2008-12-03_PERMIT FILE - C1992081A (12)

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Seasonal Variability and Trends. Tables 7-1, 7-2, and 7-3 present the water level and chemistry data (through 1995) for wells HGDALI, HGDAL2, and HGDAL3, respectively (recent data, including data for well HGDAL4 are presented in the Annual Hydrology Reports, which are submitted to CDMG under separate cover) . Water level ranged from 1.6 to 8.9 feet below ground surface (bgs), 0.7 to 13.5 feet bgs, and 0.9 to 7.5 feet bgs at wells HGDALI, HGDAL2 and HGDAL3, respectively. On 5/4/95, Che wafer ~eacl ~,. wci~ :i~~~,,.~ wu~ <<Y.,~.~v as -0.92 feet, which indicates that the water level in the casing was above ground surface. Generally, no water level trends or seasonality are evident at the wells, however, water levels tend to be higher during spring snowmelt months which indicates that snowmelt may be recharging the alluvium. Total dissolved solids (TDS), magnesium (Mg), sodium (Na) and sulfate (SOq) concentrations in We11 HGDALI are generally twice those measured in Well HGDAL2. Following the completion of well HGDAL3 in November 1993, the groundwater quality data demonstrates that a similar groundwater chemistry pattern exists between HGDALI and HGDAL3 as what existed between HGDALI and HGDAL2. The TDS, Mg, Na and SOa concentrations measured in well HGDALI were generally three times the corresponding concentrations measured in well HGDAL3, however, they were generally only twice those measured in well HGDAL2. The TDS concentrations at well HGDALI ranged from 15,000 mg/1 to 60,000 mg/1 while the TDS concentrations at well HGDAL2 ranged from 2,000 mg/1 and 28,000 mg/1 and at well HGDAL3 ranged from 19,000 to 19,000 mg/1. The TDS value at HGDAL2 for 08/13/90 appears to be erroneous as the SOy concentration is 13 times the reported TDS value. Prior to 1993, trace metal constituents (aluminum [A1], boron [Bj, cadmium [Cd], copper [Cu], iron [Fe], lead [Pb], manganese [Mn], molybdenum [MO], selenium [Se] and zinc [Zn] were analyzed for the total fraction. Following the acquisition of the Loadout by HGTI, the analytical analysis for groundwater trace metal constituents was changed to the dissolved fraction. The current groundwater analytical suite is presented in Table 13-2 under Tab 13. • RN-03 la Revised 06/08