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Finding of No Significant Impact <br />Summary of the No Action Alternative <br />Under the No Action Alternative, there would be no structural or operational changes to Kachess <br />Dam or the spillway. Reclamation would not prepare the site or the access road and would not <br />extend and line the conduit. Reclamation also would not install a filter or a stabilization berm. <br />Accordingly, the dam and spillway would not be improved, and no changes to the operation of <br />Kachess Dam would occur. <br />Without action, the seepage and internal erosion issues through the dam embankment along the <br />outlet works conduit, which conveys water from the reservoir to the Kachess River downstream, <br />would continue (see Figure 2-1, No Action, in Appendix A). Soil materials carried by the seepage <br />would leave behind voids within the embankment. This internal erosion would perpetuate a risk of <br />potential complete dam failure. <br />As stated above, as part of its SOD program mission, Reclamation is committed to ensuring its <br />dams do not present unacceptable risk levels to people, property, and the environment. These <br />requirements result in a need for Reclamation to implement corrective action to bring static and <br />hydrologic risks at Kachess Dam below public protection guidelines, while minimizing impacts on <br />the environment. Thus, this alternative would not meet the purpose of, or need for, Reclamation's <br />action. <br />Summary of the Proposed Action <br />Reclamation proposes to reduce the risk of dam failure by performing the following improvements: <br />• Constructing an access road <br />• Preparing the site <br />• Developing staging areas to support construction and long-term maintenance <br />• Extending and lining the conduit <br />• Removing the weir <br />• Installing a diaphragm filter around the conduit and a stability berm on top of the filter <br />• Installing an auxiliary drain below the outlet channel <br />The modified embankment dam, stability berm, and outlet works would resemble a T-shaped <br />mound. <br />Reclamation does not anticipate reservoir -level restrictions to occur. Also, Reclamation would time <br />construction of the extension and lining of the outlet works to avoid major issues with water <br />deliveries. Currently, Reclamation plans to comply with maintaining minimum flows through the <br />dam throughout the project, as established through negotiations with several stakeholders, including <br />the Washington Department of Fish and Wildlife, Confederated Tribes and Bands of the Yakama <br />Nation, United States Fish and Wildlife Service (USFWS), National Marine Fisheries Service <br />(NMFS), and various irrigation districts. <br />Kachess Safety of Dams Final Environmental Assessment <br />