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11.0 GROUND -WATER MONITORING The proposed ground -water monitoring system described in the Ground -Water Monitoring Plan for the North County Sanitary Landfill prepared by EMCON in March 1988 focuses on the two initial fill modules. These modules have a ser- vice life of approximately 6 years. The system incorporates the two existing ground -water monitoring wells (G-1 and G-2), plus one proposed new well (G-3). The location of the new well is approximate; it may be necessary to change the location slightly to conform with construction or operation activities. The well locations were selected to provide a sufficient number and coverage of ' wells to yield ground -water samples that represent both background water qual- ity, as well as the quality of water passing beneath the site. ' As the ground -water contour map in Figure 11-1 shows, ground water in the site vicinity is mounded, with local flow directions potentially different than the south- west gradient observed regionally. The gradient is influenced by pumpage from nearby domestic and irrigation wells. Water -level measurements from the initial ' three landfill monitoring wells and the domestic on-site well will provide data over the next few years regarding fluctuations in flow directions. ' Wells G-1, G-2 and G-3 should be operational before initiating waste disposal at ' the facility. Other wells will be added as filling progresses across the site. ' To establish baseline ground -water quality data for the site, EMCON analyzed -water from Wells G-1, G-2, G-3 for the following ground samples and parame- ters: ' • Volatile organic compounds, 9 P • Total organic carbon 9 according to EPA Method 624 Semivolatile organic • Chloride compounds, according to ' EPA Method 625 - Nitrate • Pesticides and polychlorinated • Iron biphenyls, according to EPA Method 608 . Total dissolved solids ' PJ9 9390219A.00W 48 Rev. 0 July 19 1989