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The operator has committed to a program of visual monitoring to identify subsidence caused <br />damage to surface structures, stock ponds, and major damages, and has committed to repair <br />hazardous tension cracks, subsidence features interrupting flow in Red Was or Scullion <br />Gulch, or damage to surface structures. <br />Subsequent monitoring and observation have largely verified initial subsidence impact <br />projections. Current and future monitoring includes twice-a-year visual monitoring of <br />Scullion Gulch, County Road 65, and stock pond reservoirs during periods of undermining. <br />XVI. Concurrent Surface and Underground Mining <br />No specific approvals are granted to the applicant under this section. <br />XVII. Operations on Alluvial Valley Floors <br />The permit area and adjacent lands contain three stream channels - the White River, Red <br />Wash, and Scullion Gulch - with enough associated alluvium to be considered as potential <br />alluvial valley floors. All three channels cross the permit area as well as adjacent area. The <br />permittee's alluvial valley floor analysis is contained in Section II.D of Vol. 2 of the permit <br />application. <br />Below is a detailed consideration of the alluvial valley floor potential of each of the <br />following three drainages: Red Wash, Scullion Gulch and the White River. <br />Red Wash <br />Water Availability Criteria - Artificial Flood Irrigation <br />The permittee estimated the potential average annual water yield from Red Wash drainage <br />basin using Grunsky's Formula (Grunsky 1908, Sellars, 1965; see bibliography in permit <br />application). The estimate indicates that an average of 2,090 acre feet of water could be <br />made available annually in Red Wash. This corresponds to approximately 0.32 inches of <br />runoff, which is about 3.5 percent of the annual precipitation falling on the area. <br />Actual measurements of flow on Red Wash have been made using a crest stage gage station <br />located at the mouth of the basin. With the crest stage gage approach towards stream <br />monitoring, only peak flows that occur between monitoring intervals are recorded. Flows <br />that occur at less than peak flow during any one monitoring interval will not be recorded. <br />The crest gage method is, therefore, useful for recording peak events only; the method has <br />limited application for determining duration of flow, and consequently for flow volumes <br />which occur during the monitoring interval. <br />The results of the crest gage monitoring efforts on Red Wash indicate that flow is almost <br />entirely in response to snowmelt and storm rainfall events. A total of six runoff events were <br />recorded during the two year inventory period conducted by the permittee. Events that <br />occurred during the fall and summer months resulted from thunderstorm activity; however, <br />Deserado Mine 29 September 19, 2008