40 MILES
64 KM
Morgan
City
Baton
Rouge
Natchez
New
Lake Orleans
LA. Pontchartrain
MISS.
Bonnet
Carré
Spillway
West
Atchafalaya
Floodway
Morganza
Floodway
Old River
Control
Auxiliary
Structure
At
ch
af
al
ay
a
Red
Levees
M
is
si
ss
ip
pi
M
is
si
ss
ipp
i
M
is
si
ss
ip
pi
Oh
St. Louis io
Columbus
Nashville
Minneapolis
Illi
noi
s
50 MILES
80 KM
Ohio
Red
M
is
si
ss
ip
pi
Ark
ansa
s
New Madrid
Floodway
Cairo
Caruthersville
Alexandria
Vicksburg
Baton
Rouge
New
Orleans
Memphis
MO. KY.
ILL.
MISS.
TENN.
LA.
LA.
ARK.
Levees
Gulf of M
exic
o
which begins in Cairo, the southern-
most city in Illinois—flood control is far
more advanced than in the Midwest. In
1927, floods demolished 26,000 sq. mi.
of the South, killing as many as 500 peo-
ple. It was the era’s Katrina, a disaster
that gripped the nation. The federal gov-
ernment decided that the region should
never be wet again, and the Army Corps
was tasked with the design and construc-
tion of the Mississippi River & Tributaries
Project to seize control. The MR&T Proj-
ect is so vast that it can be hard to com-
prehend as a single object: it includes
concrete floodwalls in New Orleans and
Cairo and Caruthersville, Mo.; pumping
stations that drain rainwater trapped be-
hind these walls; and nearly 3,500 miles
of levees along the river and its tributar-
ies. A fleet of towboats and barges, out-
fitted with cranes and sleeping quarters
for a crew of 200, descends the river each
year, paving its bends with concrete to halt
erosion. In the 1930s and ’40s, dredge
boats straightened the river, shortening
it by 150 miles, so that floodwater would
speed more quickly downstream.
Politicians initially considered a more
comprehensive version of the MR&T
Project that would span the whole river,
but this was deemed too expensive; the
project was narrowed to just the region
that had been inundated in 1927, leaving
the Midwest exposed. “We’re still stand-
ing on decisions that were made two or
three generations ago,” Davis says.
Still, no other river as big as the Missis-
sippi has been so thoroughly engineered.
Built in pieces over decades and still
incomplete, the MR&T Project is de-
signed to hold the “project design flood.”
This hypothetical disaster, dreamed up
in 1954, represents the largest probable
flood based on historical data available
at the time. The levees are designed to
handle only a portion of this flood; when
a trigger point is met, the Corps is au-
thorized to open one of the MR&T Proj-
ect’s four floodways, sending the excess
water down a different route to the Gulf
of Mexico. As of 2010, the Corps expected
this would be necessary about once every
10 years. Bonnet Carré has been opened
three times in the past 18 months.
The system is officially managed by the
Mississippi River Commission, a seven-
member committee appointed by the
President, but is largely dominated by the
A national problem
In recent months,
precipitation in the lower
48 states reached all-time
highs; the rains swelled
the tributaries that lead to
the Mississippi
1
Fighting Mother Nature
In Louisiana, flood- control
structures and spillways divert
excess water from overwhelming
everything in its natural path, but
the diversions cause damage too
3
Engineered
solutions
In the lower
Mississippi, nearly
3,500 miles of
levees contain
rising waters but
also exacerbate
their effect
2
41
