Gulf Intracoastal Waterway (GIWW) West Closure Complex Pump Station
Client: U.S. Army Corps. of Engineers, Rock Island – New Orleans Support Branch, New Orleans, Louisiana
The GIWW West Closure Complex is a major structure consisting of two sector gates of 75 feet and 225 feet in length. When these gates are closed due to a storm event, the storm surge is controlled, but the water behind the closure complex needs to be removed. Pump stations along the system provide that capability. Chester Engineers was tasked by the U.S. Army Corps of Engineers-Protection Restoration Office (USACE-PRO) to perform all professional services required for designing the world’s largest interior draining pump station ever built. Prior to Hurricane Katrina, the pump stations in New Orleans were not designed to operate during major storms, thus increasing the severity and duration of flooding. The West Closure Complex Pump Station was designed to withstand a Category 5 Hurricane.
The Interdisciplinary Approach
Chester Engineers assembled a team of seasoned designers and engineers in the process of planning and building a complex capable of housing a 20,000-cfs flower pot type pump station. This massive pump was designed to operate whenever the gates on the GIWW channel are closed in order to prevent the storm surge from flooding the protected area. The effort required producing a detailed engineering and design (E&D), preparation of a Design Documentation Report (DDR), preparation of plans and specifications (P&S) for a pile test, preparation of P&S for construction, and E&D support during advertisement. E&D consisted of incorporating the various design data, investigations and information developed in the Engineering Report into the P&S, performing detailed geotechnical analyses, preparing detailed quantity estimates and cost estimates, and providing the design documentation. The final P&S were used for the solicitation of bids, contract administration, construction, and inspection.
The Sustainable Result
This project provides 100-year protection to the area surrounding the GIWW channel. In addition to the P&S for the pump station, construction cost estimates using MCACES cost estimating software were provided to evaluate the RFPs for the construction contractor. The P&S also includes the design of cofferdams and dewatering systems necessary for the construction of the project since it will be built in-place surrounded by water. Post-Katrina federal legislation requires that all pump stations are outfitted to remain operable during and after future storm events with safe rooms strengthened to withstand hurricane force winds up to 250 MPH, wind-driven water, and loss of power. The structure housing the pump is in excess of 80 tall.
- Provided 100-year flood protection.
- Construction Cost Estimates.
- Plans and Specifications.
- Development of Design Documentation Report.