590 A NATIONAL PLAN FOR AMERICAN FORESTRY 



irrigation, many of the eastern national forests have similar water- 

 shed importance, and are particularly involved in the protection of 

 the watersheds of navigable streams. ^ 



A few examples will illustrate the size of the values arising from or 

 potential in water coming from national forest watersheds : 



For their domestic water supply 49 cities with a population of 

 10 thousand or more each, and a total population of nearly 5 l / 4 million, 

 and 327 cities with less than 10 thousand population each and a total 

 population of over 714,000, depend on national forest watersheds. 

 The investment by these cities in their water plans approximates 

 $493,703,000. 



Of the estimated 38 million potential horsepower of water power in 

 the United States, a little over 11 million, or 29 percent, is in the 

 national forests. Already 1,618,000 horsepower has been developed 

 on the national forests which, at an estimated investment of $200 

 per horsepower, gives a present total investment of $323,625,000. Of 

 the total potential horsepower on the national forests, 78.3 percent has 

 been either developed or applied for, and this will involve an estimated 

 investment of $1,742,000,000. 



Within the 11 principal national-forest States in the West, the 

 1930 census shows slightly over $932,000,000 invested in irrigation 

 enterprises. Approximately 89 percent of this sum is estimated to 

 be based on water from national-forest streams, or an investment of 

 $827,500,000. 



Thus for domestic water supply, power, and irrigation national- 

 forest watersheds are already providing water for projects involving 

 a total investment of $1,644,828,000. 



It is impossible, of course, to ascribe an exact part of these values 

 to the fact that the watersheds are within protected and managed 

 national forests, or to measure exactly the effect of good or poor 

 management of the timber and forage resources on the maintenance 

 of these values. There is so much evidence to show that unregu- 

 lated timber cutting and livestock grazing, and uncontrolled fire, on 

 watersheds, often cause adverse effects in the form of premature 

 run-off, floods which destroy crops and property, and erosion which 

 fills irrigation ditches and reservoirs and reduces or destroys soil pro- 

 ductivity, that it is unnecessary to reduce it to refined quantitative 

 expression in order to make a clear case for the need of regulated use 

 and cultural operations which will preserve and enhance the watershed 

 values of the national forests. 



So, timber cutting is invariably regulated by the watershed factor; 

 grazing managed with one major objective to avoid watershed damage ; 

 replanting of watersheds given first consideration ; the public and live- 

 stock excluded from watersheds where necessary to protection of the 

 purity or palatability of the water for domestic use. 



RECREATION USE 



Because of their wide distribution, their highly diversified topog- 

 raphy, elevation, and cover, and their myriad manifestations of natural 

 phenomena, the national forests present large opportunities for public 

 use for purposes of residence, recreation, and education. Such uses, 

 properly coordinated with the other uses and services of the national 

 forests, do not conflict with the protection, management, and devel- 



