10 



MISC. PUBLICATION 109, U. S. DEPT. OF AGRICULTURE 



ficial run-off of rain from a slope, which means that conditions 

 have been brought about that have diminished the absorption rate 



Rainbow Falls, Sierra National Forest. California's water supply for irrigation, 

 power, and domestic use comes largely from the national forests 



of the soil on a watershed. Such accelerated erosion, with the re- 

 sulting increase in amount of debris carried by the waters, means not 



