Room for th

RIV 

Pre arednessRES O NS RE COV R Y 

Summary Report of the 2011 Mississippi River Flood and 

Successful Operation of the Mississippi River & Tributaries System
1

2 Introductio

Winning the next flood

8 2011

A record flood

18 Performance

Making room for a record flood

27 Preparednes

Coping with risk

4 Histor

Flood by flood

12 flood fig

The ultimate test

24 Recover

Restoring a flood-battered system

28 Recommendatio

A secure future

32 

Applying hard-learned lessons

CONTENTS

From Top: The flood overtops the Wappapello Reservoir Spillway, damaging

a county highway and the 

spillway itself. Maj. Gen.

Michael Walsh (right) and

Maj. Gen. John Peabod

(left) inspect flood damages. 

This publication is a summary of the comprehensive 

2011 Post-Flood Report

The complete report is 

available at www.mvd.

usace.army.mil.

Room for the River is a publication of the 

U.S. Army Corps of Engineers and Mississippi River 

Commission, ©2012. Produced under contract by 

Schneider Communications and Page 9 Design.
ROOM FOR THE RIVER / 2011 POST-FLOOD S

2

INTRODUCTION: Winning the nex

From the earliest days of mississippi river settlement, the desire to protect river 

towns and industries from floods has proven a daunting and often controversial challenge. When 

protection was needed, residents, local levee boards and eventually the Federal government would

build the banks ever higher, using horse-drawn equipment that evolved into increasingly sophisticated 

engineering designs and construction methods.

More than construction methods changed in the 1920s, spurred in part by the thinking of then

Chief of Engineers Maj. Gen. Edgar Jadwin. A massive and tragic flood in 1927 sent shockwav

through the valley—right behind the raging floodwaters that inundated 16 million acres of cities and 

farms—when Jadwin shaped national policy to direct the Mississippi River Commission to change its

flood prevention philosophy. 

Levees would remain the system’s backbone, 

but the proposed system authorized by the Flood

Control Act of 1928 would also make room for 

the river and its natural tendencies. In extreme 

flood years, and only then, floodways would 

divert flows into areas designed to be inundated—areas in some cases populated by homes, 

farms and wildlife but where flooding has been 

negotiated through purchased easements—and 

thus keep even peak floods contained within the 

walls of main channel levees. 

The Mississippi River & Tributaries Syste

the name given to the resulting system, has become one of the world’s most comprehensive and successful flood control and navigation systems. The enhanced levees and floodwalls—along with new floodways, reservoirs, backwater areas, river cutoffs, tributary improvements, pumping stations and more

were designed to operationally complement one another and significantly augment the capacity of the 

river to safely convey floodwaters and commercial/recreational navigation. (See schematics, pp.15,

The new system also veered from long-held practices in another key way. Instead of planning and

designing from the perspective of the last great flood, the integrated system was developed to contain 

the “Project Design Flood,” the largest flood considered to have a reasonable probability of occurrence.

That, to some minds, was perilously close to what hit in early spring 2011, when torrential rains fell

in the central Mississippi and Ohio river valleys, adding fury to a river swollen from a massive uppe

river snow melt (See rainfall graphic, p.9). The timing could not have been

That spring, the rapidly melting record snows and unprecedented rainfall, from six to 10 times

higher than normal, in late April created a convergence of floodwaters that delivered the system’s largest test to date, damaging property and the flood control system itself. Yet that flood control system 

prevented hundreds of billions of dollars in damages and confronted a record flood without the loss 

of a single human life. That compares to the 500 killed and 700,000 left homeless in the comparable

1927 flood. All told, experts estimate the 2011 flood was approximately 85 percent of the project 

design flood.

Leading the flood fight were Maj. Gen. Michael Walsh, then president of the Mississippi Riv

Commission and Commanding General of the Corps’ Mississippi Valley Division, and Maj. Gen. Joh

Peabody, also a river commission member and then Commanding General of the Corps’ Great Lakes 

and Ohio River Division.

As Maj. Gen. Peabody sought to hold floodwaters back through reservoirs on the Ohio River tributaries, Walsh relied heavily on the wisdom of the system’s creators. He followed carefully prescrib

operational manuals built around lessons hard-learned from repeated flooding. Just as those past lessons have been integrated into the system’s development and operation, this report similarly seeks to 

inform those who will be at the decision-making helm in future flood fights.

The post-flood evaluation, summarized by “Room for the River,” seeks to 

answer three main questions. How did the Mississippi River & Tributaries 

System perform during the record Mississippi River flood of 2011? How 

might it perform in its post-flood condition? What might it need to protect 

lives and livelihoods into the future?

“As changes happen in the system, 

from the ever-changing river and changing land use patterns, we need to track 

and learn from them in order to know if we 

have to modify the system to address those 

changes,” said Hank DeHaan, Regional Projec

Manager for the Mississippi River & Tributaries (MR&T) Post-Flood Evaluation. “If w

operate the system as we’ve done in the past, we 

won’t be doing the best we can to fight floods in the 

future.”

Post-flood evaluation in brief 

Since its inception in 1928, the Mississippi River & Tributarie

System has evolved from a philosophical concept to a multifaceted flood control and navigation system. Its backbone lies in 

the 3,787 miles of levees and floodwalls on the river’s main stem, 

backwaters and tributaries, dwarfing in magnitude those built in the 

early to middle part of the 20th century.

The Flood of 2011 tested the system like none before. Fl

and stage (height) levels broke records at dozens of river gages from 

Cairo, Ill., to Baton Rouge, La. And, for the first time, three of the 

system’s four floodways—Birds Point–New Madrid, Morganza and Bonnet Carré, were all operated during a single flood even

The comprehensive post-flood analysis indicates great success by any

measure. River flow levels exceeded all previous major floods of 1927, 1937 

and 1973, but the 2011 flood was contained within the system to a much 

greater extent. And although the 2011 flood caused extensive damages to 

many MR&T components, the system performed as designe

Collaborations with local and state partners were key in both planning and execution of flood fight measures—ringing sand boils, constructing water berms, blocking culverts and ditches, and even raising deficient sections of the Mississippi River

levees to authorized and safer grade. Floodwaters still weakened or damaged the flood

control system itself, with preliminary damage estimates in the $2 billion range. The

flood also deposited sediment in unwanted places, restricting the nation’s economically 

critical navigation system and impacting some of its most fertile agricultural lands. Although 

harm occurred, the system prevented more than $234 billion in damages that would have 

resulted due to flooding of large portions of the Mississippi River Valley

A dedicated, multidisciplinary cohort of engineers, biologists, economists, GIS technicians, 

project and emergency managers and other scientists worked on the post-flood evaluation effort 

via MR&T component teams assigned to study and assess system elements like levees, reservoir

and floodways. Through Operation Watershed Recovery Operations, work began immediately 

fix critical high-risk damages and will gradually shift to repair of less critical items until the system 

is brought back to pre-2011 conditions. The system will still contain pre-flood deficiencies, some of

which were not tested by the flood and remain a risk. For example, 11 percent of the MR&T System 

not yet complete, a construction effort that may continue for decades.

“What we’re looking at is how well we did in fighting the 2011 flood, how well the system performed, 

and what we can do better next time,” DeHaan said. “We have developed a roadmap here for future

leaders and decision makers.”

“We have developed 

a roadmap here for 

future leaders and 

decision makers.” 

2011 FLOOD BY THE NUMBERS

21,000

Residential and commercial structures 

damaged by the 2011 flood

1,500,000

Residential and commercial structures projected 

to have been impacted had the Mississippi River 

& Tributaries System not been in place.

$2.8 billion

Value of damage from the 2011 flood

$234 billion

Value of damage prevented by the MR&T System

$612 billion

Cumulative damages prevented by the MR&T System

$14 billion

National investment in the MR&T System

41 percent

Portion of the contiguous states in the Mississippi River 

drainage basin. Rainwater and snow melt from 

31 states and two Canadian provinces drain into the 

main stem of the Mississippi.

3

A Commission with

River Missi

The Mississippi River Commission, which directly oversees the 

Mississippi River & Tributaries 

System, was established by an 

Act of Congress in June 1879. 

Benjamin Harrison—who would 

go on to serve as the 23rd U.S

president—was one of the group’s 

charter members.

Charged with improving the 

condition of the river, fostering 

navigation, promoting commerce 

and preventing destructive floods, 

the Presidentially-appointed 

group has overseen the river’s 

transformation from one in which 

boats were regularly caught on 

snags, sandbars and uncharted 

shoals and river towns subject to 

repeated flooding to a successful 

conglomeration of locks, levees, 

spillways and reservoirs. The advancements improved navigation 

and are credited with protecting 

many lives in the 2011 flood.

Headquartered in Vicksburg, 

Miss., the seven-member commission today seeks solutions for 

flood control problems as well 

as all water resource challenges 

facing the watershed, working 

with other agencies and groups 

to develop a sustainable longterm and collaborative vision for 

the balanced and appropriate 

use of this nationally significant 

resource.
ROOM FOR THE RIVER / 2011 POST-FLOOD S

5

HISTORY: FLOOD BY

 Nearly all civilizations have settled along rivers first, due to the natural source of transportation 

and water supply, often relying for flood protection on banks raised a yard or two by the rivers’ natural 

processes.

In 1717, the French sought to protect their investment in the then-new settlement of New Orlean

by ordering construction of the first manmade levee (derived from the French, “to raise”) along the

Mississippi River. It was three feet high and 5,400 feet long

Under French law, landowners on the Mississippi’s west bank were required to keep those levee

maintained or forfeit valuable land, and compliance hastened even more development. Westward 

expansion further led to a growth in commerce, as did the coming of the steamboat. Residents built 

homes and farms and industries until, by the 1850s, New Orleans was the nation’s fourth largest city. It

was booming with port trade and Parisian fashion—growth mainly attributed to the mighty river along 

whose banks it sat.

But the river still flooded regularly, as did others across the Mississippi River Valley. In 1849, major

flooding prompted the Swamp Act, which transferred low-lying lands to the states, funded levee construction and set up levee boards. A valley survey followed, and findings would prompt a lively debate 

over whether levees alone could control the river or if man-made outlets and floodways were a necessary addition.

The levee system eventually came under the purview of the seven-member Mississippi Rive

Commission, appointed by the President in 1879. Over the next 40 years, the commission worked

with states and local levee districts to set standards and improve the system. For half of that time,

federal law prohibited the expenditure of federal funds for the protection of private property for flood 

control. Then, after deadly floods in 1912, 1913 and 1916, Congress passed the Flood Control Ac

of 1917, authorizing flood control on the Mississippi River and elsewhere as a federal mission, and

hundreds of miles of levees were raised and strengthened as a result. By the mid-1920s, the commission believed the levee system to be “now in condition to prevent the destructive effects of floods.”

Then it started raining in the spring of 1927, and to quote one flood observer at the time, “it just

never did stop.”

The flood overwhelmed the levee system. When the damage was tallied, more than 40,000 buildings

were destroyed and many times that rendered unlivable. Also destroyed were industries, transportation 

systems, crops and other farm products—1.2 million chickens, 271,000 livestock and more than 6 million muskrats, those a key income source for the Louisiana Cajun population. The estimated loss of $1

billion was a third of the federal budget at the time.

The tragedy drove home the fact that walls of earth would never keep the river completely constrained, no matter how high. With the Flood Control Act of 1928, Congress directed the Corps t

develop a flood control system that would prevent a repeat of the tragedy. 

Of the 300 competing plans put forth, Congress preferred and adopted the one known as the

Jadwin Plan and its two principal innovations that would evolve over time into today’s more comprehensive system. Floodways would make room for the river by diverting peak flows and holding down

stages in the main channel. The system also would be designed to protect against a “Project Design

Flood management philosophy evolves, flood by flood.

Flood” (PDF), the largest hypothetical flood likely to occur based on a meteorological examination o

historic rainfall and runoff patterns. 

As noted in December 1927, the Mississippi River & Tributaries System developed from the act wa

“designed to conform to the natural tendencies of the river; it is not forced or driven.”

