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Mr. Archer May 6, 1986 Page 2 rock debris. This condition however, existed prior to the construction of the road. Close by, another potential slope failure has been identified above the load-out facility. This possible landslide area also was in existence prior to the construction of the road but the presence of the road, no doubt, adds to the surface instability. All other mapped potential slide areas are not in proximity to the road and are not in any way influenced by its presence. Numerous minor slides are noted on the east facing slope of Coal View Gulch. These small local debris flows originate in source areas where unconsolidated material on steep slopes become saturated and lubricate weak, non-resistant beds. Areas delineated as potential slides that were not noted on the 1985 photo coverage, were observed on the 1:12,000 scale 1977 photography. This suggests that between the period 1977-1985, the indicated areas may have stabilized due to additional vegetative growth or to a reduction in soil moisture content. A careful inspection of all available aerial photo coverage of east flowing tributary drainages within the Coal View Gulch watershed, failed to note any significant or unusual erosional changes, suggestive of instability. The reported rapid sediment filling of the stock tank in Coal View Gulch could be caused by either, or both, of the two oil well drill pads upstream from the pond. Please note that this summary is based on an interpretation of aerial photographs and topographic mapping. These comments and observations should be checked by field examination. The following is a list of aerial photographs studied stereoscopically for the accompanying presentation. Forest Service 9-18-38 Black & White 1:30,000 (scale enlarged) IntraSearch 6- 29-76 Color 1:24,000 IntraSearch 8- 7-77 Color 1:12,000 Unknown 6- 2-81 Black & White 1:12,000 IntraSearch 8- 19-81 Black & White 1: 6,000 IntraSearch 10- 16-85 Color 1:24,000