ARCHIVED REPORTS_XR0007171 - Laserfiche WebLink

Home Browse Search

' BU"Environmental Management Inc U-Haul#709-50 002-70950-02 Sema-Annual Report 12/14/00 3.0 GROUNDWATER MONITORING PROGRAM The groundwater monitoring program discussed below included two separate monitoring events conducted in June and September 2000 The current groundwater monitoring program has been modified from the previous groundwater monitoring program last conducted in February 2000 to include sample collection from all possible monitoring points This includes wells installed by SOTA and both of the well casings associated with the new nested wells installed in January 2000 Previous groundwater monitoring conducted in February 2000 only included collection of groundwater samples from one (the uppermost) of two well casings of the new nested wells The additional sampling of each well casing at the site was requested by the SJCHS The measurement and sampling methods employed during the two groundwater monitoring events are discussed in the following sections 3.1 JUNE 2000 MONITORING EVENT 3.11 Groundwater Measurements—June 26, 2000. On June 26, 2000, Blaes Environmental measured the depth to groundwater in 23 groundwater monitor well casings associated with the site Some of the gauged well casings were associated with the nested wells (MW-IAB, etc) that were installed in January 2000 Groundwater levels were measured from the top of the surveyed monitoring well casing to the groundwater surface, and were measured to the nearest 0 01-foot using a Heron TM electric water level sounder The water level depth and time of measurement were recorded on a standard field data sheet The field data sheet is included in Appendix A and summarized in Table 3 Using the elevation of the well casing, the elevation of groundwater in each well can be calculated Groundwater depth measurements were performed in accordance with Blaes Environmental groundwater monitoring procedures presented in Appendix B Groundwater depths recorded in June 2000 ranged from 42 25 feet bgs at MW- 7 to 45 68 feet bgs at IMW-6 These measurements corresponded to groundwater elevations ranging from 24 49 to 26 23 feet below mean sea level No free-phase hydrocarbons were observed during collection of groundwater level measurements The data from the uppermost well casing containing water were used to create a 6