158 LANDS OF THE ARID REGION OF THE UNITED STATES. 
gave an aggregated flow of 47 cubic feet per second. As they derive a 
greater part of their waters from the melting snows on the plateau, double 
this amount, or 94 cubic feet, would not be an overestimate of the volume 
during the irrigating season. After the union of these branches, the united 
stream flows in a deep canon until near its junction with the Fremont 
River in Graves Valley. Both Curtis Creek and the Fremont receive 
some accessions to their volume from springs in the canons through which 
they flow above this valley. If all the water in their upper courses should 
be used to irrigate lands in Castle and Rabbit Valleys, a sufficient amount 
would be returned to their channels by percolation to irrigate, with the 
addition of the accessions in the canons, all the arable land in Graves 
Valley. 
THE SAN RAFAEL RIVER. 
This stream flows in an easterly course, and enters the Green 32 
miles above the junction of that stream with the Grand. It has three 
principal branches—Ferron, Cottonwood, and Huntington Creeks—all 
rising in the Wasatch Plateau at an altitude of about 10,000 feet. These 
streams have a rapid fall in their upper courses, and leave the plateau 
through almost impassable canons cut in its eastern wall overlooking Castle 
Valley. They flow across that at intervals of a few miles apart, and, then 
uniting, cut a deep, narrow canon through the San Rafael Swell. Emerg- 
ing from the swell, the river flows across a low, broken country until its 
junction with the Green. The largest body of arable land within the 
drainage basin of the San Rafael is in Castle Valley, a long, narrow 
depression lying between the eastern escarpment of the Wasatch Plateau 
and the San Rafael Swell. It is nearly 60 miles in length from north to 
south, and has an average elevation of 6,000 feet above the sea. Its 
southern end, as has been before mentioned, is drained by the tributaries 
of Curtis Creek, the central portion by the three streams forming the San 
Rafael, and the northern by Price River. No permanent settlements have 
been made in the valley, but it is much used as a winter herding ground 
for stock owned by the settlers in other portions of Utah. Lying near the 
branches of the San Rafael that cross it, and in such position that the water 
can be easily conducted over it, are 200 square miles of arable land, 
