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1 1 L 1 1 t 1 Table 2. 1. Table showing which floodplain sites are located in which river reach and the river mile for each reach. Reach Site Code number Start RM End RM BB 1 290.0 283.0 HB,BC 2 283.0 276.0 SR,BA 3 276.0 269.0 AB 4 269.0 262.0 L7,L 10 and J4 5 262.0 255.0 SB,OCD and OCW 6 255.0 248.0 GENERAL SITE DISCUSSION To provide rearing habitat for young-of-year native species, these floodplain wetlands must be accessible to the fish during the narrow window of time in which larval fish are drifting in the river channel. As river flows rise above flooding levels, the wetlands begin to fill. The time it takes for each site to fill depends on main channel flows, the size of the site, and the configuration of the connection with the river. Levee removal sites take several days to a week to reach equilibrium with the river after connection is made. As river flows rise and fall, water will surge in and out of the wetland until high spring flows subside permanently usually in mid to late June. The number and duration of these filling surges varies widely from year to year. If the levee removal sites are to be useful to larval native fish, the filling events and inflow surges must occur at the same time as larval drift in the main channel of the river. Figures for each year since 1947 were made that depicted the correlation between water surges (days of ascending flow above 19,000 cfs pre-dam and 13,000 cfs post-dam) into wetlands and the average date for the presence of drifting larval razorback suckers (calculated from Muth et al. 1998). From these figures, a potentially good pre-dam year appears to be 1957 (Figure 2.2). We hypothesize this year was good because of the duration of surging flows and the timing of these surges. Assuming average bankf ill discharge of 19,000 cfs, water from the river would have been surging into floodplain wetlands for a total of 18 days during this flood period. Secondly, many ... of these "surge days" occurred later in the year when the likelihood razorbacks would be drifting is greater. Based on these characteristics, the best year for both pre-dam and post-dam periods was 1983. Surges would have occurred for a total of 36 days under the current levee removal x flooding level of 13,000 cfs. And many of these days occurred later in the year. Another. potential good post-dam year was 1995 (24 days of surges). For the three years of Le vee Removal Study, 1996 and 1998 were poor years for larval access of floodplain wetands (Figure 16 ?"?