Drowning the Delta: The History of the Flood-Control Project in the South Mississippi Delta

Written By: William Knotts

Mississippi Delta Flooding

The Great Mississippi Flood of 1927 was the most destructive flood in the history of the United States, but it certainly wasn’t the last time the Mississippi River overflowed and wreaked havoc.  Between the years 2000 and 2019, the Mississippi River and its tributaries overflowed their banks more than fourteen times.  In 2019, the southern portion of the Mississippi Delta experienced the worst flood since the early 1970s; it displaced hundreds of families, inundated over 500,000 acres of land, and caused an estimated $2 billion in damages.  But why does this keep happening?

For nearly 100 years, people have attempted to control the floodwaters of the Mississippi River by constructing levees, drainage ditches, flood gates, pumping stations, floodways, and backwater areas to relieve pressure on the levees.  However, regardless of the measures taken, residents of the southern portion of the Mississippi Delta are still battling devastating flooding on an almost yearly basis.  In 2019, record levels of precipitation fell in the Mississippi River’s drainage basin, causing the river to remain above flood stage for over 235 days, the longest period in recorded history. One of the most surprising things about the flooding is that it may actually be a result of attempts to control the river itself.  In 1936, Congress recognized that the construction of these levees and other structures to control the river stages prevented drainage from the interior basins that were previously safe from floods.  To mitigate these issues, Congress passed the Flood Control Act of 1936, extending federal responsibility to the river basins that feed the Mississippi River.

The Project

To combat flooding in the areas now at risk, the Flood Control Act of 1941 authorized the Yazoo Backwater Project (the “Project”) to protect the Delta from the increased river stages resulting from efforts to control the river.  The Project itself included new levees, drainage structures, and pumps. These separate components are designed to work in conjunction to prevent overflow from the Mississippi River into the South Delta.  The levee prevents overflow from the river from passing into the Delta when the stages on the riverside of the levee are higher than that in the basin; the drainage structures allow water to pass into the river when the stages on the riverside are lower; and the pumps were designed to remove rainwater from the Delta when the riverside is higher.  Even though the levees, channels, and drainage structures were completed in the late 1970s, the pumps remain unfinished to this day. 

Why Aren’t They Finished?

In May of 1986, construction began on the pump portion of the Project on the Federal Government’s dime.  However, the wording of the Water Resource Act of 1986 shifted the costs of the Project from the Federal Government to the Mississippi Levee Board, effectively shutting down the Project.  Ten years later in 1996, the Water Resources Development Act restored the responsibility for the Project to the Federal Government.  Yet, the problems still continued. Over the following ten years, arguments erupted between multiple environmental groups and federal agencies while attempting to determine the best course of action.  The Corps of Engineers released its final report in 2007, which included plans and guidelines for how the pumps would be used. This plan never went into effect, though.  The EPA vetoed the Project in 2008, stating that it would wreak havoc on approximately 60,000 acres of wetlands. 

For nearly twelve years, no progress was made towards completing the Project. That changed in November of 2020 when the EPA, under the Trump administration, revived it. The following January, the Project received approval.  However, this victory for the people of the Mississippi Delta was short-lived, as the decision was overturned in November of 2021.  The reason for again reversing approval of the Project? Concerns for the wetlands.

What Happens Now?

The total estimated cost of the Project is approximately $220 million, and it would take four years to complete. On average, flooding in this region causes $37.2 million in damages. Based on these estimations, it would take only six years for the project to pay for itself and begin providing a significant benefit to the state. Nevertheless, the EPA has not indicated any plans to overturn its most recent decision reversing approval of the Project. Without the completion of the pumps, the residents, wildlife, and the South Delta as a whole will continue to be at risk.