The South Carolina Ports Authority has submitted an application to the Department of the Army and the S.C. Department of Health and Environmental Control for a permit to dredge the Cooper River at a location adjacent to the Hugh K. Leatherman (HLT) in Charleston.
The proposed work consists of conducting new work and maintenance dredging to improve navigation access to HLT and extending the existing rock revetment to protect the shoreline and the base of the pile supported wharf, the U.S. Army Corps of Engineers, Charleston District, said in its announcement.
In detail, the applicant has proposed to dredge approximately 2.5 million cubic yards of new work material in order to deepen the -49-foot Mean Low Water (MLW) access channel to the same depth as the adjacent Charleston Harbor Post-45 navigation channel (-52 feet Mean Lower Low Water (MLLW) + 2 feet of advanced maintenance + 2 feet of allowable overdepth), and to deepen the berth to a depth of -52 feet MLLW +2 feet of advanced maintenance + 2 feet extreme low tidal variation + 2 feet of allowable overdepth.
The proposed work includes dredging an approximately 50-foot wide by 10-foot deep area and backfilling this area with a 10-foot deep layer of bedding and armor stone (approximately 130,000 cubic yards).
The construction and operation of HLT and the associated -49 foot MLW berth and access channel was evaluated in the Final Environmental Impact Statement, Proposed Marine Container Terminal, at the Charleston Naval Complex, North Charleston, South Carolina dated December 2006, and was authorized by Department of the Army (DA) permit SAC 2003-1T-016 in April 2007.
The first phase of the marine container terminal is currently under construction and is scheduled to open in 2020.
Future deepening of the berth and the access channel at HLT (and the existing berths at Wando Welch Terminal and North Charleston Terminal) was considered a cumulative impact in the Charleston Harbor Post-45 Final Integrated Feasibility Report and Final Environmental Impact Statement dated June 2015.