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-16- The Canadian River system receives most of its flow from snowmelt in the Medicine Bow Range to the east of the proposed minesite (p. 779-49 ). Tributary watersheds that cross the minesite and adjacent areas area at a lower elevation, in an area of low precipitation. Therefore, these watersheds contribute only a minor amount of surface water and alluvial ground water to the Canadian River AVF. 3. Surface coal mining and reclamation operations would be conducted to preserve, throughout the mining and reclamation process, the essential hydrologic functions of the alluvial valley floor. The alluvial valley floor would not be physically disturbed. The applicant's discussion of probably hydrologic effects (p. 780-123 to 780-126jjjjj) has identified several surface water effects caused by the mining operations, However, these effects are for the most part temporary and occur in watersheds that supply only a minor amount of flow to the AYF. These effects would not disturb the essential hydrologic functions of the Canadian River alluvial valley floor. Alluvial Valley Floor - Bolton Draw - Findings 1. The proposed surface coal mining operations would not interrupt, discontinue, or preclude farming on an alluvial valley floor. None of the proposed mining operations would be located within the alluvial valley floor. In addition, most of the surface coal mining operations included in this permit, within the Bolton Draw watershed have already been conducted under previous mining permits. 2. The proposed operations would not materially damage the quantity and quality of water in surface and underground water systems that supply those alluvial valley floors or portions of alluvial valley floors. The surface waters that supply the 55 acre flood irrigated pasture are originally derived from the Michigan River. The effects described in the applicant's statement of probably hydrologic consequences (p. 780-123 to 780-126jjjjj) do not affect this source. During mining, sediment ponds would reduce the amount of surface flow in Bolton Draw by approximately 17~ (p. 7800126eeeee). Changes in surface water chemistry (increased salt loading at the rate of 37.5 kg/y r, and changes in ion balance) would also occur to the extent that ephemeral stream flow recharges the alluvial aquifer and the quantity and quality of the water available for sub-irrigation would be affected. As discussed in the statement of probable hydrologic consequences, these effects would be short termed. With reclamation and removal of the sediment control system, these effects would be mitigated. Most of the mining that would occur in the Bolton Draw watershed has already occurred under the previously permitted operations. 3. Surface coal mining and reclamation operations would be conducted to preserve, throughout the mining and reclamation process, the essential hydrologic functions of the alluvial valley floor.