32 



transpiration is low through cloudiness, cool weather, or high 

 humidity. 



The use of water-stage recorders at control points pro- 

 vides hydrographic charts that indicate the effect of transpira- 

 tion upon the flowing stream. The effect may be too small to be 

 visible in the stream itself except in springs and small streams 

 which disappear in the sand by day and flow in the channel by 

 night. Evidence of these daily fluctuations is afforded, however, 

 in Figure 2 which was developed by Troxell (34) to show short- 



1 1 \ 1 1 1 1 



MILL CREEK POWER CANAL I El. 2950ft. Area 43 sq.m;. 



CAJON CREEK El. 2620 ft. Area 40.9 sq.mi. 



LITTLE SANTA ANITA CREEK El. 2200ft. Area 1.9 sq.ml. 



WATERMAN CANYON CREEK El.2l25ft Area 4.6sq.m;. 



SANTA MARGARITA RIVER at Ys;dora , CaHf. 

 El. 15ft. Area 740 sq.mi. 



FIGURE 2. — Diurnal fluctuations in southern California 

 streams (after Troiell). 



