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RISING WATERSCAUSES, CONSEQUENCES & POLICY IMPLICATIONS FOR
FLOODING IN THE U.S.
Samuel D. BrodySamuel D. BrodySamuel D. BrodySamuel D. Brody
The Center for Texas Beaches and ShoresThe Center for Texas Beaches and ShoresThe Center for Texas Beaches and ShoresThe Center for Texas Beaches and Shores
Texas A&M UniversityTexas A&M UniversityTexas A&M UniversityTexas A&M University
CUMULATIVE FLOOD LOSS, 1972-2015
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INSURED FLOOD LOSS, 1972-2015
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The Houston-Galveston Region
U.S. INSURED FLOOD LOSSES: 1999 – 2009(MILLIONS OF 2012 U.S. DOLLARS)
$0
$5,000
$10,000
$15,000
$20,000
1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009
Mil
lio
ns
of
21
01
2 U
.S.
Do
lla
rs
SFHA-OUT V Zone A Zone Mean $3,053.05
Median $928.98
Mean-2005 $1,299.76
THE HOUSTON-GALVESTON REGION
• 6 million population and growing6 million population and growing6 million population and growing6 million population and growing
• NationallyNationallyNationallyNationally----important population and economic important population and economic important population and economic important population and economic centercentercentercenter
• Supports the largest petrochemical complex in the Supports the largest petrochemical complex in the Supports the largest petrochemical complex in the Supports the largest petrochemical complex in the US (second largest in the world)US (second largest in the world)US (second largest in the world)US (second largest in the world)
• Port of Houston alone generates over $178 billion Port of Houston alone generates over $178 billion Port of Houston alone generates over $178 billion Port of Houston alone generates over $178 billion in economic activity annually in economic activity annually in economic activity annually in economic activity annually
• Galveston Bay provides valuable ecosystem Galveston Bay provides valuable ecosystem Galveston Bay provides valuable ecosystem Galveston Bay provides valuable ecosystem servicesservicesservicesservices
• Affected by a major storm about every 20 yearsAffected by a major storm about every 20 yearsAffected by a major storm about every 20 yearsAffected by a major storm about every 20 years
THE HOUSTON-GALVESTON REGION ECONOMIC IMPORTANCE: THREE MAJOR INDUSTRIES
• RefiningRefiningRefiningRefining
• PetrochemicalsPetrochemicalsPetrochemicalsPetrochemicals
• Natural gas processing Natural gas processing Natural gas processing Natural gas processing
→ 85% of Houston exports are → 85% of Houston exports are → 85% of Houston exports are → 85% of Houston exports are petroleum related.petroleum related.petroleum related.petroleum related.
→ → → → 4 4 4 4 ofofofof largest 8 ethylene complexes largest 8 ethylene complexes largest 8 ethylene complexes largest 8 ethylene complexes in world. in world. in world. in world.
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PETROCHEMICAL STORAGE FACILITIES
Company Plant location Capacity (million tpy)
Formosa Taiwan 2,935.0
Nova Alberta 2,811.7
Arabian Petrochem Saudi Arabia 2,250.0
Exxon Mobil Baytown 2,197.0
Chevron Phillips Sweeny 1,865.0
Dow Netherlands 1,800.0
Ineos Chocolate Bayou 1,752.0
Equistar Channelview 1,750.0
Yanbu Saudi Arabia 1,705.0
Equate Kuwait 1,650.0
Source: Oil and Gas Journal, 2013
ECONOMIC IMPORTANCE: 4 OF 8 LARGEST ETHYLENE COMPLEXES IN THE WORLD IN HOUSTON
HURRICANE SURGE ZONES & TRACKS 100-YEAR FLOODPLAIN BOUNDARIES
PHYSICAL FLOOD RISK COMPOSITE PROPERTY VALUE (2000)
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PROPERTY VALUE (2010)POPULATION DENSITY
SOCIAL VULNERABILITY INDEX (1980) SOCIAL VULNERABILITY INDEX (1990)
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SOCIAL VULNERABILITY INDEX (2000) SOCIAL VULNERABILITY INDEX (2005-2009)
PHYSICAL RISK + SOCIAL VULNERABILITY CLEAR LAKE & HOUSTON SHIP CHANNEL
CLEAR LAKE & HOUSTON SHIP CHANNEL TEXAS INSURED LOSSES: 1999 – 2009(MILLIONS OF 2012 U.S. DOLLARS)
$0
$500
$1,000
$1,500
$2,000
$2,500
1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009
Mil
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of
21
01
2 U
.S.
