SITE INFORMATION AND CORRESPONDENCE

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Mr. Carl Navarra 7500 W. Eleventh Street Page 2of4 sampling as part of the quarterly ground water monitoring program until approval for a modified monitoring schedule is issued by this agency. Installation of the additional proposed ground water monitoring wells (MW-13 through MW-19) is also approved. Please submit a drilling permit application and access agreements and/or encroachment permits as appropriate for each parcel to be drilled and the $89 fee per permit. Installation of the proposed floating product assessment wells is approved with the following conditions: • California well regulations, which are .enforced by this office, require a 2- inch annular seal around the well casings — a requirement that cannot be met with a 2-inch diameter boring and any diameter casing. The boring size must be larger and the casing diameter of sufficient size to adequately assess the floating product plume. In addition, in view of TSJCI's discussion of the benefits of larger diameter wells (limited, but measurable), the importance of representative elemental volumes and the difficulties with recharge of MW-7 following purging, EHD recommends use of larger diameter casings. • EHD believes an additional floating plume monitoring well should be installed 25 to 30 feet north of MW-7 to test the plume model presented by TSJCI. Floating product will be removed from each well following measurement of product thickness in all the wells. At this time, EHD does not approve installation of the automatic product recovery system. After the presence and persistence of floating product in the wells have been demonstrated, EHD will reconsider this system or any other system proposed by your consultant. Also at this time, EHD does not approve installation of the cutoff trench to recover the floating product. This is not a final nonapproval of such a system, or an a priori nonapproval, but simply a nonapproval until the necessity and adequacy of such a system has been demonstrated and the implementability of such a remedial system has been shown. It has always been EH-D's position that the necessity for any remedial action be demonstrated prior to receiving approval. At this time, TSJCI has provided a model of the LNAPL plume, but has not validated the model and demonstrated the extent and mass of the plume with additional data. Once distribution, mass and disposition of the LNAPL plume has been demonstrated, EHD will approve the most justifiable and cost effective remedial approach that is appropriate to address the LNAPL plume. You could expect that the state cleanup fund may not reimburse costs for a remedial system that recovers minor, or no quantities of LNAPL and is deemed to have not been necessary.