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The Water Power of Texas. 
33 
“I have no doubt but that all the masonry went, or slid, and I am 
inclined to the belief that some of the rock ledges underneath went with 
it. I think it possible that the foundation might have been good enough 
for a dam without overfall ; but it proved not to be good enough for this 
bold structure. I think it probable also that vibrations of the dam, 
caused by the fall of the water, may have had a very detrimental effect 
on the underlying foundation and also increased the lateral pressure of 
the silt and earth against the dam far beyond the generally assumed 
water pressure, until this lateral pressure overcame the combined bending 
resistance of the dam proper, together with the frictional resistance under 
the base. 
“As early as in May, 1893, in reply to a direct question from one of 
the leading members of the board, I stated that the foundation under the 
east end of the dam was not what it should be ; that it was hard to say 
whether it was safe or not, but that I thought that the dirt filling against 
the dam on the waterside would prevent undermining and save the struct- 
ure. I also suggested the necessity of close. watching below the dam. 
“Dn May 7, 1894, when replying to a letter from another of the leading 
members of the board, I suggested that they make borings below the dam 
for the purpose of ascertaining the necessity of taking some precautions 
for the safety of the dam, stating that there might or there might not be 
immediate necessity for so doing, but that I believed it would prove nec- 
essary in the course of time. In another part of the same letter I sug- 
gested concrete or paving in front of the power house. From this you 
will know they were not without friendly warnings. 
“But in spite of all this I cannot say that the works were designed and 
built with due safety or precautions, or that to my knowledge proper 
borings and examinations of the underlying formations were ever made.” 
Mr. J. T. Fanning remarks: 
“The theoretical stability of the masonry of the dam in its normal con- 
dition, as completed in 1893, was sufficient to resist a much greater 
volume of flood flow than the flood at the time of the break. The struct- 
ure substantiates this view in the fact that the westerly part of the dam, 
nearly one-half its length, resisted the force that broke out a mid-section. 
It is evident that there was a large surplus of resistance, both as to slid- 
ing and overturning in the remaining part of the structure, as, otherwise, 
the moving sections would have pulled with them those portions of the 
dam now standing erect in place. 
“Undercutting . — That there was undercutting of the toe of the dam at 
a point where the dam first yielded is attested by soundings made before 
the sliding of a portion of the dam. 
“A writer in public print has attributed this undercutting in large part 
to the flowing of the tail water from the water wheels in the power house 
along the toe of the dam toward the channel, as shown in Fig. 11. This 
theory is not sustained by the facts. 
