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Show of the economy of the basin, but neither has reached the productivity of which it is capable. Since early settlement, misuse of the land has given rise to the usual pattern of severe sheet and gully erosion so prevalent in the southeastern States, and in many other parts of the country. Approximately half of the watershed area has remained in forest. Al- though poorly managed as to timber production, and falling far short of desirable water protection possibilities, the forest lands have not been sub- jected to the high rate of erosion that has occurred on the croplands. Of the approximately 8 million acres of cropland in the basin, over 4 million have been classified as being in the critical or serious erosion category. It is tentatively estimated that to accomplish the best land use, possibly 1.6 million acres of cropland should be converted to permanent grass and a million acres to forest. On the other hand, ap- proximately one-half million acres of the land presently in forest could be safely converted to crop- land or pasture if and when it is needed for agricul- tural production purposes. Most of this forest area that could be converted to crops or pasture is not in large continuous blocks, but rather in small par- cels scattered among the farm woodland areas of the basin. The sediment problem in streams and reservoirs, except in some local situations, is not as important as in other streams in the United States. Neverthe- less, it is one which merits serious consideration. Observations of sediment load made near the mouth of the Tennessee River at Johnsonville show that during the 3 years 1935-37, prior to closing of Pickwick Dam, the river carried an average of 6,300 acre-feet of sediment per year. The mean concen- tration of suspended material in the 1935-37 period at Johnsonville was 110 parts per million. The maximum concentration at Johnsonville between 1935 and 1941 was 1,190 parts per million. The maximum sediment concentration measured any- where in the basin was 84,700 parts per million. This occurred on Potato Creek in a small local area denuded by copper-mining operations. In addition to sedimentation of reservoirs, sedi- ment damages occur on the bottom lands in the small tributary valleys as a result of erosion over their watersheds. This menace of sediment, as well as the Hood waters with which it is associated in the small tributary valleys, is a significant prob- lem to be considered in a comprehensive water resources program. Choices in approach.-Those who framed the Tennessee Valley Authority Act envisaged a co- ordination of engineering measures in the river with restorative practices on the land. They believed that a complete and harmonious watershed program would be possible which would help cure the ills of the valley. They therefore expected the watershed treatment phase would be coordinated with the engineering work. At the time TVA programs were being organized (1933) the choice of approach in watershed man- agement was mainly between establishing local organizations to deal directly with farmers and other rural people on soil and cover problems, or making use of the existing facilities and organizations. TVA chose to undertake agricultural phases of watershed management activities as part of a re- gional farm program in cooperation with the land- grant colleges and the Extension Service of the Department of Agriculture. Soil conservation thus became a part of a single over-all educational and demonstration program for farm improvement in the valley. This approach differs from the pro- gram of the Soil Conservation Service, in which local soil conservation districts organized under State law assume a major responsibility for soil conservation. Present land treatment programs in the basin.- The TVA program has been on area and unit dem- onstration farm approach. Through test demon- strations on a limited number of individual farms and in communities in which farmers joined to con- duct area test-demonstrations, an effort was made to encourage the land owners or operators to adopt new methods of soil care. Those participating re- ceive TVA-produced experimental fertilizers at less than market prices and in return agree to operate their farms in accordance with methods recom- mended by the agricultural experiment stations and extension services. They also agree to keep records of the use and effect of the fertilizers and the related improved farm management practices, and to make the records and their farms available as demonstra- tions to neighboring farmers. Of the approximately 305,000 farms in the basin, 11,676 were used as demonstration farms in 1948.8 Over 60,000 farms have participated in the demon- strations both in and outside the valley since the beginning of the TVA program. In addition to efforts by the TVA, the Depart- 8 Total area of 11,676 farms: 1,444,000 acres. 754 |