Abstract

Space restrictions at the existing sanitary landfill site in Sevier County, Utah, necessitate the development of new landfills. Proper site selection to minimize environmental impacts and their associated threat to human health is of major concern. Geologic and hydrologic information helps to identify areas with natural safeguards to protect the environment, and which require minimal engineering and construction disturbance. Proper landfill siting can help minimize any threat to ground-water quality. Fine-grained materials are the most effective barrier to leachate migration. Fractured rocks are very ineffective. Isolation from shallow ground water and flooding; placement in fine-grained, unconsolidated soil; and avoidance of Quaternary (active) faults will help provide a cost-effective and environmentally safe site. Engineered solutions to site deficiencies may be used, but increase the cost of landfill construction and operation.

This regional study has identified several potential sites for sanitary landfills within Sevier County, all of which must be confirmed by site-specific investigations. Factors used for this regional study conform with most of the criteria proposed by the U.S. Environmental Protection Agency (1988) for the location of municipal solid waste landfills; the remainder of the criteria, if adopted, must be satisfied with the use of site specific data. The most suitable sites are in the Sevier, Grass, and Plateau Valleys of west and central Sevier County, where finer-grained alluvial deposits are common. Unconsolidated deposits in the eastern portion of the county contain considerable amounts of coarser- grained sediments deposited as glacial till, colluvium, and landslide material, and are generally less suitable for sites due to permeability and workability restrictions. Suitable cover material is also available in the relatively deep, finer-grained alluvial deposits of western and central Sevier County, but high water-table conditions make some of these areas locally unsuitable.