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History of Flood Management in the United States
Martin Reuss, Ph.D.U.S. Army Corps of Engineers,
Retired
Consulting [email protected]
The Constitution of the United States of America
Commerce Clause:. . . To Regulate Commerce With Foreign Nations, And Among The Several States And With The Indian Tribes;. . .
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General Survey Act---April 30, 1824
An Act to Improve the Navigation of the Ohio and
Mississippi Rivers---May 24, 1824
What is a Navigable River?
Those waters must be regarded as public navigable rivers in law which are navigable in fact. And they are navigable in fact when they are used, or are susceptible of being used, in their ordinary condition, as highways for commerce over which trade and travel are or may be conducted in the customary modes of travel and travel on water.
---The Daniel Ball (1870)
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Mississippi River Commission1879
MRC president and two other members from the Corps of EngineersOne member from Coast and Geodetic SurveyThree civilians, two of whom had to civil engineers
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Flood Control Act of 1917
---applied only to the Mississippi and Sacramento rivers
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Flood Control Act of 1928---rejected “levees only” policy
---large scale flood relief for lower Mississippi Valley
---also some funds for Sacramento River flood control
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Flood Control Act of 1936
---established a federal responsibility for nationwide flood control
---established benefit-cost analysis as basic tool for evaluating proposed
projects
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“ABC Requirements”
n Provide without cost to the United States lands, easements, and rights-of-way
n Hold and save the United States free from damages due to the construction works
n Maintain and operate all the works after completion
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Flood Control Act of 1944
---established right of states to review federal water plans
---authorized recreation facilities
---prescribed primacy of “beneficial consumptive use” for federal projects west
of 98th meridian
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Total Dams in the United States---over 75,000
Dams Owned by the Federal Government
---less than 5%
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Federal Expenditures for Flood Control
1856-1936: $400 million1936-1952: $3.5 billion (about
100 Projects)To late 1970s: $13 billion (Grand
Total)
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21
0
10
20
30
40
50
60
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
FLOOD DAMAGES SUFFERED FLOOD DAMAGES PREVENTED
POTENTIAL FLOOD DAMAGES
Bill
ion
s o
f Do
llars
10-Year Average = 27.3 26.8
16.2
54.4
28.431.9
18.2
48.6
8.8
19.219.2
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DAMAGES PREVENTED
17.6 17.5
8.1
32.3
17.1
26.8 22.3
45.5
13.4
21.2
05
101520253035404550
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
Bill
ion
s o
f Do
llars
10-Year Average = 22.3
Flood Damages Prevented in the U.S.A. by the U.S. Army Corps of Engineers
Flood Related Lives Lost
125
58
87
109
70
103
131
98 102 105
0
20
40
60
80
100
120
140
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
10-Year Average =99
Liv
es L
ost
Fiscal Year
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Real Flood Damages 1903 - 1996 (Billions ‘95 $’s)
The Situation in the USn Over 150,000 square miles (94 million acres)
or 7% of country prone to floodsn Almost 10 million households and $390 billion
in property are at risk todayn Rate of urban growth in flood plain twice the
rest of countryn Average annual loss of life from floods stablen Average annual flood losses risingn Loss of natural flood storage continuesn But damages have increased in real dollars and
disaster relief average $3 billion per year and uninsured losses are growing.
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Future Flood Control & Protection Considerations
August 19, 2008
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Why Care about the future?
What is a flood?
Principles of Flood Plain Management
USACE Flood Damage Reduction Considerations
How flood control and disasters impact Public WorksExamples
Barriers
Trends
Strategies and Tools for Flood Plain Management
Agenda
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What we do on the land affects the water!Recognize and address barriersRe-think design standards and methods
Human health and safetyLevel of riskAccountabilityHaphazard and un-coordinated flood protection system
Why care about future flood control and protection?
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What is a Flood?Defining a Flood...100 year flood, 1% annual chance flood or base flood, a flood of size that has a 1% chance of being equaled or exceeded in any given year. (Properties beyond 1% flood area still at risk)
Normal Channel FlowBase Flood
RegulatoryFloodDatum
Secondary FloodHazard Area
(a)Primary FloodHazard Area
Secondary FloodHazard Area
FloodwayFringe
Floodway FloodwayFringe
Freeboard
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What is Floodplain Management?
…continuous decision making process that aims to achieve the wise use of the Nation’s flood plain lands and watersSimultaneously present, near future, long term Balancing of relative costs - benefits and best mix structural and non structural toolsReducing risk through loss reduction strategies and toolsWise Use: …activities compatible with naturaland human (life & property)
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Principles of US Floodplain ManagementMajor federal interest but basic responsibility
with state and local governmentsSee floodplains in context of total community,
regional and national planning and management
Flood loss reduction seen in larger context of floodplain management - not an objective in itself; integrated water resources management
Resource management often focuses on resources that extend beyond the floodplain.
