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<br />' <br /> GP.OUND IdATER F10NITORING <br />1 <br /> BEDROCK <br />' Sandstone Aquifers <br /> Four sandstone aquifers are monitored at the site. They are, in <br />' ascending order: Trout Creek Formation (2 wells), hliddle Sandstone (3 <br /> wells), Twentymile Sandstone (2 wells), and the lowermost sandst one <br /> bench of the llhite Sandstones (3 wells). The Ne. 5 t•1ine is between the <br /> Trout Creek Formation and the Middle Sandstone. The Plo. 9 Mine is <br />' between the Twentymile Sandstone and the White Sands tone. <br /> Water Levels <br />' <br /> Plots of water levels in the upper three aquifers are presented in <br /> Figure 3 to figure 10. The water level measured in the Twentymile <br />' Sandstone has continued to remain fairly constant in elevation. <br /> The plots indicate that the water levels in the Middle Sandstone have <br />' continued to decline. The maximum short-term rate of decline is still <br />approximately 33 feet per year, however, Well TR-4 now has the steepest <br /> rate of decline, when in the past it had declined the least. This is <br /> probably because the No. 5 Kline has been extended to the east and <br /> therefore closer to Well TR-4 in 1983. Based upon the 1983 piezometric <br />' map, the ground water gradient in the Middle Sandstone has not changed <br /> significantly and is approximately 450 feet per mile to the west. <br />' The 1983 piezometric levels in the White Sandstone indicate that the No. <br />9 I4ine may not be effecting the lJhite Sandstone to the degree estimated <br />in the permit application. The water levels in wells 81-03a and 81-19 <br />' are now rising at approximately the same rate that they are falling <br />(five feet per year) in well 81-04a. The rate of decline previously <br />estimated for Well 81-03a may have been incorrect. The first water <br />' levels measured in the aiell may have been abnormally high because the <br />water level in the well had not yet stabilized following drilling of the <br />well. Based upon the 1983 piezometric map, the ground water gradient in <br />the White Sandstone has not changed significantly and is approximately <br />' 100 feet per~ea-r` to the northwest. <br />rv.~ (.._ <br />4later Quality <br />' The water quality data for the sandstone aquifers are presented on Table <br />5 to Table 13. The data indicates that the water quality of all four <br />' sandstone aquifers is fairly constant over the whole period of <br />measurement. <br /> <br /> <br />I -~- <br />