Do
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rs
SFHA-OUT V Zone A Zone
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CUMULATIVE FLOOD LOSS IN TEXAS The Houston-Galveston RegionINSURED PROPERTY DAMAGE IN
COSTAL TEXAS, 1996-2007
INSURED PROPERTY DAMAGE BY
COASTAL ZIP CODES, 2006-2007
Before
Ike
After
Ike
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INSURED FLOOD CLAIMS, 1972-2014 INSURED FLOOD CLAIMS BY YEAR 1972-2013
CHANGING FLOODPLAIN BOUNDARIES CHANGING FLOODPLAIN BOUNDARIES
CHANGING FLOODPLAIN BOUNDARIES CHANGING FLOODPLAIN BOUNDARIES
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CHANGING FLOODPLAIN BOUNDARIES CHANGING FLOODPLAIN BOUNDARIES
CHANGING FLOODPLAIN BOUNDARIES FLOOD DAMAGE AND ELEVATION
Before
Ike
After
Ike
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Upstream Wetland Alteration in the Floodplain
Jamie Padgett, 2015
HURRICANESFLOODING RISK
Ike 2008 84
Rita 2005 59
Allison 2001 23
Alicia 1983 13
Charley 1998 13
Erin 2007 9
Allen 1980 7
Eight 1981 5
Norma 1981 5
Hermine 2010 5
Bonnie 1986 4
Bret 1999 4
Allison 1989 3
Jerry 1989 3
Chantal 1989 2
Danielle 1980 1
Arlene 1993 1
Claudette 2003 1
Humberto 2007 1
BolivarBolivarBolivarBolivarHURRICANES CAUSING KNOWN DEATH IN TEXAS
MAJOR TRIGGERS OF
FLOOD LOSS
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GALVESTON BAY SEA LEVEL RISE
LAND USE CHANGEHOUSTON AREA 1996 LAND COVER
Source: National Oceanic and Atmospheric Administration
LAND USE CHANGEHOUSTON AREA DEVELOPMENT CHANGE 2011
Source: National Oceanic and Atmospheric Administration
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• HGAC = 14,000 sq miles
� About 25% (233 sq miles/year)
was converted to development in
15 years
• Growth of about 2 million people
� Projected to grow by 3.7 million
more over the next 30 years
NET CHANGE BETWEEN 1996 AND 2011 HIGH-INTENSITY DEVELOPMENT PATTERN
LOW-INTENSITY DEVELOPMENT PATTERN
Source: Houston-Galveston Area Council, 2011
LAND USE CHANGE FORECAST(2035)
IMPACT OF DEVELOPMENT PATTERNS
• Efficacy of well-defined urban cores in reducing loss.
• Added square mile of high-intensity development
decreases losses by approximately $9.7 million.
• Outwardly expanding, low-density development patterns
can amplify flooding.
• Added square mile of low-intensity development
increases flood damage by $5.7 million.
• Harris County has 227 square miles.
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CHARACTERISTICS OF FLOOD LOSS
o Total loss (1999-2009) = $356 million (9,800 claims)
o Average claim = $36,585
o 43% from Hurricane Ike
o 55% claims outside floodplain (40% of damage)
o Average distance from boundary = 1,378 ft
o Average distance from stream = 3,178 ft
o Losses from Ike significantly closer
o Average distance from coastline = 30,177 ft
o Losses from Ike closer; Allison further inland
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IMPORTANCE OF PROXIMITY
• Properties further away from floodplain experience less damage
• 1 foot = $23.20 decrease in reported damage
…BUT…
• Living a quarter mile outside the floodplain still leaves an
expected loss of $12,972$12,972$12,972$12,972.
LAND USE - LAND COVER RESULTS
• Sprawling, low intensity development with 21-49% impervious
surface significantly increases flood loss.
• Percent increase adds $1,734 in property damage.
• Embedded open space land use significantly reduces flood losses.
• Surrounding forest and grass cover reduces flood loss.
• Palustrine wetlands strong predictor of flood loss reduction.
Houston
Beaumont
Corpus Christi
SECTION 404
PERMITS:
1991 - 2003
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WETLAND LOSS IN THE CLEAR CREEK WATERSHED
PREDICTING FUTURE
CONDITIONS
Water
Developed
Barren
Forest
Grassland
Ag/Pasture
Wetland
° 0 20 40 60 8010
Miles
Texas
HGAC Projected Development: 2025
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Development 2016 - SE Houston, TX
2016
Development 2063- SE Houston, TX
Development 2016 - NW Houston, TX Development 2016 - NW Houston, TX
INCREASING DEVELOPMENT INCREASING DEVELOPMENT 1969196919691969
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1978197819781978 INCREASING DEVELOPMENT 1989198919891989 INCREASING DEVELOPMENT
1995199519951995
1995199519951995 INCREASING DEVELOPMENT 2005200520052005 INCREASING DEVELOPMENT
2010201020102010 INCREASING DEVELOPMENT FLOODPLAIN ENCROACHMENT
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WHAT WORKS:
THE COST SAVINGS OF
FLOOD MITIGATION TECHNIQUES
AVOIDANCEVERTICAL AVOIDANCE, ELEVATED STRUCTURES
AVOIDANCEVERTICAL AVOIDANCE, ELEVATED STRUCTURES
AVOIDANCEVERTICAL AVOIDANCE, ELEVATED STRUCTURES
AVOIDANCEVERTICAL AVOIDANCE, ELEVATED STRUCTURES
AVOIDANCEVERTICAL AVOIDANCE, ELEVATED STRUCTURES
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AVOIDANCEVERTICAL AVOIDANCE, ELEVATED STRUCTURES
NATIONAL FINDINGS - FREEBOARD
• The dollar savings of a one-point increase in the
Freeboard element is equivalent to, on average,
$10,114 per community per year.
