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Transactions Texas Academy of Science. 
[ 52 ] 
DEVILS RIVER. 
Devils river is a magnified illustration of the effect of the large springs 
of the Edwards Plateau. The river rises in Pecan Spring, about forty- 
five miles north of the mouth and about sixty miles from Del Rio. This 
spring is on what is known as the old mail route from San Antonio to 
El Paso; this route followed the course of the springs on the southern 
edge of the plateau. The river is only about fifty miles long, and yet, 
of all the rivers of Texas, is has the largest minimum flow. This, as 
determined by semi-weekly measurements during 1900, was slightly over 
500 s second-feet. During 1901 the lowest flow occurred on August 29th, 
when a discharge of 509 cubic feet per second was found. The flow of 
this river could readily be utilized in irrigating vast tracts of land east 
of Del Rio. It would be necessary to construct a dam across the river 
above the railroad bridge and convey the water from the lake thus formed 
to the irrigated lands by pipe lines to prevent seepage. The water is clear 
as crystal and forms a strong contrast to the turbid water of the Rio 
Grande at their junction. 
The Pecos and Devils rivers unite with the Rio Grande within twenty- 
five miles of each other and their waters serve to make the flow of the 
Rio Grande below Del Rio reliable and commercially valuable. The 
lowest flow at Eagle Pass during 1901 was found to be 1800 cubic feet 
per second. Half of this amount turned into irrigation ditches would 
bring into cultivation for ordinary crops 200,000 acres of land, and for 
rjce in the lower and flatter country near Brownsville it would readily 
have a minimum capacity of half of the whole rice crop of Texas for 
1901. 
SAN FELIPE. 
San Felipe creek, which skirts the. extreme eastern limits of Del Rio, 
rises from large springs a little over a mile southeast of the town. The 
flow of these springs is utilized in the magnificent irrigation system 
between the town and the Rio Grande, and for one power plant. The 
irrigation system will be described fully in a water supply paper. The 
total flow of the stream was found to be, in 1895, cubic feet per sec- 
ond; in 1899, 113 cubic feet; in 1900, 14-9 cubic feet; in 1901, 150 cubic 
feet. The variation in flow was caused by the immense flood known as 
the Brackett Flood of June, 1899, and increased precipitation on the 
Edwards Plateau. There is installed on the San Felipe creek an electric 
light and ice plant, the power for running which is obtained solely from 
the flow of the creek. The dam (Fig. 1) is constructed of rubble, lime- 
stone masonry, is something over one hundred feet long, about ten feet 
high, and is built with a portion straight across the stream, the remainder 
Curving down stream, thus forming the race from that portion of the 
dam next the power house and the bank of the stream itself. The cross- 
