Vertical Constraints One bridge crosses the harbor channel at the city of Savannah. It was recently completed, opening to vehicular traffic in March of 1991. The bridge is four-lane, cable-stayed high level bridge, connecting with limited-access roadways in the immediate vicinity of downtown Savannah. The new bridge will not be a restriction to any size ship anticipated to use the Port of Savannah in the foreseeable future. The cable-stayed bridge provides a minimum vertical navigation clearance of 186 feet at mean high water over the Savannah River navigation channel, and has an 1100-foot main span, providing an increased horizontal clearance for the 500-foot wide authorized channel currently under construction. In late July 1991, a "new build/class" container vessel with a vertical clearance of 171 feet passed beneath the bridge. HARBOR MAINTENANCE In April 1982, the U.S. Army Corps of Engineers, Savannah District, prepared the "Savannah Harbor Maintenance Disposal Management Study, Operation and Maintenance Report", which is currently being revised. A more recent report on the "Waterways Dredged Material Containment Areas Study" was completed by the Georgia Department of Transportation in June 1989. The following discussion of harbor maintenance at Savannah Harbor draws from these two documents. Responsibility for Maintenance Maintenance of Savannah Harpor is a joint responsibility of the Commissioners of Chatham County, Georgia, the local assurer for the project; the Georgia Department of Transportation (DOT); and the U.S. Army Corps of Engineers, Savannah District. The Corps of Engineers is responsible for the removal of shoaled material in the harbor, jetties, and bar channels, turning basins, and sediment basin, which are necessary to maintain authorized project dimensions. The local assurer is responsible for the acquisition of lands, easements, and rights-of-way for disposal areas, and the provision and maintenance of retaining structures, dikes, weirs, and outfalls. Through the DOT, the State of Georgia provides financial assistance to Chatham County and direct assistance in the form of equipment, manpower, and engineering. In addition, DOT performs the contracting for construction of major projects. Authorized Project The Corps of Engineers conducts maintenance activities in the harbor under the authority of the River and Harbor Act of 1965, Public Law 89-298, passed by Congress on 27 October 1965. The Corps of Engineers is authorized to maintain the Savannah Harbor Project, consisting of a bar channel across the ocean bar, a jetties channel to the harbor entrance, a harbor channel from the harbor entrance upstream to river mile 21.3, six turning basins, and the sediment control works. Advance maintenance is performed in the existing navigation channel under authority delegated to the Savannah District Engineer and the South Atlantic Division Engineer. Existing Disposal Areas Figure 4 shows the seven existing diked upland disposal areas that, along with ocean disposal, are used to contain dredged maintenance material from Savannah Harbor. These areas were the subject of the Savannah Harbor Maintenance Disposal Management Study, which investigated the status of the sites and possible measures to increase their useful life. The Maintenance Disposal Management Study is discussed later in this report in the section on "Long Term Disposal of Dredged Maintenance Material." Location. Maintenance of the inland portion of Savannah Harbor currently requires the annual dredging and disposal of between 7 and 8 million cubic yards of material. The removal of this material, which is primarily sand and silt, allows the Corps of Engineers to maintain the shipping channel and turning basins at depths ranging from 30 to 40 feet mlw. Dredged material from the jetties channel and bar channel is deposited in an offshore disposal area approved by the Environmental Protection Agency. For maintenance purposes, the harbor channel is divided into three reaches. Table 6 shows the percentage of total sediment removal from the three harbor reaches and the sediment basin. This distribution is with the tide gate structure in operation. There are seven diked disposal areas located along the 20-mile reach of the harbor. Sites 1N, 1S, and 2A are located on islands in the State of Georgia, while the remaining sites are on islands and on the mainland in the State of South Carolina. The dredged material is deposited in these disposal areas as shown in Table 7. Table 8 shows pertinent information for the seven major disposal sites, including subdivisions of Areas 12, 13, and 14. A total of 4,985 acres is diked and available for use. The largest area is 12A with 1,123 acres adjacent to the sediment basin, and the smallest is Area 1N with 130 acres in the upper harbor. Areas 18 and 14A are undiked and are not currently used for disposal of dredged material. * Varies - Area 1N is used as a source of borrow material by the Source: Georgia Department of Transportation, Waterways Dredged Ownership and Easements. Much of the disposal area property is owned by governmental agencies, including the U.S. Fish and Wildlife Service, Georgia Department of Transportation (DOT), Chatham County Commission, and the Savannah Economic Development Authority. Most of the areas have perpetual dredged material disposal easements granted to the U.S. Army Corps of Engineers, which were obtained by Federal condemnation. The Fish and Wildlife Service has granted easements to the Corps of Engineers for works in Areas 1N, 15, 2A, and Jones/Oysterbed Island. Tables 9 and 12 summarize the ownership and type of easement based on information contained in the "Waterways Dredged Material Containment Areas Study", published by DOT in June 1989. Figures 5 and 6 show the location of the properties described in Tables 9 and 10. |