Mississippi River

The Mississippi River is a defining geographic and political force in the book’s account of flood risk around New Orleans. Its 1927 floodwaters helped precipitate a decision to sacrifice communities below the city to protect it, while the Katrina narrative carefully distinguishes the river from Lake Pontchartrain as the source of water approaching Memorial. The river is thus not simply a backdrop: it shapes the region’s defenses, the distribution of risk, and how people understand a flood’s origin.

The 1927 Flood Wave

In the spring of 1927, storms in the upper Midwest sent a great surge down the Mississippi River toward the Gulf and New Orleans. The water devastated cities and towns along its route. Before it reached the region, authorities tried to reassure New Orleanians that the city’s defenses could withstand the threat, in part because panic was considered bad for business.

A separate Easter-weekend storm had already tested the city. On April 16, 1927, New Orleans received 14.01 inches of rain in less than twenty-four hours, then the greatest one-day total in more than half a century of recorded observations. Streets flooded, and the drainage system struggled after lightning damage disabled one of the city’s two large generators. Two weeks later, the swell from the upper Mississippi reached Louisiana, adding the river’s regional flood threat to a city already confronting the limits of its drainage and power systems.

A Levee Sacrifice and Its Legacy

On orders from the State of Louisiana, workers dynamited a levee below New Orleans to relieve pressure on the levees protecting the city. The decision deliberately redirected danger toward St. Bernard Parish and Plaquemines Parish. The book presents the sacrifice as having been made at the behest of New Orleans’s business elite, who later failed to deliver the restitution they had promised. Resentment over the decision persisted into the next century, making the river’s management inseparable from questions of whose homes and communities were protected.

The Mississippi River floods of 1927 also drove a major change in federal responsibility. The 1928 Flood Control Act assigned the Army Corps of Engineers the task of improving levees and flood-control systems along the lower Mississippi River, placed the river under full federal responsibility, and granted the Corps immunity from liability for damage resulting from its work. The river’s flood became a turning point in the institutional organization of flood protection, not only a disaster measured by the water it carried.

Engineering the River and the City

In later decades, the Army Corps of Engineers became more involved in flood-protection projects for New Orleans itself, including drainage canals leading to Lake Pontchartrain. Meanwhile, the city’s Sewerage and Water Board obtained funds to expand drainage capacity. Fourteen custom-built examples of a pump designed by one of the Board’s engineers were installed; by the end of the twentieth century, the system’s capacity had nearly quadrupled to more than 45,000 cubic feet per second.

These works do not erase the vulnerability exposed in 1927. Rather, they show how the river’s danger became a continuing engineering and governance problem, managed through levees, canals, and increasingly powerful pumps. The history also leaves visible the unequal consequences of those interventions: the protection of New Orleans could involve transferring risk to communities downstream.

The River and Katrina’s Floodwaters

During Hurricane Katrina, the Mississippi River initially offered a plausible explanation for the water approaching Memorial. When ICU nurse Cathy Green asked whether it was coming from the river, a doctor corrected her: the water was coming from Lake Pontchartrain. The lake’s water had already reached Claiborne Avenue, which Green estimated to be roughly fifty city blocks from the lakefront.

That correction gives the river a distinct narrative role. The book invokes its history as a source of regional flooding, but does not treat every New Orleans flood as an extension of the Mississippi. By distinguishing the river from the lake during the crisis at Memorial, it makes the geography of the danger more precise—and recalls how the city’s exposure is shaped by multiple waterways and by the systems built to control them.