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Draft Supplemental Environmental Assessment

The U.S. Army Corps of Engineers, Charleston District, working in cooperation with the South Carolina Ports Authority, has prepared a Draft Supplemental Environmental Assessment to evaluate potential beneficial use of dredged material projects that could be completed as part of the deepening and widening of Charleston Harbor. In 2014, USACE prepared an Integrated Feasibility Report and Environmental Impact Statement to evaluate potential impacts associated with the navigation improvements of Charleston Harbor. A Record of Decision was signed on January 12, 2016.

The Final IFR/EIS identified several items for further evaluation during the PED phase, one of those being a commitment to evaluate additional beneficial use alternatives for the new work dredged material. This supplemental EA and Finding of No Significant Impact addresses the evaluation of beneficial uses of dredged material for the new work material dredged from the channel. It also discusses the process and results of fine-tuning the locations of artificial reefs (previously evaluated during the Feasibility Phase in the Final IFR/EIS) near the entrance channel and identifying any existing approved reefs that could be supplemented with rock material from the channel.

Our evaluation led to proposing potential projects to augment eroding islands in the Charleston Harbor (Crab Bank, Shutes Folly, and a portion of Morris Island) with dredged material from the federal navigation channel. Our preliminary findings are that the proposed beneficial use projects would have no significant environmental impacts.

In accordance with provisions of the National Environmental Policy Act (NEPA), your review of this Draft EA and any comments are hereby solicited. We respectfully request your comments by October 31, 2016.

Appendix A- SCDNR Sediment Characterization of Crab Bank and Shutes Folly	Appendix G- Subsurface Investigation and Geotechnical Lab Results
Appendix B- SCDNR Benthic Characterization of Crab Bank and Shutes Folly	Appendix H- Side Scan Sonar Results for Additional Hardbottom Habitat Identification in Entrance Channel
Appendix C- Entrance Channel Hardbottom Surveys	Appendix I- Alternatives Spreadsheet with Interagency Input
Appendix D- Hardbottom Habitat Identification in Support of Artificial Reef Sites	Appendix J- 404b1 Guidelines
Appendix E- Cultural Resources Surveys in Support of Artificial Reef Sites	Appendix K- Coastal Modeling in Support of Beneficial Use Determination
Appendix F- Lower Harbor Sediment Sampling in Support of Beneficial Use Analysis	Appendix L- Habitat Equivalency Analysis Results

Charleston Harbor Post 45 Overview

The Charleston Harbor Post 45 Deepening Project looks to address transportation inefficiencies by deepening and widening Charleston Harbor to allow for growth in the shipping industry with the influx of Post-Panamax ships calling on port in the Lowcountry.

The Charleston District has been working with the project’s non-federal sponsor, the South Carolina Ports Authority, since 2010 to complete studies and move the project toward a 52 foot deep federal channel. The project is one of the first seven that the President’s Administration expedited under its “We Can't Wait” initiative for critical infrastructure projects.

Post 45 is currently in the Preconstruction Engineering and Design (PED) Phase of the U.S. Army Corps of Engineers’ Civil Works Process. During this phase, the Charleston District will refine and finalize the design of the recommended modifications to the federal channel for Charleston Harbor. Work completed during this phase will include ship simulations, beneficial use analysis, finalizing cost estimates, and development of plans and specifications. The PED phase of Post 45 officially began in December 2015 and will take approximately 18-24 months with an estimated cost of $4.6 million.

Prior to the PED Phase, the Charleston District completed the Reconnaissance Phase in 2010, which demonstrated that a large percentage of vessels calling on Charleston Harbor were tide-restricted, and the Feasibility Phase, which determined that deepening Charleston Harbor was both economically beneficial and environmentally acceptable to the nation. In 2015, the Final Integrated Feasibility Report and Environmental Impact Statement concluded that the recommended plan for the Charleston Harbor federal channel would be to deepen it to 52 feet, as well as widening areas for turning basins. After the Assistant Secretary for the Army for Civil Works signed the Record of Decision in January 2016, the project was passed to Congress for consideration for authorization.

Post 45 is the first study to be completed in the Corps entirely under their new SMART Planning process, as part of the Corps' Planning Modernization effort. This enabled the Charleston District to complete the Feasibility Phase in four years for approximately $11 million after an original estimate of seven years and $20 million. The Charleston District worked in close collaboration with state and federal partner agencies to complete the required studies and associated environmental reviews and permits. This has led Post 45 to become a model for future Civil Works projects around the Corps.

The Corps has maintained Charleston Harbor for more than 140 years and has dredged it every year during that time to ensure the channel is at the required federal project depth, spending approximately $10-15 million and removing 2-3 million cubic yards of maintenance material from the harbor floor each year. Construction to deepen the harbor to the now federally authorized 45 foot depth began in 1999 and was completed in 2004. Charleston Harbor has strategic national importance for military readiness, supporting Joint Base Charleston, and regionally the harbor deepening is of economic importance, allowing Post-Panamax vessels to call upon the harbor.

Post 45 Draft Supplemental Environmental Assessment Comments

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Address

Draft Supplemental Environmental Assessment Comment

Post 45 Plan

The Charleston Harbor Post 45 Project has recommends deepening the harbor to 52 feet and widening associated channels and turning basins. The recommended plan will cost approximately $521 million.

Navigation Improvement #1

Deepen the existing entrance channel from a project depth of 47 feet to 54 feet mean low level water and extend it approximately three miles seaward from the existing location to a depth contour of 54 feet.

Navigation Improvement #2

Deepen the inner harbor from an existing project depth of 45 feet to 52 feet from the Entrance Channel to the confluence of the Wando and Cooper Rivers, about two miles up the Wando River to the Wando Welch container facility and about three miles up to the Cooper River to the New Navy Base Terminal, and to a project depth of 48 feet over the five mile reach leading from the New Navy Base Terminal to the North Charleston container facility.