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screened interval. The annular space above and between the sanded zones was filled with one foot of bentonite pellets and a cement-bentonite grout. This allows two different soil strata corresponding to the different depths of vapor extraction wells to be monitored independently. Construction details are shown in the well logs(App On 18 January one vapor extraction well(V3) was installed offsite and downgradient of the source of petroleum hydrocarbons,in Rosemarie Lane where the groundwater will be depressed by the groundwater extraction system. The well was installed to optimize vapor extraction and the removal of petroleum hydrocarbons presently trapped below the water table. In V3,ground- water was encountered in a silty clay 33 feet bgs,and the well was completed 40 feet bgs. The er. The well as constructed with borehole was drilled Schedule 40,f u h ti eaded FVC casing The well screen 2-inch diamete consisted of a 0-020- inch slotted PVC pipe. On 18 January a groundwater recovery well (RW4) was installed because nearby well MW10, er, an insufficient amount formerly proposed forgroundwaterton. t!e recovelad only 2.5 feet of ry well (RW4) and tiletmon monitoring well (MW 10) for groundwater extraction. were intended to contain a water column of at least 15 feet,but because static groundwater was yer at ut 39 RW4 was led to 45 feet, to ensure that a suffiat cient column of water wut 35 feet and a clay aould be aovailablee nt,tile well for pumping and draw- ensure that down during extraction. On 21 January 1991 one groundwater monitoring well (MW12) was installed downgradient and northeast of the site to further define the downgradient extent of the dissolved petroleum hydro- carbon plume. MW12 was completed 40 feet bgs, with 4-inch-diameter PVC casing; the screen was 15 feet long,and 25 feet of blank casing extended from the screen to the surface. On 18-19 February 1991 three soil valor extraction wells(V 1,V2,and V4)were installed at the site. Their construction was postponed pending the City of Stockton's decision on the permit for building construction at the site. Because the construction permit was refused,these wells were installed at or near the former tank field at locations that will be most effective for hydrocarbon extraction(Figure 3). Two vapor extraction wells (V2, V4)were completed 40 feet bgs with 2-inch•diamcter PVC casing,including 15-20 feet of screen. Well V 1 was completed with a 4-inch-diameter casing, including a 20-foot-long screen,so it could be used for both soil vapor and groundwater extrac- tion. If well,,RW 1 and RW2 cannot depress the water table,this well will help to dewater the soils,which are presently saturated with water that has been heavily impacted. esu-,cna9.u�vin. 7