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. . We can not explain why more water was entrained into Thunder Ranch in 2006 than 2005; the increase in beads entrained in 2006 is likely due to increased flow entrained, but may be due to the release location being so close to the sample site. Even though only Breach 3 was sampled in 2005, comparisons showed that more than twice as much flow was entrained into that single breach in 2006 than 2005. It is possible that breach elevation was higher in 2005 and inhibited flow entrainment, but we have no means to evaluate this hypothesis. Measurement error is also possible but seems unlikely, given the magnitude ofthe differences and that many of the same personnel were on hand to estimate flow entrainment in a consistent fashion between years. Another possible explanation for vagaries in flows and entrainment rates at this and other sites, is that flow levels fluctuate, sometimes dramatically, within a day. Our use of mean daily flow values would mask effects of those flow variations, which may in fact be responsible for some of the anomalous values we observed. We also have some evidence that bead entrainment reflects larval fish entrainment as well, because we recovered some fish from Thunder Ranch samples in 2006. For example, on 21 May, the first two samples (29 and 50 min samples, respectively) collected from Net 1 in Breach 3 after release of particles contained 129 beads and one bead, respectively. Those same samples contained 82 and one razorback sucker larvae, respectively. However, there were obvious inconsistencies in fish captures, based on numbers of larvae captured in samples collected side by side at similar times. Such inconsistencies made us cautious and prevented further interpretation of any fish entrainment data. . . . . . . . . 46 .