A NATIONAL PLAN FOR AMERICAN FORESTRY 387 



Navigation was far more important in the past than today. Not 

 only the Ohio but many smaller tributaries of the Ohio were formerly 

 navigable, at least for portions of their lengtns. The first steamboat 

 appeared on the Ohio in 1811. By 1840 there were 1,200 of them 

 plying the waters. 51 Thereafter, largely because of the appearance 

 of the railroad, boat travel declined. By raising the water level 

 through a system of Federal locks, sufficient depth (9 feet or more) 

 is now gained to float boats over the major bars and shoals. A series 

 of 49 dams was completed in 1929 at a cost to the public of over 

 $118,000,000. The annual cost of maintenance is $2,000,000. 52 

 Some 22,337,000 tons of freight were shipped on the Ohio in 1930, 

 half of which was in the vicinity of and just below Pittsburgh, Pa. 



Navigation has fallen off on the Tennessee River also. It is at 

 present interrupted by low flow about 60 per cent of the time and 

 by flood and overflow 1 or 2 percent of the time. 53 In order to restore 

 use of the Tennessee River for water transportation, Congress has 

 recently adopted a new project for this river creating a 9-foot navi- 

 gable depth from the mouth to Knoxville, a distance of 640 miles, 

 and has authorized an expenditure of about $75,000,000 to accom- 

 plish this. 



Despite the tremendous investment in water transportation, in- 

 adequate or little effort has been made to protect the watershed 

 contributing to the flow of the Ohio and its tributaries to establish 

 a more uniform flow, or to eliminate the silt burden dumped in it 

 continuously from eroding lands by unnecessary and abnormal 

 run-off. 



CAUSES OF WATERSHED PROBLEMS 



The causes of increasing floods, inadequate water supplies, destruc- 

 tive erosion, reduced efficiency of power plants, and hindrances to 

 navigation very largely arise from misdirected human activities. 

 Because these disturbances are man made, they are subject to cor- 

 rection and modification. Deforestation and destruction of surface 

 litter is a primary cause of the extremes of stream flow which the 

 communities in this region now experience. Run-off has been greatly 

 increased in times of rainfall with consequent decrease of stream flow 

 in times of drought. Several practices are responsible for these 

 circumstances. 



CLEARING OF NONAGRICULTURAL LAND 



The clearing or cultivation of land which erodes badly when cleared 

 is a primary cause of unbalanced stream flow. Many observers have 

 recorded the accelerated run-off and waste of soil which follow the 

 clearing and exposure of mountain lands within this basin. Ashe and 

 Ayres 64 credit land clearing as the most permanently destructive 

 practice used on mountain lands and maintain that much of this land 

 should forever remain in forest, some of the cultivated fields sloping at 

 an angle of 30 to 40, and some being even too steep for the mountain 

 steer and bull- tongue plow. 



Switzer, J. E. The completed Ohio River Project. Proe. Indiana Acad. Sci. 41: 339-349. 1932. 



s Annual Report, Chief of Engineers, U.S. Army. 1929 pts. I and II, 1932, pt. I. 



" Report from Chief of Engineers on Tennessee River and Tributaries, 71st Cong., 2d sess., H.Doc., 

 pt. (1): 328, 38-41. 



M Ayres, H. B., and Ashe, W. W. The Southern Appalachian Forests. U.S. Oeol. Survey. Prof. 

 Paper 37, 1905. 



