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l i• e' , <br />Cavalli (2000) studied the effects of the Tusher Wash Diversion Dam on upstream movement of <br />native fishes and entrainment of larvae into the raceway and Green River Canal. He found that <br />at least some sub-adult fish are able to pass the diversion dam at a discharge of 4,820 ft3/s <br />(136.49m3/s; the flow when he did his study in 1998). He pointed out, however, that flows are <br />almost always below this level from August through February. Cavalli (2000) captured one <br />Colorado pikeminnow larvae in the canal in a year when only 12 were captured in the main <br />channel passing the diversion; in most years the river catch is near 100. This suggests that a <br />substantial number of larval Colorado pikeminnow and razorback sucker may be entrained into <br />the canal system. <br />Objectives <br />Cavalli (2000) raised concerns that large numbers of larvae, sub-adult, and adult razorback <br />sucker and Colorado pikeminnow could become entrained and possibly perished in the raceway <br />and Green River Canal. However, little data are available. Anecdotal information suggest that <br />native and non-native fishes have been stranded in the canal and after dewatering (Cavalli 2000). <br />Therefore, the objectives of this study were to: <br />1) determine the number of razorback sucker and Colorado pikeminnow in the raceway <br />and Green River Canal; <br />2) determine the locations where these native fishes are found within the canal; and <br />3) determine if they become stranded in the canal during dewatering. <br />STUDY AREA <br />The Tusher Wash Diversion Dam and complex are located approximately 7.5 miles (12.07 km)