90 



DIVISION OF WATER RESOURCES 



control. In 1932 the same controls were continued and, in addition, 

 another bedrock control, designated as the "npper control," was 

 installed 5875 feet npstream from the middle control, and a snpple- 

 mentary bedrock control was installed on the only branch entering- the 

 main canyon from the east between the middle and lower controls, at a 

 point about 300 feet above its month. This branch canyon enters the 

 main canyon 800 feet above the lower control. 



The approximate elevations above sea level of the conti'ols are 

 2300 feet for the lower control, 2500 feet for the middle control, and 

 3100 feet for the upper control. 



A general view of Coldwater Canyon is shown in Plate XIX, the 

 white marks indicating the location of the controls. 



The canyon bottom vegetation between the controls is composed 

 mostly of alders, bay (California laurel), sycamore, willow, and maple, 

 with a few oak, mountain mahogany, cedar. si:)ruce, and cottonwood 

 trees. Also, there is considerable smaller growth of grapevine, black- 

 berry, poison oak, ferns, etc. Table 31 shows the number and kinds 



TABLE 31 



CLASSIFICATION OF TREES BETWEEN MIDDLE AND LOWER CONTROLS 



IN COLDWATER CANYON 



of trees between the middle and lower controls, and Table 32 is a 

 similar table of the trees between the upper and middle controls. 

 These two tables show the difference in vegetation of the two sections 

 of the canyon. In the lower section the alders constitute 81.9 per cent 

 of the total number of trees, while in the upper section they consti- 

 tute only 47.9 per cent of the total number. The lower percentage of 

 alders in the upper section is accounted for principally by the increased 

 number of bays which constitute but 4.1 per cent in the lower section, 

 but make up 26.1 per cent of the total in the upper section. The lower 

 section has a higher percentage of larger trees, while between the upper 

 and middle controls the percentage of smaller trees is the greater 

 and also the number of different kinds is greater. Views of the canyon 

 bottom vegetation between the middle and loAver controls are shown in 

 Plate XX. 



