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National King Coal water supply well is completed in the Hay Guich alluvial aquifer just west of the <br />facilities area. The La Plata No. 1 Mine well, which has been reported to be in existence since about <br />1905, is located neaz the facilities azea of that mine. This well, for which a water right has been <br />filed, is probably completed in the Point Lookout Sandstone. <br />Information concerning other wells within one mile of the permit boundary is contained in section <br />2.04 of the permit document. <br />Surface Water Hydrology <br />The surface facilities of the King Coal Mine are located in a small ephemeral drainage basin which is <br />tributary to Hay Gulch. The permit azea and underground mining extending to the south of the <br />surface facilities underlay another smaller ephemeral drainage basin, Pine Gulch. Pine Gulch flows <br />into Hay Gulch approximately 4 miles downstream of the facilities azea. Hay Gulch is a tributary of <br />the La Plata River and their confluence is located about 8 miles downstream (southwest) cf tl.e King <br />Coal Mine. <br />There aze no perennial streams within the permit azea. Surface water within the small ephemeral <br />drainage basin in which the mine is located is limited to runoff from rainfall and snowmelt events. <br />Runoff from the undisturbed upper parts of the east basin is routed aoound the disturbed azeas <br />through a ditch system. Runoff from the undisturbed west basin and the disturbed azea is conveyed <br />through a system of culverts and ditches to two sediment ponds at the base of the 86 acre <br />contributing azea. Dischazge from the ponds enters Hay Gulch, a tributary of the La Plata River. <br />There is no flowing stream within the valley of Hay Gulch at the location of the mine. Historically, <br />streamflow has been diverted into an irrigation ditch on the north side of Hay Gulch. Water for <br />irrigation purposes is taken from the La Plata River and at times has been reported to be high in <br />salinity and therefore not suitable for irrigation. Because ofthis fact, the King Coal Mine has agreed <br />to sample the irrigation ditch twice a yeaz for two irrigation seasons to create a baseline and <br />determine the quality of the ditch water. <br />An ephemeral stream channel may have existed in the bench area of the mine prior to disturbance of <br />the site in 1941. This pre-mining channel would have been located in the lower portion of the mine. <br />Runoff from lazger events would occur as channel flow, whereas smaller events would primazily <br />rechazge the alluvium from side-slope areas. For this reason, apost-mining channel will be <br />reconstructed in the current location ofthe facilities area. A review ofthe channel design indicates it <br />meets the requirements of Rule 4.05.3. <br />Two sediment ponds aze located at the base of the facilities azea to control runoff and sediment <br />generated within the disturbed azea. Boundaries of the azea contributing runoff to each pond are <br />delineated on Map C-4 in the permit document. Runoff from the undisturbed eastern portion of the <br />upper basin area is routed around the disturbed azea in the east ditch and passes through a straw bale <br />dike before entering Hay Gulch. Runoff from the undisturbed western portions of the upper basin <br />and the disturbed area is dischazged to Hay Gulch after passing through the sediment ponds. <br />The sediment ponds have been designed to treat the runoff from the 10-yeaz, 24-hour precipitation <br />event. Calculations used in the pond designs indicate the ponds to be in compliance with the <br />