AZ vs. CA:11 California Exhibits, Vol. XI; Nos. 1001-1011; 1101-1109; 1201-1251; 1301-13431301-1343

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CALIFORNIA DEFENDANTS Exhibit No. 1251 Identification: .................... Admitted: July 12, 1957 Extract From Hydrology Handbook, A. S. C. E., Manuals of Engineering Practice, No. 28. (p. 136) 10. Evapo-Transpiration or Consumptive Use In much of the experimental work that has been done on the use of water by vegetation it was found most convenient to combine transpiration and evaporation from the land area, including interception, in one measurement. As a result the terms "evapo-transpiration" and "consumptive use" have received general acceptance, these terms denote the quantity of water transpired by plants during their growth or retained in the plant tissue, plus the moisture evaporated from the surface of the soil and the vegetation, expressed in feet or inches depth of water lost or used in a specified time. The consumptive use of water has become an important factor not only in the consideration of the economics of irrigation projects but also in the arbitration of controversies over major stream systems where the welfare of entire valleys, cities, states, and, in a degree, even nations, is involved. Consumptive use consists of two major water losses- namely, transpiration and evaporation from soil and vegetal cover. Transpiration depends primarily on the kind and quantity of crop or plant tissue produced. These in