This dissertation is about water and power in the American South between 1890 and 1990. Corporate monopolies, state agents, and citizens clashed over the answer to a basic question: Who was best equipped to manage natural resources equitably and stimulate economic growth? Corporate and state representatives understood the direct relationships between rivers, energy production, and political economy. Between 1890 and 1930, New South corporate capitalists and transnational engineers laid claim to water resources to fuel industrial and urban development. Regional planners created the Tennessee Valley Authority to counterbalance commercial monopolies. After 1945, Congress rejected New Deal liberalism and turned the Army Corps of Engineers into the Sunbelts go-to water management agency. Powerful institutions built levees, dams, and reservoirs throughout these periods to solve old water problems, generate energy, and consolidate power. In doing so, these organizations took part in an ongoing social, racial, and ecological discourse about the cultural benefits and natural functions of these new hybrid environments.The environmental challenges were substantial. Scholars have documented the regions historic water problems associated with flooding, navigation, and erosion. The industrial and agricultural South, however, has been equally influenced by a less well known water problem: water scarcity. Corporate and state responses to multiple, dramatic droughts shaped the southeasts watersheds and modernization. There are no natural lakes in the Piedmont and Blue Ridge South, yet major and modest reservoirs dot the land from Virginia to Alabama. Investigating the corporate and state institutions responsible for building the regions extensive reservoir system illuminates how boosters, engineers, and conservationists attempted to resolve water problems, and the social conflict and environmental questions those solutions sparked. Furthermore, this dissertation enriches New South to Sunbelt scholarship by integrating critical factors water resources, political power, and energy production into existing narratives.Southerners have toiled for over a century to make use of and control water. But for all the corporate, state, and citizen investment, the flooding and droughts continue to threaten communities, damage economies, and shape river valleys. The American South has much to share with, and learn from, other regions grappling with what are clearly national water problems.