REP43232 - Laserfiche WebLink

Home Browse Search

GROUND WATER MONITORING ' BEDROCK Sandstone Aquifers ' Three sandstone aquifers are monitored at the site. They are, in ascending order: Trout Creek Sandstone (2 wells), Middle Sandstone (6 wells) and Twentymile Sandstone (3 wells). The No. 5 and No. ' 6 Mines are between the Trout Creek Sandstone and the Middle Sandstone. ' Water Levels Plots of the water levels in wells in the three aquifers are presented in Figures 3 through 13. The water levels in the Middle ' and Twentymile Sandstones generally are showing an upward trend. For most wells, this trend began in 1983 or 1984. As discharges from the mines in the area were constant or increasing during this ' period, the water level changes appear to be the result of climatic factors. The years 1980 and 1981 were very dry years and the following two years were more normal years. During this earlier ' period, water levels generally fell. Years 1984 and 1985 were very wet years and the spring runoff in 1986 was above normal. During this period, the water levels in the aquifers rose. However, the water levels in the Trout Creek Sandstone have declined in 1988. ' In addition, the water levels in the No. 5 Mine well show the effects of pumping the well. ' Based upon the 1988 piezometric map (Figure 14), the ground water gradient in the Middle Sandstone ranges from 140 feet per mile to the southwest to 240 feet per mile to the northwest. The water ' levels in most of the Middle Sandstone wells were constant or rising in 1988. However, the water levels in Well 83-02 declined dramatically in 1988. This is probably due to its proximity to active longwall mining. A piezometric contour map of the Twentymile sandstone is presented on Figure 15. The indicated ' gradient is 260 feet per mile to the northwest. The water level in the No. 9 Mine w ell fluctuated considerably in 1988 but did ' return to fluctuation near its has been previous level. No explanation for this found, but the well may have been pumping when some of the readings were taken. Water Quali ty The water quality data for the sandstone aquifers are summarized in Tables 5 through 18. Plots of field conductivity are presented in Figures 16 through 18. The data indicates that the water ' quality of all four sandstone aquifers is fairly constant over the whole period of measurement. The field conductivities seem to show 2