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Water entered the wetland at a much lower discharge through the inlet channel maintained by the ONWR to deliver water into the wetland. Prior to 1994, the inlet channel elevation was 1417.6 mamsl and estimated discharge of approximately 240 m3/s would be required to deliver water into the wetland. However, the bottom of the wetland has an elevation of 1417.0 mamsl so that if the inlet canal is lowered through dredging, water could access the wetland at a slightly lower discharge. DISCUSSION Overbank connection between the Green River and Old Charley Wash in 1993 occurred at a discharge between 405 m3/s and 455 m3/s. No observations were made on the date of inundation, so the specific discharge causing inundation is uncertain. In 1995, it was observed that flows began inundating the river levee on May 23 (personal observation). Estimated Green River flows at Ouray (Jensen gage on the Green River plus Ashley and Brush creek gage records) were 454 m3/s on May 22. Estimating one day delivery time between Ouray and Jensen (about 100 river kilometers), the flows in 1993 that inundated Old Charley Wash were probably closer to the higher range of the estimate. Although the inlet and outlet structures allow water to enter Old Charley Wash at flows approximating 240 m3/s, overbank flooding does not occur until flows are almost twice this high. Connection of Old Charley Wash occurs at a lower discharge than the flood stage (524 m3/sec). Irving and Burdick (1995) identified the largest terrace and depression wetlands in the Green River between Flaming Gorge Dam and the confluence of the Colorado River. Among those wetlands listed, Old Charley Wash was smaller and inundated at lower flows than many other depression wetlands. A more thorough discussion of floodplain distribution and relationship of flow to floodplain connectivity is found in Irving and Burdick (1995) and Flo Engineering (1996). MANAGEMENT IMPLICATIONS Floodplain habitat in the middle Green River is used by razorback sucker during high spring river flows. Use of this habitat may be associated with warmer water and higher prey density. Spawning migrations of razorback sucker seemed to be initiated primarily by rising discharge. Tag-recapture and telemetry data showed that posts pawned fish moved to tributary outlets and the vicinity of the Ouray wetland complex. Thus, timing of spring flows seems to be an important cue for congregating spawning adults and postspawning movement. When available, the invertebrate-rich floodplain habitat created by high flows provides important postspawning habitat for immature and adult razorback sucker. High flows and the duration of flows which maintain connectivity of the river and floodplain are, thus, important attributes in defining quality and quantity of spring habitat for all life stages of the razorback sucker. Inundated floodplain habitat provides an important nutrient source to both off- channel and mainchannel riverine environments. High nutrients produce standing stocks of invertebrates much higher than mainchannel habitat. The high invertebrate production, elevated temperature, and cover provided by abundant aquatic vegetation growth in floodplain wetlands provide excellent environments for growth and survival of 29