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ATTACHMENT D:MAP AND CROSS SECTIONS OF USDWS deep well abandonment, and it provides a record of the interval targeted for protection by state and local agencies. The primary sources of groundwater in the STIG-LEC facility are the Tertiary and Quaternary shallow non-marine sediments identified previously. When the original STIG-1 permit was prepared, California Division of Oil and Gas (CDOG [now DOGGR]) estimated the fresh water base, defined as 3,000 mg/L TDS,to be at an elevation of 450 feet. Two regional assessments of the base of the fresh-water aquifer (Figure D-8) support that estimate. This is consistent with the depth of the existing domestic and irrigation wells in the area. TDS Changes with Depth A vertical profile of the salinity changes in the units penetrated by the STIG-1 well was prepared for the original 1993 permit (Figure D-9). The profile was created by: • Chemical analysis of the formation waters sampled from the proposed Domengine Formation injection interval (4,234 to 4,507 feet). • Evaluation of geophysical logs for eleven permeable intervals that occur from ground surface to the bottom of the Domengine Formation,performed by Halliburton Logging Services. • CDOG (now the DOGGR) estimated depth of the 3,000 mg/L TDS. • Chemical analysis of shallow groundwater This profile indicates that the base of the USDW at the STIG-LEC facility is either the base of the Markley formation or the Nortonville shale. Each of the samples collected from the Domengine Formation prior to injection indicates that it is below the USDW. Although different methods were used to estimate or determine salinity values in the vertical profile, there is agreement between two approaches that obtained salinity values from similar intervals within the Domengine Formation. An estimated value of 14,000 mg/L sodium chloride (NaCl) was obtained from log-derived salinity methods for the 4,270-to 4,300-foot interval,which is the upper portion of the injection interval. This compares favorably with the laboratory-derived value of 14,066 mg/L from the 4,234 to 4,507 foot interval. D-4 SAC/371322/082550018(ATTACHMENT-D.DOC)