CHAPTER V. SUMMARY, CONCLUSIONS, AND RECOMMENDATIONS 



This chapter presents a concise summary of the 

 ve,?;etatlve water use studies, the conclusions drawn therefrom, 

 and rocotninendatlons v/lth regard to the future lines of study. 



Summary 



Precise Jcnowi edj-e of the total seasonal as well as 

 the distribution pattern of water use throughout the year is 

 basic to the plannlnc> desi;;n, and operation of comprehensive 

 water development projects. In developing this essential 

 knov/ledge, the department has been engaged in studies directed 

 tov;ai'd determination of evapotranspiration. During the period 

 from 193^1 to i960, these studies v/ere limited to certain geo- 

 graphic regions of northern and central California. 



Accurate measurement of evapotranspiration is so 

 complex and costly that practical considerations limit collec- 

 tion of these data to relatively fev7 locations. Recent re- 

 search work by various groups throughout the world has pointed 

 out certain fundamental relationships between the evapotranspira- 

 tion process and climatic factors. Transpiring crops respond 

 to the same energy sources as evaporation devices. The response 

 of crops, however, is modified by physical and physiological 

 characte':'istlcs. Under any given climatic condition, factors 

 such as availability of soil moisture, percent of vegetative 

 gi'-ound cover, and physiological development control the rate 

 of ovapoti'anspiratlon. 



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