IBEIGATION AND DBY-FABMIMG 691 



About one-third of this area was irrigated in 1915. Many 

 of the dams and canals involved are of stupendous size 

 and necessitate feats of bold engineering. Often hydro- 

 electric power is developed in large amount in the passage 

 of the water from the reservoirs to the fields where it is 

 to be used to grow crops. 



593. Legal, economic, and social effects of irrigation. — 

 The practice of irrigation on an extensive scale has caused 

 important changes in the construction of law ^ relative to 

 water and property rights and in commercial and social 

 organization. 



Riparian rights in streams and lakes under humid 

 conditions, for purposes of domestic use, power, and trans- 

 portation, must be modified in an arid country. Here 

 values of all real property depend largely on the supply 

 of water for purposes of irrigation. The control and use 

 of water becomes of the utmost public concern. Conse- 

 quently the use of water for the purpose of growing crops 

 takes precedence over use for all other purposes except 

 domestic use. In nearly every country in the world 

 where irrigation is extensively practiced, the state or 

 the government has assumed ownership or a large measure 

 of control over the water in all lakes and streams. The 

 necessity of the use of water for irrigation has conferred 



^ Mead, E. Irrigation Institutions. New York, 1903. 



Mead, E. Irrigation Institutions in Different Countries. 

 American Cyclopedia of Agriculture, Vol. IV, p. 154. New 

 York, 1909. 



Hess, R. H. Further Discussion of American Irrigation 

 Policies. American Cyclopedia of Agriculture, Vol. IV, p. 

 160. New York, 1909. 



Hess, R. H. Socio-Economic Aspects of Irrigation. Ameri- 

 can Cyclopedia of Agriculture, Vol. IV, p. 167. New York, 

 1909. 



