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Following the Great Flood of 1927 Congress passed the Flood Control Act of 1928 which recognized that flooding due to the Mississippi River is a federal responsibility because 41% of the continental United States drains down the Mississippi River to the Gulf of Mexico,. This Act authorized the Mississippi River & Tributaries Project (MR&T) which called for levees and floodwalls, floodways, channel improvement and stabilization, and tributary basin improvements. In 1936, Congress recognized that some of the levee construction work cut off drainage outlets for interior basins, therefore Congress passed the Flood Control Act of 1936 which extends federal responsibility to many river basins that feed into the MS River, including the Yazoo Basin.

In 1941 the Congress, at the request of the Arkansas delegation, removed the Eudora Floodway from the MR&T Project. At the same time, the Mississippi delegation recognized that this action would result in higher stages on the Mississippi River at the mouth of the Yazoo River and cause flooding in areas previously safe from floods in the Mississippi Delta. The Flood Control Act of 1941 authorized the Yazoo Backwater Project to protect the Delta area of Mississippi from these increased stages. This project included a combination of levees, drainage structures and pumps.

The Yazoo-Mississippi Delta is bounded by the Mississippi River on the west side and by the bluff hills from just south of Memphis, TN through Greenwood to the Yazoo River. The Delta then follows the Yazoo River to it’s outfall into the Mississippi River just north of Vicksburg. The Delta is approximately 200 miles long and 60 miles wide.

The Yazoo Backwater Area (the "South Delta") comprises approximately 1,550 square miles of alluvial valley in the lower Yazoo Basin of Mississippi. It encompasses the area south of the line between Hollandale and Belzoni, east of the Mainline Mississippi River Levee and west of the Yazoo River Levee.

Components of the Project

There are four major components of the Yazoo Backwater Project:

1. Levees. The Yazoo Backwater Levee begins at the end of the Mainline Mississipi River Levee and proceeds upstream along the Yazoo River on the west bank to the West Guide Levee of the Will Whittington Auxiliary Channel near Spanish Fort, MS. During highwater, when overflow water from the Mississippi River backs-up the Yazoo River, the Yazoo Backwater Levee, along with the closed drainage structures, prevents the backwater from entering the South Delta. The Yazoo Backwater Levees were completed in 1978.

2. Connecting Channel. The original Yazoo Backwater Project included drainage structures and pumps at the Little Sunflower River, Deer Creek and Steele Bayou. In order to be cost effective, the Connecting Channel was constructed and completed in 1978 to connect the Big and Little Sunflower Rivers, Deer Creek and Steele Bayou to bring water from 4093 sq. miles of the Delta to one point at the Steele Bayou Drainage Structure where one pumping plant can be constructed.

3. Drainage Structures. These structures allow the Delta’s stormwater to pass through the open gates into the Mississippi/Yazoo River when stages on the riverside of the levee are lower than the stages on the interior basin. When the stage of the Mississippi/Yazoo River is higher than the stage on the interior basin, the gates are closed keeping flood waters from backing up into the South Delta. The Steele Bayou and Little Sunflower River Drainage Structures were completed in 1969.

4. Pumps.

During highwater situations when the gates are closed on the drainage structures to keep out the MS River floodwaters, Pumps are needed to evacuate rainfall that occurs in the Delta and is trapped on the landside of the levee and drainage structures. The Pumps are the last remaining unconstructed feature of the Yazoo Backwater Project.

The Yazoo Backwater Project works flawlessly during MS River floods, as long as the Delta does not have any rainfall. In 1995, the Yazoo Backwater levees and drainage structures held out 8' of water that would have backed up into the South Delta.




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