2011-18417. Designation of an Ocean Dredged Material Disposal Site (ODMDS) in the Gulf of Mexico Off the Mouth of the Atchafalaya River, St. Mary Parish, LA

AGENCY:

Region 6, U.S. Environmental Protection Agency (EPA).

ACTION:

Notice of intent to prepare an Environmental Impact Statement (EIS) for the designation of an ODMDS in the Gulf of Mexico off the mouth of the Atchafalaya River, St. Mary Parish, LA.

SUMMARY:

The U.S. EPA, Region 6, in accordance with EPA's October 29, 1998 Notice of Policy and Procedures for Voluntary Preparation of National Environmental Policy Act (NEPA) Documents (63 FR 58045), and in cooperation with the U.S. Army Corps of Engineers, New Orleans District (the Corps), will prepare an EIS for the designation of an ODMDS in the Gulf of Mexico off the mouth of the Atchafalaya River, St. Mary Parish, Louisiana. An EIS is needed to provide the information necessary to designate an ODMDS. This Notice of Intent is issued Pursuant to Section 102(c) of the Marine Protection, Research and Sanctuaries Act of 1972 (MPRSA), and 40 CFR Part 228 (Criteria for the Management of Disposal Sites for Ocean Dumping).

DATES:

Comments or names for the project mailing list must be submitted in writing on or before August 22, 2011.

ADDRESSES:

Comments and/or names to be placed on the project mailing list should be sent to Jessica Franks, PhD, U. S. Environmental Protection Agency, Region 6, 1445 Ross Avenue, Dallas, Texas 75202-2733, telephone [phone] or e-mail: [e-mail] or Mr. John F. Fiorentino, U.S. Army Corps of Engineers, New Orleans District, Coastal Environmental Compliance Section, P.O. Box 60267, New Orleans, Louisiana 70160-0267, telephone [phone] or e-mail: [e-mail]. Additional information is available on the EPA Web site at: http://www.epa.gov/​region6/​water/​ecopro/​current_​action.html.

FOR FURTHER INFORMATION CONTACT:

Jessica Franks, PhD at [phone] or Mr. John Fiorentino at [phone].

SUPPLEMENTARY INFORMATION:

The Atchafalaya River and the Atchafalaya River Bar Channel (ARBC), located within the Federally-authorized and maintained Atchafalaya River and Bayous Chene, Boeuf, and Black, Louisiana project, provide vessel access to Morgan City, the Gulf Intracoastal Waterway (GIWW), and Bayous Chene, Boeuf, and Black from the Gulf of Mexico.

The ARBC is located in an area of heavy sedimentation. The bed load fraction of the sediment carried by the Atchafalaya River is deposited mainly in Atchafalaya Bay, resulting in delta accretion and progradation. The ARBC must receive periodic maintenance dredging to ensure safe navigation. Shoal material that could not be used beneficially has been placed (prior to 2002) at an existing MPRSA Section 102(c) ODMDS on the east side of the channel (the ODMDS-East). Concern has been expressed, and Corps studies have shown, that maintenance-dredged material—especially fluid mud, or “fluff”—placed on the east side of the ARBC (particularly at the ODMDS-East) is rapidly transported back into the navigation channel by prevailing littoral currents.

Since 2002, shoal material from the ARBC not suitable for beneficial use has been placed at a temporary (i.e., 5-year) ODMDS on the west side of the channel (the ODMDS-West) under the authority of MPRSA Section 103(b). In 2007, the Corps requested, and received from EPA Region 6, a 5-year extension for the continued use of the MPRSA Section 103(b) ODMDS-West. The approval for ODMDS-West use is scheduled to expire in August 2012, at which time it can no longer receive shoal material dredged from the ARBC unless it is re-designated as a MPRSA Section 102(c) site by EPA.

Following the MPRSA Section 103(b) designation of the ODMDS-West in 2002, the Corps Engineering Research and Development Center, performed monitoring studies to determine if placing maintenance-dredged material on the west side of the ARBC was more effective at reducing shoaling in the channel, thus, reducing the dredging frequency and costs. These studies found that while placing material on the west side of the ARBC did not eliminate shoaling, it did reduce the rate of shoal material runback into the channel, when compared to placing material on the east side of the channel. These findings were corroborated by the results of more recent studies on sediment transport in the project area performed on behalf of the Corps in 2006.

Need for Action: The Corps has requested the permanent, Section 102(c) designation of the ODMDS-West for the disposal of maintenance-dredged material from the ARBC when ocean disposal is the preferred disposal alternative. Placement of dredged material at the ODMDS-West would reduce the amount and rate of shoal material runback into the ARBC (i.e., reduce the shoaling rate), and thus, decrease the overall annual maintenance dredging effort needed for the ARBC while providing vessels with a longer period of safe navigation access between maintenance dredging events. An EIS is required to provide the necessary information to evaluate alternatives and designate the preferred ODMDS.

Alternatives: “No action” alternative. The no action alternative is defined as not designating an ocean disposal site. Additional alternatives under consideration include: Non-ocean (beneficial use) placement alternatives; Nearshore Area Disposal Site; Mid-shelf Area Disposal Site; and a Deepwater Area Disposal Site.

Scoping: Scoping will be accomplished by correspondence with affected Federal, State, and local agencies, and with anticipated interested parties. Appropriate Federal, State, and local entities will be invited to participate as a cooperating agency. Scoping will be initiated with the distribution of a scoping input request letter. If, based on the results of the comments received from the public scoping letter, there are identified significant interests and concerns expressed by the public, a public meeting may be needed.

Estimated Date of Release: The Draft EIS will be made available in December 2011.

Dated: July 8, 2011.

Al Armendariz,

Regional Administrator, Region 6.