ARCHIVED REPORTS_XR0003775 - Laserfiche WebLink

Home Browse Search

' s r ' 29 October 1998 AGE-NC Project No 98-0448 ' Page 3 of 9 , ' 2 14 Monitoring Well Completion Soil boring MW-4 was dual-completed and soil borings MW-5 through MW-7 were single- completed as ground water monitoring wells utilizing schedule 40, 2-inch diameter blank polyvinylchlonde (PVC) casing and perforated, 2-inch diameter PVC casing (0 020-inch slot) Each well was installed by placing the PVC well casing assembly through the hollow stem of the augers to the total depth of the boring The augers were incrementally raised as a#3 Lonestar Lapis Luster sand(filter pack)was slowly poured down the annulus between the well casing and the inner J wall of the hollow stem auger The filter pack was placed adjacent to the screened casing from the bottom of the boring to a point approxunately two feet above the top of the screen The depth to the top of the filter pack was measured and approximately two to three feet of bentonite chips (annular seal) were placed above the filter pack and hydrated with clean tap water The remaining annular space was sealed with portland type II cement As-built well-construction diagrams are included as ' Figures 5 through 8 1 i 2 15 Surveying of Monitoring Wells On September 24 1998, a California state-Incensed survey engineer from Baumbach & Piazza, Inc ' surveyed a reference point on the top of each ground water monitoring well at the site to the nearest 0 01-foot relative to the City of Stockton Bench,Mark Datum # COS 101 The results of the monitoring well survey are contained in Table 3 The surveying report(Baumbach& Piazza Job No ' 9797) is presented in Appendix B ' 2 16 Well Development Activities ' On 25 August 1998,monitoring wells MW-4 through MW-7 were developed utilizing a Teflon hand bailer and a two-stage submersible pump Prior to development activities, depths to ground water and total well depths from MW-1 through MW-7 were measured to the nearest 0 01-foot utilizing ' a Solinst water level meter Ground water elevations were calculated by subtracting the depth to ground water from the surveyed casing elevations (Table 3) Ground water elevations were plotted %/ and contoured on a scaled site map(Figure 9) Approximately 40 to 45 gallons of ground water were ' purged from each screened interval; however, monitoring well MW-4B only' produced approximately 11 gallon of ground water prior tobeing pumped "dry" Ground water was purged from each well until the water produced was essentially sediment free Purged ground water was contamenzed in properly labeled D O T-approved model 17H 55-gallon drums and was stored on- site in an area lacking public access Monitoring well field logs for development activities are ' included with Appendix C Advanced GeoEnvironmental,Inc I