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2.06.8 Surface Coal Mining and Reclamation Operations on Areas or Adiacent to Areas, Including Alluvial Valley Floors To obtain the information required by this rule, the Chimney Rock Mine environmental personnel investigated a variety of sources. Color infrared aerial photography was used for the basic preparation of the information reflected on Figure 5. In addition, panchromatic aerial photography, field surveys, and discussions with SCS were used to more accurately define the past and present agricultural uses of the land downstream of the mining area. The actual historic use of the land was somewhat difficult to ascertain. Use of the Stollsteimer basin for agrarian purposes dates back well over 100 years. Much of the land has been used intermittently over this time as irrigated pasture, dryland pasture, or simply rangeland. At present, only a relatively small percentage of this portion of the AVF is intensively managed. The majority of the alluvial zone downstream from the mine site is occupied by willows and other riparian plant species. These areas are typically underlain by large cobble close to the surface. Much of this area, especially that near the confluence is highly dissected by the old Stollsteimer channels. Due to the presence of large cobble and the low elevation of this zone is relation to the creek, water transmissivity is apparently high. It is difficult to determine the historic use of this riparian area. Several stands of immature willows could indicate that management has been attempted at some time in these areas. The reasons for abandonment are not clear. Perhaps the cobble nature of this zone allowed for very wet conditions in the Spring, which would hinder establishment of pasture species requiring a - more well-drained condition. These areas would become dry in the upper rooting zone during the summer, and irrigation would be difficult due to the lack of storativity in the cobbled soil materials. The areas that are now occupied by sagebrush have probably been used as pasture historically but evidence of past flood irrigation was not apparent. This area probably would have potential for irrigation if water were available. The areas designated as dryland pasture have probably been irrigated at some point in the past. However, irrigation structures were not evident from field investigations. The dryland pasture areas would have potential for flood irrigation. The mountain shrub/pinon-juniper areas tend to define the limit of significant alluvial influence. These areas are typically more sloping and drier than the land closer to the creek. The absence of riparian vegetation suggest that sub-irrigation is not occurring. These areas would not be suitable for flood irrigation. The irrigated pasture and dryland pasture downstream from the mine site are used for the production of hay crops and for grazing. Pasture species include alfalfa, smooth brome, bluegrass, clover, and a variety of other grasses and fortis. Productivity ranges from 2.06-2