Levees remained the system’s first line of defense in protecting the vast river valley from the most frequent periodic overflows of the Mississippi. Such a defense certainly was needed in the world’s third largest

drainage basin—exceeded in size by only the Amazon and the Congo. Runoff from as far east as New York 

and as far west as Montana contributes to flows that make their way down the river, into the Gulf of Mexic

But under the plan, excess water, during extreme events, would be allowed to spill out of the main 

channel into carefully prescribed floodplains. Those so-called floodways would be operated only, as in the

case of the Birds Point–New Madrid Floodway, when river gages reach a carefully designated heigh

That location, near the confluence of the Ohio and Mississippi, is the system’s first check. When t

river reaches a critical stage on the Cairo gage, the Birds Point–New Madrid Floodway—one of fou

system floodways—would be activated to divert up to 550,000 cubic feet per second (cfs) and prevent 

floods from overtopping levees in the Mississippi-Ohio confluence area, along and immediately downstream of the Birds Point–New Madrid Floodw

Across a broad geographical landscape, the MR&T System, in addition to levees, uses a combination o

flood control reservoirs, backwater areas and channel improvements to help manage floods. The backwaters of the St. Francis, White, Yazoo and Red Rivers assist the Birds Point–New Madrid Floodway

The lower river is basically a funnel for the world’s 

third largest drainage basin—exceeded in size by only 

the Amazon and the Congo. 

To divert or not to

The 1927 flood demonstrated 

that the confined channel along 

the Mississippi River didn’t have 

the capacity to pass great floods 

without considerably increasing 

levee height. Original plans for 

the Mississippi River & Tributaries System thus provided for 

five floodways (four of which 

were eventually constructed) 

designed to safely divert excess 

floodwaters past critical reaches 

in the levee system to keep major 

floods from overtopping the most 

vulnerable levees.

The five proposed floodways 

were Birds Point–New Madrid 

(SE Mo.); Boeuf (SE Ark./N. La.), 

Morganza and West Atchafalaya 

(paralleling the Atchafalaya River), 

and the Bonnet Carré Spillway 

(near New Orleans).

It was generally accepted that 

floodway inclusion was a necessary turning point from pre-1927 

engineering policy, but the reality 

of their implementation proved 

a tough political sell. Private land 

once protected by levees would in 

some cases be subject to inundation to benefit more largely populated areas farther downstream. 

It was a controversial concept, 

though less so where the government was agreeing to compensate 

floodway landowners.

President Calvin Coolidge approved the federal acquisition of 

land and payments to floodway 

landowners for flowage easements within the Bonnet Carré 

Spillway and Birds Point–New 

Madrid Floodway. Controversy 

arose when Coolidge acquired a 

right of way for construction in 

the Boeuf and Atchafalaya floodways but didn’t include similar 

flowage easements, claiming the 

protection level wouldn’t change.

above: Refugee camp set up

following the 1927 flood. opposite:

Greenville, Miss., one of many river

towns devastated by that flood.

1782

Greatest flood in 

the first century 

of Louisiana 

settlement.

R

1782

Crevasses 

repaired, no 

serious loss by 

planters.

1849, 1850

Repeated 

flooding along 

Mississippi

Valley.

R

1849

Swamp Act 

represents first 

steps toward 

federalizing flood 

control.

1861–1865

Civil War 

leaves levees in 

disrepair.

R

1879

Mississippi River

Commission 

(MRC) created.

Flood control,

through leveesonly policy, seen 

as integral part of 

river navigation.

1890

Floo

R

1890

Efforts initiated

to raise levees 

from 38 to 46 feet.

1927

Great Flood:

27,000 square 

miles of lower 

river flooded, 

up to 500 

dead, $1 billion 

economic losses 

equaled a third 

of federal budget.

R

1928

Flood Control

Act implements 

Jadwin Plan/

adds floodways 

to supplement 

levees. Project 

flood developed 

by MRC and

Weather Bureau.

1929–

1932

Boeuf and 

Atchafalaya 

floodways 

challenged in 

court.

R

1932

Cutoffs added; 

significantly 

lowered flood 

stages in 1937, 

beyond.

1937

Flood: 365

die, $500 million 

in losses; 

New Madrid

Floodway and

Bonnet Carré 

Spillway opened 

for first time. 

R

1938

Flood Control

Act adds 

reservoir 

construction 

and headwaters 

projects.

1940s

Studies indicates 

potential of 

Atchafalaya 

capturing 

Mississippi River

flow.

R

1963

Old River

Control Complex 

construction 

completed

1973

Largest water 

volume flows down 

Mississippi since

1927 flood; Bonnet 

Carré Spillway 

and Morganza

Floodway both

activated.

R

1973

Flood Disaster

Protection Act 

makes purchase 

of flood insurance 

mandatory in some 

cases; floodplain 

mapping gets more 

sophisticated.

2011

Great Flood

of 2011 flows 

largest on record; 

3 of 4 floodways 

open for first 

time in history; 

no deaths.

R

2011

Supplemental 

appropriation 

funds flood 

damage repairs; 

post-flood report 

documents 

system 

performance/

improvements.

Flood History on the 

4
6 7

1844 1882 1914 1928 1942–1972

ENLARGEMENT

1973–present TYPICAL ENLARGEMENT

EVOLUTION OF MISSISSIPPI RIVER LEVEES

Highest projected water level

making extra room for the Mississippi River. From the Red River to the Gulf of Mexico, the plan is mo

elaborate, starting with the Old River Control Complex, which was constructed in 1954 to prevent the

Atchafalaya River from capturing a portion of the Mississippi on its way to the Gulf. The Control Complex was constructed with the intent to maintain a regular 70/30 split in flow between the two river

Thirty miles further downstream, the Morganza Floodway stands ready to divert up to 600,000 c

from the Mississippi River to the Atchafalaya basin, when flows are projected to exceed 1,500,000 cfs

at Baton Rouge. Additional control is offered through the floodway in the West Atchafalaya basin and 

the Bonnet Carré Spillway, located 30 miles upstream from New Orleans. The six-mile-long Bonne

Carré Spillway empties into Lake Pontchartrain and is designed to ensure that peak flows at New 

Orleans do not exceed 1,250,000 cfs

Testing the system 

A flood in 1929 tested the new system, and all mainline levees held. One of the system’s largest floods

followed in the winter of 1937, due to record flows from the Ohio. The combined flows of the Oh

and Mississippi rivers then surpassed the highest flood stages ever experienced between Cairo and

Helena, Ark., and on Jan. 24 and 25, 1937, the newly-established Birds Point–New Madrid Floodw

was used for the first time.

The Bonnet Carré Spillway operated for floods that followed in 1945, 1950, 1973, 1979, 1983, 1997

and 2008. While the Bonne Carré was operated for each of these floods, the Morganza Floodway

which sends diversions into the Atchafalaya Basin at up to 600,000 cfs, was operated only in 1973. 

Birds Point–New Madrid was not needed again until 2011’s flood set records with its flows. The Wes

Atchafalaya Floodway has never been activated.

The Pittsburgh Press

Editorial, August 12, 1929

An uneasy compromise

“So much has been written in 

criticism of the Jadwin plan since 

the Mississippi flood control was 

adopted that a certain amount 

of uneasiness exists regarding its 

feasibility.

“The Jadwin plan is simple in 

theory. It recognizes that during 

flood periods all the water cannot 

go down the main channel of the 

river without causing widespread 

inundation of surrounding territory. 

To relieve the main channel, several artificial channels, or spillways, 

are created to divert the water.

“Some civilian engineers assert 

that the Jadwin plan is unworkable, 

that the government expenditure 

far in excess of $400,000,000 

will be wasted. Other criticism is 

directed against the manner in 

which landowners in the artificial 

spillways are to be reimbursed for 

flood damages. But additional legislation can be enacted, if necessary, 

to correct this.

“We cannot see this is the time 

to rehash the old engineering 

dispute, which so long delayed 

any kind of plan being put 

through. Coolidge approved the 

Jadwin plan. Congress approved 

it. Work has begun. Already some 

$70,000,000 has been allotted and 

much of it spent.

“Considering these facts, and the 

additional fact that an engineer 

is in the White House to guard 

people’s interests, it does not 

seem that any good purpose can 

be served by this periodic professional opposition to the official 

flood control project.”

Mississippi River & Tributariesyste

Channel Stabili

Revetments, dikes and dredging are tools that direct the river flow to protect levees, channels and shorelines from erosion. The channel protection features are used both as a tool for keeping a reliable depth for the navigation channe

and keeping flood control features from weakening. Cutoffs shorten the river, thereby increasing river velocity and

riverbed destabilization. Revetments control the river’s meanderings, and dikes direct the flow

Floodway

Four floodways, three in Louisiana and one in Missouri, can be used to divert excess flows past critical riv

stretches to keep river water from overtopping or otherwise breaking through (breaching) levees. Planned 

flooding can occur in the Birds Point–New Madrid’s 133,000 acres; the Morganza Floodway’s 71,500 ac

the Bonnet Carré Spillway’s 7,600 acres or the West Atchafalaya Floodway’s 154,000. Operation is di

by the VD commander after consultation with the Chief of Engine

Tributary Improveme

These are the dams, levees, reservoirs, control structures and pumping plants that offer flood

protection or drainage on tributaries that contribute significant flow to the Mississippi. They includ

major backwater areas that act as flood storage, including St. Francis (500,000 acres); Whi

River (145,000 acres), Yazoo (634,000 acres) and Red River (373,000 acres). Improveme

also include “the Old River Control Complex,” a key modification made in 1954 to maintai

70/30 flow split between the Mississippi and Atchafalaya rivers, respectivel

Levee

Project levees, constructed of compacted clay and rivaling in length the Great Wal

of China, are designed to contain swelling floodwaters. Levees form the backbon

of the MR&T System. Some 3,727 miles of levees have been authorized thr

the project, 3,486 miles of those completed, providing protection from Cape Girardeau, Mo. to Venice, La. Levees, constructed by the Federal Governme

routine maintenance performed by local interests, protect the fertile lands of 

the river valley from recurrent annual flooding, except where it enters the 

natural backwater areas or is purposely diverted.

Levees are man-made structures, usually an earthen embankment, designed and constructed 

with sound engineering practices to contain, control or divert the flow of water in order to 

reduce risk from temporary flooding. A levee is built parallel to a body of water (most often a river) 

to protect the lives and properties behind it.

Evolution 

Mississippi River Levees

SINCE 1

Above, from Left: Early levee construction, around 1910. Workers construct a willow mat that will

loaded with rock for channel protection or wing dike formation.

ROOM FOR THE RIVER / 2011 POST-FLOOD Sumay REPO
ROOM FOR THE RIVER / 2011 POST-FLOOD S

8 9

2011: a Record

The first ingredients of the Great Flood of 2011 were an unseasonably wet autumn of

2010 and a record snowfall in Iowa, Minnesota and Wisconsin.

Frigid cold followed, and severe winter storms piled even more snow across the Upper Mississipp

River states and the Ohio River Valley. By mid-February, far more snow cover than typical extende

across large sections of the Mississippi River basin, upstream of Cairo, Ill., where the Ohio River join

the Mississippi. Up to 40 inches of snow fell in some areas in a single month

In essence, nature had created a massive reservoir of frozen water, one that would quickly make its 

presence felt as soon as temperatures started to rise.

That would not be long. Spring thaw began in February in the middle Mississippi and Ohio Ri

valleys. Unseasonably warm temperatures and heavy rainfall rapidly melted the remaining Ohio Valley

snowpack in less than 48 hours, releasing up to four additional inches of water as runoff. The one-two

punch—rapidly melted snow, combined with sudden new rainstorms—caused widespread but minor 

flooding along the Ohio River and Upper Mississippi. There was much more to co

By mid-April, flood waters on the upper Mississippi and Ohio rivers were bearing down on Cairo, Ill

Complicating matters, another massive storm system packing torrential rains was heading toward the region. 

Combined, these ingredients equalled a recipe for disaster.

