45 



TABLE 4 



CONSUMPTIVE USE OF WATER BY WIRE RUSH IN TANK 

 AT SANTA ANA, CALIF., 1930-32 



Year 



unreliable and are omitted from present consideration. 



The transplanted bush consisted of a single clump of 20 

 stems, each from 1/2 to 1 1/4 inches in diameter, growing from 

 the same root. Their average height was 7 feet. The tank in 

 which the bush was transplanted was 6 feet in diameter by 3 feet 

 deep. Water table was constant at a depth of 2 feet. The drip 

 line was approximately the same as the tank perimeter and consump- 

 tive use was computed on this basis. The general appearance of 

 the bush is shown in Plate II-A. 



Willow is a user of relatively pure water and normally does 

 not grow where alkali salts are in high concentration. Neverthe- 

 less, some salts were present in the willow tank soil. Regardless 

 of this, the willow bush produced a thrifty growth which consumed 

 52.70 acre-inches of water in 11 months, as represented in Table 5. 



The relation of consumptive use to evaporation from water 

 surfaces in the Santa Ana Valley (Table 44) indicates that water 

 consumed by willows grown in isolated tanks exceeds evaporation 

 from a Weather Bureau pan in but a single month of the year and 

 averages 92 per cent of the total evaporation from June to October, 



