Laserfiche WebLink
"The earthen floor of a secondary containment system may be <br />r <br />considered "capable of containing oil until cleanup occurs or <br />"sufficiently impervious" under §§ 112.7(c), 112.8(c)(2), ... if there <br />is no subsurface conduit to navigable waters allowing the oil to <br />reach navigable waters before it is cleaned up." <br />®?V 'GO®4. <br />, � Based on the regulatory guidance described above, ERM undertook the <br />analysis contained herein to determine (1) whether a subsurface conduit <br />to navigable waters exist, and if so, (2) if there is sufficient time to stop the <br />progress of an accidental release prior to it reaching navigable waters. <br />Utilizing engineering judgment and knowledge of the site-specific <br />geologic, hydrogeologic, and operational conditions for the given Chevron <br />Terminal at the time of this analysis, ERM employed the following <br />methodology to certify that the secondary containment meets the <br />sufficiently impervious requirements of 40 CFR 112: <br />(1) Determine the vertical Time to Groundwater. This portion of <br />the analysis estimates the time for a release to move vertically <br />through the subsurface to a potential groundwater. <br />Determine whether the Time to Groundwater provides the time <br />needed to discover and stop the progress of a release. This <br />determination is based on site-specific conditions, operations <br />and controls in place. <br />(2) For a terminal which has a Time to Groundwater that is less <br />than the time estimated to discover and stop the progress of a <br />release, determine if Groundwater potentially is Hydraulically <br />Connected to a potential Water of the U.S. <br />(3) For a terminal found to be potentially hydraulically connected <br />to a potential Water of the U.S., determine Time to potential <br />Water of the U.S. after a release has reached groundwater. This <br />portion of the analysis estimates the time for the release to move <br />horizontally through the subsurface after it has reached <br />groundwater. <br />This report was prepared by ERM on behalf of Chevron based on <br />conditions existing at the time the report was prepared. This report and <br />certification of this information by the Professional Engineer under SPCC <br />requirements is intended for use by Chevron only with regard to <br />Chevron's operations at the terminal indicated, and is not to be relied <br />upon by any third party for any reason. <br />ERM 1-3 110870\CHEVRON\SPCC -JULY 2010 <br />