elects to perform maintenance dredging with a hydraulic cutterhead dredge, the dredge must act as a probe for obstructions. If an obstruction is found in the dredging prism options will be exercised that include diving and obstruction removal to remove the obstacle from the dredge prism. The object removed will become the property of the Contractor.

The depths indicated below also have an optional -2.0’ of allowable pay overdepth added to the required depth if the contractor decides to excavate this additional material.

A limitation on disturbance of materials is in effect for the Savannah Inner Harbor Channel. The no disturbance depths are as follows: -54 ft mllw between Stations 0+000 and 24+000, which is -3.0 ft below the allowable overdepth of -51.0 ft mllw. The disturbance depth is limited to -56.0 ft mllw between stations 24+000 and 35+000, which is -3.0 ft below the allowable overdepth of -53.0 ft mllw. The disturbance depth is limited to -58.0 ft mllw between stations 35+000 and 37+000, which is -3.0 ft below the allowable overdepth of -55.0 ft mllw. The disturbance depth is limited to -56.0 ft mllw between stations 37+000 and 70+000, which is -3.0 ft below the allowable overdepth of -53.0 ft mllw.-52 feet MLLW from Station 102+000 to Station 103+000 which is 3 feet

Formatted: Font color: Auto below the allowable overdepth elevation. Disturbance depth is limited to -54 feet (ft) MLLW throughout the rest of the channel and -60 ft MLLW in the KITB and transition (to Station 102+000). Disturbance depth is defined as the lowest elevation the cutterhead reaches to achieve grade and does not apply to spuds and anchors.

If the Government determines that the indicated disturbance depth has been exceeded, cease dredging operations for a maximum of 48 hours and consult with the CO to prevent future disturbances and to determine remediation to the affected areas. The Government will not compensate the Contractor for delays and associated expenses and costs incurred by the disturbance of materials below the defined limits.

Table 1. Savannah Inner Harbor Advanced Maintenance Locations and Depths

Stations Current Project Depth

Advanced Maintenance

Current Required Depth

New Project Depth

Advanced Maintenance

New Required Depth

0+000 to 24+000 42’ 2’ 44’ 47’ 2’ 49’

24+000 to 33+000 47’ 4’ 51’

33+000 to 35+000 47’ 4’ 51’

35+000 to 37+000 47’ 6’ 53’

37+000 to 55+000 47’ 4’ 51’

55+000 to 70+000 42’ 4’ 46’ 47’ 4’ 51’

70+000 to 102+000 47’ 2’ 49’

102+000 to 103+000 47’ 0’ 47’

103+000 to 105+500 36’ 2’ 38’

105+500 to 112+500 30’ 2’ 32’

Oysterbed Island Turning Basin

30’ 2’ 32’

Fig Island Turning Basin

34’ 4’ 38’

Marsh Island Turning Basin

34’ 0’ 34’

Kings Island Turning Basin

42’ 8’ 50’ 47’ 8’ 55’

Argyle Island Turning Basin

30’ 0’ 30’

Port Wentworth Turning Basin

30’ 0 30’