Flood Management Experiences in the United States

January26, 2001

Santiago Chile

by

Jerome Delli Priscoli Ph.D.

What I Will Cover

1. Context and History

2. Current Situation and Trends

3. Institutional Coordination

4. Strategies for Food Plain Management

5. Aspects of Policy, Planning and Analytics

6. Overcoming Barriers and New Directions

Context • Federal System: state, local – resistance to Federal interference

– limited coordination on water

• Property rights– individualism

– free market, private ownership

• Resistance to land use planning– Flood management must integrate

land use

• Lingering culture of primary structural responses

• Tradition of helping the victims– reinforces discontinuity b/w

assistance vs.mitigation, prevention

What is Flood Plain Management?• …continuous decision making process that aims to achieve the

wise use of the Nation’s flood plain lands and waters• Simultaneously present, near future,long term • Balancing of relative costs - benefits and best mix structural

and non structural tools• Reducing risk through loss

reduction strategies and tools• Wise Use: …activities

compatible with natural

and human (life and property)

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 FlowNormal Channel FlowBase FloodBase Flood

RegulatoryFloodDatum

RegulatoryFloodDatum

Secondary FloodHazard Area

Secondary FloodHazard Area

(a)Primary FloodHazard Area

(a)Primary FloodHazard Area

Secondary FloodHazard Area

Secondary FloodHazard Area

Floodway

Fringe

Floodway

Fringe

FloodwayFloodway Floodway

Fringe

Floodway

Fringe

FreeboardFreeboard

Principles of Flood Plain Management in US

• Major Federal interest but basic responsibility with sate and local governments

• See flood plains in context of total community, regional and national planning and management

• Flood loss reduction seen in larger context of flood plain management - not an objective in itself

• Resource management often focus on resource which may not be entirely in flood plain.

• Benefits and costs interrelated impacts• Evaluation of alternative strategies

The Situation in the US• Over 150,000 square miles (94 million acres) or

7% of country prone to floods• Almost 10 million households and $390 billion

in property are at risk today• Rate of urban growth in flood plain twice the

rest of country• Average annual loss of life from floods stable• Average annual flood losses rising• Loss of natural flood storage continues• But damages have increased in real dollars and

disaster relief average $3 billion per year and uninsured losses are growing.

Situation (con.)• Unprotected development in the 100 yr. plain and

continued development just outside the 100 yr.. Plain.

• Those deciding to live and do business in flood plain not paying proportionate costs of the decisions

• Grants and other post flood assistance reduce incentives to take preventative measures.

• 20,000 communities in flood plains, 90% participate in NFIP but less then 20% of occupants buy insurance.

Trends• Movements to coastal communities, adjacent to lakes

and rivers

• Reduced ability to fund large capital measures those other measures such as codes, regulation increasing

• Rebalancing from structural to: local planning, regulations, zoning, multipurpose management

• NFIP a primary tool of management and increased litigation over local government failure to endorse flood plain ordinances

• New awareness on natural functions of wetlands and internalization of EQ values

• Balance between public and private rights shifting to: stronger pubic rights as pubic nuisances costs grow high Courts and legislatures evolving to reflect these concerns

Real Flood Damages 1903 - 1996 (Billions ‘95 $’s)

Figure 5Benefits of Federal Projects (Damages Prevented)

Accumulative Corps Expenditures (Principle plus O&M)

Bill ions of Dollars (Adjusted to 1999 using Construction Cost Index)

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Fiscal Year

Accumulative Benefits

Accumulative Expenditures

Annual Benefits

National Flood Damages Suffered

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Flood Plain Management US

• 18th and early 20th century Local problem and small scale structures

• Mid 20th century Federal role and large structures• Later 20 the century back to more local and

movement to mix small and large and non structural

• Can track approaches in language we have used:– 1800s flood prevention– early 1900s flood control– mid 1900s flood reduction– latter 1900s flood plain management

History (con.)• Flood Control Act of 1928: 1927 floods greatest disaster

in US history 700,000 homeless, $250 million in losses

– previous 200 yrs. locals spent $300 million in lower Miss

– In single 1928 act Congress authorizes $325 million - the greatest % of budget for water projects ever in US!

