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e results indicate that the sand and gravel overburden is highly permeable and, therefore, would either have to be treated or removed. In the bedrock, however, testing indicated very low permeability; therefore ATEC believes that water loss through the Wasatch Formation would be minor. A permeability test run in the conglomerate also showed it to be very tight and essentially impermeable. D. LABORATORY INVESTIGATION Samples from the drill hole cuttings were returned to ATEC's Denver laboratory for testing. The grain size distribution and Atterberg limits were determined on the alluvial deposits to aid in evaluating their permeability. These test results were correlated with the field permeability test results. A permeability of 10-1 cm/sec was assigned to the alluvial deposits for use in the seepage analyses. This value is somewhat high (conservative) because this report is only preliminary. Alluvial-deposit permeability will be re-examined during final design when additional data are available. . The strength of the bedrock samples was tested to aid in evaluating foundation and abutment stability. The strenqth and density of the Wasatch Formation materials were good (6900 psi and 157 pcf minima) and indicate that all of the Wasatch Formation materials (sandstone, siltstone, shale) should be competent as abutment and foundation material. E. PRELIMINARY FEASIBILITY EVALUATION The following evaluation is based on the preliminary geologic mapping and field and laboratory investigations performed to date. The proposed Webster Hill Dam site, as with any dam, has four possible paths of seeoage that could decrease the dam's ability to retain water: seepage beneath the dam, seepage around the dam (through the abutments), seepage through the dam, and seepage losses in the reservoir. . 3686-a/8 IV-4