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.
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. 
