2018-02-05_REVISION - C1992081 (29)

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Below is a detailed consideration of the alluvial valley floor potential of each of the following two drainages: Dry Creek and Sage Creek. Evidence of vegetation and surface water quality at the loadout seems to suggest that the alluvial valley floor and surface water within the permit area is unsuitable for flood irrigation or subirrigation of hay or other field crops. However, based upon information included in the permit application (including mapping of alluvial deposits, agricultural fields located below the rail loop which may be subirrigated, and alluvial waters from Dry Creek apparently being used to irrigate hay fields downstream) and previous findings by the Division for the Seneca II -W Mine concerning Dry Creek, those portions of Dry Creek mapped as alluvial deposits will continue to be designated as part of the Dry Creek alluvial valley floor. The loadout has existed on the Dry Creek valley floor since early 1978. The area of the valley floor affected by the disturbance comprises approximately 4% of the area of unconsolidated alluvial deposits in the valley. None of the disturbance impinges upon the area of irrigated agriculture indicated by the applicant. No further disturbance is planned for this operation. Because of the small area involved and because the disturbance is contained with a sediment control system, the operation will have no significant effect on the integrity of surrounding agricultural activity. Impacts on surface water quality due to disturbances at the loadout will be minimal due to the size of the permit area with respect to the surface area drained by Dry Creek. Furthermore, data provided by the applicant indicates that coal stockpiled at the loadout does not contain any chemical constituents at high enough concentrations to be of concern with respect to contamination of surface water. Surface water effects will be monitored during and after mining by surface monitoring stations on Dry Creek upstream and downstream of the disturbance to verify this conclusion. A. The Division has determined that an alluvial valley floor exists within the affected or adjacent area. Therefore, the following findings are in order for the alluvial valley floor located on Dry Creek and Sage Creek. 1. The Division finds that activities proposed by the applicant will not interrupt, discontinue, or preclude farming on the alluvial valley floors that are irrigated or naturally sub -irrigated (4.24.3(1)). The only mining related activity which would interrupt farming on an alluvial valley floor is the TAHR which has already been completed. 2. The proposed activities will not materially damage the quantity or quality of water in the surface or ground water system described above (4.24.3(3) and 2.06.8(5)(a)(ii)). Due to the extremely limited acreage of proposed disturbance within the Sage Creek watershed, and the fact that regional ground water flow is to the west, 31