490 SCIENCE OF HOME AND COMMUNITY 



secure control and monopoly of this power. Immediate 

 steps should be taken by governments, both national and 

 local, to secure supervision and control of this great resource. 

 Streams for navigation. As our country continues to grow, 

 additional methods of transportation will be needed, and the 

 navigable rivers furnish one important means. Here, too, 



FIG. 192. Destruction of farm land by flood. North Carolina. 



it is necessary that there should be an even flow of water 

 throughout the year ; so that the river shall not be so flooded 

 in spring nor become so low in summer that it is not navi- 

 gable. It is also essential that the channel shall not become 

 filled up with soil brought down from the hills. r 



Streams for irrigation. In the western part of our country 

 are vast areas with rich soil, capable of producing the best 

 of crops and thus supporting a large population, which never- 

 theless are barren at present on account of lack of sufficient 

 rainfall. In many cases it is possible to irrigate the land by 



