Gulf Intracoastal Waterway West Closure Complex

The Gulf Intracoastal Waterway West Closure Complex is a part of the New Orleans Drainage System; it consists of a navigable floodgate, a pumping station, floodwalls, sluice gates, foreshore protection, and an earthen levee. The complex was designed to reduce risk for residences and businesses in the project area from a storm surge associated with a tropical event with an intensity that has a 1 percent chance of occurring in any given year. This project was operated for the first time on August 29, 2012 in response to Hurricane Isaac.

Location
The project is located approximately one half mile south of the confluence of the Harvey and Algiers canals on the Gulf Intracoastal Waterway. The location is next to the to the Environmental Protection Agency’s Bayou aux Carpes Clean Water Act (CWA) 404(c) area, a wetland area of national significance.

Features
The GIWW West Closure Complex consists of a navigable floodgate, a pumping station, floodwalls, sluice gates, foreshore protection, and an earthen levee. The project also required the dredging of Algiers Canal, as well as the realignment of Bayou Road. Project challenges consist of maintaining navigation traffic on the GIWW (a Federal navigation channel with heavy commercial barge traffic) and the location of the complex in relationship to the Environmental Protection Agency’s Bayou aux Carpes Clean Water Act (CWA) 404(c) area, a wetland area of national significance.


 * A 225 ft navigable floodgate
 * When the gate is closed during a storm event, the 19,426 cubic feet per second (cfs) (551 m³/s) 11 bay pump station is required to evacuate the rainwater that is pumped into the Harvey and Algiers canals by 9 other pump stations along the canals.
 * The pump station complex, which is the largest of its type in the world, consists of 11 each 5444 horsepower Caterpillar engines.
 * To minimize environmental impacts to the Bayou aux Carpes 404(c) area, the floodwall will be constructed on the eastern edge of the wetlands, within 100 ft from the western bank of the GIWW for a 4,216 ft. The floodwall starts north of the pump station and gate structure with a water control structure across the Old Estelle Outfall Canal, and extends southward along the eastern edge of the Bayou aux Carpes 404(c) area. A canal closure wall connects the floodwall and navigable floodgate on the GIWW. A protective berm will be constructed on the channel side of the floodwall to protect it from barge impacts. Foreshore protection will be constructed along the GIWW, adjacent to, but not within, the Bayou aux Carpes CWA Section 404(c) area and along the new earthen levee to prevent impacts due to discharges from the pump station.
 * A new earthen levee has been be constructed east of the closure complex and ties into the existing levees.
 * Bayou Road has been realigned to provide access around the new levee on the protected side.
 * Dredging of the Algiers Canal has been competed from the Belle Chasse Tunnel south to the confluence of the Harvey and Algiers canals, a distance of approximately 4.8 mi. Approximately 700,000 cubic yards of material has been excavated from the Algiers Canal. Consequently, the dredged material was used beneficially in a marsh restoration project in the Jean Lafitte National Historical Park and Preserve (JLNHPP) or placed in borrow sites near Walker Road.

The GIWW West Closure Complex will reduce the risk to a large area of the west bank by removing over 25 mi of levees, floodwalls, a floodgate, and pumping stations along the Harvey and Algiers canals from the direct impacts of storm surge. The risk reduction surge barrier will be completed by the 2011 Atlantic hurricane season with reduced pumping capacity. All project construction is scheduled for completion in late 2012.

Status
Final approval of the Individual Environmental Report #12 for the GIWW West Closure Complex was completed 18 February 2009. On 28 May 09, the Environmental Protection Agency granted the US Army Corps of Engineers permission to modify the Bayou aux Carpes 1985 determination to allow for construction on the western-most boundary of the wetland area. The Corps held a joint public hearing with the EPA to address all questions and concerns regarding the request for modification of the Bayou Aux Carpes 404(c) area.

On 17 April 2009, the Corps awarded the base portion of the Early Contractor Involvement (ECI) contract to Gulf Intracoastal Constructors for pile load testing and pre-construction services. The ECI contracting method (also known as Construction Management at Risk in private industry) allows the construction contractor to work hand-in-hand with the Corps and the design team on plan revisions and construction sequencing that will improve the constructability and cost-savings of the project. Several more construction options have been awarded since April. Construction of this risk reduction features began 6 August 2009.

On 6 & 10 March 2011, installation of the 653 ton ea. sector gates were completed.