58 



DIVISION OF WATER RESOURCES 



when the tanks were protected from rainfall. If there had been no 

 protection consumptive use would have been slightly increased. The 

 San Bernardino district has an interior climate which increases evapora- 

 tion and consumptive use of water to an amount greater than that in 

 the coastal climate of Orange County, and irrigation requirements also 

 are higher. The use of water by Bermuda grass is probably somewhat 

 higher than the use by citrus, but less than that by alfalfa. Bermuda 

 grass, therefore, does not make an excessive demand upon the ground 

 water supply. 



Monthly consumptive use of water by Bermuda grass for the 

 period covered by the investigation is shown in Tables 18, 19 and 20. 

 These tables also show the total use of water for each year, ending 

 April 30. Some months are omitted, but percentages of use for the 



PLATE VII 



vap 



I Ai pa/7 Bernardino (Bermuda) 

 " At Santa /}na (Salt Grass) 



I. from ground iank 

 >. 16 a/ San fa ^na 



5 



Apr. 



: 



I 



May- iJune.lJuly. 



^ ^- 



\ 



Aug. 



R 



< 



Sept. 



Oct. 



Nov. 



Dec. 



1931 



COMPARISON OF USE OF WATER BY BERMUDA GRASS AT SAN BERNARDINO 



WITH THAT OF SALT GRASS AT SANTA ANA AND EVAPORATION FROM 



WATER IN TANK NO. 16 AT SANTA ANA. 



months of record, based on the evaporation from both the circular 

 sunken evaporation tank and the Weather Bureau pan, separately, are 

 given for the same period. It is through these percentages that com- 

 parisons of consumptive use with the same or different crops grown 

 under different climatic conditions may be made. 



Use of Water by Tules and Cat-Tails 



A study of consumptive use of water by aquatic growth was begun 

 in the summer of 1929 at the Santa Ana station by transplanting rooted 

 plants of round stem tules into a single tank. In the following spring 

 investigation of triangular stem tules and cat-tails was begun at Santa 

 Ana and later one tank of triangular stem tules at Prado and one tank 

 of round stem tules at San Bernardino were included. 



The round stem tule or common bulrush (Scirpus acutus) is a 

 perennial plant with a round, dark green stem which grows to a height 

 of 6 to 12 feet. It is found in abundance in some sections where water 



