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No Further Action Required Request Report <br /> IMountain House Development Site#6 September 15,2011 <br /> 18. Provide a rationale why the conditions remaining at the site will not adversely impact <br /> 1 water quality, human health, and safety, or other beneficial uses. The rationale for NFAR <br /> must include a finding about present and future water use, and risks the site may still <br /> represent to human health and safety, and water quality. <br /> ' Please see Section 4, Conclusions and Recommendations. <br /> 19. Provide a list of technical reports submitted for site assessment, corrective action, <br /> confirmation sampling, and closure. <br /> ' A list of technical reports is provided in Section 5 and Appendix A. <br /> 20. Provide any additional comments supporting site NFAR. <br /> ' Please see Section 4, Conclusions and Recommendations. <br /> 4. CONCLUSIONS AND RECOMMENDATIONS <br /> ' Past site investigations performed by SAIC identified the presence and delineated the extent of <br /> TPH in soil and groundwater near the former OVP and TAOC pipelines. At least 40 years have <br /> 1 elapsed since the former OVP and TAOC systems were decommissioned, and the plume size has <br /> stabilized and may now be shrinking as natural attenuation continues to remove TPH from soil <br /> and groundwater. <br /> ' Consistent with SWRCB Resolution No. 92-49, Section IILA through C, SAIC evaluated <br /> alternative cleanup technologies and found that all technologies other than natural attenuation <br /> would be ineffective, infeasible, and costly given the nature of the crude oil in soil and <br /> ' groundwater. COPCs at the Site will naturally attenuate over time to below WQOs. There are <br /> no current or anticipated future uses of the shallow groundwater due to its poor quality and likely <br /> low yield, and the availability of alternative water supplies, and as noted, any new water supply <br /> well installed at the site is unlikely to be impacted by the shallow affected groundwater. The risk <br /> evaluation demonstrated that COPCs do not pose a threat to human health. It is unlikely that <br /> sensitive receptors near the Site have been significantly affected by on-site soil and groundwater. <br /> 1 A soil and groundwater management plan (SGMP) will be prepared by CEMC and provided to <br /> the property owners to protect workers in the event that affected soil and groundwater related to <br /> former crude-oil operations are encountered during future on-site construction. The SGMP will <br /> also serve to document on-site conditions. <br /> This report contains the technical data and rationale necessary to support a decision by the <br /> ' Central Valley RWQCB to issue an NFAR letter for the Site. SAIC prepared this report taking <br /> into consideration the documentation outlined in Appendix A of the Tri-Regional <br /> Recommendations. CEMC requests that the Central Valley RWQCB issue an NFAR letter for <br /> ' this low-risk site for the reasons provided in this report and summarized in this section. <br /> 5. REFERENCES <br /> ' Cal/EPA, 1999. Preliminary Endangerment Assessment Guidance Manual, Department of Toxic <br /> Substances Control. June. <br /> CDFG, 2010. California Natural Diversity Database, Los Banos Quadrangle and Volta <br /> ' Quadrangle. July. <br /> ' 11 <br /> SAIC <br /> 1 <br />