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operation. The first lies in an area immediately adjacent to the proposed operation and the existing surface mining operations. The second area occurs downstream in Sections 21, 22 and 28 and the third area is located at the confluence of Foidel Creek and Middle Creek. (The third area will be discussed in combination with Middle Creek.) As discussed previously in the AVF section of this document, the first area adjacent to the proposed operations has been determined not to be an alluvial valley floor and will not be discussed further. The second area, a body of alluvium of approximately 100 acres located downstream from the permit area below the water gap in Section 21, 22 and 2B (TSN, RB6W) was previously found to be an alluvial valley floor based on an assumed capability to support subirrigated agricultural activities. The positive finding was made due to the fact that insufficient hydrologic or vegetative information was provided to determine conclusively the presence or absence of subirrigation. Additional data on alluvial ground water depth and quality for the area in question has been provided in Table 67 of the life of mine application. The presence of ground water at depths of 4.3 to 5.7 feet suggests that subirrigation would be possible. Due to relatively high salinities (up to 5.4 mmhos/cm) it is probable that the site would not be particularly productive, however, vegetation information has not been provided. Division staff conducted field visits to the site in May and August, 1986 and it was observed that a silver sage community indicative of subirrigation existed in a relatively narrow belt along the stream. Areas further from the stream appeared to have been treated at some point in the past and seeded recently to pasture grasses including intermediate wheatgrass and timothy. Due to the age of the stand, annual weeds were quite numerous. Based on the water level information and vegetation observations which indicate the presence of subirrigation, the Division concludes that the alluvial body in question is an alluvial valley floor. information concerning significance of the AVF to farming has not been provided. Therefore, the Division will proceed by assuming the area is significant and will make the three required AVF findings. The proposed mining operations would not interrupt, discontinue, or preclude farming on the alluvial valley floor. Proposed mining activity would not directly impact any portion of the AVF, as it is outside of the proposed Foidel Creek Mine Permit Area and would not be undermined or disturbed by proposed surface facilities. The proposed mining operations would not cause material damage to the quantity and quality of surface and ground water that supply the alluvial valley floor. Since this area was designated an AVF on the basis of subirrigation, it is necessary to maintain the quantity and quality of water which supplies the alluvial ground water system. In the findings previously issued by the Division for the Foidel Creek Mine (pilot project) in 1983, it was projected (based on information available at that time that concentrations of dissolved constituents such as sodium, sulfate, iron and TDS would increase in the alluvial ground water. This effect was predicted based on the assumption that Foidel Creek surface waters affected by mine water discharge would recharge the alluvium. 25