ARCHIVED REPORTS XR0001831 - Laserfiche WebLink

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• isoconcentrations of TPH-g and benzene, analytical laboratory reports, and quarterly report signed by a state licensed registered geologist Task 4- Geophysical Clearance Survey A magnetic and electromagnetic survey of the property will be conducted to determine the location of all underground facilities at the site such as buried electrical, power, and sewer lines The survey will be to assist in determining the best locations to place the soil borings in order to minimize unanticipated dig in of these facilities by exploratory soil borings The survey will be planned to encompass the main portion of the former station UST and dispenser locations and all soil boring locations Date will be acquired on a 5 x 5 foot grid that will be tied to the California State Plane Coordinate System, Zone 7 A series of contour maps will be made at acceptable contour intervals to determine if any UST's or piping still exist in the subsurface Task 5- Site Conceptual Model An initial site conceptual model will be developed using existing subsurface geological, chemical, and hydrological data In addition, information from the sensitive receptor survey will be included in developing a model of the extent and nature of the identified petroleum hydrocarbon release and how best to implement additional site assessment work to define missing data points Task 6- Expanded Site Assessment Subsurface Investigation To evaluate the horizontal and vertical extent of petroleum hydrocarbon impacted soil and to determine if groundwater beneath the site has been impacted by gasoline compounds, Consultant proposes to permit and advance a series of approximately 10 soil borings on and adjacent to the site Soil borings will be drilled at the locations shown on Figure 9 after the individual sites will be cleared by the Task 4 geophysical clearance survey Prior to conducting any intrusive methods at the site, Underground Service Alert of Northern California will be utilized to map out the underground structures Based on the clearances obtained, Consultant will site the soil bonngs in a safe locations A licensed drilling contractor will advance the soil borings approximately 60 feet below the ground surface using a hollow-stem auger drilling rig The drilling contractor will be an experienced contractor who has worked in this portion of California successfully on previous projects Drilling contractor will arrange for USA callout and will obtain all necessary permits for drilling Mam\D\Environmental\FarmarTexaco\Workplan\042003 wpd 13