Laserfiche WebLink
All monitoring must continue until discontinuation is approved by the Division in <br /> writing. <br /> Stipulation No. 14: <br /> Prior to secondary or retreat mining under Apache Canyon or Santistevan Canyon, <br /> the Permittee must submit to the Division sufficient evidence for the Division to <br /> make findings that secondary or retreat mining under these canyons will: <br /> 1) Not interrupt, discontinue, or preclude farming on the alluvial valley floors. <br /> 2) Not cause material damage to the quantity of ground water that supplies the <br /> alluvial valley floors. <br /> 3) Preserve the essential hydrologic functions of the alluvial valley floors. <br /> Apache Canyon <br /> Apache Canyon is south of the New Elk Mine and west of the Golden Eagle Mine. It <br /> drains an area of 7566 acres which is covered primarily by woodland. Grazing and wildlife <br /> are the primary land uses within the canyon. Mining is also a minor land use with two <br /> shafts (ventilation and emergency escape) and a power substation located in the lower <br /> canyon. <br /> Surface water monitoring of Apache Canyon began in April 1984 with the <br /> installation of a flume equipped with a Stevens Type F continuous recorder at Station <br /> ACF-1 (Figure 1). Flow has been monitored from April 5, 1984 through August 27, 1985 <br /> (Appendix 1). During this period flow was recorded on 28 days with mean 24-hour <br /> discharge ranging from 0.0001 to 0.70 cfs. Maximum peak flow was measured on August <br /> 21, 1984 at 51.6 cfs. Over the 17 months in which flow was monitored, summer <br /> thunderstorms during July and August were the major contributor to stream flow. The <br /> other three seasons of the year indicate limited water availability from showers or snow <br /> melt with low flow conditions being recorded only on occasion. The typical runoff <br /> hydrograph recorded at the flume exhibits a spike of flow for only those intense <br /> precipitation events producing significant runoff. Since grazing is the major land use of <br /> the canyon, vegetation in the valley bottom is sparse which increases the runoff potential <br /> causing the short duration hydrograph spike. There are also four on-stream impoundments <br /> in the upper drainage which impound surface flow for cattle. Grazing is the only <br /> agricultural use of water in the drainage. <br /> -3- <br />