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<br />Green River Floodplain Inundation <br /> <br />June 2005 <br /> <br />ABSTRACT <br /> <br />Information in the recent Green River Subbasin Floodplain Management Plan indicates <br />that flows of about 396 m3/s (14,000 cfs) would maintain connectivity with an area of priority <br />floodplain depression habitat that is equivalent to that provided by 527 m3/s (18,600 cfs), the <br />lowest connecting flow identified in the existing flow recommendations for the Green River <br />downstream of Flaming Gorge Dam. We used this current information about floodplain habitats <br />to identify a peak flow management strategy that (1) is consistent with the objectives identified <br />in the existing flow recommendations, (2) may provide additional benefits to endangered fishes <br />that utilize floodplain habitats, and (3) would reduce the need for bypass and spillway use at <br />Flaming Gorge Dam. The proposed management strategy would provide the same instantaneous <br />peaks as the existing flow recommendations, but it would lower the minimum targets for <br />floodplain connecting flows from 527 m3/s (18,600 cfs) to approximately 396 m3/s (14,000 cfs). <br />The lower connecting flow would inundate the same amount of priority depression floodplain <br />habitat (approximately 1,027 ha) as would be inundated by the higher connecting flow, but <br />would allow the duration of connections between priority depression floodplains to be extended <br />by approximately 1 to 3 weeks. We believe that extending the duration of connecting flows may <br />benefit endangered fishes by improving opportunities for entrainment of native fish larvae, <br />especially razorback sucker. <br /> <br />v <br />