Reducing the crest

On April 21, forecasters predicted the Mississippi River could rise to 61.1 feet at the Cairo gage—21.

feet above flood stage—by the first week of May.

That forecast prompted Army Corps officials to take the first of what would become a series of decisive actions to manage a massive river that was growing larger by the day.

As the first line of protection, Corps-operated reservoirs along tributaries of the Ohio and Mississippi Rivers were used to capture extensive stormwater runoff. Filling some reservoirs to historic 

near-historic levels helped keep the lower river’s crests from overtopping the flood control structures 

authorized in 1928 as part of the ambitious Mississippi River & Tributaries Syste

Convinced that the flood had the potential to reach record levels, Maj. Gen. John Peabody issued

overarching guidance to senior leaders and district commanders in the Ohio basin. Peabody directed

that flood duty missions took priority over everything else his staff was working on; he also wanted his 

staff to consider all alternatives, including those outside of the division’s normal operating procedures, 

to contain the flood on the Ohio River and its tributaries

“We must do every single thing we possibly can do—no matter how small or seemingly insignificant—to reduce the projected maximum crest at Cairo,” Maj. Gen. Peabody wrote in his order. “It is

essential that we pull out the stops to fight the peak river crest for this event.”

It was a tall order: The city of Cairo, at the confluence of the Ohio and Mississippi rivers, was near

an island because a vast area of land around Cairo was underwater. Standing water already covered 

low-lying farmland in the four-state area of Illinois, Missouri, Kentucky and Tennessee

Water levels were so high in the Mississippi River’s main stem that excess water had nowhere to

go but up; all of the river’s natural relief valves for flooding and several levee districts were already 

inundated. Rising floodwaters from St. John’s Bayou in Missouri began to encroach upon Interstate 55,

the major north-south thoroughfare in the Mississippi Valley, and levee conditions were deteriorating

around Cairo.

The 2011 Mississippi River flood played out over the course of 

several weeks in April and May, but U.S. Army Corps of Engineers officials already suspected in late March there might be 

trouble ahead.

It was a tall order: The city of Cairo, at the confluence of the 

Ohio and Mississippi rivers, was nearly an island.

Although no improved 

MR&T dams or levees hav

ever failed, small boils of water 

began showing up on the land 

side of levees across the region. The

boils, caused by the immense pressure 

exerted by the river, were a major concern. When river levels rise, the additional 

weight of the water creates pressure that tries 

to find an escape route through the foundation of the levee system. Water essentially finds 

conduits under the levees and boils up through the 

ground on the land side of the levee.

The boils can carry sand, clay and other foundation materials from beneath a levee, weakening the

structure’s foundation. Left unchecked, a sand boil can 

increase in flow and undermine the protective levee, causing it to fall, often with catastrophic consequences. 

A Flood Forecasting Fu

The National Weather Service forecasts the weather, while the U.S. Army Corps of E

translates what that weather’s likely to mean, particularly if it involves heavy rain and snow, to 

the levels of the Mississippi River and those who live along i

River forecasting plays such a key role in how society responds to flooding that a Fusio

Team was formed in 2008 to improve interagency synchronization and use of river and

rainfall observations and related river forecasts. The team includes representatives of

three agencies—the National Weather Service, the Corps and the U.S. Geol

Survey. The team works collaboratively to identify improvements, develop plans

innovate and implement new flood forecast tools. The ultimate goal is to optimize accuracy and usability of forecasts they send out to the public

Forecasts were especially key in the 2011 flood because projected

heights at river gages trigger operation of floodways and other aspects of 

the flood control system. It’s a dynamic process that kept changing in 

the midst of heavy, unexpected rainfall. The Fusion Team was key 

improving collaboration, leading to improved forecasting and information dissemination.

Glossary of FLood Ter

Floodplain: Area along the banks

of a river or stream which is inundated during a flood. May consist of backwaters, woodlands, 

farms or homes and businesses. 

Floodway: A designated area

which diverts flows from the main 

river, thus reducing the risk of 

overtopping of other flood control 

structures and providing flood 

protection to people and property.

Flowlines: The MR&T Project

Flowline is the level or stage of 

the water surface for the project’s 

design flood at every point along 

the system, i.e., the maximum 

flood event for which the project 

is designed. When plotted on a 

graph of stage versus river length, 

it shows as a flowline.

Revetment: A hard substrate

like rock or concrete that helps 

‘revet’ or retain an embankment 

to protect it from getting eaten 

away by a strong river current.

Sand boil: An eruption of water

and foundational material through 

a bed of sand, such as occurs 

when pressurized water penetrates beneath a levee and comes 

out on the landward side.

Spillway: A structure in a dam or

levee used to safely allow flood 

flows to pass downstream or into 

a side channel while protecting the 

dam or levee from overtopping

14-Day Percentage of Normal Precipitati

Valid April 23–May 7, 2011
10 11

ROOM FOR THE RIVER / 2011 POST-FLOOD Summry REPORt 

Staving off catastrophe

Faced with the prospect of a bad flood potentially becoming a catastrophic event, Maj. Gen. Peabod

and Deborah Lee, chief of water management in the Corps’ Great Lakes and Ohio River Division,

sought to hold back the worst of the Ohio River flood waters with flood control reservoirs under their

control. 

Gen. Peabody directed that many of the Ohio basin dams hold additional water above their normal

operating levels but still within their safe operating bands—a deviation from the approved Water 

Control plan.

The river’s level at Cairo was at 57.9 feet on April 26, and the rising waters were projected to stop at

a height of 60.5 feet within five days. The goal was to keep the river from rising above 60 feet, a level

that signaled an approximate trigger point for activation of the Birds Point–New Madrid Floodwa

Army Corps officials who participated in a surveillance flight over the region around Cairo on April 

26 were stunned by what they saw: Water was everywhere and, in some areas, extended as far as the 

eye could see. The volume of water was almost beyond comprehension.

Between April 20 and April 27, at least six inches of rain had fallen over a huge section of Illinois, 

Indiana, Kentucky, Tennessee, Arkansas and Mississippi. That was the minimum amount. Most ar

received a foot or more and, in some cases, 10 times the typical rainfall. The town of Springdale, Ark.,

recorded 19.7 inches. 

But the rains stopped on April 27, and there was a glimmer of hope. Members of the Mississipp

River Commission believed that if the rain held off, and waters could be held back at the flood control 

reservoirs along the Ohio, northern tributaries of the Mississippi and the Missouri rivers, the flo

might be manageable. But the weather didn’t cooperate. Heavy rains returned on April 30, and water

levels began to rise again across the Mississippi River valley.

Uncharted territory

By May 1 it was obvious that reservoirs and levees alone would not stem the steadily rising river. Th

river gage at Cairo, Ill., was at 60.5 feet and rising, a key decisional trigger point that signaled the 

need to call into use a rarely used flood relief valve: the Birds Point–New Madrid Floodway. It woul

need to be activated for the first time since 1937, a decision that meant the additional flooding of 

farmland and homes lying in the floodway.

River gages provide data needed to man

Structures called river gages played a key role in how the U.S. 

Army Corps of Engineers managed the Mississippi River flood of 

2011. 

Gages throughout the Mississippi River Valley are operated and 

maintained through cooperative efforts between the Corps, U.S. 

Geological Survey (USGS) and NOAA/National Weather Service 

(http://waterdata.usgs.gov/nwis/rt). The National Weather Servi

then uses the data in concert with weather patterns to make forecasts that inform the public, emergency managers, and some of the 

Corps’ most important river management decisions. 

Some 50 gages are located on the main stem of the Mississippi River and 

near the mouths of major tributaries to the Mississippi, south of the confluence of the Ohio River. Each gage measures stream stage, in most cases 

flow, and in some cases water quality as well, at that strategic river point.

Traditional gages are stone or concrete 

structures, generally located above the 100- 

or 200-year floodplain so they don’t become 

inundated by the floods they’re designed to 

monitor. Gages are connected to the river 

by pipes (or intakes), and the movement of 

floats and wires within the stilling well turns 

wheels and dials that measure water surface 

elevation and flow, according to Robert 

Hainly, Acting Deputy Chief of the USGS 

Office of Surface Water. Newer gages use 

more advanced electronic and pressure sensing systems to make similar readings. Rapid 

deployment gages also were used during the flood when there was 

need for additional measurement at an ungaged location if there was a 

question about the reliability of a given reading.

The gage readings are provided in real time, allowing anyone—including those who live along the river—to monitor actual and forecasted flood stages. The Corps site, rivergages.com, includes a custom 

reference table that equates stage and flow to potential inundation of 

affected local landmarks like highways. The readings are also key to the 

operation of the MR&T System, where specific river elevation and flows 

determine when to operate floodways or other components. Without 

them, the Corps and other agencies “would essentially be operating 

blindly, unaware both of the river’s stage at a certain point or floodcontrol structure and also of what’s coming downstream,” Hainly said.

The long-developed flood management plan, for example, calls for 

the operation of the Birds Point–New Madrid Floodway when a certain 

level is reached on the gage in Cairo, Ill. That was surpassed on May 2, 

2011. 

The Corps was in uncharted territory. Never before had water

levels at the Cairo gage risen to 61 feet. The volume of water flowing down the middle Mississippi River in 2011 surpassed even th

historic floods of 1927 and 1937. 

The river continued to rise on May 2 as heavy rains pelted th

Mississippi River Valley. That day, Maj. Gen Michael Walsh, 

president of the Mississippi River Commission and Mississipp

Valley Division commander, was surrounded by MRC commissioners and his command staff aboard the MVD command flagship, th

MV Mississippi, and pondered what lay ahead for the river and the

communities that lined its banks.

During that somber moment of reflection, Walsh said he told 

himself: “This is the big one, the flood we’ve always feared.

The Corps of Engineers had spent several decades designing an

building the Mississippi River & Tributaries System, an elaborate network of levees, floodways, backwaters, reservoirs, relief wells and floo

control structures. It was designed to handle more water than had ever 

flowed down the Mississippi River in recorded history. Then natur

came with a formidable challenge in 2011, adding an unprecedented 

amount of precipitation on top of already swollen rivers. Rainfall measured 600 percent to 1,000 percent above average (See Graphic,

Near the end of the flood, Mississippi Gov. Haley Barbour sai

the bulge of floodwater that passed through the Mississippi River

system was like “a pig moving through a python.”

As the flood progressed, the big question remained: Could the 

Army Corps safely shepherd that proverbial pig (the floodwaters) 

through the proverbial python (the MR&T System) and out to se

without tremendous loss of life and property? The stakes could not

have been higher.

The magnitude of water was almost bey ond comprehension.

above, from left: Deer flee to 

higher ground in the Atchafalaya 

basin, following the opening of the 

Morganza Floodway. A mid-flood

algae bloom in Lake Pontchartrain.

Flooded grain bins in a barge loading terminal.
ROOM FOR THE RIVER / 2011 POST-FLOOD S

12 13

FLOOD FIGHT: THE ULTIMA

The 2011 Mississippi River flood tested the Mississippi River & Tributaries System—a

those who manage it—as never before.

River stages and flow rates broke records up and down the river during what was the largest flood in 

recorded history on the Mississippi River. The flood was contained within the system to a greater extent than earlier comparable floods, but not without a battle fought on numerous fronts, by a multitud

of partners.

The flood fight began early with the implementation of Emergency Operation and Action Pla

maintained by each district within the Mississippi River & Tributary System—St. Louis, Memphi

Vicksburg and New Orleans.

The staff at the river’s U.S. Army Corps of Engineers Districts and area levee boards knew fro

past floods where trouble spots might pop up, and that’s where monitoring started. Action plans also 

detailed the specific operational requirements of the components within each district. Those plans

outline a district’s roles and responsibilities, decision criteria for operating various aspects of the system, communications guidance and detailed information addressing trouble spots. Similarly, local levee 

districts, states, counties and other authorities—working in close coordination with the Corps and 

each other—relied on their flood plans, which were used, adapted and adjusted for each flood event to 

ensure appropriate warnings and evacuations or flood fight measures. 

