The Yazoo Backwater Project which will help prevent flooding in a vulnerable area of the Mississippi Delta has a history stretching back to its origins in the Flood Control Act of 1941
Three of the project’s four components were completed by 1978 and are in place north of Vicksburg where the Yazoo River flows into the Mississippi River. There are levees to keep backwater from entering the South Delta, a connecting channel to bring water to a pumping plant and drainage structures that are opened or closed depending on water levels. The final piece is a set of 12 pumps that form a pump station that will evacuate heavy rainfall and prevent Delta flooding when the gates are closed against floodwaters from the Mississippi River.
“Think of the backwater as a bathtub, and the pump is where the stopper is in the tub,” said Kent Parrish, senior project manager for the U.S. Army Corps of Engineers (USACE) Vicksburg District. What’s filling that “tub” is the large drainage area from Memphis to just north of Vicksburg, some 4,039 square miles. “Any time it rains in Clarksdale or Greenville, that water has to flow south and with the gates at the Steele Bayou Control structure closed, it congregates in the backwater area until the Mississippi River drops down,” Parrish said.
The drainage structures allow the Delta’s stormwater to pass through the open gates into the Mississippi/Yazoo River when the water level on the riverside of the levee is lower than the stages on the interior. When the river stage is higher than the interior level, the gates are closed to keep flood waters from backing up into the South Delta. The pumps will be used to evacuate rainfall that is trapped on the landslide of the levee and drainage structures.
Construction on the pumps actually got under way in 1986 but when the Water Resources Development Act of 1986 changed the cost sharing requirements, the Mississippi Levee Board could not afford the project and work was stopped. In 1996, Sen. Thad Cochran worked through the WRDA 1996 and got the cost-sharing requirement restored to those under which the project was originally authorized.
Since then, the pump project has launched volumes of studies and fired up battles between backers and environmental groups. The legal challenge sparked up again as recently as January after USACE announced it was moving ahead with a revised pump plan. The on-again-off-again project was last halted in 2008 by a rare EPA veto over impacts to fishery and wetland resources. The agency recently reversed the veto.
“Basically the project sat still and nothing happened since the project was vetoed by the EPA in August 2008, other than the backwater area flooded nine out of the last 10 years, with 2019 being a record flood,” said Parrish.
The backwater reached 98.2 feet which flooded 550,000 acres including 225,000 acres of cropland and was reportedly the highest the backwater has ever gotten since the backwater levees were completed in 1978. Two deaths and hundreds of millions of dollars in damages were blamed on the flooding which also caused significant harm to the environment, agricultural interests, homes and businesses, according to the agency.
The record flood is what galvanized renewed support for the pumps and helped get recent federal funds for an update to the recommenced plan from the 2007 report and now to start design of the project, Parrish said.
USACE has been working with the EPA for the last couple of years on moving the pump project forward. “They came to the Mississippi Delta and did several tours during the floods and saw the devastation to people and their livelihoods and also to the animals,” Parrish said.
The revived pump project includes a new location near Deer Creek about eight miles from the earlier proposed site. The pump station will be capable of pumping 14,000 cubic feet per second. The pumps will be operated when water levels exceed 87 feet in the Yazoo Backwater Area, and at this elevation, more than 135,000 acres of land will be underwater. The new location also allows the use of natural gas as a power source instead of diesel motors fed from storage tanks. “It also gives us the opportunity to pick up flood waters sooner and pump it over the levee into the Yazoo River, which flows into the Mississippi River,” Parrish said.
Also new is the planned installation of 34 supplemental low-flow groundwater wells that would add water to interior streams and establish environmental flows to 9,321 acres of streams to help sustain aquatic habitat, fisheries and mussels during the low flow times in late summer and fall, according to USACE.
In its final environmental impact statement, USACE said the renewed push to build the pumps is fed by “a combination of more frequent and significant flooding; substantial environmental, economic and safety concerns; and new and improved environmental and hydraulic data.”
Congress still has to approve funding for the multi-million dollar project
“No contracts will be awarded or any dirt moved with this initial funding,” said Parrish of the $9.2 million the project recently received to initiate design and to continue to gather environmental data on baseline conditions. “It will be 18 months to two years to pull the trigger on any contract.” Once the design is complete, contracts will go out for competitive bids.