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BUdErEnvironmenta!Management,Inc U-Haul#709-50 002-70950-02 Semi-Annual Report 12/14/00 3 2 5EPTEMBER 2000 MONITORING EVENT 3.21 Groundwater Measurements=-September 26. 2000 On September 26, 2000, Blaes Environmental measured the depth to groundwater in 23 groundwater ' monitor wells casings associated with the site Groundwater levels were measured with the same method as described in Section 3 1 1 The water level depth and measurement time were recorded on a field data sheet by the field technician The field data sheet for the September 2000 monitoring event is included in Appendix D and the measurements are presented in Table 3 ' Groundwater depths recorded in September 2000 4 ranged from 50 g 8 feet bgs at MW-4B to 53 10 feet bgs ' at MW-2 These measurements indicated that theoundwater level dropped pped approximately seven feet compared to the June 2000 groundwater levels As a result, the upper wells ("A" casings) did not contain ' groundwater in September These wells are indicated as "well dry" on Table 3 Depth to groundwater measurements corresponded to groundwater elevations ranging from 32 24 to 32 58 feet below mean sea level No free-phase hydrocarbons were observed during collection of groundwater level measurements ' The data from the middle well casing containing water were used to create a groundwater surface map showing the groundwater flow direction across the site The average groundwater flow direction as of �j September 26, 2000 was inconclusive since the groundwater surface was relatively flat Other water level data collected from well casings with screened intervals below the groundwater level indicated that water levels in the lower casings were slightly lower than water levels in the upper well casings by approximately 0 2 feet This data suggested that groundwater flow had a slight downward gradient of approximately 0 007 feet per foot Monitor wells used to compare water Ievels included MW- 1, MW-113, MW-2, MW-2B, MW-5, MW-513, MW-6, and MW-6B These monitor wells include one lower "C"casing and a nearby nested well (within approximately 10 feet)with upper"A' and middle "B" casings The water levels in the lower casings were approximately 20 feet above the screened interval Blaes Environmental technicians also collected dissolved oxygen level measurements from each well casing using a YSI-85 dissolved oxygen meter Measurements indicated that dissolved oxygen levels in groundwater ranged from 0 3% at monitor wells MW-4 and MW-6 to 412% at monitor well MW-8 Dissolved oxygen levels above 10%were observed at monitor wells MW-3, MW-5, and MW-8 (Table 3) �1 f � II G