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Work Plan for Monitoring Well Installations Austin Road Landfill Unit,California Page 3 been utilized in monitoring well installation projects in the past. Minimum 3-foot bentonite transition seals will be placed above the primary filter sand-pack. The surface seal will extend from ground surface to the top of the transition seal and will be filled with cement/bentonite slurry. Tremie pipes will be utilized as necessary when emplacing the transition and annular seals, in accordance with California well construction regulations. Additionally, the casings will be supported and centered within the 10 inch borehole every 20 feet using centralizers. A minimum 5-feet long locking protective cover will be placed in the hole, and will extend at least 6-inches above the top of the PVC riser. The protective cover will be encased in cement or other appropriate material up to the ground surface. Coarse sand or pea gravel will be placed inside the protective casing to about 6 inches below the top of the PVC riser. Weep holes will be drilled into each protective casing. A concrete pad,at least 30-in x 30-in x 4-in in dimension, will be constructed surrounding each well, sloped away from the well to promote drainage. A minimum of three bumper posts,at least three inches in diameter,three feet above ground, will be placed immediately outside of the pad. The posts will extend at least two feet below ground, will be cemented in place, and will be filled with cement or grout. The posts will be painted bright yellow or similar easily identifiable color. Weather-resistant padlocks will be placed on each locking well lid. Drilling equipment,including the drill rig,will be decontaminated prior to mobilizing to the site. All downhole equipment will be decontaminated between each borehole using a high-pressure rinse. It is not necessary to contain the decontamination water generated during the project. Wells will be developed for a minimum of two hours using surging and pumping to remove suspended sediments. Development will continue until two conditions have been attained: an equal volume of water utilized during drilling activities has been removed from the borehole, and field parameters (pH, specific conductivity,temperature,and turbidity)have stabilized at acceptable levels. Well development activities to be conducted on the newly-installed wells will attempt to decrease the turbidity levels as much as possible, with a goal of 5 NTUs. Installed Deep Zone wells AMW-1313, AMW-21, AMW-22, and AMW-23 were able to achieve 5 NTUs after development,which suggests that 5 NTUs are possible for the proposed wells. However, available data collected during routine sampling of the monitoring well network at the facility suggests a range of about 14 to 215 NTUs. Development activities will not occur until at least 48 hours after the well is completed. The driller will supply all necessary development equipment. During development,water removed from the monitoring well will be containerized and subsequently analyzed for all the organic parameters listed in the Austin Road Waste Discharge Requirements Order No. R5-2003-0049 Table VI (Appendix A). If laboratory results indicate that the containerized water demonstrates any detectable concentrations, the water will be disposed of in accordance with applicable regulations. If the containerized water exhibits no detectable concentrations,it will be discharged to the ground in the general vicinity of the collection tank. Upon completion, each well will be surveyed by a California licensed surveyor. Each monitoring well will be surveyed for vertical and horizontal datum coordinates to the nearest hundredth of a foot. Horizontal coordinates will be recorded in state plane coordinates and longitude / latitude coordinates. Vertical measurements will be recorded in feet below or above mean sea-level from the ground surface at the base of the protective outer casing and a designated reference point on the top of the well casing. Groundwater elevation measurements and total depth measurements will be made to the nearest hundredth of a foot at each well at the completion of the drilling process as well as during routine site-wide groundwater elevation collection events in the future using a calibrated depth indicator instrument. California drilling and well construction requirements will be adhered to. In the event that particular items in this scope of work conflict with California requirements,the California requirements will take precedent. It is expected that Level D health and safety protection will be sufficient. The drilling contractor will supply all of the necessary personal safety equipment for its employees. Herst & Associates, Inc. has developed a site- specific Health and Safety Plan(Appendix A)that indentifies specific action levels.