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<br />Green River Floodplain Inundation <br /> <br />8 <br /> <br />June 2005 <br /> <br /> <br />Figure 2. Diagrammatic Representation of Depression and Terrace Floodplain Habitats. <br />Source: Valdez and Nelson (2004). <br /> <br />When the Muth et al. (2000) flow recommendations were developed, the identified <br />connecting flow magnitudes (i.e., flows that would be maintained for two weeks or more to <br />connect floodplain habitats to the main channel) were based on the relationship between flow <br />and total area of inundated floodplain habitat with levees in place, as determined by surveys and <br />aerial photography (Figure 1). These relationships do not differentiate between depression and <br />terrace floodplain types and do not consider the length of time these habitats would hold water. <br />More current and site-specific information compiled by Valdez and Nelson (2004) on depression <br />and terrace floodplains in the middle Green River enables a more informed evaluation of the <br />effects of peak flows on razorback sucker nursery habitats. <br /> <br />Valdez and Nelson (2004) evaluated floodplain areas in the Split Mountain to Desolation <br />Canyon portion of the Green River (Reach 2 and upper Reach 3 as identified by Muth et al. <br />[2000]). Based on their evaluation, Valdez and Nelson (2004) identified 16 priority floodplain <br />sites (Figure 3) for the Recovery Program and evaluated the potential importance of each of <br />these sites as razorback sucker nursery areas. Important floodplain characteristics considered by <br />Valdez and Nelson (2004) included the type of floodplain (e.g., depression or terrace), the flow <br />at which the floodplain becomes inundated, the potential area of inundation, and the distance <br />from the only known razorback sucker spawning bar in the Green River, which is located <br />upstream in Dinosaur National Monument. Characteristics of these priority floodplains are <br />summarized in Table 2. <br />