PERMFILE46234

• Permit No: C1994082
• IBM Index Class Name: Permit File
• Doc Date: 12/11/2001
• Section_Exhibit Name: TAB 07 HYDROLOGIC DESCRIPTION
• Media Type: D
• Archive: No

porosity (due to weathering end fracturing) may slgniflcently increase the pe rmeebi ll ties
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then those of mapped su rf tctel materials. The hydraulic properties (trensmissivlty end
hydraulic conductivity) of saturated bedrock are addressed in the "Aquifer
Characteristics" portion of this tab.
Discharge. Discharge is the process by which ground water is removed from the saturated
zone across the water table or pi exometr is surface. Discharge mechanisms include
evapotranspiration, flowing or pumping wells, springs and seeps, leakage through confining
layers that are not completely impermeable, and ground water movement into discharge areas
(e.g., streams, swamps, lakes, springs, and seeps).
Although it is difficult to accurately quantify the amount of ground water discharging
from bedrock units out of the permit area, ground water can be estimated using Dercy's
Lew:
q = -Kib
where:
• q = discharge through a unit width slice of the aquifer normal to the direction of
flow
K = hydraulic conductivity
i = hydraulic gradient
b = aquifer saturated thickness
Estimates of discharge in both the Yadge underburden end tool units can be estimated in
both the northeastern portion and western portions of the leasehold that are separated
structurally by the Fish Creek anticline. The potentiometric surface for the Yadge
underburden is defined only in the southwestern portion of the Yoast permit area (see
Exhibit 7-4 ); hence, an estimate of discharge for the Yadge underburden tan only be
determined for the southwest portion of the permit area.
wydraulic conductivity values (K) used to estimate discharge from the three geologic uni tc
ere geometric means presented in Table 7-9. Saturated thickness (b) for the overburden
end underburden were taken from lithologic logs and water Levels collected at the nearest
monitoring well(s) proximate to the downgr adient discharging area in each unit (i. e.,
• saturated thickness of Yadge overburden in the northeast area estimated et Yell YDV28).
An average saturated thickness of 13.5 feet was selected for the Yadge coal based on drill
hole end monitoring well lithologic logs collected throu8hout the Yoast permit area.
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