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r ` STUDY AREA .~~~ ~,;Y~ °~ ' -~ is ~. ~~~~~`~ ISMP Late-iuvenile/Adult Monitoring Monitoring within UDWR's Northeastern Region was conducted in 3 reaches of the upper Green River and 1 reach of the lower White River (Figure 1). Reaches were selected based on Colorado squawfish catch rate data from years prior to 1985 and accessibility to electrofishing. The uppermost Green River reach (Reach 1) is an 8 mile section located in the Island and Rainbow Park areas between Whirlpool and Split Mountain canyons within Dinosaur National Monument. The upper portion of this reach, Island Park, has high gradient with an abundance of cobble/rubble substrate. Islands and divided river channels are numerous in this section. The lower portion, Rainbow Park, has reduced gradient and finer substrate. There are no significant tributaries within Reach 1. The second Green River reach (Reach 2) begins at the Dinosaur National Monument bridge near the Chew Ranch and continues downstream 19 miles to a point about one-half mile below Ashley Creek confluence. The upper 8 miles of this reach is high gradient with cobble-rubble substrate. The lower 11 miles is low gradient with sand substrate. Two significant tributaries, Brush Creek and Ashley Creek, join the Green River within this reach. The lowest Green River reach within the Uintah Basin (Reach 3) begins at the upstream. end of Leota Bottoms within the Ouray National Wildlife Refuge and continues downstream to an island about 1 mile below the White River confluence. The entire reach is low gradient with sand-silt substrate. Both the Duchesne and the White rivers flow into the Green River within Reach 3. The White River monitoring reach (Reach 13) extends 21 miles from the Mountain Fuel bridge to the confluence with the Green River. This section is below the canyon portion of the White River and flows through a wide flood plain with comparatively low gradient and predominately sand substrate. ISMP Youn -og f-the-year Monitoring The upper Green River YOY Colorado squawfish monitoring reach (Reach 4) extends from the Split Mountain Campground (RM 319), Dinosaur National Monument, 104 miles downstream to a point just below the Sand Wash boat launching (RM 215) area above Desolation Canyon (Figure 2). The upper 10 miles are characterized by steep gradient and cobble/rubble substrate. Below that point, the river enters the broad Uintah Basin floodplain and is relatively slow and meandering with a predominantly 2