PERMFILE46234 - Laserfiche WebLink

Home Browse Search

locations and the potentiometric surface for the Yedge overburden, respectively. Water level date for Yells YOY1 to 19 end 22 to 27 were collected from August, 1980 through August, 1983 end then again from June, 1990 to the present. Yell YOV20 collapsed some time prior to 1990, thus its period of record is from August, 1980 until August, 1983. Peter level monitoring et Wells YOV28 to 30 began in July, 1990 (see Table T-3). Monthly water level date for the overburden wells, including hydrogrephs, are presented in Appendix 7-2. Table 7-2 summarizes the general well completion information for these wells. Ground water in the Wedge overburden appears to occur under both confined and unconfined conditions. Aquifer tests conducted at Yells YOV9, 28, and 30 indicate confined conditions exist at those sites, whereas a stmt ler test et Vell YOV•1 indicates unconfined conditions exist there (see "Aquifer Characteristics" section, Tab 7). It should be noted, however, that the calculated transmissivity of 838 gpd/ft for Yell YOV1 is much higher then one would expect from an overburden well. The bottom cement plug at 62 to 69 feet is suspected to have failed (see completion summery on Page 7-1-54) for this well. A seal failure is also indicated by the November and December, 1980 water levels which ere • deeper then aLl subsequent water levels (see Page 7-2-59). For the most part, the overburden near the Yedge coal crop in the Yoast area is dry or unsaturated. Mean water levels for ell wells range from 7.70 feet at Yell YOV1 to 218.09 feet at Yell YOV29. The high degree of variability in the mean depths to water ere primarily a function of boring depth, downgredient distance from outcrops, end topography. Nean saturated thicknesses in the Yedge overburden geologic unit range from 4.1 feet at Yell TOV15 to 200.41 feet et Well TOV28. Table 7-5 shows the saturated thickness and percent saturation of the 4adge overburden at each of the wells monitored. Neasureble seasonal water level changes have been monitored in the Yedge overburden. Although there is no distinct trend concerning seasonal mean water levels, the shallowest mean water levels occur predominantly in The spring and summer (see Appendix 7-2). This suggests that both spring and summer ere significant recharge periods for the overburden. the deepest mean water levels appear in Che winter at all wells except Wells YOV25 and YOV28. Nean water levels at YOY25 and YOV28 are shallowest during the winter, end deepest during the spring (TOV25) or fall (TOV28). This seasonal leg is likely due Co the more highly confined nature of these wells (Table 7-5 ). 1< Revised 03/01/95