Built in 1831, London Bridge was falling down by 1962. To make way for a new and bigger bridge, London sold its famous bridge to Robert McCulloch of chain saw fame, who had it disassembled stone by stone and rebuilt in his newly created desert oasis: Lake Havasu City, Ariz. Today, the resort town is halfway through its 11-year, $450 million conversion from septic tanks to a citywide wastewater treatment system. Photo: William D. Palmer Jr.
Bullhead City relies on the Colorado River, seen here in the distance, for water and recreation. Photo: City of Bullhead City
SID1 and SID2 were contracted as design-bid-build. By the time SID3 was ready to bid, Arizona had approved alternative procurement methods and Bullhead City opted to use construction-manager-at-risk. This means the city hired the construction contractor during design but pays only for that portion of the project. Construction proposals were submitted as the design neared completion.
“If we didn't like it, we could have rejected it and the contractor would've been out of the picture,” says Agrawal. “That's the risk.” Luckily for Condie Construction of Springville, Utah, that didn't happen.
Meanwhile, in 2001 Lake Havasu City held a special election to approve borrowing $463 million to fund the Wastewater System Expansion Program. The referendum passed by a 3-to-1 margin. The debt will be paid back partially through a $2000 per-customer treatment capacity fee, which can be paid as a lump sum or financed over 10 years at 4% interest.
Most of the city's project is traditional design-bid-build. “Construction-manager-at-risk and design-build are great from a schedule standpoint, but can be more expensive,” says AMEC's Hassert. “So as long as we stay on schedule, the design-bid-build approach is probably better for the city.”
In the end, Lake Havasu City's entire wastewater treatment system will have been designed with the same criteria, resulting in a much more consistent system than would be possible in a city where the system evolved over many years.
“We're developing a system-wide hydraulic model using InfoWorks (developed by Wallingford Software),” says Hassert. “Each day we update the information on the system, and will end up with a comprehensive model. We can run different scenarios to see what would happen. We're excited about that because you don't often get the opportunity to do a hydraulic model this big. We'll train the city's technical staff at the end of the program to operate the model.”
Both Lake Havasu and Bullhead City are also updating their geographic information systems (GIS) to accommodate information on sewers, manholes, and pump stations.
“Our GIS program now has a full-time person,” says Bullhead City's Agrawal. “We started with the base map and incorporated everything into the GIS. At the end of the project we expect to have a full GIS layer of sewer lines so we can see each reach and have pipe materials, maintenance logs, and other attributes.”
The biggest prize, though, will be a modern wastewater infrastructure that has been planned to meet the current and future needs of these growing cities in the incredibly dry Arizona desert alongside the coveted Colorado River.
Each city has taken the path that works best for its situation and citizens, and that's what good public works is all about.
— Palmer is a construction writer based in Lyons, Colo., and former editor of PUBLIC WORKS.