A NATIONAL PLAN FOR AMERICAN FORESTRY 345 



soils is very rapid. It is only where a loamy condition is approached 

 that there is appreciable sheet erosion even from cultivated soils. 



The relation of forest cover to erosion and other watershed and 

 stream flow problems in the South Atlantic drainages is diagra- 

 matically shown in figure 4. In the mountains steep slopes and 

 relatively heavy rainfall combine to make a permanent vegetative 

 cover necessary if erosion is to be minimized. Forests still cover a 

 high percentage of the mountains, and clearly exert a major influence 

 on erosion. A considerably smaller proportion of land remains 

 forested on the piedmont, in the mountain valleys of Virginia, and 

 on the coastal plain adjoining the piedmont, where topography is 

 only moderately broken and slopes are relatively short. In spite of 

 this fact the absolute area of forest is so large, and erosion of the 

 cleared land is so general, that here also the forest is considered to 

 exert a major influence. The forests of the mountains, the piedmont 

 plateau, and a strip of the coastal plain bordering the plateau may 

 properly be classified as protection forest. In the greater part of 

 the coastal plain, however, low relief would render serious erosion 

 unlikely even in the absence of forests. 



Wind erosion is common along the seacoast, where sand dunes 

 occur. The drifting sand is held in place in some localities by a 

 cover of pine and brush species, but elsewhere marches upon roads 

 and other improvements, and in some places fills dredged channels. 

 Fixation of drifting sand is a problem of some importance at points 

 along several hundred miles of coast in Virginia and the Carolinas. 



WATER POWER 



Water power is an extremely important and valuable natural 

 resource in the South Atlantic drainages. According to the United 

 States Geological Survey, North Carolina ranked third among all 

 States in the Union in 1929 in generation of power from streams, and 

 South Carolina ranked sixth. 



Water storage on a large scale is highly desirable in producing 

 power in this region, because of the extreme fluctuations in stream 

 flow. The maximum flow of the major streams is here from 150 to 

 400 times the minimum flow; this contrasts with a ratio of 100 to 1 

 in the case of the Kennebec River in Maine. In order to maintain 

 a steady flow for the generation of water power, artificial reservoirs 

 have been created. The reservoir at Dreher Shoals, on the Saluda 

 River in South Carolina, has a storage capacity of 524 billion gallons, 

 which is said to be the largest capacity of any reservoir constructed 

 for power, flood control, or water supply in the United States. 



Control of silting is a grave problem in the management of storage 

 reservoirs throughout the region. The Whitney Dam, above Badin, 

 N.C., on the Yadkin River, was a 38-foot dam constructed in 1910. 

 In 15 years silt filled the reservoir within a few feet of the top of the 

 dam. Another example of a reservoir completely filled with silt 

 from erosion is the Parr Shoals Reservoir in Saluda County, S.C. 



NAVIGATION 



Maintenance of navigable channels in streams and harbors, in the 

 face of continuous deposition of enormous quantities of solid matter 

 the product of erosion, is the third major stream-flow problem of 



