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42GG . in red rock and surrounded by dark green vegetation. During the construction of a campground, the toe of an ancient landslide was removed causing some movement. This slide was stabilized by the use of gabions placed at the toe of the slide. The large mass of gypsum and anhydr i te known as Gyp Hill, is upstream from the right abutment of Ruedi Dam. Sin~loles, potholes, and solution cavaties or channels were known to exist here before construction. These features were, for the most part, masked and filled with slopewash materials. The introduction of a fluctuating reservoir washed away the covering materials along the foreshore and "flushed" out the material filling the solution cavaties. The gypsum, being a relatively weak rock, then collapsed and slumped under its own weight. The result is a grotesque, jumbled, almost skeleton- looking agglomerate of white rock. Most of the rock is covered by water for the majority of the year. Indications are, however, that the collapse of the gypsum is slowly making its way above the high water line. This could undoubtedly be slowed, or perhaps eliminated, by greatly reducing the drawdown rate of the reservoir; however, water scheduling may not allow for this. . Mt. Elbert Pumped-Storage Powerplant - The Mt. Elbert Powerplant is now under construction on an ancient landslide, the presence of which was known prior to construction. The slide area is currently being ~c~itored for movement and will continue to be monitored after construction by Lilt: use of s.lope indicators in deep drill holes. The forebay located above the pow~,- plant will be completely lined with impermeable materials with the intent of keeping water percolation recharge less than or equal to annual precipitation to prevent saturation of the slide. A stability analysis indicates that the 2800 by 2500 by 100-foot-deep slide area will remain stable after construction. The slide area is probably a series of slides rather than one large one. In addition to these two slide areas, there have been minor slides primarily in the form of bank sloughing along relocated roads and access roads. llI-19 .