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Best Civil Works/Infrastructure Project: Glendale Water Supply Improvement
Hampered by a river diversion that impeded flows, the Glendale Water Treatment Plant's water supply was modernized to ensure adequate and consistent water service to customers in Reno/Sparks, Nev.
Because the Truckee River is a highly regulated body of water and a major recreational site, careful pre-planning, testing, design and construction were required. To support and balance the needs of a long list of stakeholders, a professional facilitator maintained thorough records of all issues and concerns and how they were resolved. Through ongoing regular meetings, the team weighed issues such as flood control, sediment transport, recreational safety and boat and fish passage to optimize the design and construction methods.
Designers modeled flows and performed physical testing, building a 60-ft by 20-ft scale replica of the diversion to critically evaluate velocities and hydraulic properties.
Construction crews temporarily diverted the 6-ft-deep by 150-ft-wide river while minimizing impacts on river water quality and native habitats and continuing to serve the plant with 28 million gallons of water per day. A new intake structure and weir were built, and 500 truckloads of rip-rap and boulders were placed to form the roughened channel to provide a passageway for fish and recreational users. A deeper center channel with a chute and pool arrangement to gain elevation more accurately simulates natural fish habitat.
As the project neared completion, the site was overwhelmed by a breach of the temporary bypass channel due to record-setting rainfall that caused a fourfold increase in river flows. "The project was planned for fall and early winter, when the river is historically at its lowest flows," says Rob Bagley, general superintendent with Q&D Construction, Sparks, Nev. "A flood was completely out of the norm to happen at that time of the year." But the team completed the construction on time and for less than the engineers' original estimate.
In addition to improved flood control and passage for boats and fish, the new structure has increased the plant's treatment capacity by 30%.
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