Still, it took a determined and coordinated effort by thousands of individuals to guide the severely 

swollen river from Cairo, Ill., to the Gulf of Mexico—through the MR&T System’s thousands of mil

of authorized embankments, levees and floodwalls—while preventing the loss of life, maintaining 

navigation on the river and limiting property damage. Working with local and state agencies across the 

lower Mississippi River basin, the Corps fought the 2011 flood for six months, from March to August

The fight

The Corps’ Memphis District declared a flood emergency on March 14. Others further downriver s

followed suit. By early April, it was obvious that the 2011 flood could reach record-setting proportions. 

As the first line of protection, Corps-operated flood control reservoirs along tributaries of the Ohio

and Mississippi rivers captured some of the flow. Maximizing the holding capacity of the reservoir

helped delay and lower the river crests as they met the lower Mississippi. But the reservoirs alone

would not control the steadily rising river. 

Hundreds of sand boils, ranging from the size of a baseball to one that was large enough to swallow

a large sedan, were developing all along the Mississippi River, on the landward side of levees. It was

a major concern, particularly near Cairo, Ill., located at the lowest elevation of any location within Illinois and totally surrounded by levees.

Crews fought thousands of sand boils along the river, using sandbags, plastic and rock to build 

circular rings around the boils as a barrier. Encircling the sand boils halted the movement of sand and

soil, thereby reducing the risk of the boils causing levee failure. The strategy worked; not one mainline

MR&T levee along the Mississippi fail

In late April, the Army Corps’ division commanders—Maj. Gen. Michael Walsh and Maj. Gen. Jo

Peabody—went to Cairo to inspect a mega boil that had developed near the floodwall where the Ohio

River joins the Mississippi. They were stunned by what they saw. It was the largest sand boil ring tha

they, or even the most seasoned and experienced flood fighters, had ever seen.

The river rose six feet in six days at Cairo, Ill. On the morning of May 2, the river gage at Cai

A system successfully passes a record flood.

passed 60.5 feet and was still rising, a tipping point that signaled the need to use explosives and operate another key feature in the flood control project. The Birds Point–New Madrid Floodway wou

need to be activated for the first time since 1937, a decision that meant intentionally increasing the 

flooding farmland and homes lying in the spillway.

That afternoon (May 2), Walsh issued the order to breach the Birds Point Levee. It wasn’t an orde

hastily made. In his brief the day before, Memphis District Commander Col. Vernon Reichling had

requested permission to move into position barges laden with explosives needed to fill pipes within the 

earthen levee, an 18-hour process, saying the situation had become a “when” and no longer an “if.” 

But Gen. Walsh was still holding a slim hope that rains would subside. They didn’t, and the river

continued the steady climb that had raised water levels six feet in six days. “Sometimes people celebrate records—but not this time,” Walsh said. “Making this decision is not easy or hard—it’s simply

grave—because the decision leads to economic hardship and damage to affected property owners ... I 

don’t have to like it, but we must use everything we have in our possession in the system to prevent a 

more catastrophic event.”

Over the course of several hours, crews working in a driving rain pumped 115 tons of binary blasting

agents into 27,000 linear feet of buried pipes within the center of the levee. The project was delayed

Technology key in flood risk sharing

There are a few refinements yet to be worked out, but social media, smart phones and customdesigned apps that allow for instant field reporting are clearly here to stay after offering valuable and 

real-time communication sharing for river managers and decision-makers during the 2011 flood fight.

The Mississippi Valley Division Public Affairs Offices and the Joint Information Center used Facebook, 

Twitter, YouTube and Flickr as ways to post information updates as flood waters both grew and subsided, 

as well as to dispel rumors. A Facebook page devoted to the Birds Point–New Madrid floodway, for example, peaked at 16,500 fans who turned to the site to learn about operation timing, condition of setback 

levees and current floodway status. 

But one of the most promising technologies was developed by the U.S. Army Corps Engineer Research 

and Development Center in Vicksburg, Miss. A new smart phone application provided real-time GPS 

pinpointing of flood-fight progress and related issues in the field, giving trained floodfighters the ability 

to use a phone to upload images, descriptions of flood damage and other critical data to the Command 

Center. The experimental technology was employed by the Memphis District in the flood’s early stages 

as one of the first true field tests of this technology. These devices were later transferred to New 

Orleans and Missouri flood fighters. Enhancements and refinements of this new flood fight tool were 

made from these field tests, ensuring this tool will be even more useful for the next flood fight.

TOP: This explosion light

the sky during the late evening 

activation of the Upper Crevasse 

at Birds Point–New Madrid. Hi

winds and lightning prevented 

daytime activation. MAP GRA

The maps compare rainfall totals 

observed during the 2011 flood 

(right) with those of hypothetica

Flood 58A (Left). Also called the

Project Design Flood, 58A consists

of combined rainfall totals from 

the floods of 1937, 1938 and 1950. 

The Mississippi River & Tributarie

System was designed to protect 

against this hypothetical super-storm.

“We must use everything we have in our possession in the 

system to prevent a more catastrophic event.” 

—Maj. Gen.Walsh, on ATIVATING the Birds Poi

Hypothetical Flood 58A: Rainfall To

Isohyets in intervals of 5 ̋

Maximum value: 33 ̋ in Northeast Arkansas

April 19–May 4, 2011 Rainfall Tota

Isohyets in intervals of 5 ̋

Maximum value: 23.4 ̋ in South Missouri

From Top: Maj. G

Michael Walsh. Maj

Gen. John Peabody
14 15

ROOM FOR THE RIVER / 2011 POST-FLOOD Summry REPORt

for 12 hours by a powerful storm that buffeted the region with 70 mph winds and numerous lightning 

strikes, conditions that made a potentially dangerous operation even more challenging. 

At 10 p.m. on May 2, after the thunderstorm cleared, the order was given to explosively remove the

upper fuseplug (nearly one mile in length). A series of massive explosions shook the ground and lit up 

the night sky. People reported hearing the explosions 50 miles away, in Cape Girardeau, Mo

Earlier that day, the National Weather Service predicted the Ohio River would crest at 63.5 feet o

the Cairo gage on May 5. But on May 5, three days after the Birds Point levee was breached, the Cair

gage read 59.6 feet—several feet lower than it would have read without operation of the levee. 

With the Birds Point–New Madrid Floodway in operation, some 130,000 acres of farmland and 

limited number of buildings and homes were further inundated with floodwaters, but the mighty river 

began to recede. The MR&T System was performing as designed: It gave the river room to move laterally, which reduced flooding downstream and eased pressure on the mainline leve

By May 4, river levels on the Cairo gage dropped below 60 feet, and flood fight teams in the Memphi

District began reporting that conditions in all sectors, though still grave, had stabilized. But the flood fight 

was far from over. Much work remained downstream to prevent flooding in the many river-based industries, property and cities lining the river’s floodplain to the Gulf.

In Mississippi, the mainline levee at Buck Chute (near Eagle Lake) threatened rich farmland an

numerous occupants of the Yazoo Delta. If that levee failed, the delta would see flooding not experienced 

S

T

Cairo

E S TIMA TED I NUNDA TION EXTEN T S

Background Image from ESRI Online - World Street Map

Map prepared by Mapping, Modeling, & Consequences

Production Center

MR&T

Post Flood Report

Mississippi River

Normal Inundation

August 6, 2012

US Army Corps

of Engineers ®

USACEUS ARMY CORPS OF ENGINEERS

les

N

The Battle R

During the month of May, Maj. 

Gen. Michael Walsh led what 

could have been called the Battle 

of the Mississippi. That he was 

in a conference room rather than 

a bunker, or that his “soldiers” 

were local flood fighters armed 

with sandbags, plastic sheeting 

and bulldozers as weapons of 

defense, doesn’t change one fact: 

the complexities of decisions and 

potential consequences to human 

life make a flood fight as close to 

a real battle as one can come in 

civil works.

From a flood fight command 

center, run around the clock, the 

Major General and his senior 

advisers held twice-daily regional 

teleconferences with his front line 

commanders to gauge the “battle 

rhythm” and key decision points. 

These important meetings 

discussed weather forecasts, 

reservoir releases, projected river 

stages, inundation scenarios, 

trigger points, floodway activation 

timing, yield points, interagency 

coordination and more. The inbetween times were filled with 

more focused evaluations and 

decision making, coupled with 

regular communications and 

personal calls—to governors, 

members of congress, Corps headquarters, levee districts, mayors 

and members of the media.

Key Actions

Memphis distr

A: Cairo, Ill

Action: Contained numerous

sand boils that threatened the 

integrity of levees; river water 

seeping under levees causes 

sand boils. 

B: Near Cairo, Ill.

Action: Activated the Birds

Point–New Madrid Floodway 

to reduce flooding and relieve 

pressure on levees downstream.

Vicksburg dist

C: Near Eagle Lake, Miss

Action: Placed four miles of

plastic sheeting on the Yazoo 

Backwater levee to protect 

from landside levee erosion and 

reduce risk of levee failure.

D: Eagle Lake, Miss

Action: Stabilized significant

sand boils on land side of 

mainline levee at Buck Chute by 

allowing water levels to rise in 

Eagle Lake to reduce pressure 

differential, arresting underseepage and sand boils.

New Orleans dist

E: Morganza, La

Action: Activated the Morganza

Floodway, alleviating pressure 

on mainline levees and reducing 

flood risk in Baton Rouge and 

New Orleans.

F: Norco, La

Action: Activated the Bonnet

Carré Spillway, which diverted 

floodwater to Lake Ponchartrain 

and reducing flood risk in New 

Orleans.

G: Angola, La.

Action: Contained 87 of 190

sand boils that threatened the 

integrity of levees upstream of 

Baton Rouge.

The MR&T System was performing as designed: It gave 

the river room to move sideways, which reduced flooding 

downstream.

Mega sand boil at Cairo, Ill

A

C

F

Birds Po

New Ma

Floodwa

St. Fra

BACKWA

Yazoo R

BACKWA

WHITE

BACKWA

RED R

BACKWA

Old River Cont

Str

West At

Floodwa

Morg

Floodwa

BONNET 

SP

Floodways & BACKWATER
16 17

ROOM FOR THE RIVER / 2011 POST-FLOOD Summry REPORt

Located in SE Missouri below the 

confluence of the Mississippi and Ohio 

rivers and designed to be operated at 

specific conditions to pass extreme floods 

that would otherwise exceed system 

capacity. Prior to 2011, operated only once, 

during severe flooding in 1937. It’s operated 

by detonating explosives within fuseplug 

pipes installed in three sections of the 

frontline river levee. Explosives create 

crevasses to divert up to 550,000 cfs from 

the Mississippi River through the floodway. 

When operated, inundates 130,000 acres 

along the west flank of the Mississippi River. 

Operation lowers the flood stage by up 

to 7 feet near Cairo, Ill. and lowers the risk 

of a catastrophic failure or overtopping of 

mainline levees protecting more than 2.5 

million acres.

The mainline levee at Buck Chute is located 

near Eagle Lake, Miss., 15 miles northwest 

of Vicksburg, part of a sub-system that 

protects over 1,400 square miles in 

the lower Mississippi River Delta from 

flooding but is a chronic problem area with 

underseepage and sand boils commonly 

forming at low flood stages. Massive 

sinkholes were detected, and sand boils 

developed at low flood stages, indicating 

a significant problem. Repairs from prior 

floods had not yet begun, and temporary 

measures installed in March 2011 were 

not sufficient for forecasted flood stages. 

By April, Buck Chute was considered a 

critical flood fight area and deviation from 

the Muddy Bayou Water Control plan was 

considered as an emergency measure to 

keep the mainsteam levee from failing in 

the 2011 flood.

