FM-S104b-Recent US Experiences and Lessons Learned -Gerald Galloway Jr

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Flood Risk Management:

Recent US Experiences and Lessons Learned

December 4-5, 2012

Manila

Gerald E. Galloway, Jr., PE, PhDWater Policy Collaborative, University of Maryland

[email protected]

Philippine

Flood Management Knowledge Sharing Forum

The views expressed in this paper are the views of the authors and do not necessarily reflect the views or

policies of the Asian Development Bank (ADB), or its Board of Directors, or the governments they represent.

ADB does not guarantee the accuracy of the data included in this paper and accepts no responsibility for any

consequences of their use. Terminology used may not necessarily be consistent with ADB official terms.



The Bottom Line – US Lessons Learned1. Absolute protection from floods is not possible - plan for

exceedence

2. Cannot not rely on single structural approach - implementa portfolio of measures

3. Risks must be identified and decisions made based onrelative risk –everyone will not get same protection

4. Decisions must be made with imperfect knowledge - thefuture will be different from the past

5. Responsibilities must be clear; must have clear leadershipbut all groups must share responsibilities and take localactions

6. Life-cycle infrastructure needs and costs must beaddressed at national and local level

7. Effective communication of risk is essential



Floods Have Been Part of North American History



And People Tried to Deal with the Flood Challenge



The Mississippi Basin Drains 41% of the

Contiguous United States

Mississippi River Basin3.1 million km2

32% of total US farm acreage

Ohio

Missouri

Mississippi

Mississippi RiverLength - 3730 km

Average flow – 12,700,000 m3/sMax Flow -85,000 m3/s



Levees Became the Way of Life – “Levees Only”



And More Recent US History A Major Flood Occurred in 1927

and Gained National Attention



The 12 Month Solution:Federal Project -Levees, Floodways, Storage,

River training, Dredging, Dikes, Dams

Mississippi River Commission in

Charge

Navigation, Flood Control,

Environmental protection



Miss aerial (memphis)

http://blogs.sacbee.com/photos/2011/05/high-water-pushes-past-memphis.html



Jeff Roberson/AP

http://blogs.sacbee.com/photos/2011/05/high-water-pushes-past-memphis.html



L O W E R M I S S I S S

I P P I R I V E R

A T C H

A F A L A Y A R I V E R

NEWORLEANS

BATON

ROUGE

NATCHEZ

VICKSBURG

GREENVILLE

ARKANSAS

CITY

MEMPHIS

CAIRO

HELENA

NEW MADRID

ST. LOUIS

1 , 2 5 0 , 0 0 0

1 , 0 6 0 , 0 0 0

1 , 5 0 0 , 0 0 0250,000

West

AtchafalayaFloodway

MorganzaFloodway

620,000

600,000

Old

River

250,000 1 , 5 0 0 , 0 0 0

2 , 8 9 0 , 0 0 0

540,000400,000

550,000

New Madrid

Floodway

100,000

U P P E R M I S S I S S I P P I

R I V E R

1 5 0 , 0 0 0 Project Design

Flood

LAKE

PONTCHARTRAIN

Bonnet Carré

Spillway

Lower Atchafalaya

Floodway

30 / 70 Split

Wax LakeOutlet

MORGANCITY

Plan: 85,000 cms

2011: 70,000 cms



Birds Point-New Madrid Area April 29, 2011



Birds Point-

New MadridFloodway

538 square km

impacted byfloodway

10,100 square kmprotected by

floodway

I

P j D i



L O W E R M I S S I S S

I P P I R I V E R

A T C H

A F A L A Y A R I V E R

NEWORLEANS

BATON

ROUGE

NATCHEZ

VICKSBURG

GREENVILLE

ARKANSAS

CITY

MEMPHIS

CAIRO

HELENA

NEW MADRID

ST. LOUIS

1 , 2 5 0 , 0 0 0

1 , 0 6 0 , 0 0 0

1 , 5 0 0 , 0 0 0250,000

West

AtchafalayaFloodway

MorganzaFloodway

620,000

600,000

Old

River

250,000 1 , 5 0 0 , 0 0 0

2 , 8 9 0 , 0 0 0

540,000400,000

550,000

New Madrid

Floodway

100,000

U P P E R M I S S I S S I P P I

R I V E R

1 5 0 , 0 0 0 Project Design

Flood

LAKE

PONTCHARTRAIN

Bonnet Carré

Spillway

Lower Atchafalaya

Floodway

30 / 70 Split

Wax LakeOutlet

MORGANCITY



(68,000 km2)

(26,300 km2)

(40,500 km2)



BUILDING STRONG ®

Lessons Learned

• The System performed as designed but work is needed to

repair, rebuild, complete and reinvest in the infrastructure

• The Nation avoided damages in the 2011 flood of morethan $50 billion

• The $13.9B invested in the System has prevented over $350 Billion in damages – a 34-1 return on investment

• 547,000 acres was used for floodways and backwater

storage. The issue of floodways and off-river storage ispolitically sensitive.

