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� - �,��.._ a;1�,� �'� 3a�"��` c =��"� ,y �,�'ui� .� Y'`':�,�7 ��-; t �,�� `�;,�` ev 6 ..r �'�G��' �" :�� ""a""r"'r3t•:' G�"v."" :.,. ti 3� �:�v �.r- .S: rty -,�ry.� a pis• rt �':.v '. a '�;J�:+, �,y' r��;c� xu.�'•...i :,ac o �`'`i�'�+.4; i,».: Ma •c9�`� gyp; r; �;i>.. .a:. .ay.-. r,�k'r y.x:,E..-� v. r,,:v r - .,,._ :,",-'� v�.v;r "e w�w�u�' ea^; ,v -r r"T' =...i .�; cry- -vf:.,'.ai.v. 'f...-•� '�*^�., " a � 0.. sin 2 of S Pages The materials penetrated in our borings are chiefly clay, silty ,,. clay and clayey silt. Sandy strata, although present, are relatively minor and are silty or clayey and fine-grained, ' Bedding is absent or nondistinct but appears to be essentially horizontal, Owing to a moderate to high silt and/or fine- grained sand content, the clays are not highly plastic. Permeability of the clays and silts is low whereas the sands exhibit somewhat higher permeability. 'h . Modesto Formation is known to be underlain by older Pleistocene and Tertiary strata which in turn rest on crystalline basement: However, these formations are of no significance to this present study because of their depth. No faulting or fracturing is evident an or near this site, HYDROLOGY Owing ti., the fine-grained character of the sediments here the " position of the water table was difficult to determine during drilling but post drilling measurements show the static level to be about 44 feet below ground elevation. Free moisture on core t• samples was apparent beginning at about 35 feet in all holes. The water table at this time slopes very gently north westward, A However, regional trends, especially during summer months when there is considerable pumping east of Stockton are easterly. Published data show a fluctuation of 10 feet or more from season to season, for example in the spring of 1986 the wate:-..table here was less than 30 feet deep (See Ground Water and Hydraulic Maps in Annex). Owing to hydrologic and geologic features described above it seems likely that horizontal movement of ground water, and any contaminant, is very slow. Two municipal wells are located ,lust over 1/4 of a mile from the site. Well Sta. 30 is at the Corner of American and Taylor and it 2100 Feet from the site. Well Sta 50 is located at the corner of Wilson Way and Clay abo:;t 2200 Feet from this site. We understand the wells are pumping from deep aquifers and do not tap the ground water we are investigating, SAMPLING k" Borehole :samples were taken every 5 Feet during drilling. Most of these samples were sent to the California Water Lab in Modesto. The results of the soil samples are given in Table 1. Water samples were obtained using a clean bailer and decanted into VOA Vials supplied by the laboratory. The results of this ,�, sampling are shown in Table 2.