Located 10 miles north of Vicksburg, 

Miss. and extending 28 miles from the 

Mississippi River mainline levee along 

the west bank of the Yazoo River to 

Yazoo City, it’s one of four backwater 

levees in the MR&T System designed 

to slowly overtop and take pressure off 

the system during extremely high flood 

stages (approaching Project Design Flood 

elevations). The 1941 Flood Control Act 

authorized the Yazoo Backwater Levee 

to be built to a height equivalent to 56.5 

feet on the Vicksburg gage (which is what 

exists today), as long as the levee did not 

push river levels to within five feet of the 

top of mainline MR&T levees. Subsequent 

authorization allows for an additional six 

feet of height on Yazoo Backwater levee 

to ensure it performs in concert with the 

MR&T System.

Located in central Louisiana near river 

mile 280 on the western bank of the 

Mississippi River, the Morganza Floodway 

begins at the river, extends southward to 

the East Atchafalaya River levee and joins 

the Atchafalaya River Basin Floodway 

near Krotz Springs, La. The purpose of 

the floodway, in conjunction with the 

Atchafalaya Basin Floodway, is to operate 

during extreme flood events to carry flood 

water from the Mississippi River to the 

Gulf of Mexico via the lower Atchafalaya 

River and the Wax Lake Outlet. Designed 

to pass up to 600,000 cfs of water to 

the Gulf, alleviating stress for mainline 

levees downstream along the Mississippi 

River. Prior to 2011, operated only once, 

during severe flooding in 1973, passing 

approximately 170,000 to 180,000 cfs at 

its peak operation.

Operation began April 25 with the loading 

of barges with materials, equipment and 

personnel and culminated with floodway 

activation on May 2 and successful passage 

of the flood through this constricted reach. 

Factors considered included: the floodway 

operating plan; actual and forecasted flood 

crests at Cairo, Ill.; potential damages caused 

by operating the floodway and effects 

on future MR&T System performance; 

significant precipitation/saturated hydraulic 

conditions throughout the basin; use of 

all available reservoir storage capacity to 

reduce the flood crest at Cairo; deteriorating 

conditions of levees near Cairo, Ill., and in 

Fulton County, Ky.; and the time needed to 

prepare the floodway for operation. 

Approval to deviate from the Muddy 

Bayou Operating Plan was given by 

the MVD commander on April 28 and 

resulted in successful passage of the 

2011 flood waters through this part of 

the MR&T System. Many factors were 

considered in making this key operational 

decision. Some of the most prominent 

include: actual and forecasted flood 

crests at Vicksburg, Miss.; the significant 

underseepage issues of mainline levee at 

Buck Chute and impacts of levee failure; 

potential emergency measures to reduce 

the risk of failure of the Buck Chute Levee 

and the possible impacts of deviating from 

the Muddy Bayou Operating Plan.

Approval to perform flood fight measures 

along a four-mile stretch of the Yazoo 

Backwater Levee (forecasted to overtop) 

was given by the MVD commander on May 

4. Approved flood fight measures included 

filling deficient low spots to authorized 

levels and armoring the landside of the 

levee with polyethylene plastic sheeting 

to reduce the risk of erosion and potential 

levee failure. Considered factors included: 

authorized flood fight activities for this 

backwater levee; actual and forecasted 

flood crests at Vicksburg, Miss.; potential 

impacts of full levee failure compared to 

levee overtopping without failure; 2008 

flood data and observations; additional flood 

fight measure effects on mainstem levels.

Operation was initiated at 3 p.m. on May 

14 and resulted in successful passage 

of 2011 flood waters through this part 

of the MR&T System with a peak flow 

of 186,000 cfs through the floodway. 

Many factors considered, including: the 

floodway water control plan; discharges 

at Red River Landing, La.; stages and 

remaining freeboard at the Morganza 

Spillway structure; flow conditions at 

the Old River Control Complex; potential 

impacts of activating the structure on 

the floodway; potential impacts of not 

activating the structure on MR&T mainline 

levees and the areas they protect; and 

potential impacts based on how quickly 

the floodway is operated.

Per the 1986 Operating Plan, the floodway 

normally will not be operated until flood 

stages exceeding 60 feet (or 58 if the 

system is in danger of failing) are predicted 

on the Mississippi River gage at Cairo. Then, 

the upper fuseplug section will be prepared 

for operation, with the lower fuseplug 

section to follow. Operation requires 150 

people, specialized equipment.

Developed as a fish and wildlife mitigation 

feature for the Yazoo Basin Project to 

prevent agricultural runoff from Steele 

Bayou from entering Eagle Lake. The 

operating plan allows for water level 

management of Eagle Lake January to 

June to support fish and wildlife. Raising 

waters higher than the prescribed level in 

Eagle Lake to protect the Buck Chute Levee 

required plan deviation.

Backwater levee systems are meant to take 

pressure off the MR&T System mainline 

levees by overtopping during extreme flood 

events. The Yazoo Backwater Levee was 

designed to overtop when the Vicksburg 

gage reached 56.2 to 56.6 feet. Further 

analysis by the Vicksburg District refined 

this estimate to 56.3 feet using updated 

data collected during the 2008 Mississippi 

River flood.

The plan is based on the Morganza 

Floodway design and Water Control 

Plan. Through that, the central Louisiana 

Floodway is slated to be operated when 

the flow of the Mississippi River at Red 

River Landing, La., (located 20 miles north 

of Morganza) reaches 1,500,000 cfs and 

is rising.

If and when to operate the Birds Point–New 

Madrid Floodway

Whether to deviate from the Muddy Bayou 

Water Control Plan to help protect the Buck 

Chute Mainline levee

Whether or not to perform flood fight 

measures at the Yazoo Backwater Levee

If and when to operate the Morganza Floodway 

in conjunction with conditions at Bonnet Carré 

spillway and Old River control structure

Key De

LOCATI

BACKGROUN

OPERATI

DILEMM

FACE

THE DECIS

Birds Point–New Madrid Muddy Bayou

Floodway

Yazoo Backwater Levee Morganza Floodway

Operating the floodway requires evacuating 

230 residents and explosively removing 

the crevasse portions of the frontline levee 

which would then need to be repaired 

after the flood. Operation also inundates 

homes, structures, and increases the 

level of flooding in up to 130,000 acres 

of agricultural land. Not operating the 

floodway, on the other hand, can result in 

other mainline levees overtopping or failing 

with much more significant damages and 

potential loss of life. 

Deviating from the water control plan to 

raise the level of Eagle Lake would reduce 

the risk of levee failure at Buck Chute, 

but it would also potentially impact 800 

residents and properties along Eagle Lake. 

Not deviating from the plan would result in 

much higher head differential between the 

wet/dry sides of the weakened mainline 

levee at Buck Chute and high risk of levee 

failure, potentially inundating 1,450 square 

miles and impacting up to 3,000 homes.

Up to 300,000 cfs of water would need to 

be diverted through the floodway based 

on the water control plan and forecasted 

Mississippi River flow. Forecasted flow 

conditions on the Atchafalaya River 

(760,000 cfs) combined with floodway 

operation could impact 2,500 people and 

2,000 homes and up to 22,500 people 

in the floodway and 11,000 homes in 

backwater areas. Not operating could 

mean other mainline levees overtopping or 

failing with more significant damages and 

potential loss of life. 

Forecasted flood stages in early May 

indicated possibility of levee overtopping 

by a foot of water for up to 10 days, putting 

the levee at high risk of failure. If the levee 

overtopped and did not fail, some 450 

square miles would be inundated. If it failed, 

that would increase to 1,900 square miles 

and affect 3,000 people. Flood fighting 

could reduce failure risk but might increase 

risk to mainline MR&T levees. In addition, 

there was a question as to type and extent 

of authorized flood fighting options.

Key Operational Decisio

since 1927. About 3,000 homes and 1,450 square 

miles of land faced inundation.

To reduce pressure on the levee, the Corps deviated

from its usual Muddy Bayou water control plan, intentionally allowing water to be diverted into Eagle Lake. T

strategy resulted in the successful passage of the floodwaters 

through that section of the MR&T Syste

In Louisiana, the operation of Morganza and Bonnet Carré

lowered the flood crest at New Orleans and Baton Rouge by 2.5

feet, protecting a 200-mile-long corridor of levees and floodwalls and 

sparing those cities from a massive flood. Before floodway activation, flood fighters in the New Orleans

District found 190 sand boils in just the Angola area; 122,000 sandbags were placed at Duncan Point to 

form a berm and address seepage.

Some of the flood fight’s greatest drama unfolded on May 12 in Mississippi, when a high-energy san

boil threatened a critically important levee near Greenville, Miss. The sand boil sat at an extremel

critical location under the Mississippi Levee Board’s jurisdiction. A levee break there would have

unleashed a torrent of water that could have endangered thousands of people and engulfed the Yazoo 

River delta region. 

Upon discovering the sand boil, Corps and local officials quickly assembled a flood fight team – 

comprised mainly of inmate labor – and formed a human conveyor belt. The workers passed sandbags

from the levee, through the knee-deep water, into an adjacent ditch to construct a sandbag and plywood dike to trap the seepage and create a water berm. Crews also dumped tons of stone over the sand 

boil to create a filter that stopped erosion under the levee. The levee held

The Mississippi River finally crested in Vicksburg, Miss., on May 19, setting a record at 57.1 

but not overtopping the Yazoo backwater levee. Once the flood crest completed its pass through the

MR&T System, the bulk of the flood fight was ove

Soon, the Corps would turn its attention to a new battle: Repairing the levees and other structures 

that bore the brunt of the floodwater.

above, from left: A high-energy 

sand boil threatened the Greenville, 

Miss., levee. Capt. Todd Mainwarin

said he could feel the Mississippi

River’s power and energy beneath

him here near the Old River Contro

Structure, where floodwaters were 

diverted down the Atchafalaya River

Complex situations required tough decisions during the 2011 flood event. Flood fight procedures and past experience helped inform ke

decisions. But they still weren’t easy. Here’s a sampling of what decision-makers evaluated, faced and ultimately decided
ROOM FOR THE RIVER / 2011 POST-FLOOD S

18 19

The 2011 flood may have come as close as the Mississippi River has reached to the act of Divin

Providence prophesied in 1927 by Maj. Gen. Edgar Jadwin, then Chief of Enginee

Were those provided floodways adequate for floodwater passage? Did it succeed in its ultimate test?

By all accounts, yes. But the flood nonetheless left significant economic, environmental and structural damages and exposed vulnerabilities in portions of system components. It also identified areas for 

improvement in some decision-making tools, process documents and emergency action, water control 

and communications plans.

Passing the Project Design Flood

Assessing performance requires a little history on the basis of design and operation plans. The Mississippi River & Tributaries System was constructed to protect against the “Project Design Flood” (

or maximum flood with a reasonable chance of occurrence. Even when not reached (the 2011 flood

peak flows were about 85 percent of the Project Design flows), the Project Design Flood remains key

to system operation by dictating levee heights and requirements as well as dozens of trigger points for 

activation of various MR&T System feature

Those trigger points were originally established based on a hypothetical “super storm” modeled in

1954 by the U.S. Weather Bureau and Corps hydrologists. System components and activation points 

were based on that hypothetical storm and related flows.

How much flow each MR&T component could handle safely during such a storm prompts activati

of floodway and backwater storage areas and lowers risks across the system. Operating a floodway basically floods an area designed and compensated for that likelihood to lower the risk of more catastrophic

damages elsewhere.

For the first time in the MR&T project’s history, the Birds Point–New Madrid and Morganza Floodways and the Bonnet Carré Spillway were placed into operation during a single flood event. Eme

flood fight measures, synchronized with partner agencies, levee districts and municipalities, were also 

needed, primarily at weak points identified before 2011 or spots where the MR&T System is not ye

complete. Communication with those other agencies was accomplished via direct liaison, new internal 

and external websites, social media and regular meetings and conference calls.

Floodways: Activating 3 of the system’s 4 

The Birds Point–New Madrid Floodway was operated as the system’s upper floodway which direct

impacts the area around the Mississippi and Ohio River junction or “confluence area.” If not operated when needed here, a mainline levee break or overtopping could have inundated 2.5 million acre

across parts of Missouri and Arkansas, as it did in 1927.

