9700 - Laserfiche WebLink

Home Browse Search

Green River Floodplain Inundation 2 June 2005 information and strategies identified in the recent Green River Subbasin Floodplain Management Plan (Valdez and Nelson 2004) to identify a peak: flow management strategy that is not only consistent with the objectives identified in Muth et al. (2000), but that may also provide additional benefits to endangered fishes that utilize floodplain habitats and reduce the need for bypass and spillway use at Flaming Gorge Dam. Specifically, the information in Valdez and Nelson (2004) suggests that flows of about 368 m3/s to 396 m3/s (13,000 to 14~000 cfs) would maintain connectivity with an area of priority floodplain depression habitat that is equivalent to that provided by 527 m3/s (18,600 cfs), the lowest connecting flow recommended by Muth et al. (2000). We do not suggest that the magnitudes of instantaneous peak flows that were recommended by Muth et al. (2000) should be reconsidered. However, the magnitude of flows that Muth et al. (2000) recommended for maintaining connection to floodplain habitats for two weeks or more appear to be higher than necessary for connecting priority floodplain habitat. Muth et al. (2000) recommended those longer duration flows to provide an opportunity for larval razorback sucker to be entrained into floodplain nursery habitats. The peak flow management strategy we propose is intended to accomplish all of the peak: flow channel maintenance and floodplain inundation objectives identified by Muth et al. (2000) while providing an opportunity to (I) increase the frequency of floodplain connection with the main channel and (2) increase the duration of floodplain connectivity in a given year. We believe that this will provide an opportunity to improve entrainment of native fish larvae into floodplain nursery habitats. Thus, the peak: flow management strategy described here is intended to improve the potential for the flows from Flaming Gorge Dam to benefit endangered fishes in the Green River. The proposed peak: flow management strategy is consistent with the implementation guidelines and objectives identified in Muth et al. (2000) and the overall objectives of the Upper Colorado River Basin Endangered Fish Recovery Program.