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Finding of No Significant Impact <br />As a result, Reclamation began investigating Kachess Dam to understand the extent of the safety <br />risk it presents under the Dam Safety Priority Rating (DSPR) system. This system provides a means <br />for Reclamation to establish the urgency of risk management activities and the relative priority of <br />these actions within the overall inventory of dams. Kachess Dam was previously designated as a <br />DSPR 3 facility (moderate to high priority). This category is reserved for annualized life loss risks or <br />failure probabilities estimated to be moderate to high with generally moderate to high confidence. <br />Based on Reclamation's recent investigations, the dam is now judged to be in the DSPR 2 category <br />(urgent priority). This category is used for situations where expedited action to reduce the risk of <br />failure may be appropriate. A timely transition into the final design process will help ensure a long- <br />term risk reduction without delay. <br />With this rating change, Reclamation has determined that, although the estimated risk is high, the <br />dam's overall condition is good for its age with no significant adverse performance to date; further, <br />the responsible office does a good job of monitoring the dam and responding to any concerns in a <br />timely manner. However, the risk of failure is comparatively high such that timely modification of <br />the dam is necessary. The primary reason is that, while the dam is currently stable, seepage in the <br />areas of concern is both quantifiable and predictable over the normal operating range. The <br />recommended interim risk reduction action is therefore focused on enhanced performance <br />monitoring. The need for additional interim risk reduction actions will be revisited if conditions <br />change prior to the completion of the dam safety modification. <br />Accordingly, to prevent eroded soils from exiting the dam, Reclamation is proposing this project to <br />filter and monitor the seepage. Reclamation's primary project goals are to limit internal erosion and <br />decrease the risk of dam failure with moderate certainty; its secondary project goal is to limit impacts <br />on fish and irrigation. <br />The purpose of and need for the proposed project include <br />1. Implementing cost-effective measures to reduce the risks, per Reclamation's Public <br />Protection Guidelines <br />2. Maintaining water deliveries to irrigation districts, tribes, and others throughout the Yakima <br />River basin <br />3. Minimizing impacts on the environment <br />4. Maintaining water flows for endangered species <br />As part of its SOD program mission, Reclamation is committed to ensuring its dams do not present <br />unacceptable risk levels to people, property, and the environment. These requirements result in a <br />need for Reclamation to implement corrective action to bring static and hydrologic risks at Kachess <br />Dam below public protection guidelines, while minimizing impacts on the environment. <br />Alternatives <br />This EA analyzed two alternatives: the No Action Alternative and the Proposed Action Alternative <br />(Proposed Action). <br />Kachess Safety of Dams Final Environmental Assessment <br />