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w W Y. I MWOM M 94 L+7 ^ Prior to sampling, tra well was developed ter' purging a tctal .. of cne well casing volu,.e. Development volumes were reduced ; . from the five used in Phase I, to one, when it became apparent. LA that neither well was capable of yielding signiti.icant amounts of water. Development ,rater was periodically mor:itored for PH and electrical conductivity, and drummed onsite for ultimate disposal pending analytical results. t � F' A ground water sample from each well was collected immediately after development. Upon col�?ction, groundwater samples were + stored on ice, and delivered that day to Anlab, Sacramento, ! + for chemical analyses. ; , 4 . 2 LITHOLOGIC SEQUENCE AND FIRST GROUNDWATER Boring logs for all threemonitor wells are presented in the �w+ Appendix. Briefly, the subsurface strata consist primarily of sandy clays and silty ;ands of variable moi.sture content through a depth of 95 feet . For M11-1 , both coarsest lithologic units and elevated '.INu readings, as shown in :Table 4-2 and Figure ..4--3, were i � associated primarily with the depth interval' 65-75 ft, and s,. served as the basis for setting the well screen interval at a depth sufficient to intersect this lithologic sequence. z should be noted however, that HNu instrument malfunction prevented PID readings over the entire boring (during Phase b. I ) . Similarly, field evaluation of moisture content did not suggest the need for a sha-1.1over screening interval, to the j onsite geologist. During Phase I1', field HNu readings were inconclusive, and were not used in determining screening interval. After well completion and development, water levelrnc overed ;,. to a depth of approximately 31 feet below ground surface 11111- �.: 1 '9a.i:fir level was subsequently remeasured on July 27, 6 P1'1, 4-7