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. . epicenter was approximately 20 miles southwest of Montrose, and the quake measured 4,6 on the Richter scale. There are also several landslide areas near the reservoir. . 4.4 Soils. Soils within the project area are primarily alluvial, derived from adjacent sandstone, claystone, and shale deposits of the Mancos Shale Formation. Fine textured soils are referred to locally as "adobe" soils. These upland soils are slightly impermeable and shallow over the underlying shale bedrock. The Log Hill Mesa soils are residual, formed on and from the Dakota Formation. Due to the nature of stream alluvium and glacial deposits, the river and creek beds are armored with coarser soils, large gravel, and cobble. . . Within portions of Ridgway State Park, wetland and riparian soils are mostly black clay deposited as point bars, islands, and alluvial fans within flood plains, Some wetlands grow from gravel and cobble beds containing only fine sediments. Formerly upland soils along the eastern park boundary are saturated by seepage from irrigation water and now exhibit wetland soil characteristics (i.e. gleying, root channeling, and mottling). These soils are subject to slumping or mass wasting as a result of saturation. . Sediment deposition in Ridgway Reservoir was estimated using runoff models prepared by the USBR's Denver Technical Services Center, Sedimentation Section. The studies revealed that the watershed above Ridgway Reservoir is relatively stable, but still produces some sediment. Accumulated sediments are expected to occupy a total volume of 4,100 acre-feet in 100 years, with about 1,470 acre-feet in the active pool. . . 4.5 Land Use. Approximately 3,925 acres of public and private land was originally acquired for construction of Ridgway Dam and Reservoir. The reservoir basin required 1,125 acres, and the recreation, wildlife habitat, and buffer zones encompass nearly 2,800 acres. The land base within the reservoir boundary remains in Federal ownership under the jurisdiction of USBR. These lands are not automatically open to the public and multiple uses, but are available fo uses that are compatible with the reservoir and in compliance with regulations governing project lands. USBR reserves the right and is responsible for issuance of outgrants for land use and resource management within the reservoir area, A primary resource management use of the reservoir is currently recreation, with three developed recreation sites within the state park boundary. . Adjacent land is primarily privately owned. The U.S. Bureau of Land Management administers approximately 1,720 acres of public lands adjacent to the east boundary of the park. Easements on the property, including scenic, landscape, access, utility and cattle trails, have been negotiated and approved by USBR. The reservoir 11 .