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CHAPTER VI PRELIMINARY FINDINGS o N CJ1 presents hydrographs of three observation wells. Figure 5 presents ~ hydrographs of two selected springs, one approximately 500 feet west of the Meeker Well and one about 700 feet to the east. The only wells not exhibiting a downward trend were the alluvial wells on the east flank of Meeker Dome. Most of the spring stations established along the south-central face of Meeker Dome have ceased flowing entirely, although some continue to flow at drastically reduced rates. The overall quality of the saline ground water and springs has not changed appreciably over the course of this study. Minor water quality differences between the wells and the spring stations are believed to be due to minor differences in local geochemistry. Also, due to the effect of rainfall and runoff, more variability occurred in the quality of water in springs and seeps than in wells. In the year following plugging--July 1981 through June 1982--salt loading from the dome was reduced to an average of 12,OOO tons per year from an estimated 0.73 cfs of seepage. This represents a reduction of 9,400 tons per year. In addition, the salt loading continued to decline and, as of June 1982, the loading rate had decreased to 5,600 tons per year from 0.34 cfs of seepage for a total reduction of 15,800 tons. This represents a 1.6-mg!L reduction at Imperial Dam, Thus, at the end of the first year after the wells were plugged, the salt loading in the White River from Meeker Dome seepage was reduced 74 percent from pre- plugging levels. Additional monitoring is expected to show a further reduction in salt loading. An unusual fluctuation in sodium and chloride concentrations oc- curred during the July 1981-June 1982 period at the gaging station 1 1!2 miles upstream of the dome. Although analysis of the most recent water quality data indicates that sodium and chloride levels have returned to preplugging concentrations, sodium and chloride levels will continue to be monitored occasionally even after the current studies end. Initial Conclusions The spring and well data support the conclusions made in the veri- fication program, that is, the springs flowing from the Morrison Forma- tion along the base of Meeker Dome were a direct result of hydraulic communication between that formation and deep saline aquifers through the unsealed Scott, James, and Marland Wells. . Analysis of the monitoring data collected at the observation wells and spring stations indicates that the plugging of the James, Scott, and Marland Wells impeded the hydraulic connection that existed between the shallow and deep aquifers. Furthermore, the continuing decline in water levels in the observation wells provides strong evidence that the well plugs are still intact. 22