COASTAL WETLANDS PLANNING, PROTECTION AND RESTORATION ACT

PROJECT STATUS REPORT as of 20-Dec-2024

Benneys Bay Diversion DEAUTHORIZED

PROJECT DATA

Point of Contact:

DEPT. OF THE ARMY
CORPS OF ENGINEERS

COASTAL WETLANDS PLANNING, PROTECTION AND RESTORATION ACT

PROJECT STATUS REPORT as of 20-Dec-2024

Benneys Bay Diversion DEAUTHORIZED

PROJECT LOCATION:

The project is located in Region 2, Mississippi River birdsfoot delta, Plaquemines Parish. The diversion inlet would be located on the east bank of the Mississippi River at Mile 7.5 Above Head of Passes (AHP), and would divert sediments into Benny's Bay, on the east side of the river.

PROJECT DESCRIPTION:

The project area lost over 15,000 acres of emergent wetlands since 1932, due mainly to subsidence and sediment deprivation. A 50,000 cfs uncontrolled sediment diversion near mile 7.5 AHP in the Mississippi River is proposed to restore wetlands in the area. This site was chosen because it is at the trailing end of a sandbar where sediment capture would be maximized. The conveyance channel would be approximately 670 feet wide and 47 feet deep and slope up to the existing bottom depth of the receiving area (-2 ft). Some dredged material would be placed on either side of the cut for stabilization and the remainder would be placed in shallow open water to create about 100 acres of marsh. To aid in delta growth, bifurcation channels would be dredged about every five years. Two facilities would require relocation: a 16-inch crude oil pipeline owned by Shell and power lines owned by Entergy and Bell South. In addition, approximately 1,100 feet of foreshore dike would need to be removed. This diversion would cause induced dredging downstream in the Mississippi River. Outfall management would be done with sediment retention devices. These would be ten 3-foot high earthen dikes with 1 on 2 side slopes, a 4-foot crown and 27,400 feet in length. They would have low-level weirs at 1,000-foot intervals to allow natural water level fluctuations and fisheries access. They would be built from the receiving area with either a barge-mounted or marsh buggy dragline. The first dikes would be placed fairly near the river. After the area fills, a second set of dikes would be built further out.

PROJECT STATUS: (Project Status Last Updated: 25-Mar-2006 )

This project was approved for Phase I design on PPL9 in January 1999. The project work plan for Phase I was submitted to the P&E Subcommittee in May 2001. Right of Entry to perform surveys and geotechnical borings was received in August 2001. Site surveys were performed in October 2001 and geotechnical borings were collected in June 2002. A 30% design review was completed in September 2002. At the design review meeting agreement was reached to proceed further with the proposed design except for one feature (SREDs - sediment retention enhancement devices) which were removed at the request of the local sponsor. A Final Design Report has been developed and is being reviewed by the LDNR. A revised WVA and design cost estimate are in preparation for review at the CWPPRA working groups. The project is scheduled to complete all design work in 2006 in preparation for a Phase II funding request.

FUND STATUS:

The current project estimate is $978,100 , which includes $974,114 for construction first costs, and $3,986 and $0 for 20 years of monitoring and operations and maintenance, respectively.