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• Community Acceptance—Indicates whether community concerns are addressed by the remedy and whether or not the community has a preference for a remedy. This detailed analysis of each alternative is presented in Table 7. Additionally, Appendix D documents an evaluation of the remedial alternatives against criteria specified in California Health and Safety Code Section 25356.1(d). 4.4 Comparative Analysis Cost estimates for Alternatives 1 through 5 were developed to support the detailed and comparative analysis. The estimated costs for Alternatives 1 through 5 are summarized in Table 8. Table 9 summarizes the relative rankings of the five alternatives for the evaluation criteria and presents an overall ranking of each alternative based on the detailed analysis. Alternatives 1 and 2 do not satisfy both threshold criteria and are therefore ineligible for selection and are not discussed further. Considering Alternatives 3 through 5, the three are ranked highly in terms of overall protectiveness, compliance with ARARs, and long-term effectiveness and permanence. Alternatives 3 and 5 outrank Alternative 4 based on cost. Alternatives 3 and 5 are better in terms of short-term effectiveness, as they will have less of an impact to the workers constructing the remedy(i.e., less exposure to COC-impacted dust due to grading versus grading and excavation with Alternative 4). Overall, Alternatives 3 and 5 provide comparable performance relative to the NCP evaluation criteria, and the performance of both Alternatives 3 and 5 exceeds that of Alternative 4. Alternative 5 is directly tied to the Project Sierra development with near-term economic benefits to the region. As a result, the benefits of Alternative 5 appear to outweigh those of Alternative 3. 4.5 Description of Recommended Alternative — Expanded Excavation with On-Site Consolidation, Existing Durable Cover, Expanded New Durable Cover, and Institutional Controls Alternative 5 is the recommended alternative for soil, and sediment at Site 47 to protect humans and wildlife. This alternative involves installation of a durable cover that is integrated with and supports the Project Sierra development. The elements of the durable cover within the Project Sierra development would consist of a demarcation layer and clean imported fill. The clean imported fill would then be covered by the finished surfaces depicted on Figure 15. Portions of the Project Sierra development located outside of the ARIC (Figure 11) do not require remedial action and are therefore not included in Alternative 5. Alternative 5 also involves installation of new covers and repair of existing covers in areas within the remedial boundary but outside the Project Sierra development. Unpaved areas would be covered with a demarcation layer and 2 feet of clean soil. Existing covers in other areas (i.e., building foundations and paved areas) would be repaired, as needed, to serve as a physical barrier(Figure 15). The existing and new covers would be inspected and maintained regularly, and future land use and activities within the ARIC (Figure 11) would be restricted by a LUC. Site 47 RAP for Soil 14 October 2023