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<br />002456 <br /> <br />The recovery actioHs described herein are intended to contribute to the ultimate recovery of these <br />species, consistent with the purpose ofthe Recovery Program. These RlPRAP actions are classified <br />into five broad categories: <br /> <br />I. Provide and Protect Instream Flows <br />2. Reduce Negative Impacts of Nonnative Fishes <br />3. Restore Habitat (Habitat Development and Maintenance) <br />4. Manage Genetic Diversity/Augment or Restore Populations <br />5. Monitor Populations and Habitat <br /> <br />These recovery actions, and the process for their development, are specified in this management <br />plan, along with approaches to account for depletions, monitor fish populations, and evaluate the <br />effectiveness of these actions in recovering the endangered fishes. Schedules to initiate and/or <br />,complete recovery actions will be specified in the RlPRAP and incorporated into annual work plans. <br />The Recovery Program will be responsible for funding and implementing these recovery actions. <br /> <br />Provide and Protect Instream Flows <br /> <br />Background <br /> <br />In the Yampa River, peak flows have not been significantly reduced by large reservoirs, direct <br />diversions and their associated depletions; however, with relatively little water storage capacity in <br />the Yampa River Basin to augment flows from mid-July through mid-March, depletions may reduce <br />base flows to a greater extent, based on the percent reduction of natural (i.e., undepleted) flows. <br />Moreover, depletions generally peak in July (Table 7; Figure 7), after spring runoff has subsided. <br />Nevertheless, because peak flows playa significant role in the life histories of the endangered fishes <br />(see discussion of peak flows on page 5), impacts to peak flows are considered, as well. <br /> <br />Flows in the Yampa River typically are low during August through October, as water demand for <br />irrigation, power production and municipal consumption remains high (Table 7; Figure 7), and <br />stream flows naturally decline following spring runoff. The lowest flows generally occur in <br />September, with an average minimum flow at Maybell of 137 cfs; however, flows as low as 2 cfs <br />have been recorded. Modde et al. (1999) recommended that daily average flows at the Maybell gage <br />should not fall below 93 cfs during August through October with any greater frequency, magnitude <br />or duration in the future than had been observed under historical conditions. The rationale for their <br />recommendation is that the area of available rime habitat begins to fall off sharply at flows less than <br />93 cfs. Riffles serve as primary production areas for macro-invertebrates which, in turn, are an <br />important constituent of the food web for the endangered fishes. Because riffles are especially <br />sensitive to changes in flow, Modde et al. (1999) considered maintenance of riffle habitats, and the <br />invertebrate prey base they support, to be one of the most important functions of base flows in the <br />Yampa River. <br /> <br />~ <br />~ <br /> <br />Gage records also show that daily average flows in July historically fell below 93 cfs in 3 of 83 <br />years, whereas the CROSS predicts that July daily average flows will fall below 93 cfs in roughly <br />10% of years by 2045. Therefore, the Service extended the low-flow period to encompass all base- <br />flow conditions from July I through October 31 and adopted the 93-cfs flow target of Mod de et al. <br />for this period (Appendix D). <br /> <br />Management Plan for Endangered fishes in the Yarnpa River Basin <br /> <br />32 <br />