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HYDROLOGY DESCRIPTION
<br />SURFACE HYDROLOGY
<br />Map King I-007 shows the runoff flows in the mine plan area and the permit
<br />area. Current sediment pond design and drainage plan are discussed in Section
<br />2.05.6. These designs are entitled Hydrologic Design of Sedimentation Ponds and
<br />Drainage Features, by Don R. May, P.E. This report describes in detail control of
<br />surface runoff including storm runoff and sediment control (See Appendix 11).
<br />Map King I-007 shows the completed open channels, ponds, and culvert
<br />construction. The ponds have never overflowed, and completed channels and pipe
<br />will allow the up-slope runoff to bypass the disturbed permit area and flow into the
<br />meadow. There should be no effect on water quality in Hay Gulch attributable to the
<br />King I Mine.
<br />The only water use downstream of the permit area in Pine Gulch is water from
<br />diversion ditches originating at the La Plata River. This water use is in a portion of
<br />the W/2, Section 12, T34N R12W, at the confluence of Pine Gulch with Hay Gulch,
<br />approximately 3 miles southwest of the permit area. Water is used for irrigation by
<br />ditch right owners L. Huntington, D. Huntington and J. Wiltze. Source of
<br />information is ditch right owners; Brad Gosche, V. P., National King Coal, LLC; and
<br />site specific reconnaissance of the Pine Gulch drainage from Section 33, T35N
<br />R11W, to Section 12, T34N R12W, by Fred M. Johnson, C.P.G. and Clifford M.
<br />Schmid, L.S.. As the Colorado M.L.R.D. has found there is not sufficient alluvial
<br />groundwater to enhance productivity of agriculturally useful vegetation along Pine
<br />Gulch with the permit area, and Pine Gulch is not a renewable resource, it
<br />contributes nothing to agriculture or irrigation within the Hay Gulch AVF at or
<br />beyond the confluence with Pine Gulch.
<br />Water contained in the sediment ponds will not be discharged into the
<br />meadow, but allowed to evaporate. The only water to be discharged from the ponds
<br />will be treated water from precipitation events approaching or exceeding the ten
<br />year, twenty-four hour storm event. The ponds are described in Section 2.05.6 and
<br />are designed to manage the ten and twenty-five year precipitation events as required
<br />by regulation and in accordance with the requirements of National King Coal's
<br />N.P.D.E.S permit No. CO-G-850001. The sediment ponds outlets and spillways are
<br />designed by Don R. May, P.E., and are described in detail in Section 2.05.6.,
<br />Appendix 11 and Map King I-007A.
<br />By regulation, the mining company must manage water expected in a twenty-
<br />four hour storm event predicted to occur once every ten years. The National Oceanic
<br />and Atmospheric Precipitation Frequency Atlas of the Western United States -
<br />Colorado predicts the ten year, twenty-four hour precipitation event at the mine site
<br />to be 2.2 inches (See Appendix 5).
<br />As of August 26, 1999, the records of the Colorado Division of Water
<br />Resources show the following wells which are within 1 mile of the permit boundary:
<br />1) 186332: Ted Compton; NW SW Sec. 8, T34N R 11 W, use D,
<br />2) 50641 : Colorado State Land Board; SW SE, Sec. 4, T34N R 11 W, use 8,
<br />yield 7 gpm., depth 225', water level 140'.
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<br />National King Coal, LLC King I Mine
<br />Section 2.04.7
<br />Page 4 February, 2007
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