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groundwater depths at various dates and for approximating the direction of the dip of the water table (hydraulic gradient) . The water table dip is and has been approximately east from the project site, perhaps with a northerly component This is shown on Figure 3 . Figure 5 shows that ' the water table in the Spring, 1991 was at an elevation of about -50 ' below MSL Because the ground elevation is about +27 ' , the depth to groundwater would be about 77 ' from the surface This is shown on Figure 6, a depth to groundwater map a TehJghest 'ate a e, ls�yi • recent y,ea„ra occurred Yn the 5p�ri g o V;Jk9J86 Figure 7 This shows the depth to groundwater to be -201 below MSL, or e l 4g oud I le a The excavation and sampling byTO in 1988 was at depths of -28 ' and -29 ' below ground level (bgl ) , only about ' 18 ' above the high water level in the vadose zone that occurred in 1986. This means that any migrating plume of hydrocarbons would not be found above about -47 ' because ' lateral migration is curtailed as a general rule to a 30 to 40 degree angle from the vertical That is , as an example , at a depth of 50 ' bgl , lateral migration might be in the ' order of 40 ' or so and would not reach test wells located at much greater distances, unless carried by groundwater flow. Qe o e he ado�s a nye 'w'ou'ld not, e� wo ,� e a ove e h ghes g o n a ev on-r—M,,MIMan_y, sfoAL und a +hallo •de hs o d a e a ther sources , he samp g •pr„o,grr1am p opos , 7 •Rereiri 1s-na7flFd on thi s ani ept � 1 1 Figures 8 and 9 are from SOILS OF SAN JOA UIN COUNTY CALIFORNIA, By Walter Weir z pro}ect acre idem i ied a�s Stac on Adobe a al hough they spoi excava s from to- are was called � nd ' � WORK PLAN ' GENERAL ' It is proposed that three monitor el s be drilled located as shown on Figure— 3 . Me ed t 1 e"ask' s o�u�rc a an n a o e da n g ad a 1 1 o is p ' ' that this well bye s,ampled at -2 gl -3 gl and ' highes , r'a aZn`d -7r. 'bg�l ar at the ,oap o the water to 1 e i f f o�und —e—,e was samp,lied at -29 ' bg l i n 1986 I * is ' recom en ed that the first` core sample in MWW 2 land #3tobe fi -- 7 One and one half to two feet long sampling devices wil be used (detailed below) . This depth will gave ' samples at the highest level reached by groundwater in the vadose zone The next sample would be 5 ' lower at -52 ' and then at 10 ' intervals, -62 ' and -72 ' The water table is , expected to be found at about -77 'bgl . This program should ' give ample coverage through the vadose zone while keepingi 3