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CHAPrER 2 - PROPOSED ACTIONS AND ALTERNATIVES Prooosed Actions I ! Two actions are proposed. One is to construct a fish passageway around the east side (right abutment) of the RedIands Diversion Dam. The other is to provide water when needed from the Aspinall Unit under an interim (temporary) water agreement as needed to operate the fish passageway and maintain downstream flows. Flows required to operate the passageway would either be released from water stored in the Aspinall Unit or consist of natural Gunnison River flows in excess of the needs of the senior downstream Gunnison River Basin water rights, including the RedIands Diversion Dam and the city of Grand Junction. Fish Passal?eway Desi~ The proposed design for the fish passageway is a concrete chute, 6-feet wide and 350-feet long, routed around the RedIands Diversion Dam and the city of Grand Junction's pump station located on the right bank of the river (Figure I). The chute will be divided into a series of small pools by baffles; the water flow through the chute will be approximately 25 cfs. The upstream entrance to the fish passageway will have a log boom and trash rack to prevent debris from entering. There will be a forebay (widened section of fish passageway) near the upper end that allows . fish to be trapped and separated before they move upstream into the river. Non-native fish will be returned to the river downstream from the diversion dam. A concrete wing wall and forebay structure, approximately 80 feet long and extending 2 feet higher than the existing bank will be constructed upstream and downstream from the forebay. The fish passageway forebay, where the entrance to the 42-inch bypass pipe, baffled chute, and 24-inch Grand Junction pumping plant intake are located, is protected by two sets of trash screening devices. The screening devices prevent floating debris from entering and obstructing the fish passageway structure and also prevent fish from being drawn into the Grand Junction pumping plant intake. The initial screening device consists of a rack of vertical steel bars with 4-inch openings between bars. The secondary screening device also consists of a rack of vertical steel bars; however, the openings between these bars will be only l/4-inch wide. No "take" (harm) of endangered species is anticipated by the construction and operation of the fish passageway as the screening devices should prevent fish from being drawn into the city of Grand Junction's pumping plant intake. No "take" is anticipated to occur as a result of the continuing operation of the RedIands Diversion Dam. Successful use of a passageway by razorback suckers and Colorado squawfish is currently . undocumented; and water flow velocities, barriers, and attraction to the fish passageway entrance may control whether passage is successful. Therefore, the passageway will be designed to incorporate measures for added flexibility in controlling water velocities and entrance conditions. The design will allow for variation in baffle spacing, pool length, height of water drop between pools; and water flow rates in order to test various conditions. 5