water in streams. 



lie snow-fall and rae- 

 :he annual rain-fall . . 



me of water largely 

 ater for irrigation. . 



seventeen years 



en cut off. 



Etfect3 of forests on the water supply. 



They tend to increase the water supply. 



But little in this county; amount of rain-fall or 

 precipitation determined by the condensation 

 as caused by the mountain ranges. 



Forests prevent the snows from melting too rap- 

 idly in the spring and protect the springs and 

 rivulets. 



They keep the ground moist and promote rain- 

 fall. 



The headwaters of all important streams are 

 protected and nourished by forests. 



