Laserfiche WebLink
<br /> <br />XV. Operations on Alluvial Valley Floors <br />The narrative below is excerpted from the November 1983 original Findings <br />Document. <br />J.F. Sato and Associates developed the Alluvial Valley Floors section of the permit <br />application, through the Small Operators Assistance Program (SOAP). There are <br />three drainages within the permit and adjacent area that contain mappable alluvial <br />deposits: Lewis Gulch, South Oak Creek, and Oak Creek. Lewis Gulch is a narrow <br />ephemeral tributary to Oak Creek and flows adjacent to and below the western <br />perimeter of the portal area. There is insufficient alluvium and/or water present in <br />this gulch to consider it an alluvial valley floor (AVF). <br />South Oak Creek, also an ephemeral tributary to Oak Creek, flows northeast through <br />the permit area and is undermined by the operation. The Chandler Syncline roughly <br />parallels the drainage of South Oak Creek. The alluvial deposits in South Oak <br />Creek are discontinuous and are under ten acres th size. In the sales area, the stream <br />flows through abandoned strip mined areas, where in low flow conditions it may <br />become impounded. Based on these facts, South Oak Creek is not considered to be <br />an alluvial valley floor. <br />Approximately one mile north of the proposed portal area is the Oak Creek <br />drainage. The stream is considered to be perennial; however, during the fall season <br />the base flow is diverted into alluvial wells which supply the town of Rockvale with <br />water. The alluvial deposits adjacent to the stream are over 50 feet in width and <br />over ZO acres in size. Flood irrigation has been historically practiced and is <br />practiced today along the Oak Creek Valley. The Division therefore has determined <br />that an alluvial valley floor exists within the affected or adjacent area. Therefore, <br />the following fmdings are in order for the alluvial valley floor known as Oak Creek. <br />Potential impacts to the Oak Creek AVF continue to be minitnal. There was no <br />physical disturbance to the AVF in the construction of surface facilities, and the <br />AVF was not undermined. The only potential impact is from degraded water flowing <br />from the area to be disturbed by the Twin Pines No. 2 Mine into the adjacent AVF. <br />Throughout the duration of mine operations at the mine site, all surface flow was <br />treated either in the upper or lower sediment pond before leaving the site. Lewis <br />Gulch, the tributary to Oak Creek, and the stream feed to Oak Creek, never received <br />any surface flow that was not treated in either of these two ponds, allowing the <br />sediments to settle out before any discharge occurred. Therefore, the Division finds <br />that the proposed activities by the applicant will not damage the quantity or quality <br />of water in the surface or ground water system described above (4.24.3(3)) and <br />2.06.8(5)(a)(ii). The proposed activities will comply with the requirements of the <br />Act and the Regulations with respect to alluvial valley floors (2.06.8(5)(a)(iii). <br />XVI. Operations on Prime Farmland <br />No lands within the permit area have been identified as prime farmland. Page 64 of <br />the permit application contains a letter from the Soil Conservation Service indicating <br />this fact. <br />\twnpns. fd <br />29 <br />