WATER LOSSES FR01\T WET AREAS 



93 



was flowin<i>. Tliis makes a total above tlie upper control of 15,090 

 linear feet of canyon, including' all the branches, that had flowing water 

 at the end of the 19;?1 p'l'owing season. 



Above the lower control the area of the watershed is 3.4 square 

 miles, of which area the east branch, on which the branch control is 

 located, drains 0.9 s(}uare mile. 



Records were obtained during the 19)11 season at the middle and 

 lower controls on the main canyon, from August 1 to October 17, and 

 also during the 1932 season at the three controls on the main canyon, 

 from June 24 to November 3. Water was also measured at the branch 

 control from June 24 to July 9, 1932, no water passing this branch 

 control at any other time during the periods of record. 



EQUIPMENT 



Controls 



In 1931, the two bedrock controls were established in Coldwater 

 Canyon at the locations previously described. At each of these con- 

 trols, a low concrete dam was biiilt on bedrock across the bed of the 

 stream. The flow of water was passed through a 3-incli Parshall meas- 

 uring flume placed in one end of each dam, and water stage recorders 

 were installed to record the head on each flume. On September 17 of 

 the same year a flow recorder for recording the discharge directly 

 was installed at the lower control and Avas operated during the 

 remainder of the season. The flow recorder is described in detail on 

 page 96. 



PLATE XXI 



MIDDLE COLDWATER CONTROL SHOWING 3-INCH PARSHALL MEASURING 



FLUME AND FLOW RECORDER. 



