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Atchafalaya River & Bayous Chene, Boeuf, and Black, LA Dredged Material Management Plan (DMMP) |
Official Project Name
Atchafalaya River & Bayous Chene, Boeuf, and Black, LA Dredged Material Management Plan (DMMP)
Location
The study area is located in south-central Louisiana in Assumption, St. Mary, and Terrebone Parishes Louisiana, in the vicinity of Morgan City, Louisiana. It includes the Atchafalaya River and adjacent areas south of Morgan City; Bayous Chene, Boeuf, and Black and adjacent areas between the Atchafalaya River and Amelia, Louisiana; and Atchafalaya Bay and the Gulf of Mexico, south of Morgan City.
Purpose
The purpose of the project is to develop a dredged material management plan for the disposal of dredged material from routine maintenance of the Atchafalaya River and Bayous Chene, Boeuf, and Black for the next 20 years.
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Status
A brainstorm session for the Atchafalaya River and Bayous Chene, Boeuf, and Black Dredged Material Mangement Plan was held on August 17, 2005 at the U.S. Army Corps of Engineers, New Orlenas District, Room 251, 7400 Leake Ave, New Orleans, LA 70118. Since that time, the DMMP has been ongoing in concert with a channel deepening feasibility study for the same project area. Many of the tasks performed as part of the DMMP were applicable to the feasibility study and vice versa. Some of the tasks performed to date include:
Completed sedimentation modeling in Bayous, Bay, and Bar channel.
Completed salinity modeling Dec 05
Awarded contract for Wetland Value Assessment and other related Environmental activities.
Completed Final Beneficial Use Analysis November 06
Field work was completed in Oct 06 on Wetland Value Assessment Sampling
Completed HTRW and Cultural Resource Investigations
Finalization of Transportation Savings and Economic Market Analysis Report by URS
A public notice for incorporation of additional open water disposal in Crewboat Cut to be used for dredging in the Horseshoe Reach was sent out Nov 21, 2007. Many comments were received opposing this idea and requesting a public hearing, therefore a public hearing was held on Jan 22, 2008 in Morgan City. The transcripts of the public meeting along with written statements and other comments are attached at the Crewboat Cut button. After reviewing the decision on the way ahead for this proposal and any other proposed actions to address issues discussed at the hearing, a decision was made to eliminate the alternative of placing dredge material in Crewboat Cut and to focus on other options. Numerous comments were received suggesting that the navigation channel be moved to Crewboat Cut instead of Horseshoe Bend. The Corps is looking at this option and the studies that would be required to validate this proposal. The Corps will coordinate with the Port on the proposed actions and post updates this website.
The team met with resource agencies in Baton Rouge on May 14, 2007 to discuss the draft Wetland Value Assessment report. The draft report is being submitted for review by the Corps prior to coordinating with other agencies.
Ocean Disposal Site Designation work has been initiated with Galveston District.
EPA approved 5-year extension of Ocean Dredged Material Disposal Site (ODMDS) west of Bar Channel
A contract for water quality sampling was awarded Sep 24, 2007. Sampling should begin in the spring of 2008.
Site locations identified as potential CDF’s along with other potential dredge disposal areas have been mapped and submitted to MVN in order to initiate soil borings. A contract for soil borings at potential disposal sites is currently being negotiated by MVN. The results will be used in design activities relative to the cost and methods of disposal.
A meeting was held at LA Department of Natural Resources on Dec 4, 2007 to discuss dredge material placement options in the vicinity of Bayou Chene. Landowners are concerned about erosion of the marsh in this area. The purpose of the meeting was to get input from DNR regarding placement of dredge material along the channel to higher elevations in order to protect the existing marsh further from the channel.
Related Efforts
Feasibility Study: The Port was briefed on 13 November 07 that based on current benefits and costs; we would not be conducting further analysis on the feasibility study. The Port requested the Corps not taking any formal action to place the study in an inactive status until they have had time to re-look at the project economics. The DMMP will continue to utilize information developed as part of the feasibility study however.
Demonstration Channel Alignment Structure: A Value Engineering effort has been underway to evaluate measures to reduce dredging costs in the Bar Channel where fluid mud or “fluff” presents challenges to channel maintenance. After reviewing, modeling and testing several options, a rock structure was proposed to be placed on the east side of the Bar Channel to determine whether it would restrict the flow of fluff back into the channel following dredging. A test section was planned in conjunction with monitoring of current, sediment loads, etc. to determine whether the concept would be successful. A contract for the test section was awarded with the Notice to Proceed issued on 2 November 2007. The contractor commenced delivery of stone and placed permanent markers on the east side of the channel. The placement of stone along the channel was then temporarily suspended due to weather conditions, however stone delivery to a storage site has continued. Safety conditions will be monitored on a weekly basis.
DCAS monitoring is being performed by the U.S. Army Engineer Engineering Research and Development Center (ERDC) and Computational Hydraulics and Transport (CHT) for the Vicksburg District. ERDC field crew visited the study site on 15 and 17 January 2008 to retrieve and swap out current profiler/wave gauge units. A pump- profiler system was also brought online. Field activities were limited by weather conditions in March. Seventy-two water samples were processed at CHT for suspended material and salinity.
Benefit to the Community & Project Features
No Information at this time.
Authority
The DMMP is being prepared under the authority for the Atchafalaya River and Bayous Chene, Boeuf, and Black Project. The project was authorized by the River and Harbor Act of 1968 in accordance with House Document 155, 90th Congress, 1st Session. The navigation channel across Atchafalaya Bay was originally authorized by the River and Harbor Act of 1910, which provided for a 20- by 200-foot channel for a length of 15.75 miles from the -20-foot MLG contour in Atchafalaya Bay (which is approximately 4 miles beyond the mouth of the Atchafalaya River) to the -20 foot MLG contour in the Gulf of Mexico. The project was incorporated into the Atchafalaya River and Bayous Chene, Boeuf, and Black, Louisiana project in 1968.
Scope
The DMMP will determine the best plan, based on Federal criteria, for the continued maintenance of the Atchafalaya River and Bayous Chene, Boeuf, and Black project for the next 20 years. The end product of the study will be a dredged material management plan presented in a report including an environmental impact statement, an engineering appendix, a real estate supplement, and other supporting appendixes, as required.
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