Evaluate alternative strategies
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USACE Flood Damage Reduction Considerations
Local DrainageHistorical ReductionReasonableness of DamagesFuture DevelopmentResidual RisksBenefits During ConstructionInduced FloodingRecreationMitigation vs. Restoration
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Land Use decisionsStructural development and infrastructureEmergency response, evacuation plans, disaster response – displaced residentsBuilding codesEarly warning systemsChanges in state and federal regulations
Flood insurance - Changes and updates to flood plain mappingDam Safety (also addresses impoundments, dikes surrounding facilities such as POTWs, PW yards and operations centers)Municipal stormwater management facilities – MS4 Program
Application of design requirementsConcern for rising water levels in low-lying areas (Global warming)
How flood control and disasters impact Public Works
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FEMA Tracking of Displaced Residents
Louisiana
Mississippi
AlabamaCirca May
2006
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Building Codes
Bayou La Batre, AL May 2006
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Bayou La Batre, AL - Coastal devastation…
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Bayou La Batre, AL - Coastal devastation…
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Post-Katrina:Updated building code requirementNew construction first floor occupied level 16-feet above MSL (Katrina storm surge – 16-feet @ Bayou La Batre)Previously established at ~11-feet above MSLDoesn’t protect pre-existing properties
Trends Continuing to Impact PW – Mobile County, Alabama
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USACE Levee Safety Certification/De-certification (Wednesday’s StormwaterSummit at Congress)
Previous FIRM Mapping missed some PW facilities
Changes in dam safety law - Virginia Increased inundation zone analysisExtended and applied to stormwatermanagement facilities
Trends Continuing to Impact PW
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Water Surface
Anatomy of a Levee
Water-side Berm
Levee Crown
Land-side Berm
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August 29, 200580% of City inundatedConfirmed fatalities – 1,118More than 400,000 residents fled CityEducational and healthcare systems are crippled, recovering50 levees breached, most failed due to over-topping & erosionAugust 29, 2005
Peak water level estimated at 1.7-feet over the top of floodwalls
New Orleans - Katrina
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Basically two types:Traditional levee (43 over-topping & erosion)Levee with I-wall (7 failures)
Flawed design:Low factor of safetyInappropriate interpretation and application of geotechnical dataSPH (101 – 111 mph) versus PMH (NWS 151 mph) meteorological parameters (wind speed)
Katrina maximum recorded wind speed – 161 mphPiecemeal levee system constructionDifferent vertical datum - some floodwalls were 1.7-feet lower than other areas
New Orleans – Levee Breaches
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17th Street Canal
0 ftLevee Fill-2 ft Marsh
Soft Clay
Sand
+5 ft
+12 ft
+7 ft
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London Avenue Canal
Levee FillMarsh
Sand
Top of I-wall
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London Avenue Canal
Levee FillMarsh
Sand
Top of I-wall
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Pumping stations collect storm runoff, were not in those areas where levee breaches occurredOperators in Jefferson & St. Bernard parishes were evacuatedStations lost power, suffered significant damageUnintended reverse flows occurred through pumps, adding to flooding
New Orleans – Storm Pump Stations
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Plant site
Berms
Crown
To waterway
Original Height
Proposed Height
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Virginia Dam Safety Regulations
Most Probable Flood Analysis
Dam Breach Analysis
Emergency Action Plans (EAPs) need to be modified
May be applied to stormwatermanagement facilities
Inundation Zone Analysis – Most Probable Flood Elevation
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Auxiliary Spillway Analysis
400
410
420
430
440
Valley Floor
SC1
SC2SC3SC4
0 100 200 300 400Distance, feet
Elev
atio
n, f
eet
Aux. Spillway Erosion
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Constructed Flood Control FacilitiesVirginia Flood Control Facilities may be subjected to Dam Breach AnalysisTrickle-down effect on smaller regional stormwatermanagement facilities
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Non-Structural BarriersAssessing environmental quality and intangible social benefits is difficultProcedures used for benefit/cost analysis are based on certain assumptions that limit non-structural Emergency flood relief and recovery payments by Government create incentives against non structuralFloodplain management not being pursued in comprehensive fashion at all levels of governmentThose who live and work in flood zones not paying proportional cost of the decisionsNational policy on disaster response and assistance not aligned to management: in some cases incentives still exist for locating in flood plain.
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Barriers (cont.)
Unprotected development in the 100-year flood plain and continued development just outside the 100-year plain.Those deciding to live and do business in flood plain not paying proportionate costs of the decisionsGrants and other post flood assistance reduce incentives to develop preventive program.20,000 communities in flood plains, 90% participate in national flood insurance program, but less then 20% of occupants buy insurance.
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BarriersFederal System: state, local
resistance to Federal interferencelimited coordination on water
Property rightsindividualismfree market, private ownership
Resistance to land use planningFlood management must integrate land use
Lingering culture of primary structural responsesTradition of helping the victims
assistance vs.mitigation, prevention
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TrendsMovements to coastal communities, adjacent to lakes and rivers
Reduced ability to fund large capital measures. Increased scrutiny, enhancing codes, regulations, zoning, and multipurpose management
Flood insurance a primary management tool. Increased litigation over local government failure to endorse flood plain ordinances.
Application of probable maximum hurricane (MPH) instead of standard project hurricane (SPH). Katrina levee breaching in New Orleans is example.
New awareness of natural functions of wetlands and of environmental quality values
Balance between public and private rights shifting in favor of stronger public rights as public nuisance costs grow
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Strategies and Tools for Flood andFloodplain Management
Modify Human Susceptibility to Flood Damage and DisruptionModify the Impact of Flooding on Individual and the CommunityPay attention to structural factor of safety, geotechnical dataPreserve and Restore the Natural Resources Regulations, comply with RPAsIncreased Ratcheting Down on StormwaterManagement Facilities
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Conclusions
Flood Management & Control is ComplexWe have much experience but still tryingWe have moved from attempts to control to attempts to manage floodsStructural and non-structural measures must work together.Changing behavior is critical.We must acknowledge and accept risk.The civic culture and civic infrastructure come together in flood management: a learning ground for building democratic civic culture.
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ASCE June 2007 Civil Engineering Journal The ERP Report – What Went Wrong And Why, Hurricane Katrina External Review PanelAvailable for purchase: [email protected]
USACE - Planning Community Of Practice-policy Review Conference, May 2006
Acknowledgments
Contact:
Ken Eyre, P.E.Greeley and Hansen6564 Loisdale Court – Suite 100Springfield, VA 22150703.922.7302e-mail: keyre@greeley-
hansen.com
