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Lk'Y 3 e \Pn. J . Hunter do Associates informally visited the site during the latter part of 1989 and after accepting the job of preparing this report , re-visited the site on March 14 , 1990. The photos used in Figs . 6 and 7 were taken at that time. AREA GEOLOGY AND HYDROGEOLOGY The project lies in an area that is classified in Reierer:ce I as a flood basin of the San Joaquin River , having; shallow deposits of Recent to Pleistoce" Age, of flood basin, low permeability, clay, silt , sand, gravel and sometimes organic materials. Sand content in the area is estimated to vary from 0 feet to i0 feet in the upper 50 feet of material (0 to 20 %) . The preparers; of this report did not witness either excavation and have seen only the material remaining in the spoil pile seen on Fissure 7 . the materials here, disturbed and mixed by the excavating process, appeared to be yellow colored, silty sand. The materials excavated were described by Richard Thorpe, who supervised all site operations , as tan co ored silty sand. No clays and organic materials were found, The upper 2 feet or so were probably sandy fill material covered by asphalt . at 12 feet in No groundwater was encountered during excavating, Excavation /I 1 ; however , some water entered the hole at night . and disappeared during the day, indicating some sort of tidal effect . Earth tides can be seen in some shallow water areas even when actual ocean tides are not involved. In any event , ground- water appears to be found at just below 12 feet , surface refer- ence. Inasmuch as the port deepwater channel is only about 150 feet north of the first excavation and the MSL elevation is only about plus 10 feet , water should have been encountered. Average od groundwater depth as estimated by the San Joaquin County Control District is shown on Figure S . The 1989 groundwater elevation shown for the project site is either outside or at the very perimeter of reap data. Mr. Freggiaro, Port of Stockton, reported that to his knowlede O there are no water wells within perhaps a one mile radius of the site. All water used in the Port is piped- in municipal water . Reference 0 1 shows the site to overly degraded aquifers which had a chloride content of over 300 ppm as far back as 1963. The current pumping depression of -40 feet shown northerly of the project site likely has drawn and will draw degraded water in that direction. - - - _.port i s i n a rection- naturally l_E y _l low _area_ t1-,at- a ithe r--had--_to -be - _--- The entire p - -- filled or regraded during port cartstruction: 5