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Mr Martin Harris Page 4 of 7 • The pilot borings for groundwater monitoring wells MWS MW9 and MW 10 were advanced to a depth of 21 feet bgs using 1—'/4 inch diameter direct push-drilling rods The pilot boring for MWI ID was initially advanced using CPT rods, but drilling was terminated at 32 feet due to rod refusal The boring was completed using direct push-drilling rods to a depth 38 feet bgs Soil samples were collected at 5-foot intervals in borings MWS, MW9 and MW 10 for soil characterization and possible laboratory analysis A soil sample was collected from MW I ID at a depth of 36 feet Samples collected from the capillary fringe (excluding MW11D) and the bottom of each pilot hole were submitted under chain of custody protocol to Argon Laboratories (ELAP #2359) for analyses Monitoring Well Construction The pilot borings for MW8, MW9, MW10, and MW11D were overdrilled with 8-inch diameter, hollow stem augers and converted into 2-inch diameter groundwater monitoring wells Based on static depth to groundwater (approximately 5 feet bgs), wells MW8, MW9, and MW10 were screened from 4 feet bgs to 19 feet bgs Well MWl lD was screened from approximately 30 feet_ bas to 40 feet bgs in sandy soil The wells were constructed of 2-inch diameter, Schedule 40 PVC casing and 0 010-inch slotted screen The filter pack in wells MWS, MW9, and MW10 consists of 16 feet of#2/12 Monterey sand The filter pack in well MW1 ID consists of 12 feet of#2112 Monterey sand The annular seals are constructed of 2 feet of hydrated bentonite pellets overlain by neat cement grout The wells were completed at the ground surface with traffic- rated, flush-mount well boxes and locking well caps Groundwater monitoring well locations are shown on Figure 2 Well construction details are shown on boring logs included in Attachment C All soil generated during drilling is currently being stored on site In DOT approved 55-gallon drums Wellhead Survey As required by AB 2886, the wellheads of the new monitoring wells were surveyed by a licensed surveyor to a horizontal accuracy of less than one meter and a vertical accuracy of 0 01 feet On March 25, 200, CSS Environmental Services, Inc surveyed the latitude and longitude of the site wells relative to the North American Datum (NAD83), and surveyed the wellhead elevations relative to the North American Vertical Datum (NAVD 88) using GPS observations The survey data is provided in Attachment D Well Development and Quarterly Groundwater Monitoring and Sampling On March 28 and 29, 2005, a Ground Zero technician monitored all site wells, developed the newly installed wells, and collected groundwater samples from all site wells Each new well was developed by surging, bailing and pumping until turbidity was minimized During the well development process, temperature, pH, and electrical conductivity were measured and allowed to stabilize prior to collecting a groundwater sample Groundwater purged from the wells was placed into marked DOT approved 55-gallon drums, which are currently stored on site pending disposal GtiGROUNDZL�TuffBoy\RcportslQMR1200511QM2005 doe