– Ellet view of structures comes back

– Benefit cost ratio introduced

– DOA to work upstream and the Corps down but no coordination mechanism put in place

– Between 1936 -1952 spent $11 billion for flood control projects and storage: single and mutli- purpose

– Idea was to build way out of the problem

1954 Watershed and Flood Prevention Act SCS of DOA

• 1940s to 1960’s Broadening views, U of Chicago,

History (con.)• 1953 first first major test by TVA land use and flood control

measures

• 1950’s, 60’s move for water resources coordination - WRC and River Basin Org.’s

• 1968 Flood Insurance Act

• 1976, 79, 86 and 94 National Program for Flood Plain Management revisions

• 1993 Upper Miss flood: Galloway Report and 1994 Revisions to President - 3 major recommendations;

– Full consideration to all possible alternatives, evacuation, warning, proofing, natural and artificial storage

– full weight to social economic and environmental values in analysis

– more non structural: to reduce vulnerability through use of flood plain management activities and programs

Institutional Coordination• Private Sector

• Local Communities

• States

• Federal Agencies

Multiple actors: owners, businesses, officials at all levels, farmers developers, etc.

Resource Protection

Flood Management

in U.S.

DisasterAssistance

Red Cross

Federal Emergency Management AgencyUS Army Corps of EngineersSoil conservation ServiceNational Weather ServiceUS Geological SurveyHousing and Urban DevelopmentSmall Business AdministrationEnvironmental Protection AgencyDepartment of EnergyForest ServiceEconomic Development CommissionDepartment of TransportationPubic Health ServiceBureau of ReclamationUS Fish and Wildlife ServiceBureau of Indian AffairsNational Ocean ServiceNational Park Service

Large Number of Actors Involved:

•No WRC or formal coordinator

•Federal Agencies

Cost Sharing Today• Evolves in Legis, of ‘36 ‘38, ‘41, ‘74, ‘86, ‘96• LERR & D needs identified: Value set and

credited to non Fed contribution.• Value of LERR & D and 5% cash added: if less

then 35% extra cash paid: if more then 50% non Fed is reimbursed.

• Non Feds pay 50% of separable navigation and recreational costs assigned to project

• Non Feds provide all LERRD’s and perform all related necessary relocations

Strategies and Tools for Flood Plain Management

Strategies and Tools for Flood Plain Management

• Modify Human Susceptibility to Flood Damage and Disruption

• Modify the Impact of Flooding on Individual and the Community

• Modify Flooding• Preserve and Restore the Natural Resources

Regulations• Increasing Focus Non Structural Measures:

– reduce or avoid flood damages without significant altering the nature or extent of flooding….

Modify Human Susceptibility to Flood Damage and Disruption

• Flood Plain Regulations (Codes and zoning)• Development and Redevelopment Policies• Disaster Preparedness• Disaster Assistance Flood Proofing, Flood

Forecasting and Warning System and Emergency plans– Problems linking evacuation

and warning

• Preservation of

Natural Resources

Elevating the StructureElevating the Structure

Utilities and electrical circuits moved aboveflood level

Utilities and electrical circuits moved aboveflood level

Wall openingsWall openings

Construction BarriersBerms, Levees and Floodwalls

Construction BarriersBerms, Levees and Floodwalls

Berm orLevee

Berm orLevee

Sump and pump forinternal drainage

Sump and pump forinternal drainage

One-way valveOne-way valve

SewerSewer

FloodwallFloodwall

Maximum ProtectionLevel is Three FeetMaximum ProtectionLevel is Three Feet

Dry Flood ProofingDry Flood Proofing

One-Way ValveOne-Way ValveSewerSewer

Closures for OpeningsClosures for Openings

Flood Proofed WallsFlood Proofed Walls

Wet Flood ProofingWet Flood Proofing

Opening to LetWater In

Opening to LetWater In

Furnace and UtilitiesRelocated

Furnace and UtilitiesRelocated

Appliances Moved or Wrappedin Waterproof Bags

Appliances Moved or Wrappedin Waterproof Bags

Preserve and Restore Natural Resources and Functions of Flood Plains

• Floodplain, wetland, Coastal Barrier regulations– Federal, State, Local, Reg’s, Zoning

• Development and Redevelopment Policies– land acquisition and open space, relocation,

restoration, habitat preservation, location of service utilities

• Information and Education• Tax adjustments• Administrative measures• Beach Nourishment

and Dune Building.

