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There is no flowing stream within the valley of Hay Gulch at the location of <br />the mine. Instead, an irrigation ditch has been constructed on the north side <br />of the valley to transport seasonal streamflow. Prior to diversion, the stream <br />flowed in a westerly direction on the south side of Hay Gulch. <br />An ephemeral stream channel may have existed in the bench area of the mine <br />prior to disturbance of the site in 1941. This pre-mining channel would have <br />been located within an alluvial body in the lower portion of the mine. Runoff <br />from larger events would occur as channel flow, whereas smaller events would <br />primarily recharge the alluvium from side-slope areas. For this reason, a <br />post-mining channel will be reconstructed in the current location of the <br />facilities area. A review of the channel design indicates it meets the <br />requirements of Rule 4.05.3. <br />Two sediment ponds are located at the base of the facilities area to control <br />runoff and sediment generated within the disturbed area. Boundaries of the <br />area contributing runoff to each pond are delineated on Map C-4 in the permit <br />document. Runoff from undisturbed eastern portion of the upper basin area is <br />routed around the disturbed area in the east ditch and passes through a straw <br />bale dike before entering Hay Gulch. Runoff from the undisturbed western <br />portion of the upper basin area and the disturbed area is discharged to Hay <br />Gulch after passing through the sediment ponds. <br />The sediment ponds have been designed to treat the runoff from the 10-year, <br />24-hour precipitation event. On both the east and west ponds, the original <br />spillways have been modified to act as both the principal and emergency <br />spillways. Calculations used in the pond designs indicate the ponds to be in <br />compliance with the requirements of Rule 4.05.6. The east pond will act to <br />capture sediment from high-flow events in the east ditch. Although the east <br />ditch acts primarily to transport undisturbed runoff around the disturbed <br />area, high flows will be routed through the east pond in order to deposit any <br />sediment in the pond instead of on the adjacent meadow in the alluvial valley <br />floor. The west pond receives drainage from the bench area through a <br />ditch/culvert system and acts as the primary sediment control device for the <br />disturbed area. It also discharges directly to the alluvium of Hay Gulch. <br />Monitoring of surface water is limited to NPDES discharges as no other streams <br />occur within the permit area. Water quality of ground water is monitored <br />downgradient of the ponds to insure alluvial ground water in Hay Gulch is <br />being protected. <br />The operation is in compliance with the requirements of this section. <br />VII. Water Rights and Replacement - Rule 2'.04.7(3), 2.05.6(3)(a)(ii). <br />- --' <br />Water rights and replacement information may be found in Section 2.04.7 of the <br />permit application. <br />As discussed in Section V - Ground Water Hydrology of this document, <br />operations at the King Coal Mine are not expected to impact water rights to <br />ground water sources. <br />As no adjudicated ground water rights will be impacted, no replacement plan is <br />necessary. <br />-10- <br />