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 and the location of the complex in relationship to the Environmental Protection Agency’s Bayou aux Carpes Clean Water Act 404 area, a wetland area of national significance.
A navigable floodgate
When the gate is closed during a storm event, the 19,426 cubic feet per second 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 5,444 horsepower Caterpillar engines.
To minimize environmental impacts to the Bayou aux Carpes 404 area, the floodwall will be constructed on the eastern edge of the wetlands, within from the western bank of the GIWW for a. 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 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 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.
The GIWW West Closure Complex will reduce the risk to a large area of the west bank by removing over of levees, floodwalls, a floodgate, and pumping stations along the Harvey and Algiers canals from the direct impacts of storm surge. The risk reductionsurge 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 on February 18, 2009. On May 28, 2009 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 area. On April 17, 2009, the Corps awarded the base portion of the Early Contractor Involvement contract to Gulf Intracoastal Constructors for pile load testing and pre-construction services. The ECI contracting method 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 risk reduction features began on 6 August 2009. On March 6 & 10, 2011, of the 653 ton ea. sector gates was completed. The Notice of Construction Complete was issued on April 8, 2014.