Modify Flooding• Dams and Reservoirs

• Dikes, Levees and Flood walls

• Channel Alterations

• High Flow Diversions

• Land Treatment

• On site Detention Shoreline protection

• Special Grasses

Modify the Impact of flooding• Information and education

• Flood Insurance

• Tax Adjustments

• Flood Emergency Measures

• Post Flood Recovery

Key Rules for NFIP• No residential living area below 1% flood level

• No non-residential development subject to damage by 1% flood

• No rebuilding below 1% if damage 50% or more of structures value

• Moving to actuarially based premiums or adjust according to use of mitigation

• Insurance industry participation in WYO program to: bring expertise, spread coverage, improve service

•Measures must meet minimum FEMA and include: zoning, subdivisions, building requirements, special purpose ordinances, outreach, education, others

Policy, Planning and Analytic Approaches for Choosing Strategies and Tools

Analytic ApproachesBCA, Design StandardsHydrologic Analysis

Planning

Policy

Principles and Guidance forWater Resources Planners 1983

Uniform NFPM Prg. ’76,’79,’86,’94Exec Orders, Fed -State - Local Laws

Some Project Level Policies• Must look at without Project Condition• Flood Plain Management: avoid its dev. and focus

is on existing development• Use risk based analytical framework; expected

performance (no minimum) not levels of protection– can more small dams + more residual

• Reflect residual damages • Mitigation of induced flooding• Address minimum flow Evaluate EQ mitigation• No projects for single properties• Include steps of the NFIP: maps, etc.

Benefits Calculations• Urban

– Inundation Reduction Benefits

– Intensification Benefits

– Location Benefits

– Damages: Physical damages, Income loss, emergency costs

• Agriculture

– Damage Reduction

– Intensification

– Reduction in damage costs; erosion, sedimentation, inadequate water supply

– Value of increased production of crops

– Economic efficiency of increasing production of crops

NOT CREATING NEW FLOODWAY DEVELOPMENTBenefits cannot exceed the increased flood damage potential in comparing existing activity to the intensified/ changed activity

Delineate Affected Area

Determine Flood plain

Determine existing flood damages

Estimate otherflood related costs

Estimate futureflood damages

Forecast activitiesin affected area

Estimate potential land use

Allocate land use

Collect market value data

Compute benefits

Urban Flood Damage Benefit Evaluation

Problems/Analytical-Planning Impediments• BCA does not account

for EQ, Social and Distribution effects

• Project by project impedes systematic

• Poorest with most serious problems not participating

• Lower value of poor in flood plain provide less economic justification

• Exclude reduction in disaster recovery cost as benefit

• Does not include avoided damages as additional benefits

• Communities w/o vitality resist NSF

Benefits of Non Structural Measures

Stage

Dam

age

Flood Warning PreparednessMethods for Quantifying Benefits

“Ad Hoc Method”

Warning shifts stage-damage curve downward

Flood Warning Preparedness (“Day Curve”)

0 6 12 18 24 30 36 42 48

0

5

10

15

20

25

30

35

40

Red

uction in D

am

age

s (%)

Forecast Lead Time (in hours)

Policy Barriers to Non Structural• Full accounting of EQ and non monetary social impacts on

NSF is difficult

• Procedures used for BCR are based on certain assumptions that limit non-structural

• Emergency flood relief and recovery payments by Government (FEMA) create incentives against non structural

• FPM not being pursued in comprehensive fashion at all levels of government

• Those who live and work in flood zones not paying proportional cost of the decisions

• National policy on disaster response and assistance not aligned to management: actually still creating incentives for locating in flood plain.

Analytical Barriers to NSFC• Analytical: Benefit Cost Analysis BCA

– Assess aggregate and blind to distribution

– Perfect market conditions assumed

– Dealing with non-monetized impacts

– based on economic return thus may encourage investments in high risk areas

• Policy: Principles and Guidance P & G and Policy– NED maximization rule biased against EQ -Social Accounts

– Bias against broader non traditional benefits of NSF

– System not set up to recognize least cost alternative which may not be the best BCR

– Issue for Treasury is cash flow and policy does focus on minimizing tomorrow's losses

Overcoming Barriers: Policy Directions

• Sustainability

• Nonstructural

• Structural

• Agricultural Policies

• Coastal

• Data and Technology

• Risk

• Repetitive Losses

• Property Rights.

