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I I I I I I I I I I I - 4 - DES I GN CRI TERIA We did not' find any better location for t,he dam site upstream from the present proposed dam loeatlon. We do not see any reas~n to change the present dam location. By increasing the height of the dam, the following additional precautions and investigation should be taken Into Cons i dera t ion: Dam Axis: The exploratory holes drilled along the dam axis by us only penetrate a maximum of 8 feet into bedrock. Drive samples were taken in the bedrock, but these samples are highly fractured and disturbed and will not provide information on the presence of fissures and seams in the bedrock. We propose that further investigation should be made by core drill ing the bedrock in at least two places along the dam axis to depth 'probably 20 feet into bedrock. Careful examination of the core samples will reveal the competency of bedrock against seepage loss. If necessary, on-site packer tests can be conducted to determine seepage loss. Drawdown Analysis: For the new height of the dam, there is an estimate of 43 feet of drawdown. In the stability analysis for the existing design, onl y 21 feet of drawdown was allowed. Therefore, it wi II be necessary to make a new stability analysis of the dam with drawdown criteria of 43 feet. It may be necessary to alter the slopes of the dam. Borrow Material: We previously investigated two possible sources of borrow in the vicinity of the dam. It is possible that the source of borrow material will not be sufficient to cope with the additional 208,000 cubic yards of material required for the new dam height. At the upstream side of the dam there should be many potential borrow sites which can offer the necessary borrow material. 0;