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' impermeable clay is available in order to construct the structures. Based on using this material, a Homogeneous embankment is recommended. ' 3. Based on the erratic stratification of the foundation soils with both ' high and low permeable layers, a positive cut off trench extending to the medium hard bedrock should be utilized for the dams. A maximum ' trench slope of l:l, and a minimum bottom width of 10 feet is recommen- ded for the cut off trench. The downstream edge of the trench bottom ' should be constructed on the centerline of the crest embankment. ' 4. Based on the foundation soils encountered, we recommend upstream and downstream slopes of 3:1 (horizontal to vertical). 5. It is our understanding that seepage losses through the dams are not important considerations for the type of storage planned. Pressure 1 relief wells are recommended to relieve uplift pressures due to seep- ' age at the downstream toe of the proposed embankments. A minimum of three pressure relief wells should be utilized for each dam: one loco- ' ted on the centerline of the length and one each towards the abutments. They should be constructed with a minimum 6 inch diameter perforated pipe set into a minimum 18 inch diameter hole drilled into the rela- tively pervious clay-gravel strata. The wells should be a minimum of 10 feet deep. The area between the perforated pipe and hole should ' be packed with a coarse sand or fine gravel filter material meeting ' the following gradation filter requirements based on the clay-gravel mixture gradation from test hole 1-1 at 10.5 feet, Figure 8: the 015 ' size of the filter material should range from 1.3 to 10.4 mm in size and less than 5ro of the material should pass a #200 U.S. Standard Series ' Sieve. In addition, the D85 size of the filter material should be ' greater than tvrice the perforation size of the perforated pipe and the -4-