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and ranged from 64 to 65 feet in most monitor wells on December 3 Recent construction and grading activities on the former Barbot property have resulted in a rise in the ground elevation around GT-9, so the depth in that well was more than 67 feet A standpipe has'been added to the top of the PVC casing on this well, but it has not been-re-surveyed and was not used in the calculation of the elevation of the water table Groundwater was not encountered'm any of the CPT borings between 64 and 65 feet Feist groundwater was reached at a depth of between 69 and 75 feet in these borings This implies that groundwater in the Riverbank Formation is semi-confined by the basal Modesto Aquitard and perhaps by the haidpan layer near the top of the Riverbank Formation 3.3 Hydraulic Gradient and Groundwater Flow Direction The calculated water table elevations were used to construct the groundwater elevation map in Figure 7 Elevation contours again form an are that is centered in the southern part of the site, but has shifted eastward and is no longer centered on GT-1 The water level is higher to the east, north, and west of GT-1, implying that the groundwater flow direction is radial toward the low spot in the vicinity of GT-10 From there, it appears that the flow converges and flows southward onto the Barbot property As previously stated, the casing elevation of GT-9 has been changed, so this well cannot be used until it is re-surveyed 3.4 Analytical Results In this section, groundwater analytical results from the three Riverbank channel deposits (aquifer . zones) are discussed Groundwater was not present in the Modesto Channel 3.4.1 First Riverbank Channel Figures 3-6 show the sampled intervals in all CPT borings and monitor wells except GT-5 and GT- 9 wluch are not included in any of the cross sections Samples were collected from the 1St Riverbank Channel in GT-6 (cross section F-G) and GT-5, which are screened from 50-75 feet and therefore intersect the channel Well GT-9 is also screened in this interval, but as shown in cross section A-B the 1St Riverbank Channel pinches out between GT-3 and CPT-5 and could theiefoie riot be sanpled in GT-9 or CPT-5 In all, a total of seven of the samples were from this channel Groundwater was encountered very near the base of this channel in CPT-1, and samples were collected in the interval 69-74 feet across the contact between the channel and the underlying mudstone (cross section D-E) The samples contained high concentrations of sand and mud, but were not filtered before being preserved The laboratory reported extremely high concentrations of both gasoline and diesel in the sample (Table 2) Iii fact, if accurate, the TPH-d concentration of 670,000,000 parts per billion (ppb) would indicate that the diesel sample was two-thirds diesel and one-third water This value is not consistent with visual and olfactory observation of the sample, as well as with previous results from nearby bonngs The sample exhibited a moderately strong diesel odor, but had neither the color nor typical odor of free-please diesel fuel Further, this sample was collected at a depth of 5 feet below the static watei level in the wells, which would suggest that a layer of free product approximately 5 feet thick is present in the vicinity of CPT-1 A water sample collected in 1996 from GT-4, which is no more than 5 feet away fiom CPT-1, had a TPH-d Is concentration of 1,730,000 ppb (less than 3% of the concentration reported from CPT-1), which 5