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Figure 7 shows that the per-dam flows were significantly <br />different than the post-dam flows, In addition, the pre-dam <br />regression lines are steeper than the post-dam regressions, <br />indicating that the larger water years have larger differences in <br />flows between the two periods of record. Large water years have <br />approximately 2,500,000 acre feet of total flow, and a peak flow <br />of approximately 18,000 cfs in the pre-dam period. However, a <br />water year with this same total annual flow would have a peak <br />flow of only 10,000 cfs in the post dam period. This is the <br />difference between flooding and not-flooding in the study-area. <br />Reduced flood frequency has a number of repercussions, <br />including; (1) reduced floodplain dynamics resulting in fewer <br />backwaters and oxbows being created and maintained, (2) fewer <br />sites suitable for cottonwood regeneration, (3) reduced frequency <br />of connection with existing backwater and oxbows, (4) reduced <br />flushing of floodplain soils to remove salts. Although it seems <br />that this later point is of less importance, we have found that <br />portions of these floodplains are not completely connected to the <br />Gunnison River, and groundwaters in close proximity to the <br />floodplain may contain high salt concentrations. <br />The fact that neither May nor June flows retain their <br />natural peak pre-dam condition is not encouraging. In fact these <br />flows are very different. It indicates that floodplain dynamics <br />are at a standstill, and the integration of native fishes into <br />the floodplain will be possible on a very irregular basis, unless <br />flows of greater than 12,000 can be restored. <br />13 <br />