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passageway is designed to withstand expected high flows during heavy runoff years. Figure 1 presents an artist rendition of the fish passage while Figure 2 presents additional details. A physical model of the dam with the proposed passage improvements was developed and tested at Reclamation's laboratory in Denver, Colorado. Through a series of tests and modifications under streamflows between 740 and 10,000 cfs, optimal placement and configuration of the rocks was determined. The pools would provide resting areas for migrating fish and the riffles would be designed to accommodate the swimming speeds of the fish. During low streamflows, a discharge of about 100 cfs would be needed to provide about 2 feet of depth and a water velocity of about 3 feet per second through the notch in the diversion dam. The results of the model testing indicated maximum water velocities in the riffle sections would be between 3.5 and 4 feet per second under low water conditions. The pool and riffle design would also maintain relatively low velocities at higher flows. Under high streamflow conditions at certain times of the year, nonnative fish species can also negotiate the present GVIC Diversion Dam without any improvements to the diversion dam. Therefore, a fish trap to separate native and nonnative fishes would not be installed at this structure. A strong population of nonnative fish already has become established upstream. In the future, if a passageway is constructed at the Price-Stubb Dam, a fish trap for separation of native and nonnative fishes may be installed at that location to prevent further upstream access by nonnative fish. The Fish and Wildlife Service and Colorado Division of Wildlife are also implementing a program to reduce the number of non-native fish in gravel pits and ponds along the Colorado River that periodically flood and introduce the non-natives to the river environment. Construction Agreements such as easements would be required from private landowners and from GVIC prior to construction. Protective measures would be negotiated with the private landowners to reduce impacts during construction and to restore any damaged lands following construction. An existing bridge to the site would be improved to more safely accommodate construction equipment and the hauling of materials. Construction material may be stored on nearby vacant land and the rocks would be obtained from existing commercial sources. A cofferdam would be required to dewater the area where the riffles and pools would be constructed. A Section 404 permit, required under the Clean Water Act prior to any construction, has been applied for; and if discharging water from dewatering is needed, a Section 402 permit would also be obtained. Construction is scheduled for late 1997 or early 1998 during low water conditions and would be done by GVIC work crews or a private contractor. Construction costs are between $250,000 and $1,000,000 (an exact estimate has been developed, but is not presented in the EA due to bidding processes) . 8