ARCHIVED REPORTS_XR0009517 - Laserfiche WebLink

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I r ' 4.0 CONCLUSIONS f • 4.1 Groundwater Flow Direction and Gradient rJJW prepared a groundwater potentiometric surface map based on the static groundwater elevations measured on December 13, 2000. The shallow groundwater was calculated to flow r toward the north-northeast (N 4 E) at a gradient of approximately 0.0042 ft/ft. Figure 3 illustrates the groundwater potentiometric contour surface and flow direction. 4.2 Groundwater Contamination Groundwater contamination was detected in monitoring wells MW-2 and MW-5. The r groundwater contamination consisted of total petroleum hydrocarbons as gasoline, and associated aromatic volatile fuel components (BTEX). No contamination was detected in the other three wells. No MTBE was noted in any of the five wells. rThe groundwater contaminant plume in the vicinity of well MW-2 and adjacent MW-5 is inferred to extend down-gradient of well MW-2 approximately 60 feet. The plume is inferred to extend up-gradient and cross-gradient approximately 15 and 20 feet, respectively. Figure 4 illustrates ' the inferred limits of groundwater contamination for the December 2000 sampling event. 5.0 RECOMMENDATIONS The San Joaquin County Environmental Health Division requested that a closure report be r written if the data suggests that the site might be considered for closure. JJW is in the process of collecting the required data and information to support closure and will be submitting a closure report for review. 1 6.0 LIMITATIONS ' The lack of identification of contamination on a site does not preclude its existence. JJW Geosciences incorporates the current, standard of care when making judgments concerning ' the presence of contamination on a site. However, due to natural circumstances, it is not always possible to identify and/or accurately determine the presence of contamination. Additionally, changes in appropriate standards may occur, whether they result from legislation, the broadening of knowledge, or other reasons. Such changes may invalidate certain findings ' of this report. This report has been prepared for the exclusive use of the client and is applicable only for the r subject site. JJW Geosciences is not responsible for interpretations by others of the data presented in this report. This report does not represent a legal opinion and no warranty is expressed or implied. This report is issued with the understanding that it is the responsibility of the property owner to ensure that the information and recommendations contained herein are brought to the ' attention of the appropriate regulatory agency. This work was performed in accordance with 40 the generally accepted standards of care existing in Northern California at the time of the investigation. r rJJW GEOSCIENCES Inc. 3