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Detali REPORT

i AAftervisiting the site of the St. Francis Dam and

hearing all evidence brought before us, we submit the

following report

Defects Relating to Dam

The destruction of this dam was caused wholly· or in

part by the failure of the rock formations upon which it was

built and not by any error in the design of section of the

dam i itself or defect in the materials of which the dam was

constructed. The gravity section accorded with standard

practice and would have produced a safe structure if it had

been built upon hard, impervious rock as was supposed to be

the case by those who built it.

On account of the great destruction wrought by the

disaster and the absence of living eyewitnesses, much

important evidence bearing on the cause of failure was

obliterated, making it impossible to determine, with anything

approaching complete accuracy, the exact cause of the initial

break and the sequence of events thereafter.

However, there remains a large amount of very con-

vincing evidence of a number of vital weaknesses in the bed-

rock and in the design with reference to its adaptability to

a weak bedrock, any one of several of which weaknesses may

have been the primary cause of the failure, and all did con-

tribute to the terrific destruction wrought by the collapse.

The dam was in a defective condition due to the

following·

1st, The dam was built upon two formations meeting at a

fault contact which naturally caused a line of weakness across

the axis of the dam

2nd The schist upon which about two-thirds of the mass of

the main dam rested, is a weak material, badly shattered, very

susceptible to seepage of water, and to slippage along the

planes of cleavage,

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