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I w 11 Chevron/Alrport February 1991 above the top of the well screen. A 1-foot thick layer of hydrated bentonite pellets was placed above each sand filter pack and a cement surface sea[was set to grade level above the bentonite• he wellheads were sealed with locking plugs and a traffic-rated EMCO Wheaton street box was placed over the cap. Well depths are 65-feet below grade. Well construction details are presented with the drill logs 4 '.n Appendix B. t Standard Groundwater Technology well development procedures require neer we!is to be developed using a combination of balling,surging and pumping. Groundwater Technology employed a truck-mounted surge block and bailer system to develop the throe e to new wells. Monitoring well(MW-2)was developed on December i9 �90. San s as�d gtrawas s ndM1N 3 I develop monitoring wells MW-3 and MW 4 on December 4 further development of this well. A caused the serge-block to bind In the casing temporarily,preventing clayey sift was encountered within the casing In MW-4 at approximately 47-feet below grade. This F . . prevented further development and sampling of this well. Additionally,on D�_cember 3, 1990, approximaiely four well volumes were bailed from monitoring well MW-1• When the well volume had " recovered to approximately 60 percent of Its static water level,the well was sampled. i M An additional well permit was obtained frjm the County Environmental Health Division for the reinstallation of MW-4(Appendix A). On January 14, 1991,MW-4 was drilled out and a new well reconstructed In its place. This well was developed on January 24, 1991,and sampled following the SOPs described earl`'or(Appendix C). GROUNDWATER MONITORING AND SAMPLING On December 3, 1990,the four monitoring wells on the site were professionally surveyed to a common datum to determine location and wellhead elevations. On January 24, 1991,Groundwater einstalled monitoring wets MW- Technology shot levels of the r4 top of casing In relatlon to the top o`ecember 3,1990,prior .. casing of MW-2. Monitoring wells MW-1,KIW-2 and MW-3 were monitored on D to development and sampling using an electric probe: The well survey and monitoring data which were gathered on January 24 are presented on Table 3,and Appendix E presents the monitoring data on the appropriate record sheet. No separate-phase hydrocarbons were detected. _ GROUNDWATER TECHNOLOGY,INC.