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str � <br /> Prior to sampling, the well was developed by purging a total <br /> Of one well casing volume. Development volumes were reduced <br /> from the five used in Phase I, to one, when it became apparent <br /> that neither well was capable of yielding significant amounts <br /> of water_ Development water was periodically monitored for pH <br /> and electrical conductivity, and drummed onsite for ultimate <br /> disposal pending analytical results. <br /> A ground water sample from each well was collected immediately <br /> after development. Upon collection, groundwater samples were <br /> stored on ice, and delivered that day to Anlab, Sacramento, <br /> fvr chemical analyses. <br /> 4 .2 LITHOLOGIC SEQUENCE AND FIRST GROUNDWATER <br /> Boring logs for all three monitor wells are presented in the <br /> Appendix. Briefly, the subsurface strata consist primarily of <br /> sandy clays and silty sands of variable moisture content <br /> through a depth of 95 feet. <br /> For MW-1 , both coarsest lithologic units and elevated HNu <br /> readings, as shown in Fable 4-2 and Figure 4-3, were <br /> associated primarily with the depth interval F5-75 ft, and <br /> served as the basis for setting the well screen interval at a <br /> depth sufficient to intersect this lithologic sequence. It <br /> should be noted however, that HKu instrument malfunction <br /> prevented PID readings over the entire boring (during Phase <br /> I ) . Similarly, field evaluation of mo 5ture content did not <br /> suggest the need for a shallower screening interval to the <br /> onsite geologist. During Phase II, field HNu readings were <br /> inconclusive, and were not used in determining screening <br /> interval . <br /> After well completion and develepment, water level recovered <br /> to a depth of approximately 31 feet below ground surface (MW- <br /> 1 ) . Water level was subsequently remeasured on July 27, b PM, <br /> 4-7 <br />