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2.3). In 1996, the peak occurred in mid-May. Access to the floodplain would have been limited to approximately 2 days (assuming 19,000 cfs is bankfull) at a time when the fish were just starting to hatch (Muth et al. 1998). This duration improves to 10 days if breaches had been cut in 1996 that allowed flooding at 13,000 cfs. In 1998, we did have sites designed to flood at 13,000 cfs. Based on the average drift period, larval fish had 12 days to drift into the wetlands. However, we know larval fish did not appear in our light traps until early June, after most of the surges had subsided. Flows did appear to be good for access in 1997. However, preliminary indications are that razorbacks may not have been very successful spawning during this year. In nearly all cases (except Baeser Bend and Leota 7), sites were breached at the downstream end, based on the assumptions that: 1) Rates of sediment deposition would be lowest with a downstream breach, resulting in less need for annual excavation to maintain connections between the site and the river; and, 2) Downstream breaches would be less risky in terms of affecting site morphology and main channel stability, and would be less likely than an upstream breach to reroute the main channel or convert the wetland into a secondary channel. Contrary to the first assumption listed above, it appears sites that backfill through breaches at the downstream end deposit more sediment in the breach than sites where the levee was breached in the center (Baeser Bend, Leota/L7). At these locations, the current tends to push water into the wetland cutting the breach deeper. However, over time, sediment deposition within the wetland may become a problem and will need to be monitored at these sites. Large breaches like the one cut at Horseshoe Bend also appear to have positive features. Two deep channels were cut as a result of flows entering the site on the upstream end and exiting on the downstream end. These deep channels may enable longer periods of connection and higher use by endangered fish. They also provide a larger "door" for fish to enter the wetlands. However, sediment deposition at this site may also become a problem. Long narrow channels like the one cut at the downstream end of the Stirrup may also plug with vegetation and debris over time. Large breaches such as L7 and J4 where vegetation was not cleared from behind the breach may also inhibit fish movement. Based on preliminary results, it appears that to maintain levees that will flood at 13,000 cfs, it may be necessary to breach levees near the center or in a combination of top/center with the bottom. This may also facilitate access to the floodplain by drifting larval razorback suckers. However, regardless of how levees are configured, flows that cause surges of water into floodplain wetlands need to occur at the time when larval razorback suckers are drifting in the river. Based on the three years of this study, it appears the later in the year these surges occur the greater the likelihood of entraining drifting larval razorbacks in the sites. 1 1 1 ?I 1 t