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Show Waterway by the 1946 River and Harbor Act.8 This project, as planned by the Corps of Engineers, provides for an excavated canal extending from the Pickwick Landing Reservoir on the Tennessee River through the divide into the Tombigbee watershed; a lateral canal with locks along the upper Tombig- bee River; and a series of locks and dams on the Tombigbee River, connecting with the existing Warrior-Tombigbee Waterway at Demopolis, Ala. Sufficient water for lockages, estimated at about 400 cubic feet a second, would be diverted from the Tennessee River into the proposed waterway. The channel would have a project depth of nine feet and a minimum width of 170 feet in the river and canal sections and 150 feet in the divide cut. Locks would be 110 feet wide by 600 feet long. The proj- ect would provide a slack-water alternative to the Mississippi River for upbound traffic between the Gulf and points in the Midwest. Important bene- fits might accrue to the Tennessee Valley as a result of the establishment of this new transportation route. Suggestions have been made that consideration should be given to the possibility of utilizing the fall of 350 to 400 feet in the Tombigbee watershed to develop hydroelectric power, using flows diverted from the Tennessee River. If the total fall of the Tombigbee could be so used, such diverted flows could pass through an incremental head of approxi- mately 300 feet. With an assumed diversion of 10,000 cubic feet a second for power purposes, the new installed generating capacity that could be pro- vided is estimated to amount to at least 300,000 kilo- watts. This proposed diversion calls for detailed study because of the effect it might have on existing projects in the Tennessee Valley. The development of hydroelectric power, if fea- sible, in connection with the Tennessee-Tombigbee Waterway would result in modifications of the waterway which would be beneficial to navigation. For example, a channel of sufficient size to handle the diverted power flows at low velocity might pro- vide a much wider and deeper waterway than contemplated under the authorized plans. Concen- tration of the fall in a few relatively high power heads could result in a substantial reduction in the number of lock-lifts required. Among the problems encountered by such a com- bined development are those of land inundation, adequacy of foundations for project structures, and obtaining a dependable water supply for power * Act of July 24, 1946, § 1, 60 Stat. 634. purposes. As the effects of such diversion on the Tennessee Basin system might be serious, further exploration of the possibilities are needed. Diver- sions from the Tennessee River would reduce the power output of existing Tennessee Basin projects, but this might be more than offset by power pro- duced in the Tombigbee Basin. Removing water from the Tennessee River during periods of low flow in the Mississippi River would be detrimental to navigation on the latter. Thorough studies need to be made, therefore, of the benefits to be gained and the problems involved in modifying the authorized Tennessee-Tombigbee Waterway. Electric power interconnections.-The power service area of TVA is roughly twice the size of the Tennessee Basin. Included are all or parts of sev- eral Mississippi River tributaries; a large part of the Tombigbee Basin; portions of the Alabama- Coosa Basin; major portions of the Cumberland Basin; and the upper part of the Green River watershed in the Ohio Basin (fig. 5). Although construction in the Cumberland Basin is being undertaken by the Corps of Engineers, the hydro- electric power produced in that basin will be mar- keted through the system of the Tennessee Valley Authority. Power produced at the Corps of Engineers' Alla- toona Dam in the Alabama-Coosa Basin, however, is marketed by the Southeastern Power Administra- tion of the Department of the Interior. Other projects including power are authorized for con- struction by the Corps of Engineers in the Alabama- Coosa and the Green River Basins, but none of these is under construction. Presumably, however, their power also will be marketed by the South- eastern Power Administration. Later coordination of the TVA system with the power marketed by the Southeastern Power Administration therefore is likely to be desirable. The power system of the Tennessee Valley Au- thority is well interconnected with the adjacent existing utility systems in the region, and inter- changes of power are effected under various agree- ments. Hydroelectric plants in the basin owned by the Aluminum Co. of America are operated under agreement by the Tennessee Valley Author- ity as part of the coordinated system. Conclusions There are important problems of coordinating the operation of Tennessee Basin projects with im- 911610-51- 747 |