While the other floodways are designed to be opened in a slow, sequential manner, Birds Point—due to 

its infrequent usage—is designed with earthen fuseplugs instead of gates. Originally designed to degrade

naturally by the river’s forces at a certain flood stage, the floodway is now activated by detonating explosives within fuseplug wells and lateral pipes installed in the 1980s at three sections of the frontline levee. 

The floodway creates a 30-mile bypass which diverts up to 550,000 cfs from the river, inundating about

130,000 acres for which the Corps had secured permanent flowage easements from landowners. 

Experts concluded that the Commerce mainline levee would have also been overtopped without the

operation of Birds Point–New Madrid. Using lessons learned from 2011, the U.S. Army Corps of Engineers studied the operational features, including potential methods to activate the floodway withou

the use of explosives.

Should Divine Providence ever send a flood of the maximum predicted by 

meteorological and flood experts as a remote probability (but not beyond 

the bounds of ultimate possibility), the floodways provided in the plan are 

still normally adequate for its passage without having its predicted heights 

exceed those of the strengthened levees. —Maj. Gen. Edgar Jadwi

PERFORMANCE: Making room for a re

... for the first time, all three floodways would be activated 

in the same flood event.

1927 vs. 2011 16,800,000 acres flooded

1927

Levees only

2011

Floodways & 

backwaters 

make room 

for the river 6,350,000 acres flooded

212,000 acres

inundated in 2011

2011 Backwaters

1,652,000 acres

2011 Floodways

366,000 acres

335,000 acres

inundated in 2011

Floodway Activa

a Last 

A lot changed in the 74 years 

between the first activation of 

the Birds Point–New Madrid 

Floodway and the second. The 

first year, 1937, hand-written U.S. 

Army field notes dropped from 

the sky reading “Levee has broken. Get out at once!” were one 

communication source.

In 2011, floodway residents 

were evacuated by more modern 

means: updates broadcast via 

news media, Facebook, Twitter 

and town hall meetings called by 

the area’s congresswoman. But 

while communicating was easier, 

the decision to activate was not.

Birds Point–New Madrid is one 

of four floodways in which the 

Corps purchased flowage easements, giving the government the 

right to activate when called for 

by extreme flooding and specific 

flows or stages. Operation requires 150 personnel, it inundates 

130,000 acres of already-flooded 

farmland and requires evacuation 

of 230 residents.

Among those whose land 

would be flooded was MRC 

member R.D. James, who nonetheless lent his support when 

realizing there was no choice but 

to activate. Within an hour after 

activation, the river dropped by 

six inches. By the next morning, 

it was more than a foot lower 

and the risk of system failure was 

reduced.

BIrds Point–New Madr

 at a glance • Completed in 1933

• Operated in 1937 and 2011

• 3–10 miles wide; 36 miles long

• 133,000-acre floodway, when activated, provides 

protection to 2.5 million acres

• Diverts 550,000 cfs

• Activated by removing fuseplug levee sections with explosives

• Alternate methods of operation were evaluated to 

improve performance
20 21

ROOM FOR THE RIVER / 2011 POST-FLOOD Summary REPORt

This graphic represents the Project Design Flood, developed to depict worst-case-scenario flows 

generated from a hypothetical super storm 58A conceived by the Weather Bureau (now National 

Weather Service). The current Project Design Flood was adopted in 1956 and used as the basis for 

operation of the various features of the MR&T System. Starting with 35 hypothetical combinations 

of storms and related runoff, the Weather Bureau ended up combining three severe storms (from 

1937, 1950 and 1938) and related flood flows to determine the peak discharge at key locations. A 

post-1973 flood review determined the Project Design Flood metrics and trigger points were further 

validated.

Lessons also were learned from the opening of the Morganza Floodway, operated only one other tim

in floodway history, 1973. An extensive public notification and coordination effort ensued in this floodway, where operation affects some 22,000 residents including nearby Butte La Rose and Morgan City.

It also affected a variety of wildlife, including the endangered Louisiana black bear. Detailed maps 

were generated to show residents how much floodwater they could expect, and were also useful in 

planning potential evacuation. Extensive coordination was also done with state/local officials and other

federal agencies, including the Fish and Wildlife Service and U.S. Environmental Protection Agency, t

limit effects on wildlife and fisheries.

The operation of Bonnet Carré (see timeline, page 20) similarly prevented catastrophic flooding

river communities and cities, such as Baton Rouge and New Orleans, and offers a peek into the tricky

intricacies of floodway operations.

Navigation 

Navigation continued largely uninterrupted by the 2011 flood with only minor brief restrictions in certain 

stretches of the river. Important trade commodities were able to reach their export or import locations nearly 

unimpeded. Ports, harbors and areas where sediments accumulated during high water were identified in 

damage assessments and addressed without any further delays to traffic.

Cultural and environmental factors

The strongest environmental concerns centered around water quality, sedimentation, erosion and

wildlife impact issues. 

Interagency teams convened while floodwaters rose, established monitoring protocols and made 

contacts to initiate background research and sampling during the flood. Water quality studies were 

conducted, one focused at several sites along the Atchafalaya and Mississippi, the second on movement

of water from the Bonnet Carré Spillway through Lake Pontchartrain. There, despite the high amounts

of nutrient-rich water that created swirls of duckweed, no anticipated nutrient-infused algal blooms were 

observed.

Monitoring teams from the U.S. Geological Survey also surveyed for oil and grease in the Atchafalaya

Basin, where spillway waters rushed over hundreds of gas and oil wells. Only a few samples showed

any hydrocarbons and they were at very low concentrations.

Cultural concerns centered around the activation of the Birds Point–New Madrid Floodway, wel

known as an area with a high density of Native American sites on the National Register of Historic Places.

Spillway changes benefit region’s wildlife

Lessons learned from the first opening of the Morganza Floodway were incorporated into this year’s 

operation plan. The first operation, in 1973, proved problematic for the eastern Atchafalaya basin, a 

prized wetland that’s home to deer, bobcat, beaver, coyote, mink, armadillo and the endangered Louisiana black bear. This year’s goal was to offer the creatures a chance to escape floodway water, intentionally flooding their home through a slower opening. Wildlife officials say the controlled opening at 

25 percent capacity generally worked, with animals for the most part reaching higher ground in time. 

Deer squeezed under fences and hopped through floodwaters, leaving the greatest impact on fawns, 

due to the stress on pregnant deer. Adult bears for the most part were able to climb trees or reach 

higher ground, but the impact was similarly highest on cubs. Earlier lessons learned were also applied 

to the federally-endangered pallid sturgeon. The Bonnet Carré Spillway was of particular concern for 

this ancient fish. The peak discharge of 300,000 cfs created a huge side channel that sucked sturgeon 

in with it. Crews helped collect, tag and return many of them to the mainstem of the river. Oyster 

populations, however, suffered unavoidable damage from the influx of fresh water from the Bonnet 

Carré Spillway, leading to disaster declarations for the oyster industries of Louisiana and Mississippi.

above, from left: Biologists rescue

endangered pallid sturgeons trapped 

by spillway operation. Louisiana 

black bears, another endangered 

species, fared well during flooding as 

they moved out of harm’s way or 

climbed trees for periodic rests in 

their evacuation of flooded areas.

Floodway timeline samp

Bonnet Carré Spillway

May 5

Mississippi Valley Division commander concurred with request to 

operate the Bonnet Carré Spillway 

and consulted with the Mississippi 

River Commission, which concurred 

with the decision. MVD commander 

contacted Louisiana and Mississippi 

officials to inform them of the possibility of operation.

May 9

The first bays were opened at the 

Bonnet Carré Spillway based on a 

computed discharge of 1,240,000 

cfs at Red River Landing on May 8 

and an assumed one-day lag time 

between Red River Landing and 

New Orleans.

May 14

The discharge through the 

spillway was increased above the 

design discharge of 250,000 cfs 

to preserve a desired level 

of freeboard on these levees, in 

accordance with the Water Control Manual. This increase above 

the design discharge was approved 

by the district commander and 

a white paper was written titled 

“Commander’s Assessment” to 

document the reasons for this 

increase.

May 17

At peak operation, 330 of the 350 

bays were open and 316,000 cfs 

passed through the spillway.

June 1

The New Orleans District began 

closing the Bonnet Carré Spillway.

June 2

The final gates were closed at the 

spillway. Neither the Bonnet Carré 

structure nor the spillway was 

significantly damaged during the 

flood of 2011.

Proje
22 23

Proving its v

Summary of MR&T System Performance in 2011

• The 2011 flood was one of the largest on record between Cairo and Baton Rouge. 

• Flood-fighting techniques employed at the tactical level were generally successful in maintaining 

the integrity of the primary Flood Risk Management System.

• The operation of the MR&T System, as a whole, was adequate to minimize flood impacts. This includes 

the operation of gates, reservoirs, spillways and diversions located throughout the system. This was 

particularly evident in New Orleans where the operation of the Bonnet Carré Spillway and Morganza 

Floodway kept river levels very close to design levels and prevented widespread flooding in the area.

• For the first time, Morganza, Bonnet Carré and Birds Point–New Madrid were operated during the 

same flood. Each of the floodway operations reduced stages by several feet, both downstream 

of the floodways and for varying distances upstream, while operations at many reservoirs also 

provided stage reduction benefits. 

• None of the MR&T authorized backwater areas were operated during the flood of 2011 because 

river stages remained below their operation level and the backwater levees did not overtop.

• No significant accidental breaches occurred in the primary flood risk management system.

• New technologies presented opportunities to use enhanced tools not fully considered in pre-flood 

plans. These tools were quickly applied and used successfully to improve internal and external 

communications during the flood. But poor cell phone access in remote areas caused frustration, 

as did the need for more training on the most effective use of social media.

• The system prevented $234 billion in flood damages in the single flood, and $612 billion cumulatively, with a $14 billion investment.

Federally recognized tribes were notified of the possibility of activation and periodically briefed,

while county coroners and area sheriffs were advised of procedures to follow which would 

include full tribal consultation and monitoring, should activation inadvertently expose buried 

artifacts or human remains. 

Flood damages prevented

Project effectiveness is primarily measured by the magnitude of flood risk reduction, also referred 

to as the “degree of protection” offered by the project, and it is in this calculation that the greatest 

success of the 2011 flood operation can be measured.

To calculate this, performance evaluation teams ran various scenarios looking at the expected magnitude of damage if various MR&T System components hadn’t been in place. Results of this analys

were then compared to the actual happenings with full system use.

Calculations factor in an estimated $2.8 billion in actual flood-related damage to urban and agricultural areas, noting the levees protect one of the most productive agricultural areas in the world. With 

the project, about 1.2 million acres of unprotected farmland were impacted, compared to the 10 million 

that would have been flooded without the system. Without the project, an estimated 1.5 million residential and commercial structures would have been impacted. With the MR&T project, that decreased t

21,203 structures. 

Based on post-flood calculations, the system prevented $234 billion in total flood damages during 

the 2011 flood event. This brings the cumulative damages prevented to a total of $612 billion, a $44

return on every $1 invested, based on $14 billion invested to date. 

Perhaps even more significant, hydrologic models showed that without the system, an estimated 

3.6 million people would have been impacted by the 2011 flood event. That compares to the 43,358

people actually impacted. 

opposite: Cranes lift gate “needles,” 

one by one, to allow for a controlled 

spillway opening at Bonnet Carré.

“By operating the MR&T System as designed... the value of this investment to our nation can be counted by what we have not lost— lives, 

critical infrastructure for the energy industry and more than 50 billion 

dollars in damages to homes and businesses.” 

—Col. Ed Fleming,

ROOM FOR THE RIVER / 2011 POST-FLOOD Sumary REPORt 
ROOM FOR THE RIVER / 2011 POST-FLOOD S

24 25

RECOVERY: RESTOING A FLOO

As floodwaters were still rising, teams of engineering specialists started walking the 

thousands of miles of levees and floodwalls that make up the Mississippi River & Tributaries System

identifying seeps, boils, slides and other anomalies that marked the system’s damages and vulnerabilities needing repair and attention. There would not be time to waste

The flood came on so fast and forcefully that while there were no levee (or human) casualties, there

would be a certain need for infrastructure triage. When waters receded, teams continued the intensive 

post-flood damage assessments to identify the location, nature and extent of needed repairs and preliminary costs. That information was uploaded into a comprehensive database and documented in 44

regionally explicit Damage Assessment Reports. Hundreds of one-page project information papers were

prepared for critical and non-critical projects to allow decision-makers comparative data for classification, prioritization and funding of damaged areas.

