1 Floodplain Management 2050 Are Gilbert’s Adjustment Factors Sufficient? Larry A. Larson, P.E....
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Transcript of 1 Floodplain Management 2050 Are Gilbert’s Adjustment Factors Sufficient? Larry A. Larson, P.E....
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Floodplain Management 2050 Are Gilbert’s Adjustment
Factors Sufficient?
Larry A. Larson, P.E. CFMAssociation of State Floodplain Managers
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Overview
Early approaches to Flood losses The Foundation for change in last
60 yrs- Human Adjustments To Floods
Trends/drivers of change in 2050 Strategies to adapt in 2050 A Charge to Forum participants
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Early approaches to Flood losses
Engineering solutions
1850-Congress asked the Corps to study flood control on lower Miss. River
1917-$45 M for levees on Lower Miss. 1927 flood affected social change 1936 FCA—Federal lead in flood control Billions spent on structural works Damages continued to mount
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A Shift in Managing Floods
Engineering had some success, but long term losses continued and risk increased
Contributions to losses from external factors such as land use, population, etc
Gilbert’s dissertation suggests adjusting human behavior, not engineering nature
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Importance of White’s Work
Defined what was later called Floodplain Management
Introduced the human element Impact Responsibility Need to Adjust
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Human Adjustments to Floods Elevation Flood Abatement (Watershed management) Flood Protection (Structural flood control) Emergency Measures Structural Adjustments (adjustments to
buildings and infrastructure) Land Use Public Relief Insurance(Adapted from Gilbert F. White- 1942 Dissertation)
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Experiences of the last 60 years?
NFIP biggest added tool Quid pro quo flood insurance—land use Over 20,000 communities participate
by Regulating land use in floodplain Keeping floodways open Elevating structures in flood fringe
$1.2 billion/yr in reduced damage
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Experiences of the last 60 years?
Heavy top down approaches by federal agencies to “stop” flooding continued
Continued building structural projects
Spent over $35 billion on projects Dams, levees and channels
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Experiences of the last 60 years? Flooding Still Increasing-
More watershed runoff Loss of floodplain storage Floodwater transfer Current process looks at
Development in floodplain, but not impacts of all development in watershed (NAI)
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Results? Those living at risk pay part of the
cost of living at risk in flood hazard areas
Over 5 million flood insurance policies that help property owners recover
Structural projects cost shared But: Damages still increasing, albeit at a
slower rate
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Factors affecting human adjustment approaches
Population and development patterns Climate variation Human and Social factors Environmental/resource Economy and government budgets Institutional programs and policies Financial incentives/disincentives
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Population 100 Million more people by
2050 How does that impact:
Coastal zones? Failure zones of Levees and dams? Arid region Hazards? Natural and Beneficial resources in
hazard areas Infrastructure needs?
Transportation and water
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Housing Housing Trends
Condo and High Rise Development, thus increased density
Affordability- 40 year or longer mortgages Increased percentage of personal balance sheet In California, 50% of all mortgages are interest
only right now More risk for lending community and tax
payers
Increased
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Environmental Variables
Climate Change Where, When, How Much?
Environmental health of waters Improved?? Impacts on society
Aesthetics—quality of life Environment and Recreation Economic- Food Source
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Aging Infrastructure Including levees and dams
Repair? Replace? Remove? Who Pays?
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Federal Budgets
Can the Federal Budget Support Disaster Assistance? Projects? Flood Insurance Catastrophic Claim
Years? Natural Resource Restoration?
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Flood Damages in 2050 Prior to Katrina Flood damages
estimated at approximately $6 billion annually
By 2050 annual damages may exceed $10 billion annually- again ignoring Katrina—Cat event $200-400 billion
…Unless we change the current process to address future changes and needs
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Katrina questions and lessons
Adequacy of 100-year standard in high risk areas? Critical facilities?
Layered protection (e.g. levees with flood insurance and/or floodplain management requirements)?
Should many areas plan for gradual retreat from high risk areas? Coast?
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Current Policy Disconnects
Who benefits---who pays Development benefits go to locals
who control land use, but can externalize…
Costs of damage to federal taxpayers Disaster assistance—PA and IA Tax deductions for casualty loss Tax bailout of bankrupt programs
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Current Policy Disconnects
Public Safety v. 100 year flood Public sees:
100 year flood line as the “safe vs. not safe” line
Behind levee as safe v. not safe Primary function and duty of local
and states is public safety---Police and fire, but its also flood!
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Current Policy Disconnects
Risk communication Risk is probability times consequences
Buy down the risk with a variety of tools-elevate, insurance, levee, but
Still have residual risk Maps and insurance must convey the
gradation of risk, not all or nothing
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Institutional Roles
Federal-state-local In light of trends, can current heavy
federal top down approaches work? Who is best suited to do risk
communication, technical assistance, mapping, data collection, mitigation planning and implementation, etc
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Controlling Risk in 2050 Either by:
Control severity of flooding Control value of what is placed at risk
Personal risk vs. societal risk Who benefits---who pays?
Data—how will we get data to show the facts and make these decisions?
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Public Policy
“In effect, the national treasury bears a large part of the costs of those who prefer to live on floodplains, and does so without inquiring as to whether or not such plains afford any pronounced advantage for such occupance”
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Public Policy
“On the whole, present policy fosters an increasing dependence by individuals and local governments upon the federal government for leadership and financial support in dealing with flood problems”
…has it changed?
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Public Policy
How do we change bad public policy? Public outrage Political will
Information and education are key
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Which adjustments effective?
Gilbert said:“All possible adjustments except
those in land use and insurance tend to favor the preservation of existing land occupance” (in flood risk areas)
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Human Adjustments to Floods Elevation Flood Abatement (Watershed management) Flood Protection (Structural flood control) Emergency Measures Structural Adjustments (adjustments to
buildings and infrastructure) Land Use Public Relief Insurance(Adapted from Gilbert F. White- 1942 Dissertation)
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Does Future Demand Additional Adjustment
Factors?
If so, what might those factors be? What strategies will get us
prepared? What is success? How measure it?
Those in this room you have the experience, knowledge and ability to develop recommendations that will guide the nation next 45 years
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These two days at Forum
Listen Think Contribute Debate
Lets lay the foundation for that change in these two days
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Floodplain Management 2050
Larry Larson ASFPM
www.floods.org