30 Transactions Texas Academy of Science. [76] 
The average depth on the crest for the four years was .417. Making 
H=.417 in the weir formula we get Q=910. Adding to this the flow 
through the penstocks, we have as the average flow for the four years 
1160 second-feet. This, with the conditions prevailing at the Austin 
dam, would have given if it had all been used 6264-horse power. Thus, 
the average flow would not have produced half the power the minimum 
flow was supposed to produce. 
The Austin dam failed on April 7, 1900. _ Upon the present condition 
of the foundation of that part of the dam that was broken out hinges the 
proper interpretation of the cause of its failure. So important was this 
special feature that the writer made an elaborate set of soundings in the 
latter part of 1900 in that part of the broken section through which at 
present the water flows. Four lines of soundings (marked ,x, y, z, and T) 
w^ere made, parallel to and at distance of 0, 16.5, 42, and 60 feet from 
the upper face. The result is shewn in the following table : 
SOUNDINGS AT SITE OE WRECKED PORTION OF DAM, DECEMBER, 1900. 
Distance. 
Depths Below Top of Toe. 
Line x. 
Line y. 
Line z. 
Line T. 
600 
13.0..... 
550 
9.5 feet..'. 
9.1 feet.....:........ 
io.l feet...... 
12 feet. 
14 feet. 
14 feet. 
15 feet. 
15 feet. 
500 
10.9 feet 
1 1 .8 feet, 
1 1 9 feet 
450 
12.6 (S) 
12.9 feet..... 
12.6 feet... 
400 
11.6 feet 
11.6 feet 
12.2 feet.... 
350 
8.1 feet... 
8.9 feet. ... 
p.6 (S) 
Distance were measured from east bulkhead, 
All these soundings were to solid rock except those marked (s). 
If we remember that the height of the top of the toe of the dam above 
the rock bed of the river was, on an average, six feet, and that the foun- 
dation was not (with the exception of the trenches) over eight feet below 
“low water,” a glance at the above table will convince any one that there 
is. no part of the foundation in the western 300 feet of the broken section 
remaining. From the present ordinary eastern water edge a large sand 
bank extends to the end of the eastern standing section, which covers 140 
feet of the former bed of the dam. Soundings were not made through 
this sand bank, but the crest of the big section of the dam carried down 
stream, but still standing, is on an average only four feet lower than the 
crest of the standing dam, which indicates very clearly that its founda- 
tion went with it, as it is resting practically in the old tail race,, whose 
bed was lower than the bottom of the dam. 
In all seventy-four soundings were made, and sixty-seven of these show 
that the depth of present rock is over eight feet below “low water,” and 
at the other seven soundings, the rod could not be driven through the 
