278 SOILS 



and enthusiastic assemblage. When this single 

 unit is completed it will cost about ninety millions 

 of dollars and will water about three hundred and 

 seventy-five thousand acres in excess of the area 

 now supplied. 



In addition to providing irrigation systems, the 

 National Government is endeavouring to aid 

 arid farming by protecting the forests of the West. 

 Most of the streams from which the water is drawn 

 have their origin in forested mountains. Cutting 

 off the forests or allowing them to be burnt off 

 would make the water supply more uncertain. 

 Contrary to the popular notion, forests have but 

 little effect in increasing rainfall, but they have a 

 very marked effect in regulating the flow of streams. 

 Over forty-seven million acres of forests have been 

 set aside for the protection of the headwaters of 

 irrigation streams. President Roosevelt said in 

 his message to Congress, December 3, 1901 : "The 

 forests are natural reservoirs. By restraining the 

 streams in flood and replenishing them in drought 

 they make possible the use of water otherwise 

 wasted. Forest conservation is therefore an 

 essential condition to water conservation." 



This is a development scheme of stupendous 

 proportions. It is worthy of the genius and enter- 

 prise of the American people who, as a people, are 

 now pledged to execute these plans. 



Windbreaks. In the subhumid sections of the 

 central West, particularly eastern North Dakota, 

 eastern South Dakota, central Nebraska, western 

 Kansas, central Oklahoma and central Texas, 

 windbreaks are frequently of great service for pro- 

 tecting the ground from the sweep of dry winds, 

 which evaporate much moisture from the soil, and 

 often blow the lighter soils into drifts. Sometimes 



