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• • 2.5 GEOTECHNICAL CONDITIONS The field investigation and laboratory testing pro- grams documented in the appendices and our previous geo- technical mapping were used to characterize the geotechnical conditions at the site. The locations of all borings and test pits are shown on Plate 2, Plot 1'7.an. Natural colluvial soils at the site were sampled both below the crushing and screening Level fill (Borings B-4 through B-7) and above the fan level fill (Borings B-1 and B-2). The soils at both locations are similar in charac- ter, being predominantly silty to sandy low plasticity clays with varying amounts of gravel and cobbles (generally CL in the Unified Soil Classification System described on Plate A-1 of Appendix A). LJater contents generally ranged from slightly moist to moist, typically being in the range of 10 % to 17 `/,. Monitoring of observation wells indicates that there was generally little or no ground water within the col- luvial soils to the depths drilled, which was to bedrock or about 50 feet. One exception to this general description of the colluvial soils was noted in Boring B-5, where 16.5 feet of cobbles and boulders with little or no fines were encountered. Below this layer more than ten feet of tyoical clayey co1- luvium overlay bedrock. Large boulders are present ;it the ground surface in the vicinity of the boring, su;gesting that a layer of boulders may be corrunon in this immediate vicinity. It cannot be excluded that this accumulation of cob- bles and boulders comprises an old rock failure from the Rol- lins Sandstone cliffs above that location. 'fhe depth of bedrock below ground surface varied front about 23 feet in Boring B-5 to in excess o° 99 feet in Boring B-6 below the crushing and screening level fill. Bedrock was not encountered in either of the borings located above the Can level fill; both were drilled to approximately 50 feet. - 10 - GE6MYDRO CONSUITING.INC.