A recovery unit was, in fact, already working during the flood to identify immediate actions based on 

near-term threats to the system: the damage assessments, post-flood evaluations, interagency collaboration and construction repair needs to get the system back up to at least a basic level of flood protection.

“We knew we needed to start developing our recovery strategy even in the midst of still-rising flood 

waters,” said Scott Whitney, the Mississippi Valley Division’s Regional Flood Risk Manager. As dama

assessment teams worked in the field, state and federal partners were assembled into an interagency 

recovery task force that helped formulate a comprehensive and collaborative regional recovery strategy.

The Mississippi Valley Division grouped repair projects into four categories, based on risk posed t

human life and the river economy, with Class 1 representing the highest human life/safety threat. While 

some seeps and boils were expected and treated as routine, others—particularly those demonstrating the 

movement of “material”—were signs of a potentially dangerous situation that needed to be addressed.

The immediate questions and concerns, Whitney said, were “Can we flood fight it again?” and “What

are the life/safety and economic risks and consequences of failure?” The answers to those questions

A winning performance still comes at a cost. The Mississippi River & 

Tributaries System emerged from the record 2011 flood a winner but, 

as one commander put it, like Rocky Balboa after his title match with 

Apollo Creed.

Regional Task F

coordinates

“It is unfortunate that it has taken 

a natural disaster to bring us all 

together in such a collaborative 

fashion. We should have been doing 

this years ago!”

“The experiences shared at the meetings helped me see how each agency 

was connected (and sometimes 

disconnected) to and from the flood 

response and recovery process.”

“The CorpsMap and NWS extended 

28-day forecasts are two products that 

would likely not have come about, or 

been shared as extensively, without 

the IRTF discussion and dialogue.”

Those are just a few responses 

from members of an Interagency 

Recovery Task Force (IRTF), formed 

under a new charter, to collaborate 

on solutions for short- and longterm restoration efforts and ongoing flood risk issues throughout the 

Lower Mississippi River Valley.

Team members were federal 

and state-appointed members 

with expertise in assessing, 

documenting and repairing flood 

risk management and related 

systems. The multi-agency forum 

was set up to solve regional issues 

and challenges that would be 

presented by the flood and work 

to consider traditional and nontraditional repair alternatives, 

better communication on flood 

risk issues, and work toward 

actions that would reduce future 

flooding vulnerability.

Scour and bankline erosion at Merriwether-Cherokee Bend, a nine-mile bend where 

the Corps had invested approximately $60 million in channel improvements to maintain 

the meander pattern needed for navigation. During the flood, the river attempted 

to straighten out the bend and create a new channel. Repairs recreated the protective 

shoreline where the river scoured out the previous bank, creating a huge opening. 

This one repair costs an estimated $30 million.

above: A dead alligator found after 

high waters receded. below: The St. 

Francis sand boil. 

helped differentiate between repairs deemed critical (requiring immediate action) and noncritical 

(deferring actions for several months). 

Through this framework, the division identified 143 projects requiring critical repairs at a cost of $1.04

billion, plus another 262 non-critical projects at another $543 million. Repairs to the top 29 critical 

projects were initiated in summer and early fall of 2011 using $170 million borrowed from ongoing Corps 

projects elsewhere in the country. (See “The Funding Scramble,” page 26.) After Congress passed The Disaster Relief Appropriations Act of 2012 on Dec. 24, 2011, the Corps was able to aggressively sched

secure services needed to attack all critical repairs and the majority of non-critical repairs.

Ranking priorities

Initial “make-safe/make stable” work at the Birds Point–New Madrid Floodway topped restoratio

priorities, followed by other significant levee issues around the confluence of the Mississippi and Ohi

rivers. That included uncontrolled seepage and sand boils, leaking joints and possible stability issues

in the floodwall. Some high-energy boils measured 8 to 15 feet, dwarfing the hundreds more small-tomedium boils located throughout the system.

Riverbanks suffered too. At the Merriwether-Cherokee Bend in the Memphis District, the river attempted to cut through a mile-wide bend, shortening the river by some nine miles. River shortening act

to destabilize the navigation channel and unravel some $60 million in channel improvements invested in 

this nine-mile bend over the years. 

Areas of seepage required emergency fixes, mid-flood, with permanent fixes launched at many of the 

most severe sites as part of the Phase 1 critical repairs. Many scour and erosion repairs were critical as

well, consisting primarily of slope paving and protection above water lines and the addition of Articulated Concrete Mattresses below the water line

Most efforts are expected to be completed by the 2014 flood season. Completion of several expansive

critical repair projects had to be divided into construction stages, the latter stages extending into 2014. 

Some vulnerabilities and possible operational changes have been identified and are recommended for 

further investigation and action.

Damage & recovery highlights: 

Fl

Damages were centered around scour and sediment deposition in inflow and outflow channels, wave 

wash erosion, and loss of some monitoring equipment, all being repaired through appropriate repair 

methodologies.

Rese

The only MR&T reservoir experiencing damage was Wappapello, and it was still able to function despi

damage to the roads and utilities. Immediately after the flood, the Corps and Missouri Department of

Repair  S

Channel Improvement 257 $877.9 millio

Levees 72 $434.4 millio

Dredge 41 $174.5 millio

Structures 30 $84.2 millio

Drainage 11 $25.7 million

Recreation Sites 26 $4.5 milli

TOTALS 437 $1.6 

*Documented damages as of Dec. 31, 2012. Of the above system repair 

needs, $990 million were funded by an emergency supplemental 

appropriation, $170 million were self-funded by the Corps, and 

$441 million remains unfunded.

2011 Flood damages

Mississippi Valley Divis

“We knew we needed to start developing our recovery 

strategy even in the midst of still-rising flood waters.” 

PRI FL A
26 27

ROOM FOR THE RIVER / 2011 POST-FLOOD Summ

There will always be risk. That is never truer than after a major flood event destabilizes levees, changes flows and weakens water control structures. So while $802 million in MR&T flood repair construction is underway, attention has turned to managing ri

for when flooding threatens again. This is the “preparedness” phase of the Corps’s four-stage

flood risk life cycle, where residual risk is assessed by experts so that flood fighting and other 

actions, including communications, coordination and collaboration, can augment the protection 

offered by the existing flood risk management system. 

In the case of the Mississippi River & Tributaries System, risks are exacerbated by the fact tha

the system was unfinished, at 89 percent complete prior to the flood. Risks also remain in the system 

due to the inability to fully address certain levee, structural and channel improvement repairs over the 

next several years while 2011 flood damage repairs continue.

Development drives up risk

Development is increasing in floodplain lands, which drives up both economic and human risk. 

Damages—if they occur—are naturally larger in highly developed areas than they would have been predevelopment. Throughout the nation, both existing and new development tends to be located in flood

prone areas, a topic being increasingly addressed as part of a broader flood risk management strategy.

In the meantime, the Corps has further cemented relationships with other federal, state and local government agencies with whom it shares responsibility for reducing flood risks. Creation of a regional Interagency 

Recovery Task Force has led to closer working relationships as well as a specific list of flood preparednes

actions. The Corps, in part through the task force, took additional steps to reduce risk for upcoming seasons,

developing information papers and fact sheets, educational videos and an extensive regional flood risk management website (www.mvd.usace.army.mil). Other highlights of the risk reduction strategy include

A Flood Season Preparedness and Emergency Response Summary

In general terms, this report captured efforts the Corps has taken to manage and mitigate risks associated with, 

and in preparation for, the next flood event. It included the damage, repair and recovery needs and interim plans 

for reservoir/floodway operations and was distributed via website and directly to federal and state partners.

Risk Management Information Pap

These described how risks at 45 damaged and high-risk locations within the MR&T were being addressed through construction, interim measures and flood fight preparation. They also identified fl

fight activation stages and included a link to the National Weather Service site for stage forecasts.

Inundation Mappi

A process standardized across the region was developed to produce inundation maps that display potential 

timing, depth and inundation consequences to better prepare for the 2012 flood season. Maps were generated for eight high-risk areas, with a regional team quickly poised to prepare inundation maps as needed

Regional Communication P

Established in March 2012, this gave guidance for sharing of flood risk information via CorpsMap, fa

sheets, social media and more. It also highlighted key groups with whom regular communication is required.

A Flood Preparedness Works

Preparing for the worst is the best protection when repairs are still under way and a new flood season approaches. That was the philosophy behind the 2012 Flood Preparedness workshop held in Memphis 

Feb. 23, 2012. The meeting brought together more than 80 state and federal agency representatives fo

a day-long series of case studies presented, by district, and an overall look at the vulnerable spots within 

the Mississippi River & Tributaries System, coupled with the National Weather Service spring forecast

Annual flood preparedness workshops are in the planning stages.

A Cycle of Flood R

Manage

In its early days, the U.S. Army 

Corps of Engineers worked on 

“controlling” floods to reduce 

“flood damages.” However, the 

Corps’ philosophy has evolved, 

just as has the technology available for flood protection. The 

Corps is taking the lead on better 

management of “flood risk” with 

the understanding that flood risk 

management projects cannot 

completely eliminate all flood risk, 

particularly as we experience more 

extreme flood events.

Effective flood risk management requires the integration 

of four steps—preparedness, 

response, recovery, and mitigation 

programs—into a coordinated 

life cycle framework. The Corps’ 

major role in driving down flood 

risk focuses on: planning structural and nonstructural projects to 

manage risks; inspecting existing 

flood infrastructure; communicating risk to communities and 

stakeholders; technical and planning support to communities 

and states; and rehabilitation 

of levees and other flood risk 

management structures damaged 

by flooding. However, managing 

flood risks doesn’t lie exclusively 

with the Corps or any other single 

entity but instead across multiple 

federal, state and local government agencies, and the choices 

and actions of private citizens.

At flooding ri

Check Corps

A flood is coming, and you know 

that the levee just upstream 

of your home or business was 

severely damaged in the last one. 

Has it been fixed? Are you still at 

elevated risk?

Along the Mississippi River, 

finding that information is now 

possible via the web, through a 

site called CorpsMap. The geospatial web platform was, until recently, available through internal 

Corps systems only. However, the 

2011 flood prompted the Mississippi Valley Division’s GIS team to 

work with regional and national 

experts to establish one of the 

first public CorpsMap sites, at: 

www.mvd.usace.army.mil.

The site provides general 

background information on MR&T 

component flood damages, 

potential consequences of failure, 

repair schedule and monthly 

status updates. Users can zero in 

on specific locations of concern 

and select the desired layers of 

information.

Preparednes

Man has yet to create a flood control system that is 100 

percent effective against the potential fury of nature, but the 

MR&T System is about as close as it gets.

Transportation worked together to construct a temporary

bypass for Highway T, a main thoroughfare which wa

washed out during the flood.

Channel Improve

Unlike many other components of the MR&T, damage t

channel improvement structures was not entirely visible 

since much of this protection largely remains underwater. 

Sonar systems were used to evaluate damages occurring 

below the water’s surface. Some 44 sites were identified 

that, if not repaired, could impact future system performance. The most critical were revetments

located in close proximity to the mainline Mississippi River Levee, since revetment failure could

compromise levee integrity and seriously damage the navigation channel. Relocation of the Mississippi

River channel nearly occurred at Merriwether-Cherokee and President’s Island where, at both sites,

the river scoured the bank to such a degree that the river attempted to carve a new channel and basically change its historic course. At Merriwether-Cherokee, the volume of material that eroded away is

estimated at 8 million cubic yards.

