HUMIDITY IN A RECLAIMED DESERT 



51 



through June, July, August and September. October and No- 

 vember witness a sharp decline followed by a substantial increase 

 in December. In other words, there is a fairly good agreement 

 between the seasonal humidity fluctuations for El Centro and 

 San Diego as visualized by the charted data. Most especially 

 we would emphasize the fact that the great increase in humidity 

 from May to July is very evidently a regular phenomenon over 

 an extent of territory including both the Imperial Valley and the 

 coast region in the vicinity of San Diego. 



75 40% " 



JUL. 



AUG. 



SEP 



OCT 



Fig. 3. Graphs showing water shortage in August, 1917, and accompanying 

 humidity. Use of water (light line) in thousand second-feet, shortage indicated 

 by shading. Relative humidity (heavy line) for the same months. 



During August 1917 the valley suffered a rather severe water 

 shortage through low water and engineering difficulties at the 

 intake. During the very height of summer heat the distribution 

 of water dropped from 127,294 second feet in July to 85,349 sec- 

 ond feet in August, or a reduction of over 33 per cent. By refer- 

 ring to figure 3 it will be noted that this sudden checking of irri- 

 gation produced no apparent effect on the general seasonal trend 

 of humidity for the same period. 



