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06 February 2003 AGE-NC Project No. 98-0504 Page - of 9 4.2. WELL COMPLETION AND WELL ELEVATION SURVEY The 8.25-inch diameter pilot borings will be single-completed as a ground water monitoring wells utilizing 2-inch diameter schedule 40 polyvinylchloride (PVC) 0.020-inch slotted well screen and blank well casing. A 20--foot length of well screen is anticipated for installation of the monitoring well. A proposed monitoring well construction diagram is depicted in Figure 3. Alter installing the well casing in each pilot boring, a filter pack material consisting of-pre-washed #2/12 Lonestar sand will be added through the augers over the screen interval to approximately two feet above the screened interval. Following placement of the filter pack, the well will be surged to assist in settling the filter pack. Additional sand will be added if settling occurs. A nominal two-foot bentonite seal (pell plug non-coded bentonite pellets) will be placed above the filter pack to minimize the potential for grout penetration into the screened section of the well. 'I he bentonite seal will be formed by pouring bentonite pellets into the annulus and allowing them to settle on the filter pack. The bentonite pellets will be allowed to hydrate for a ri-onimum of one-half hour prior to grouting. The remaining annular space will be filled within one foot of the ground surface with a ccment grout. The grout mixture will consist ofType €III portland neat cement and not more than 6 gallons ofwater per 94-pound sack of cement. The grout will be placed by pumping through tremmic pipe. -routing inspection will be scheduled with EHD personnel. Following completion of the monitoring wells, wc;11 elevations will be surveyed by a California- licensed surveyor relative to a City of Stockton elevation ben.c.h .tar;`. 4.3. WELL DEVELOPMENT Development of the proposed wells will consist of a combination of bailing with a stainless steel bailer to remove the major portion of fine-grained sediment from inside the well, surging to flush out or draw in sediment from the filter pack and additional ground water evacuation(pur%ing)with a Waters bailing pump to finish the removal of fine.-grained sediment. Development'-d purging activities will be continued until field parameter fp 1-1. electrical conductivity, and temperatur;) readings have stabilized and purged water is visual!; sediment-free. 4.4. GROUNDWATER SAMPLING PROCEDL.TES Gr AM&N,ater sample will be perfon-ned in accordance with pertinent applicabic sampling protocols, details of which are presented below. Advarwed GeoFnvironnwntal,Enr..