Laserfiche WebLink
1 <br /> 3 <br /> Mr. H. C. Winsor <br /> September 9, 1987 <br /> Page 5 <br /> i' <br /> These elevations were used to construct the groundwater elevation <br /> contours shown on Figure 1. The groundwater flow direction has <br /> jf changed since April 1987 to a more westerly direction. The ;apparent <br /> mounding effect around Well 12 may be dve to the shutdown or Well. 12 <br /> in December 1986, coupled with increased pumping of nearby municipal <br /> and irrigation wells in the spring and summer of 1987. Depth to <br /> static groundwater level in Well 12 is shown in Table 2. <br /> i--'� Table 2. Depth to Static Groundwater Level, Well 12 <br /> Depth to groundwater,- <br /> Date Feet <br /> w _ <br /> January 6, 1987 52.7 <br /> February 3, 1987 S1.? <br /> :larch 3, 3.987 <br /> k <br /> April 7, 1987 51.053.1 <br /> May 5, 1987 54.8 <br /> . June 2, 1987 56.0 <br /> a� July 7, 1987 58.2 <br /> s August 4, 1987 61.3 <br /> Soil and Groundwater Quality <br /> €' <br /> Selected subsurface soil samples from each borehole drilled in July <br /> 1987 and one groundwater sample from each monitoring well were <br /> i analyzed for fuel characterization and benzene, toluene, and xylene <br /> at California Department of Health services (DIiS) certified Eureka <br /> laboratories in Sacramento. Laboratory results for soil samples <br /> a � analyzed are summarized in Table 3. Complete results are shown in <br /> Exhibit D. Benzene concentrations in Samples B-1D, B-IG. B-1a, and <br /> B-2I exceed Regional Boarl designated levels. Benzene conn-entra- <br /> tions in all other soil samples analyzed were below Regional Board <br /> designated levels. it is probable that the <br /> towards the y gasoline migrated down <br /> groundwater table in the vicinity of Borehole B-1. <br /> 6 f Sample B-21 is the bottom-hole sample taken from just above the <br /> groundwater surface in Borehole B-2. The benzene concentration <br /> this sample is probably. due to a capillary_ fringe eff_e_ct._--Toluene_-_._ <br /> _ a_ ---and-.xylene 9f <br /> y levels--are- below--Regional'-Soard desicnated levels in all <br /> soil samples analyzed. No levels have been established for total <br /> y: <br /> fuel hydrocarbons. <br /> a R Groundwater` .samples from monitoring Wells W-1, W-2, W-3, W-4� <br /> W-S, and . W-6 were collected b BC p <br /> t y personnel on July 23, 1987. <br /> k Results are summarized in Table '4. Complete reeults are shown in <br /> is Exhibit D. Benzene concentrations in samples from Wells W-1, W-2, <br /> W-4, and W-y; exceeded: DHS action levels for drinking water. <br /> ;. -.•.....A ...tea-,-.:.:: , <br /> r <br />