Providing a Renewable Water Source to Residents
Phoenix, Arizona, experienced vast growth in the early 2000s. This growth was stressing the city's supply of potable water service. The City of Arizona's solution was to transport treated Central Arizona Project (CAP) surface water through eight miles of new 78-inch welded steel pipe within a corridor that will house a second 78-inch steel pipe and distribution lines to deliver water locally as development continues.
The water line planning and siting process started with master planning efforts by the City, leading to the hiring of Stanley Consultants in 2000 to assist in the route selection process. The City's proactive planning for the northern service areas determined a water line location over a year before actual design began. When the schedule dictated that design commence, the City chose Stanley Consultants to continue with its project efforts. In addition, the City chose the CMAR contract delivery method, which involves a contractor during the design phase to provide reviews and oversee design cost estimates as the design progresses. PCL Civil Constructors (PCL) was chosen for the task, and worked with Stanley Consultants throughout the project.
The project faced several challenges during its design and construction phase. It required extensive property acquisition which involved contacting, negotiating, and developing agreements with over a dozen federal, state, local, and private entities. The 2004 steel cost escalation was a serious project cost issue, but PCL and Stanley Consultants worked with the City to procure the steel pipe before costs peaked, saving over $2,000,000. This project marked the first time the City procured materials prior to delivery in this fashion.
In addition, environmental and cultural concerns were of paramount importance, as this project was built through almost eight miles of open desert. It provides an exemplary conservation model by using such tactics as locating, salvaging, and replanting all trees in their original location; keeping the top six inches of soil on-site and replacing it at the end of the job; and performing exhaustive cultural site investigations to ensure that any cultural artifacts were located and preserved prior to the start of heavy construction.
The project provides a renewable water resource to the current and future residents in an environmentally friendly manner. With the completion of the Lake Pleasant Water Transmission Line, the City now delivers up to 160 million gallons per day of potable water from the Lake Pleasant Water Treatment Plant to customers.