Hurricane Katrina and its aftermath damaged the water distribution system and the sewerage collection system in the City of New Orleans, creating health and safety issues for both the general public and emergency and recovery personnel working in the city. The efforts by the Sewerage and Water Board of New Orleans (S&WB) in restoring these systems has been critical in making the city safe and functional for the return of its citizens.
Since 1899, the S&WB has constructed and operated sewerage, water and drainage systems to serve the population some 465,000 residents of New Orleans. Operating from water and sewer user rates plus a drainage tax, the S&WB maintained an annual operating budget of over $100 million and a staff of 1,400.
The sewer system is comprised of approximately seven (7) million feet of gravity pipeline, along with 100 miles of force mains and 83 pump stations. The S&WB’s two sewage treatment plants (STPs) provide a combined treatment capacity of 244 million gallons per day (MGD). The S&WB is in the process of rehabilitating its sewer system, with a $630 million capital improvements program initiated in 1996 and scheduled for completion in 2010. MWH Americas, Inc. (MWH) provides program management services to the S&WB for its sewer system, overseeing the day-to-day activities required for the planning, design and construction of such a large undertaking, working closely with S&WB staff along the way.
The S&WB’s water distribution system is anchored by two water purification plants providing a total production capacity of 270 MGD to the over approximately nine (9) million feet of water mains. Five pump stations maintained by the S&WB distribute water from the two plants through water transmission and distribution mains ranging in size from four inches to 54 inches in diameter. Water is delivered to approximately 160,000 accounts including residents, businesses, and industries (including free water for public use) on the East and West Banks. The S&WB completed a comprehensive analysis of its aging water system in 2003 and was embarking on the process to initiate a long-range rehabilitation program.
The drainage system network, critical to the city because of the high amount of rainfall, the locale of the city surrounded by water bodies, and the fact that most of the city lies below sea level, is made some approximately 90 miles of open canals and 90 miles of subsurface canals which tie into the 24 major drainage pumping stations plus 15 underpass pumping stations around the city. Many of the subsurface canals are large enough to drive a bus through. The pumping stations, some of the largest in the world, are capable of pumping 30 billion gallons a day, enough to empty a lake 10 square miles by 13.5 feet deep every 24 hours. That flow rate (over 50,000 cubic feet per second) is more than that of the Ohio River, the nation's fifth largest river. In 1996, the S&WB initiated a massive construction program to add pump stations and enlarge drainage canals.
In its 106 years of operation, the S&WB has always maintained service to its customers, never losing the capability to provide drinking water or to remove the stormwater resulting from frequent and intense rainfalls. This was due not only to the capability of the S&WB staff and equipment, but also because the S&WB has generated its own power (61,000 kilowatt capacity) to many facilities since the early 1900’s, serving as a dependable backup subsurface power supply needed during high wind events, when local power suppliers fail. Impressively, huge drainage pumps in several of the world’s largest stations had effectively operated continuously for over a century.