WATER LOSSES FROM WET AREAS 



65 



Consiiniptive use of water by the willow groAvth by months is shown 

 in Tables 14 and 15. The maximum monthly use in the year in which 

 the growth was in good condition, amounting to 7.8 acre-inches per 

 {'cre, occurred in August. In comparison with evaporation from a 

 Weather Bureau pan, consumptive use exceeded evaporation only dur- 

 ing the months of August and September. The total use during a 

 period of eleven months, shown in Table 14. was 52.7 acre-inches per 



PLATE X 



WILLOW TREE GROWING IN 6-FOOT TANK, SANTA ANA 



STATION, 1931. 



acre or 83.5 per cent of the evaporation from a Weather Bureau pan 

 for the same period. It is evident that willows grown in tanks under 

 the conditions of this experiment, are fairly large users of ground 

 water. The amounts used exceed consumptive u.se by either salt grass 

 or Bermuda gra.ss, but are less than consumptive use by tules under 

 natural swamp conditions. 



An adjustment factor has been computed for tules to adjust con- 

 sumptive use of water by tank growth to similar growth in large areas, 



5 — 4503 



