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y �aY s a F. Fie No.10763 19 RYa 6 December 1991 IN " .pumping test, the pump was stopped and the pumped well was allowed to recharge., A computerized data logger was used to continuously record the recharge level in the pumping, well , �,abs,• 'r* ,r ,, f Ahandheld groundwater probe was used to measure the recharge in the ob.ervation wells. h .. 4.0 RESULTS OF INVESTIGATION :3.1.;Subsurface Still Profile " Extrapolation of data obtained during the advancement of soil borings 90-1 and 90-2 enabled an I r interpretation of the subsurface soil profile to be determined. Figure 7 illustrates a lithologic cross y section for the areas near the 1987 tank excavations. According to the lithologic cross section, clay - and silt comprise the majority of the subsurface soil in the vicinity of the 1987 tank -excavations *4 ", Several discontinuous and "pinched-out" lenses of sand also exist in the vicinity of the 1987 tank I c •N"+ = „ ,4 excavations. This corresponds closely to subsurface conditions noted in the boring logs for.the i§ ..entire area of this investigation. 3.2 Local Groundwater' Well influence Survey X I . We conducted a research survey of groundwater wells located within 2,000 feet of the Rainbo Bakery to determine their possible influence on the subject property wells. According to documents » 5$# on file with the State of California Department of Water Resources, three wells existed within aZ"��s;*'' �r2,000 feet radius of the'Rainbo Bakery at the time of our investigation. All three-wells were "located south of the subject property (see Figure 8). Well A was installed to a depth of 217 fe t e Ire in,.1960 for irrigation purposes. Well B was installed to a depth of 220 feet in 1963 for irrigation purposes. Well C was installed to a depth of 84 feet in 1949 for irrigation purposes p wr i y � 1 According to this survey, the two wells in closest proximity to the subject property are:.both ' Jr. y } a` pumping from a deep aquifer approximately 220 feet below the surface and subsequently ; ,4 approximately 150 feet deeper than the Rainbo Bakery wells. Although we could not identify the b a screened interval of these wells from the well log documents, we feel that these wells,under normal IfIk a " pumping conditions, should:not influence the Rainbo Bakery wells. Well C,while'shallow enough f' I 'to potentially influence the Rainbo Bakery wells,appears to be far enough away so as to minimally r ur t,(`4 '"kr influence the subject property wells under normal pumping conditions. ' 13 Soil Analytical Laboratory Results Ell Soil samples obtained from the Rainbo Bakery site were analyzed for the presence of total `petroleum hydrocarbons (TPH), aromatic volatile organics (AVO's) and 'lead as -per's "recommendations in the Tri-Regional guidelines published by the Regional Water Quality Control r j` Board.,. Table I summarizes the analytical laboratory results for the soil samples obtained'at the i L r subject property: Figure 9 illustrates the locations where the sosamples were ined_and their, hsoil lobta i corresponding contaminant concentrations: Copies of the analytical laboratory results for the soil samples are included..as , Appendix V11L 311. CeNSU 1 �4t + L'.FNVNa.'v'n'"�/L AhG,.dAYi<F.X'(121f'3`aW'-*r.+wr�.•.�. . •.••••�•••••�••aa'LY+Wr��'Ffli]6LfA�✓K.w�1�f�[,it' pW11'Y!M'&�'�✓� r �+i„