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2.04.7 Hydrology Description <br />and within the coal seam are unlikely to contain any toxic, radioactive or organic <br />pollutants. A fourth consideration is the economical reasonableness. The Operator <br />estimates two deep well points of compliance will cost in the range of 750 thousand to <br />one million dollars. The Operator does not consider this cost to pass the economical <br />reasonableness test. For all of these reasons the Operator will not establish the subject <br />points of compliance. <br />(b) The subsurface hydrologic regime may be divided into four discrete subsystems: 1) the <br />alluvium and terrace deposits associated with the North Fork of the Gunnison River; 2) <br />localized deposits of alluvium -colluvium within the Hubbard Creek, and Terror Creek <br />areas; 3) groundwater occurrences within the Mesaverde Formation; 4) colluvial <br />discharges associated with soil moisture storage in Steven's Draw, C -Gulch and at the <br />head of Freeman, Sheep Corral, Stevens and Dove Gulches. <br />North Fork of the Gunnison River Alluvium <br />Alluvial fill associated with the North Fork of the Gunnison River and tributary drainages <br />(Terror Creek) have been extensively developed for domestic and agricultural water <br />sources. For a discussion of Alluvial Valley Floors, see section 2.06.8. The State <br />Engineer's records depict 3 registered wells completed within the alluvium located in <br />Sections 14, and 15, T.13 S., R.92 W., 6th P.M. (Bowie No. 1 Mine Area) <br />These wells range from 14 feet to 77 feet deep and typically produce water from 12 feet. <br />The well yield ranges from 5 gpm to 120 gpm with average yields of approximately 17 <br />gpm. Water quality is highly variable within the alluvial fill. Most wells completed near <br />the river sustain quality adequate for human consumption; however, the higher sulfate <br />and total dissolved solids values are probably a function of return irrigation flows and <br />well completion depths near the alluvium-Mancos shale contact. <br />Localized Alluvium -Colluvium <br />Localized deposits of alluvium -colluvial material reworked by fluvial processes are <br />present within the area, primarily within the Hubbard Creek, and Terror Creek <br />drainages. Hydrologic testing in similar material performed by Colorado <br />Westmoreland Inc. (CWI) during development of their Steven's Gulch well field <br />showed that yields from these sources are moderate (27 gpm at Steven's Gulch well <br />field), with transmissivity values ranging from 187 to 230 sq. ft. per day, and storage <br />coefficient of 0.0002. Water from wells penetrating this lithotype are classified as <br />sodium bicarbonate (Brooks, 1983). Recharge is accomplished from precipitation <br />and run-off, and water is discharged from seeps or springs. Although similar in some <br />respects, these areas do not fulfill the requirements of being Alluvial Valley Floor areas. <br />Several years of water table monitoring in the CWI wells installed in the Stevens Gulch <br />indicated the water level in this aquifer is below the local streambed for most of the year, <br />and therefore the streams are recharging the aquifer. <br />TR -99 2.04-37- 02/16 <br />