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DESIGNED
TO PROMOTE ENVIRONMENTAL BENEFITS
Great
care is given to the creation and implementation of borrow
area and berm design. Traditional borrow areas are located
on the riverside of the levee adjacent to the construction.
The Supplemental Environmental Impact Statement (SEIS) resulted
in an alternative that uses open land with suitable material
located in the batture (area between the levee and the river)
if available within a reasonable distance. In the past, borrow
areas were rectangular shaped pits that held water. Today,
the Corps of Engineers, working with the Levee Board and the
landowner, will often design two types of borrow areas: 
1.
Aquatic Borrow Areas. This borrow area is irregularly
shaped with smooth side slopes, varying depths and islands
with trees left undisturbed in the middle. This type design
promotes aquatic, fisheries and waterfowl benefits. 
2.
Reforested Borrow Areas. This borrow area is graded to
drain and is planted in trees restoring bottomland hardwoods
and terrestrial wildlife habitat. Schematic: Corps Reforested
Borrow Area Schematic Photo: Completed Reforested Borrow Area
(?)
INNOVATIVE
"AVOID & MINIMIZE" DEISGN TECHNIQUES 
To
minimize impact on surrounding land and habitat, seepage berms
are located adjacent to the landside slope of the levee to
reduce the hydraulic pressure of water passing through the
sand layers under the levee. If seep water is allowed to exit
the ground with high velocities, it will displace material,
causing cavities and voids to form under the levee, which
can cause a levee failure (crevasse). Seepage berms are very
wide, thus requiring a tremendous amount of borrow material.
To reduce the amount of borrow, the Corps of Engineers has
developed several innovative "avoid & minimize" design techniques.
These designs help avoid and minimize damage to the environment
(trees, wildlife and right-of-way acquisitions).
 1.
Relief Wells: Where conditions exist, such as limited
landside right-of-way (r.o.w.) and lack of traditional riverside
borrow area, the Corps will evaluate the installation of relief
wells instead of constructing berms. Relief wells allow for
the orderly discharge of seep water through a controlled mechanism
without the displacement of material from under the levee.
Relief wells are installed adjacent to the landside toe of
the levee, thereby reducing r.o.w. acquisitions required by
traditional berms, as well as the borrow areas required for
the material.
2.
Dredged Berms. In areas with existing berms that have
suitable material with the Mississippi River being close enough
to provide an economical source of sand, the Corps is excavating
these berms and using the material to raise the levee. Dikes
are constructed around the limits of the berms to retain the
water, while sand from the Mississippi River is pumped in
using a hydraulic dredge. Once the sand is up to grade, the
dike material is used to cover the sand berm to provide suitable
material to grow the grass cover. 
Traditional
borrow levee enlargements cost between $1 million and $2 million
per mile while the environmentally friendly dredge jobs cost
about $3 million per mile. Based upon current funding levels,
the MR&T Project is scheduled for completion in 2031.
As
of 2001, the Mississippi Levee Board currently has 18.1 miles
of deficient levee enlargement and berms under contract (7.6
miles traditional and 10.5 miles dredge). By 2003, another
17.3 miles of our deficient levee will be under contract (8.5
miles traditional and 8.8 miles dredge). These projects will
enlarge the most seriously deficient levees to protect the
citizens who live behind the levee.
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