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Geo4giral7echnics inc, Page 2 ' Groundwater Monitoring Report Project No 723 2 . October 25,2005 ithe tubing is that depth to water measurements could not be made because the instrument probe becomes lodged in the small chambers of the tubing Subsequently, Del-Tech ' Geotechnical Support has procured a micro-water level meter that can be used in the CMTrm wells The first quarter of 2005 was the first time that the well chambers could be sounded and they are now included in the quarterly monitoring scheme ' Groundwater gradient calculations show that shallow groundwater flow is N73°E at 0 0038 ft/ft This is consistent with the site's historical directions that have been predominantly to ' the northeast The intermediate and deep aquifer zones' gradients were calculated to be N50°E at 0 006 ft/ft and N50°E at 0 004 ft/ft, respectively The deepest aquifer zone gradient monitored by wells MW-101, MW-307, MW-308 and MW-309 was variable due to an ' anomalous depression near MW-101 Field evidence recorded during borehole installation indicates that petroleum hydrocarbon contamination is present on the adjacent property across N El Dorado Street— an active Shell service station The Valentine (Castle Motors) site plume extends off site toward the Shell ' Station and evidence suggests that a co-mingled plume may be present The lateral extent of the groundwater plume is undefined down gradient of CMTTm well set MW-8/108/208/308 A limited site investigation should take place to define the down gradient extent of the M plume This should consist of direct push probe drilling methods such as CPTrm to collect discrete groundwater samples rather than installing additional monitoring wells A work plan to accomplish this task was sent to SJC/EHD for approval SJC/EHD approved the work ' plan in their March 15, 2005 letter The work is in progress We have recommended that interim remediation be considered before this plume migrates ' any further and the cost for cleanup continues to increase A work plan for interim remedial action utilizing high vacuum dual phase extraction, air stripping and carbon filtration of extracted groundwater technologies has been sent to SJC/EHD for approval SJC/EHD approved the work plan in their March 7, 2005 letter and the budgeting and permitting for the extraction and treatment system procurement, installation, and operation is underway Our goal is to have the interim remedial action plan installed and operational by the end of 2005 I I