CONDITIONS REQUIRING IRRIGATION 



223 



public lands is 973 million acres, of which Newell esti- 

 mates that about 70,000,000 is of a desert character. 

 At the present time, irrigation is practiced on less than 

 1 per cent of this area, and the total water supply is 

 estimated to be sufficient for less than 10 per cent of the 

 total area. 



Fig. 72. Map of the western portion of the United States, showing in black 

 the irrigated land, and in dots the area which may be irrigated if all the avail- 

 able water supply is utilized . 



