Laserfiche WebLink
Generally, the Williams Fork is found to be in an unconfined state, however, locally <br />or seasonally the formation may exhibit semi-confined conditions. Seasonal <br />fluctuations aze probably the result of rechazging and dewatering a perched aquifer <br />within the formation. <br />Although aquifer tests were not performed on the overburden at the site, aquifer <br />chazacteristics have been extrapolated from Colorado Yampa Coal, located about 15 <br />miles southeast. Data obtained from these tests indicate that transmissivity values <br />for the overburden could range from 3 to 20 gallons per day per foot (0.4 to 2.7 fr' <br />per day), while storativity may vary from 1 x 10-Z to 1 x 10"5 as local conditions <br />change. <br />Water quality analyses generally indicate that this is a magnesium -calcium <br />bicazbonate water with elevated levels of iron, manganese, and TDS. The high iron, <br />TDS and manganese values preclude use of this water as a drinking supply. <br />Williams Fork water is suitable for stock watering and irrigation of salt tolerant <br />plants. <br />Hubbersou Gulch Alluvium <br />The alluvium in Hubberson Gulch occurs in the lower reaches of the gulch in and <br />adjacent to the permit azea. Depth to water data indicates that the aquifer may vary <br />from semi-confined to water table conditions. The amount of head, if any, is <br />generally less than 5 feet. Water quality analyses of two alluvial wells indicate that <br />these calcium-bicazbonate type waters do not meet U.S EPA drinking standards. <br />Manganese, sulfate, TDS, and chromium are found to be in excess of standards. <br />These waters do meet stock watering criteria, and may be used for irrigation <br />dependent upon crop and soil characteristics. <br />Springs and Seeps <br />An initial spring survey in July, 1979, located 49 springs and seeps in and neaz the <br />permit area. Two additional springs were identified during the 1997 baseline studies <br />for the II-W South Extension Area. The majority of the springs and seeps occur in <br />valley bottoms. The recharge to these valley bottom springs may be from a <br />discontinuous alluvial aquifer, from colluvial slumps, or from perched aquifers <br />draining to stream sediments. Several springs issue from the Williams Fork <br />Formation, while two others issue from the overlying Twenty Mile Sandstone. <br />Some of the springs aze used to fill stock ponds in the area, while the majority either <br />contribute flow to the creeks or provide rechazge to downgradient alluvium. <br />Olson Spring, which has an adjudicated domestic water right associated with it, <br />issues from the Dry Creek Alluvium about 20 feet from Dry Creek. This spring is <br />located about 9,000 feet downstream from mining. <br />Seneca lI-W Findings Document 23 November 3, 1999 <br />