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I 1 S E C 0 R • Ms Lagorio ' February 28, 2003 Page 2 1 �U� Subsurface Conditions Review of the CPT-1 profile suggests silt mixtures with sand and/or sand �! mixtures with silt from surface to an approximate depth of 40 feet bgs, ay and stiff fine grain 31 ' sediments alter ting from 40 to 70 feet bgs, a sand layer from 70 to Yeet bgs, stiff fine grain m sediment froto 105 feet bgs, and sand and sand mixtures with silt from 105 feet bgs to the total depth of 120 feet bgs at that location Review of the CPT-2 profile suggests silt and clay mixtures f ' with alternating stiff fine grain se imentq, -that location from surface to an appro ate depth of 64 feet bgs, a sant la er between�4-and feet bgs, stiff fine grain sediment from to 115 feet bgs and another �yer from 115 feet bgs to the total depth of 120 feet bgs at that location No soil ' samples were collected for chemical analysis during the advancement of the CPT borings The CPT logs are included as Attachment B CPT Groundwater Analysis Based on pore pressure and on lithologic information collected from ' the CPT logs, three depth-discrete groundwater samples were collected at each of the CPT boring locations Groundwater samples were analyzed for the presence of total petroleum hydrocarbons quantified as gasoline (TPHg), benzene, toluene, ethylbenzene, xylenes (BTEX), and the fuel oxygenates methyl tertiary butyl ether (MtBE), tertiary butyl alcohol (TBA), di-isopropyl ether (DIPE), ethyl tertiary-butyl ether (EtBE), tertiary-amyl methyl ether (TAME), ethanol, and methanol Upon completion, the borings were filled with grout from the bottom up and finished to surface grade with asphalt Groundwater analytical results are presented in Table 1 Laboratory analytical results and chain-of-custody documentation are included as Attachment C Groundwater Monitoring Well Installation One soil boring was advanced for the installation of ' MW-8 using 12-inch diameter hollow-stem augers to a depth of approximately 40 feet bgs Groundwater was encountered at approximately 30 feet bgs No soil samples were collected for w chemical analysis from this borehole and no soil samples were collected for logging purposes due to ' the location of the well in close proximity to CPT-2 Upon completion of drilling, a 6-inch diameter groundwater monitoring well was installed in the borehole The boring log with well construction details for MW-8 is included as Attachment D 1 { UPCOMING ACTIVITIES E t In March 2003 SECOR will perform a 24-hour constant rate aquifer pump test to further evaluate aquifer characteristics as described in the June 11, 2002 work plan The well will be developed and ' sampled by SECOR prior to the pump test Prior to the 24-hour constant-rate aquifer pump test, a step-drawdown test will be performed to assess the sustainable yield of the pumping well The step- drawdown test will be conducted using a submersible pump in the newly installed 6-inch well (MW- ' 8) The constant-rat p mue ping test will be_pe orrf med_using MW�8 atV the optimal flow rate determined during the step-drawdown test Subsequent to pump test activities, the well will be added to the quarterly monitoring and sampling program for this site The well location and top-of- casing elevation will also be surveyed by a licensed land surveyor prior to reporting future water level and chemical analytical data for the well A report of pump test activities will be submitted approximately four to six weeks following receipt of groundwater analytical reports 1 ' l 1Chevron1914521REPORTS\CPT and extraction well 5A report doc SECOR International Incorporated