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Show The Situation Although the water resources of the basin itself have been improved to a high degree, there remain important problems of correlating the operation of projects in the basin with certain developments in neighboring basins. Most significant among the neighboring related basins are the Mississippi, the Ohio, the Cumberland, and the Tombigbee. Present -relation to the Ohio and Mississippi.- The Tennessee River has important influences on both the Ohio and the Mississippi Rivers. The Tennessee produces 25 percent of the runoff of the Ohio River, although it has only 20 percent of the watershed area. The Ohio Basin contributes more than 40 percent of the total flow of the Mississippi River but lias only about 16 percent of the area. Water releases from the Tennessee River reservoirs during seasons of natural low flows increase the low- flow stages on the lower Ohio and Mississippi. This makes dredging unnecessary to maintain standard low-water navigable depths, thereby providing ben- efits to navigation. During hugh flow periods the operation of these reservoirs, affording some 11 million acre-feet of flood control storage, provides flood control benefits to the lower Ohio and Mississippi Valleys. Ken- tucky Researvoir, located about 22 miles upstream from the nxouth of the Tennessee River and about 67 miles alx>ve the confluence of the Ohio and Mississippi IRivers at Cairo, provides about 4 million acre-feet of flood control storage. It is particularly valuable in. effecting reductions in flood peaks at downstream locations. The 1944 Flood Control Act provides that in case of danger from floods on the lower Ohio and Mississippi Rivers the Tennes- see Valley Authority shall regulate the release of water from -the Tennessee River into the Ohio River in accordance with instructions issued by the De- partment of the Army.1 This assures coordination in the operation of the flood control features of the Tennessee Basin with flood control improvements in other parts of the Mississippi Valley. The neighboring Cumberland.-Plans prepared by the Corp»s of Engineers in 1945 for the Cumber- land River ZBasin included a navigation and power reservoir on. the lower river with a dam at the lower Cumberland site (mile 30.5). That reservoir would have been located very close to the Kentucky Reser- voir. However, plans for the Lower Cumberland Project did not coordinate it with the Kentucky 1 Act of December 22, 1944, § 7, 58 Stat. 887. Project. The proposed method of operating reser- voir levels at the Lower Cumberland Project dif- fered from those in effect at the nearby Kentucky Reservoir. According to TVA, interconnection of the two reservoirs by a short canal cut through the low divide, as had been proposed in some quarters, would not have been possible. The plan was modi- fied to include low single-purpose navigation dams on the lower Cumberland River. The modified plan was authorized by the 1946 River and Harbor Act.2 Recently, however, new studies have been initiated which may result in restoring a Lower Cumberland Project with the addition of a high multiple-purpose dam to the plan. Under this pro- posal, coordinated operation of the two reservoirs may be more feasible. (See problem A-2.) Tennessee-Cumberland-Ohio-Mississippi inter- connection.-In connection with the possible coor- dinated controls for the Tennessee and Cumberland Rivers, a suggestion has been made for further co- ordination which also would involve the Ohio and Mississippi Rivers. This coordination would in- clude an interconnection of the Kentucky Reservoir with a reservoir on the Cumberland River created by a dam constructed near the mouth of the river in lieu of the proposed Lower Cumberland Dam; a joining of the Cumberland and Ohio Rivers just above their confluence; and a connection between the Ohio and Mississippi Rivers by a canal through the Cache Valley area. The coordinated development of these four river systems, with the large storage capacities contem- plated, would provide large flood control and navi- gation benefits and power potentialities estimated at more than 1 million kilowatts capacity. The problems connected with such a development are many and complicated. Perhaps the most serious is the inundation of highly developed cultivated lands along the Ohio River. Because major floods usually occur during winter and early spring months, however, those sections of reservoirs sub- merged during the flood season normally could be cultivated, as now is the practice in the Kentucky Reservoir. Careful studies need to be made of all of the problems involved and benefits to be gained by such a combined treatment of these rivers in order to determine whether a practicable and ra- tional solution can be found. Tennessee-Tombigbee Waterway.-A n o t h e r problem of coordination has been introduced with the authorization of the Tennessee-Tombigbee * Act of July 24, 1946, § 1, 60 Stat. 634. 746 |