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29 <br /> <br />piezometric surface slope s.toward the northeast at a gradient of about <br />_004. Ground water discharge from the coal seam toward Ennis Draw was <br />estimated to be about 0.1 acre foot per year. This discharge is very small <br />and coal aquifer discharge was not considered further in our analysis. <br />Continuous water level recorders have been installed on wells 61, <br />122 and 117 to record water level fluctuations in an attempt to estimate <br />the quantity of recharge. The water level fluctuations recorded to date <br />are presented in Figure 15. Since the generated data comprises a very <br />short period of time (approximately 2 months), it is not possible to <br />draw any definite conclusion concerning recharge. However, the fluctu- <br />ations do provide further evidence concerning the confined or unconfined <br />.nature of.the overburden waters. <br />• Water levels in wells penetrating confined aquifers can.be expected <br />l <br />to respond to changes in atmospheric pressure, while the water level in <br />wells penetrating unconfined aquifers are generally insensitive to changes <br />in atmospheric pressure. The water levels in wells 61 (coal) and 117 <br />(overburden) exhibit fluctuations typical of confined aquifers responding <br />to changes in atmospheric pressure. Note that the fluctuations in these <br />two wells correlate very nicely, indicating that the cause of the fluc- <br />tuations are the same in both cases. In contrast, the water level in <br />well 122 shows almost no fluctuation during the same time period. These <br />observations strongly indicate that the overburden aquifer is confined <br />in the vicinity of well 117 and unconfined in the vicinity of well 122. <br />D. Water Quality <br />Samples for the determination of water quality were collected at <br />two locations in the overburden (wells 117 and 172), two locations in <br />the coal (well 61 and 137) and three locations in Ennis Draw (wells 96, <br /> <br />