Laserfiche WebLink
2.04.7 Hydrology Description <br />(1) Ground Water Information <br />(a)(i)(ii)(iii) and (iv) <br />Alluvial Groundwater <br />Alluvial groundwater in the permit area occurs in river alluvium that lies <br />over Mancos shale. The river alluvium is well graded sandy gravel that <br />were deposited in terraces. Terraces are areas of flat land (located on <br />either side of the flood plain) which are raised above the flood plain. <br />Monitoring wells were installed in 1981 by Gary Refining Company. The <br />wells encountered 15 to 23 feet that was described as silty clay <br />"slopewash." Underlying the silty clay is between 19 and 25 feet of the <br />river alluvium which consists of poorly to well sorted sand and sandy <br />gravel. The Mancos Shale was encountered in all boreholes, ranging in <br />depth from 34 to 48 feet. <br />Three of the Gary Refining Company monitoring wells were selected for <br />use by the Operator for its baseline ground water monitoring (RW -1, RW -3 <br />and RW -4). A monitoring well installed for the acid sludge landfill was <br />selected as a fourth monitoring well. This monitoring well, RW -2, is <br />located northeast of the acid sludge landfill. See Map 8, Hydrologic <br />Monitoring Location Map, for the location of the monitoring wells. <br />Two of the alluvial wells are located within the permit boundary, RW -1 and <br />RW -2. RW -2 is located in the northeast corner of the permit area. RW -1 <br />is located in the central portion of the permit area east of Reed Wash. <br />RW -3 and RW -4 are both located south of the permit boundary and east <br />of Reed Wash. RW -3 is near Reed Wash. RW -4 is located approximately <br />1,800 feet east of Reed Gulch. A typical completion diagram along with a <br />summary table of specific completion information for each monitoring well <br />is located in Volume I, Exhibit 3. The As -Built Drawings from 1981 when <br />the wells were drilled and completed are provided in Volume I, Exhibit 14, <br />Appendix B. <br />The number designations for the monitoring wells now being utilized have <br />changed somewhat since they were originally installed. The As -Built <br />Drawings provided in Exhibit 14, Appendix B for RW -1 a, RW -3, and RW -4 <br />are the active monitoring wells RW -1, RW -3, and RW -4, respectively. The <br />well log and location for RW -2 given in Exhibit 14, appendix B is not the <br />Permit Application 2.04 -14 07/11 <br />