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Lower Colorado Region
Boulder City, Nev.
Media Contact:
Robert Walsh
702.293.8421

Released On: January 27, 2007

Quagga Mussels Found on Hoover Dam Intake Tower and in River Below Dam
Bureau of Reclamation divers inspecting an intake tower upstream of Hoover Dam on the Nevada side of Lake Mead and a spillway outlet structure on the Nevada side of the Colorado River about one-quarter mile downstream of the dam earlier this week have discovered live quagga mussels on these structures.

The mussels were located sporadically on the steel grates of the intake tower, between about 30 and 85 feet deep, and on rocks in the bottom of the river channel near the spillway outlet. There are four intake towers at Hoover Dam; they deliver water from Lake Mead to the generating units in the dam's power plant.

The dam's water delivery and power generating functions have not been affected by the mussels.

To date, no mussels have been found inside the dam in the hydroelectric generating equipment. The water delivery systems and water supply pipes inside the dam and power plant are continuously monitored with instrumentation, and some of the piping systems are visually inspected each year. Several thousand feet of piping - some of it as large as 30 feet in diameter - are monitored and inspected.

In coming weeks, Reclamation divers will inspect an intake tower on the Arizona side of the dam, and also conduct inspections at Davis and Parker Dams.

The information gathered during these inspections will provide baseline data about the current mussel population at the dams. Additional inspections of the dams will be conducted as part of Reclamation's routine maintenance activities to determine if the mussel population is increasing, if so where, at what rate, etc. The information from these inspections will be made available to other hydroelectric power plant operators, water and power user groups, researchers, and any other interested parties.

In addition, Reclamation is researching how other hydroelectric power plants have been affected by this mussel, and what types of maintenance programs they have implemented to successfully address infestations. Initial research indicates the mussels primarily create maintenance problems that must be managed to ensure continued uninterrupted water flow.

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Reclamation is the largest wholesale water supplier and the second largest producer of hydroelectric power in the United States, with operations and facilities in the 17 Western States. Its facilities also provide substantial flood control, recreation, and fish and wildlife benefits. Visit our website at www.usbr.gov.