102 



Irrigation and Drainage 



\ / ""AH / V;\; 



v\ J-- / ^ 



L V\J .~.^ !ig 



Fig. 20. The dry-farming areas (in black) in the western United States. 

 (After Newell.) 



tributed through the growing season, while both of the 

 western areas mature their crops in from 30 to 60 days 

 of continuous nearly rainless weather ; and yet, if we 



