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

3,940-foot long distance. Using these approximate lengths of discharge zones, the total
• flow (g) discharged by the three unite downgredient of the respective permit areas has
been determined es follows:
0 = 106.8 ft3/day (Madge overburden - northeast)
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g = 23.4 ft /day (Yedge overburden - northwest)
g 14.2 ft3/day (Wedge coal - northeast)
0 = 11.7 ft3/day (Yedge coal - northwest)
g = 31.5 ft3/day (Yedge underburden)
Estimating discharges in a similar manner for the alluvium along Sege and Grassy Creeks
and Annand Draw, is not passible due to the variability in hydrologic properties (K) end
Lack of information regarding site-specific alluvial widths and thicknesses. Bedrock
units likely discharge to the alluvium in some areas (upper Sage Creek - Madge
overburden), but the magnitude end extent of this contribution is unknown.
Evapotranspiration (ET) is a significant discharge mechanism for ground water in the
alluvium within and proximate to the Yoast permit area. Peabody conducted a detailed
study of the hydrologic balance of the Hubberson Gulch watershed in 1979 end 1980 (see Teb
7, Seneca II-Y PAP, 1989). Potential evapotranspiration (PET) was calculated for the
period July, 1979 through June, 1980. The water balance in Hubberson Gulch was determined
for the same period, and using the.calculet ed PET estimate for the water balance, actual
evapotranspiration (AET) for the period was estimated. The study calculations in relation
to total watershed area indicate that out of 21.7 inches of pr etipitation, 19.8 inches
were lost to AET in the Hubberson Gulch watershed. Only 1.9 inches of [he 21.7 total
inches of precipitation that fell during 1979-1980 in Hubberson Gulch was converted to
direct runoff.
The study indicates that evapotranspiration in the upper watersheds of Grassy Creek, Sage
Creek, and Annand Draw, which ere of similar elevations, temperature, and precipitation
in comparison with Hubbe rsan Gulch, could significantly (90 percent) reduce the amount of
precipitation available for runoff end ground water recharge to the alluvium.
Several springs monitored during the baseline period discharge ground water contributed
from bedrock units. Springs YSPG 1, YSPG3, YSPG4, and TSPGS ere situated in a tributary to
. Sege Creek in the southwestern portion of the leasehold, and Spring YSPG9 is located in
the upper reach of Annand Drer (see Exhibit 7-1). Discharge from the Madge overburden
likely provides a aignificent portion of flow monitored from each spring, end a discussion
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