Original caption reads: Regulation of floods. Thirty major dams comprise the TVA system, regulating the river and its tributaries for flood control, navigation development, and power production. Of these, nine are on the main Tennessee River; the others on tributaries. Together the dams have a combined storage capacity of more than 22,000,000 acre-feet of water, of which 14,600,000 acre-feet are useful for both flood regulation and power production, and 12,000,000 acre-feet for flood regulation alone. Thus far more than $51,000,000 has been saved in flood damages in the Valley since TVA started. The system is capable of reducing the crest of Mississippi River floods at Cairo, Illinois, by from 2 to 4 feet, eliminating the flood danger from 6,000,000 acres of fertile Mississippi Valley land, and lessening it on an additional 4,000,000 acres.