Flood Control Act of 1936

The act emerged from a series of devastating floods in the 1920s and 1930s, particularly the Great Mississippi Flood of 1927, which exposed the limits of local and state flood control efforts. Prior federal involvement had been piecemeal, with the Army Corps of Engineers undertaking specific projects under separate authorizations. The 1936 act marked a decisive shift, declaring that flood control was "in the interest of the general welfare" and therefore a federal concern.¹ The legislation was championed by President Franklin D. Roosevelt and passed with broad bipartisan support, reflecting the New Deal's emphasis on federal infrastructure investment. It authorized the Corps to plan and construct flood control works, with local interests required to provide lands, easements, and rights-of-way, and to hold the federal government harmless from damages.²

The act established a cost-sharing formula that required local sponsors to contribute a portion of the project costs, typically 50% for navigation benefits and 100% for land enhancements, while the federal government bore the costs of flood control benefits.³ This formula was later modified by the Flood Control Act of 1938 and subsequent legislation, but the 1936 act set the precedent for federal-local partnerships. The act also authorized a comprehensive program of surveys and investigations, leading to the systematic planning of flood control on major rivers such as the Mississippi, Ohio, and Missouri. It directed the Corps of Engineers to prioritize projects based on economic feasibility, requiring that benefits exceed costs—a principle that became a cornerstone of federal water-resource planning.

Over the following decades, the act's authorizations funded the construction of hundreds of dams, levees, and channel improvements across the United States, transforming the nation's river systems. The Corps of Engineers became the primary federal agency for flood control, and its projects have prevented billions of dollars in damages, though they have also altered river ecosystems and displaced communities. The act's cost-benefit framework influenced later environmental legislation, including the National Environmental Policy Act of 1969, which added environmental review to project planning. The 1936 act is often cited as the beginning of the modern era of federal flood control, and its legacy is visible in the extensive network of flood control infrastructure that exists today.

One lesser-known provision of the act was its authorization of the "Mississippi River and Tributaries" project, which included the construction of the Bonnet Carré Spillway in Louisiana, a flood control structure that has been used repeatedly to divert floodwaters from New Orleans. The act also led to the creation of the "Flood Control Act of 1936" as a model for subsequent legislation, but it did not address floodplain management or land-use regulation, leaving those to local governments. Additionally, the act's cost-sharing formula was controversial, with some critics arguing that it subsidized development in flood-prone areas. The act also authorized the construction of the Fort Peck Dam in Montana, which was the largest hydraulic earthfill dam in the world at the time and provided jobs during the Great Depression.

Cost-sharing

The division of project costs between federal and local entities, as established by the act.

Army Corps of Engineers

The federal agency responsible for planning and constructing flood control projects under the act.

Benefit-cost analysis

A method of evaluating projects by comparing their economic benefits to their costs, required by the act.