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  <br />1  <br />  <br />  <br />Colowyo Mine <br /> <br />SALINITY IMPACT ASSESSMENT <br />1.0 INTRODUCTION <br />This Salinity Impact Assessment has been prepared by Cedar Creek Associates, Inc. (Cedar Creek) <br />for the Colowyo Mine. This assessment was conducted in accordance with the requirements of <br />the Regulations of the Colorado Mined Land Reclamation Board for Coal Mining. Rule <br />2.05.6(3)(b)(iii) requires that the permit applicant estimate the likely hydrologic impacts through <br />an analysis known as the Probable Hydrologic Consequences (PHC)(Rule 2.05.6(3)(b)(iii).   <br />Colorado Division of Reclamation, Mining, and Safety is required by Rule 2.07.6(2)(c) to use this <br />and other hydrologic information to determine whether the operation is preventing material <br />damage outside the permit area. This assessment included data collection pertaining to water <br />quality, soils evaluation, and vegetation composition of the irrigated fields. <br />The Colowyo Mine is located approximately 28 miles south of Craig, Colorado. Colowyo uses <br />surface mining methods to remove multiple coal seams in the upper coal group of the upper <br />Williams Fork formation. The Trout Creek Sandstone lies some 800 feet below the lowest coal <br />seam that is mined, and the only regional aquifer in the vicinity of Colowyo is below the Trout <br />Creek Sandstone. No regional ground water system exists above the flood plain of Goodspring <br />Creek other than very isolated, perched aquifers. The Colowyo Mine is bisected by a number of <br />tributaries of Milk Creek prior to entering the Yampa River. The Yampa/Milk Creek confluence <br />marks the furthest downstream extent of potential cumulative surface water impacts to the <br />Yampa River due to all mining in the region. <br />This study evaluates potential salinity impacts to irrigation waters from discharges within <br />Goodspring Creek only. Taylor Creek was not evaluated as part of this study as the only water <br />right available on Taylor Creek are used for industrial activities. Further, the water right on Taylor <br />Creek does not have infrastructure to convey irrigation water, nor are there any fields down <br />gradient of this water right that can be or have been historically irrigated from this one water <br />right. Irrigation water from Goodspring Creek is used down gradient of Colowyo’s lowest <br />discharge point to Goodspring Creek. Based on information provided by Colowyo, there are <br />approximately 259 acres of irrigated fields where irrigation water from Goodspring Creek is used. <br />Figure 1 displays the fields irrigated by Goodspring Creek.