Sustainability• Move toward likely future conditions to

make risk analysis more realistic•Including disaster resiliency in community

planning: e.g. -FC measures flood resistant construction

storm water management- Community zoning subdivision regulations

Increase Use of Non structural Measures

• Buyouts (1993 flooding)

• Elevating buildings

• Buffer zones and Levee set backs

• Keep vacated land in pubic ownership

• Seeking permanent authority for NSFC

• National riparian zone policy

• Natural storage capacity

• Building codes - International building code

Increase Use of Non structural Measures

• New construction 1 - 3 feet of freeboard above base flood elevation

• Use confidence levels (90% -95%) for flood peak flows predictions

• No rise flood ways with no surface and velocity impacts

• Record waivers and disallow flood disaster assistance

Structural• Must integrate structures and NSFC measures in planning

• Use water shed or basin wide approach

• Estimate useful life of existing FC structures and dam safety

– 200 failures in last 10yrs

– 9,200 categorized as high hazard

– 35% not inspected since 1990

– Rehab estimate = over $1 billion

• New structures should be built to protect beyond the 1% to the 0.2% chance flood - avoid catastrophic floods

• Include failure zones of structures on flood hazard maps

• Increase incentives for dam safety program in states

Agricultural Policies• Crop losses often exceed urban losses: 1/2 all losses

• Examine prevalence of repeat areas of losses

• Need voluntary permanent Easements programs- deny subsidies-disaster payments if refuse

• Buffer zones: - Conservation Reserve- 150+ ft.

• Levees; stop rebuilding where cost is greater then land value - reduce Federal subsidy of 80% of costs

• Construct levees so no impact on height of 1% flood • Crop insurance programs can

encourage plant in flood plains: • 1999 payments largest in US history at $28 billion-they guarantee 50% of average yield 60%-65% of all losses paid in 1998

Coastal • Existing polices foster rather then discourage construction

on coasts despite 1982 Barriers act

• NFIP not working for coastal areas, need:

– integrate coastal areas into NFIP

– surcharge on areas subject to erosion

– setback requirements

• Shoreline erosion: shift from jetties, sea walls to beach nourishment

– expensive and need better cost sharing

– consider setbacks and acquisition strategies

– increase pubic access to improved beaches

Data and Technology• No one entity has responsibility for collecting and storing

data about floods, defining floods, or damage!!

• # of structures in flood hazard zone not known; need data on repetitive loss structures

• FEMA Improving methods for estimating flood damage

• Stream gauge network is shrinking

• New modeling that include unsteady flow conditions, levee breaches, split flows and unstable land forms a debris flow being developed.

• Design manuals updated to include alternatives to structures and bioengineering.

Risk • Need to improve risk communication:

– 100 yr. becomes 1% or high risk flood

– 500 yr. becomes 0.2% or moderate risk flood

• Movement to risk based may mean more structures and away from design to a minimum standard and more structures will be built and increased exposure.

• Structures at 1% flood risk has 25% chance of being flooded during its 30 yr. Mortgagee: a 1% chance that same structure will have a fire - yet almost all have fire insurance and less then 25% have flood insurance.

• Residual risk below structures: Maps need to keep failure zones after structures in place

Risk - Perceptions• Key to all is linking risk with behavior: active

choice/acceptance of risk versus passive being taken care of

• Engineers argued people felt more secure if see high levee or if see high earth dams versus stronger thin shell concrete

• Risk perception: People living on St. Andraes fault cannot understand how people can live in the Delta exposed to risk: Those in delta cannot understand those living on the fault line!

Property Rights• Willing seller scenarios is basis

– key is partnership among levels of gov.and people (eg. Charles River in 1970s)

• Denial to rebuild as abridgment of rights– eligibility criteria exists

• Restriction on right to flood fight as abridgment– subject to state and community reg.’s– subject to liability of impacts on others

• National EQ programs as taking– eg. Wetland permitting

Conclusions• Flood Management is Complex• We have much experience but still trying• We have moved from fear to control to prevention to

management and working with the floods• Structures and non structures must work together.• Changing behavior is critical.• Movement to: Active acceptance of risk and

responsibility vs. passive paternalism • The civic culture and civic infrastructure come together

in flood management: a learning ground for building Democratic civic culture.

Lessons for GWP• Flood management important part of IWRM - optimal use

but brings complexity– links land to water: upstream to downstream– is a public good (eg.defense) thus offers additional

revenue sources for IWRM projects– help negotiating benefits vs. allocating flows

• Need to link post event reaction policy to anticipation, damage prevention and mitigation policies

• Hard to get benefits to poor if BC analysis is based on property values

• Critical issue is risk and culture changes– communicating risk and reacting to warnings– active choosing risk versus passive acceptance links to

governance: building civic culture and democracy– From paternalism to informed consent

The Best Flood Proofing Measure …

Don’t Build in an Area that Floods.

The Best Flood Proofing Measure …

Don’t Build in an Area that Floods.