• Communications are critical



Missouri River Basin1.3 million km2

Missouri River3,767 km

Max flow 21,000 m3/s



10 Million acre

feet = 12,300

Million cubic

meters



= 73,800 MM3



Missouri River Basin - Annual Runoff above

Sioux City, Iowa

1881 Flood = Design Criteria

1 Maf = 1233 Mm3

1%/97.2%/97

.2%

1%



20,000 MM3



Lessons Learned



BUILDING STRONG ®

Lessons Learned• The Dam System performed as designed. It serves (8) multiple

purposes and therefore cannot capably handle the most extremeof flood events

• Passing a major flood is expensive. Funds are needed to repair,rebuild, and reinvest in the infrastructure

• Must organize around a common vision and with true purpose andacceptance of shared responsibility and clear governance

• There is a lack of public understanding of how floods are handledand personal responsibilities in handling

• Flood risk can be mitigated beyond creating more space in theexisting Dam System –designating floodways, establishing floodcorridor easements - structural and non-structural



http://www.nwd.usace.army.mil/docs/MRIndependentReviewPanel.pdf

Dam Operation Review

• Operators must follow manuals• Operators must try to meet

needs; early release may harm

future needs

• Operators must always protectstructures

• Do not see how significant

changes could be made without

longer term forecasting



Lessons Learned - Mississippi vs Missouri

• Governance:

• On the Mississippi, one agency (MRC) has primaryresponsibility for management of the flood and was able toexercise authority

• On the Missouri, the responsibilities are divided among

many agencies

• System• Since 1927, the Lower Mississippi River has been

addressed as a single funding unit with flexibility inoperation and integrated approach

• The Missouri operates for fiscal and politcal purposes as aseries of unconnected parts.



What is USA Doing to

Deal with Floods?



Katrina -2005 $120B Damages



Failed Levees



A willingnessto live withfloods

•Individual and small

communities adaptto the naturesrhythm.

A desire toutilise thefloodplain

•Fertile land in

floodplain is drainedfor food production.

•Permanentcommunities areestablished on thefloodplain.

A need tocontrol floods

•Large scalestructural

approaches areimplementedthrough organisedgovernance.

A need toreduce flooddamages

•A recognition that

engineering alonehas limitations.

•Effort is devoted toincreasing theresilience of communities shoulda flood occur.

A need tomanage risk

•A recognition thatnot all problems are

equal.•Risk management isseen as an effectiveand efficient meansto maximise thebenefit of limitedinvestment.

From Living with Floods to Flood Control toManaging Risk

From Sayers et al , 2012



Risk = f ( (p) Hazard * (p) Consequences))

Identify risks and make decisions based on relative risk –recognize not all will get the same protection

R d i Ri k• Absolute protection from floods



Reducing Risk

Building Codes

Risk Communication

Evacuation Plans

Insurance

Natural Storage

Non-Structural (Floodproofing, Elevation, etc)

Structural (Levees, Dams, Floodways)

ResidualRisk

LocalState, Local

Federal, State, Local

Federal, State, Local, Individual

IndividualFederal, State, Local



Zoning

Initial Risk

Identify risks and make decisions based on relative risk –recognize not all will get the same protection

Modified from USACE

R i s k

is not possible – must plan for exceedence (Residual Risk)

• Cannot rely on single structural

approach - implement aportfolio of measures



Recognise that decisions must be made with imperfectknowledge and that the future will be different from the past

49Climate Change and Development



Life-cycle Infrastructure Requires Support

160,000 KM of LeveesOverall Condition = D-Update Cost= $50B

84,000 Dams

Overall Condition = DUpdate Cost= $50B

Th B Li US L L d



The Bottom Line – US Lessons Learned1. Absolute protection from floods is not possible - plan for

exceedence

2. Cannot not rely on single structural approach - implementa portfolio of measures

3. Risks must be identified and decisions made based onrelative risk –everyone will not get same protection

4. Decisions must be made with imperfect knowledge - thefuture will be different from the past

5. Responsibilities must be clear; must have clear leadershipbut all groups must share responsibilities and take local

actions

6. Life-cycle infrastructure needs and costs must beaddressed at national and local level

7. Effective communication of risk is essential



The Memory of a

Flood Is Very Short

53



Thank YouThank You

for YourAttention

FM-S104b-Recent US Experiences and Lessons Learned -Gerald Galloway Jr

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