Levee and Fl

Construction classified as critical began immediately on many levees and floodwalls, with first phase 

fixes repairing levees to a degree needed to sustain a 25-year flood event. The critical mass of construction priorities were centered around the “confluence area” of Cairo, Ill., where extensive underseepage and massive sand boils highlighted very serious vulnerability. In months following flood recession,

inspectors began to record a number of “slides” where saturated levee faces would simply slide off, 

creating a serious levee integrity concern. At Buck Chute near Eagle Lake, Miss., boils and seepag

discovered in a 2010 flood were so worrisome that crews patched together an emergency fix as the 

flood crest made its way down river. The permanent fix of several “relief wells” were included in the

phase 1 list of critical sites.

PREPAREDNESS

RES

P

O

N

SE

YREVOCER

M

TI GI ATION

STATE & LOCAL

PARTNERSHIPS

HAZARD

MITIGATION PLANS

EVENT USACE Disaster Preparedness &

 Levee Safety Programs

FEMA Preparedness Programs

USACE Emergency

Response Program

& Reservoir Operations

FEMA NRF

Response Activities

USACE Rehabilitation Assistance Program

FEMA Mitigation, PA, & IA Programs

Federal Recovery Programs

USACE FPMS,

Silver Jackets,

& PAS Programs

FEMA Mitigation

Programs

NRCS Conservation

Easements

far left: Post-flood cracking of the concrete at the Bato

Rouge waterfront. left: The same shot after stabilization

with rock.

Coming up with an immediate multi-billion dollar source of funding to fix a vulnerable system key to 

holding back Mississippi River floodwaters is, as one might expect, a tricky challenge. During and immediately following the flood, the Corps “self-funded” the 29 repairs deemed too critical to delay due to the 

high potential for loss of life during any future flood event. That essentially involved working closely with 

Corps districts nationwide, putting other projects on hold, to find $170 million for those critical repairs.

In December 2011, Congress authorized $802 million in supplemental funding for the Mississippi River & Tributaries System repairs. That, plus emergency supplemental funding for Operation 

& Maintenance and PL84-99 projects, allowed for another 118 critical repair projects to proceed, as 

well as 100 more deemed non-critical. 

Lesson Learned: The process of regional and national prioritization and self-funding proved to b

very challenging. Identifying where to draw the line for these initial projects required balancing the 

severity of the life safety risks with the level of funding that could be found within the Corps’ budgets. 

A significant effort was invested in explaining to stakeholders and the public why certain repair 

projects were funded and others would be put on hold until funding was available. Identifying and 

pulling existing Corps funding from other districts throughout the country was also difficult since it 

involved evaluating the financial status of thousands of projects. Transferring funds from other Corps 

projects also caused work stoppages, completion delays and other inefficiencies.

The funding scramble
ROOM FOR THE RIVER / 2011 POST-FLOOD S

28 29

RECOMMENDATIONS:  secure 

The Mississippi River & Tributaries System was, by any definition, highl

successful in passing the Great Flood of 2011. But while the system performed as

designed, the powerful flood both caused and revealed weaknesses and vulnerabilities in 

both the physical system and its operation. Multi-district Corps teams, organized by system

components, compiled and ranked post-flood evaluation recommendations intended as 

starting points for further analysis, refinement, prioritization and decision-making. Most of

the recommendations fall under one of these six overarching categories: 

• Use the information from the Post Flood Report to inform future MR&T Syste

The 2011 MR&T System performance, damage and risk assessment information develop

through the Post-Flood Report and other efforts should be used to help establish appropriate

repair processes. This includes efforts focused on improving levee resiliency, confirming level

of protection, sharing best practices, and developing system repair plans using risk-informed 

decision making. 

• Use the information from this report to guide completion of the MR&T S

Information from the Post-Flood Report effort should be used to aid in the completion of the

remaining 11 percent of the MR&T System not yet constructed. Information that would provid

insights into this include MR&T performance, changing river hydraulics, improved levee engineering, economics and associated risks, environmental and other stakeholder consideration

Moving toward a safe, secure river future.
30 31

•  Update Operation Plans/Manuals, Communications Plans, and Standard Operating Procedures using information from this report, external inputs, After Action

Use information developed through the Post-Flood Report effort, after action reviews, external

inputs, and further studies to inform the update and enhancement of MR&T operation an

flood fight plans/manuals, procedures and regionally standardized communication plans. These

efforts would focus on improving both internal and external MR&T–related operations during majo

flood events and would involve refinement of existing processes and utilization of new technologies. Sample efforts may include enhancing flood fight operations with newly developed tools and 

examining the potential need to update operations plans for key MR&T flood risk managemen

structures. 

• Regionally standardize communication approach and products with MR&T System floodway

backwater area stakeholders

Use feedback from stakeholders, lessons learned, best practices and new technologies to develop 

regionally consistent communication approaches, tools and products to improve understanding, reduce impacts and improve collaboration during future floods. The Interagency Recovery Task For

offers great potential to make this a coordinated multi-agency effort. 

• Evaluate the need to conduct an updated flow line study for the MR&T Sy

Use 2011 hydraulic flood data and associated MR&T component performance to evaluate the nee

for an updated flow line study for the MR&T System. Physical and hydraulic changes in the rive

system and complex flow patterns at Morganza, Bonnet Carré, and Old River Control Comple

should be examined to determine if a change in flow line data or water control plans is warranted.

• Coordinate a regional “triage” effort to prioritize, refine and implement the recommendation

identified in the MR&T System Post Flood R

The next steps in advancing the preliminary MR&T recommendations in this report will utilize t

existing regional program management structure and process to further screen, combine, prioritize, 

refine and develop detailed scopes to implement recommendations. This process is vitally important

due to the need to establish coordinated MR&T improvements and regional priorities and becaus

there is limited funding available to accomplish these tasks.

A resource-rich floo

The value of the Mississippi River & Tributaries System lies in part in what it prot

• 7.2 million people in 139 counties and parishes over 

roughly 39,000 square miles., from Cairo, Ill. to the Gulf

• Some 3.1 million homes, ranging in median value from

$46,000 in Quitman County, Miss., to $203,000 i

Plaquemines and St. Tammany parishes in Louisia

• Farms with an average size of 380 acres in 2007 and total

annual product value of $10.2 billion.

• Industrial infrastructure, including oil refineries, and a 

massive navigation industry that carries key resources to 

export markets.

• The largest river wetland in North America, the 500,0

acre Atchafalaya River Basin, and 40 percent of t

nation’s coastal wetlands.

• Key threatened or endangered species including the 

Louisiana black bear, the Interior least tern and the pallid

sturgeon as well as birds using this nationally significant 

migratory waterfowl corridor. 

•  drinking water supply for 1.5 million people

•  source of income and recreation, some of it based on

the 150 species of freshwater fish, increasing in abundance toward coastal estuaries—mixed fresh and sea 

water areas prized for shrimp and oysters.

• Archaeological sites, dating from post-glacial to prehistoric Mississippian cultures, and important 19th-centu

plantation and Civil War site

ROOM FOR THE RIVER / 2011 POST-FLOOD Sumary REPORt  / 
ROOM FOR THE RIVER / 2011 P

-SummaryPt

32

FUTURE: Plng hard-learned leson

In economic terms alone, the Mississippi River & Tributaries 

System is a success—one of the most successful flood risk 

reduction systems in the world. In pure economic terms, the Mississippi River 

Tributaries System is a success—one of

the most successful flood risk reduction systems in the world. In the 2011 flood alone, the system is 

credited with the prevention of $234 billion in flood damages. Since its inception, it has cumulatively 

prevented $612 billion, and that’s with an investment over the years of $14 billion. 

 “The return on taxpayer investment is an astonishing 44:1 ratio,” notedMaj. Gen. John Peabody,

who assumed command of the Corps’ Mississippi Valley Division fromMaj. Gen. Walsh, “more than

10 times better than the average project funded today.” Much of the success can be attributed to the wisdom of the Jadwin

Plan of the 1920s, its underlying “make room for the river” philosophy 

and the many improvements that followed. In addition to the property 

damage averted, not a single life was lost in the record flood of 2011.

But while the nation owes much to those who conceived, built and 

maintained the system, it is important to consider what this system needs 

to ensure successful performance for our children and future generations. This analysis of system performance and recommendations for future

study and development is a starting point toward getting there. Many of the report’s findings and recommendations help meet the

goals of the Mississippi River Commission’s 200-year working vision

for the Mississippi River watershed. Successful flood risk management

requires an intergenerational commitment and complements a national 

vision. The long-term intergenerational commitment must also balance

national security and comprehensive flood damage reduction with environmental sustainability and 

recreation, infrastructure and energy policy, water supply and water quality, and movement of agricul-

tural and manufacturing goods.

Post-flood reports have been prepared following other floods, some of them small, others major disas-

ters. This one can be of particular value because it tested the system and its components like no flood b-

fore it and also offered the chance to test innovative tools never before implemented, or on such a scale.

Delegations representing several of the world’s other major river systems have already traveled to the 

watershed, looking for ways to implement the components that protected so much life and property 

into their own flood risk reduction systems. The successful organizational structure created for the

post-flood recovery work is also serving as a national model for emergency flood and hurricane response 

operations. Old models were proven effective as well

The history of theMississippi River and attempts to tame it, however, show there’s no such thing as an

ultimate solution. Today’s river managers must adaptively and strategically integrate lessons learned into

their operational plans in a way that minimizes risk and enhances resiliency. Regular investments to operate, 

maintain, inspect, repair or enhance existing flood risk management structures will continue to be some 

of the most critical and challenging responsibilities by current and future generations. Prioritizing how, 

when and where to invest limited resources will require multidisciplinary and interagency collaboration and 

resource leveraging.

As Harvard Professor John Briscoe, director of theHarvard Water Security Initiative, wrote in a

recent analysis about Mississippi River management: “With every intervention in a hydrological system,

there are reactions to every action, and each generation has to learn how to respond to a new set of 

challenges while not jettisoning the benefits derived from prior actions.” Opportunities, as well, abound. The U.S. has the largest natural inland navigation system in th

world, with the water commerce system overlaid atop some of the most fertile and productive soils in 

the world. The secure inland port system can also accommodate more than double its current capacity.

This flood, as others, underscored the fact that there will always be risk in a floodplain, risk that’s

growing as those areas are further developed. We must not become complacent about those risks if we 

want to achieve the essence of that long-term vision: that all residents of the Mississippi River and its

tributaries experience unmatched security and quality of life.

Successful flood 

risk management 

requires an 

intergenerational 

commitment and 

complements a 

national vision. 

ReadingLi

The evolution of flood control on 

the Mississippi is a complex mix 

of cultural and political issues, 

weather pattern changes and tech-

nological advancements. 

Read more:

Upon Their Shoulders (2004) 

by Corps historian Charles 

A. Camillo and Matthew 

T. Pearcy details historic 

attempts to tame the river 

through the history of the 

Mississippi River Commission. 

Divine Providence (2012), also by 

Charles A. Camillo, includes 

the historian’s first-hand ob-

servations of the flood and of-

ten heart-wrenching decisions 

made by those fighting it. 

Rising Tide: The Great Mississippi 

Flood of 1927 and How it Changed 

America by John M. Barry (1998) 

explores how that flood not 

only inundated the homes of a 

million people but also ushered 

in new political regimes and 

transformed society.

Designing the Bayous: The Control 

of Water in the Atchafalaya 

Basin, 1800–1995 by Martin 

Reuss (1998), originally pub-

lished by the Corps, shows the 

integral link between the basin 

and flood control. 

America’s Great Watershed 

Initiative, bringing together 

diverse watershed interests 

to collaboratively manage the 

river for multiple uses, features 

papers by leading thinkers on 

water issues on its website. 

Man must not try

to restrict the

Mississippi River 

too much in 

extreme floods. The river will

break any plan 

which does this. 

It must have the 

room it needs.

—Edgar Jadwin
Fo  more in o 

USACE Mississippi Va

Division public affairs office

601-634-5760 or 601-634-7783

www.mvd.usace.army.mil

Click on Missions/Regional

Flood Risk Managemen