• Based on average amount of points accrued for
Freeboard, the total savings per year is equivalent to,
on average, $960, 817.
AVOIDANCEHORIZONTAL AVOIDANCE, OPEN SPACE PROTECTION
AVOIDANCEHORIZONTAL AVOIDANCE, OPEN SPACE PROTECTION
AVOIDANCEHORIZONTAL AVOIDANCE, OPEN SPACE PROTECTION
AVOIDANCEHORIZONTAL AVOIDANCE, SETBACKS AND BUFFERS
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AVOIDANCEHORIZONTAL AVOIDANCE, SETBACKS AND BUFFERS
AVOIDANCEHORIZONTAL AVOIDANCE, SETBACKS AND BUFFERS
NATIONAL FINDINGS – OPEN SPACE
• The dollar savings of a one-point increase in activity
420 is equivalent to, on average, $3,147 per
community per year.
• Based on average amount of points accrued for open
space protection, the total savings per year for this
activity is equivalent to, on average, $547,497.
Estimated Average Reduction in Damages
Mitigation Strategy Flood Damage Savings
Specific Policy in Plan $324,772
Protected Areas $298,965
Construction Codes $277,541
Land Development Codes $276,567
Setbacks and Buffers $199,148
Structural Mitigation Strategies
Mitigation Strategy Flood Damage (2006-2007)*
Overall Index -.078
Retention/Detention -.150*
Levees .156
Channelization .062
Dams -.072
Debris clearing -.105
*Logged per capita
Non-Structural Mitigation Strategies
Mitigation Strategy Flood Damage (2006-2007)*
Overall Index -.271**
Standalone Flood plans .078
Zoning & Land Use Restriction -.189**
Setbacks and Buffers -.273**
Protected Areas -.346**
Land Acquisition -.159*
Education Programs -.099
Training/Technical Assistance .039
*Logged per capita
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Non-Structural Mitigation Strategies
Mitigation Strategy Flood Damage (2006-2007)*
Intergovernmental Agreements .121
Referendums -.042
Computer Modeling -.118
Community Block Grants -.044
Construction Codes -.272**
Specific Policy in Plan -.379**
Land Development Codes -.316**
*Logged per capita
ActivityMitigation
Activity
Mean
Points
Maximum
PossiblePer Point
Total Mean
Savings
320 Map Information 124 140 -$140 -$13,622
330 Outreach Projects 110 315 -$164 -$13,972
340 Hazard Disclosure 12 81 -$324 -$3,737
350 Flood Protection Info. 32 66 -$873 -$18,933
360
Flood Protection
Assistance 33 71 -$290 -$8,386
410 Floodplain Mapping 29 1373 -$518 -$12,299
420 Open Space Protection 106 900 -$68 -$6,524
430 Elevation above BFE 259 2720 -$130 -$21,358
440 Flood Data Maint. 90 231 -$331 -$19,895
450
Storm water
Management 69 670 -$157 -$9,270
510 Floodplain Planning 64 309 -$273 -$13,622
520 Acquisition/Relocation 317 3200 -$24 -$6,788
540 Drainage System Maint. 216 330 -$68 -$11,937
SAVINGS FROM MITIGATION ACTIVITIES DUNE PROTECTION
RESISTANCEMULTI-FUNCTIONAL BARRIERS
COMPREHENSIVE DESIGN: MULTI-FUNCTIONAL BARRIERS
STRUCTURAL + NON-STRUCTURAL TECHNIQUES
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RESISTANCESINGLE-FUNCTIONAL BARRIERS
Coastal Spine
Bolivar Roads
Intracoastal Waterway
• San Luis Pass
Existing Seawall
High
Island
Houston Ship Channel
The Coastal Spine strategy is
to keep the ocean surge out of Galveston Bay by using
a gated coastal barrier
Bolivar Roads
Intracoastal Waterway
• San Luis Pass
Existing Seawall
High
Island
Houston Ship Channel
The first component of
the Ike Dike already exists –the Galveston Seawall
Bolivar Roads
Intracoastal Waterway
• San Luis Pass
Existing Seawall
High
Island
Houston Ship Channel
The second component –
Land Extensions of the protection afforded by the Seawall
Bolivar Roads
San Luis Pass
Existing Seawall
High
Island
Houston Ship Channel
The third component –
Flood Gates
Intracoastal Waterway
Passive Recreation Opportunities
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RESIDENTIAL CONNECTION OPTIONS RESIDENTIAL CONNECTION OPTIONS
PATH OF SYNTHETIC STORM
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FLOOD LOSS REDUCTION FROM PER STORM SCENARIO($, MILLION)
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LESSONS LEARNED FOR RESILIENCY
• Take a systems approach
• Plan for a multi-hazard setting
• Work with natural functions
• Avoidance preferred approach before new development in floodplain occurs
• Structural modifications effective with existing development
• Consider urban form and development patterns
• Move away from a recovery-based approach to management
• NFIP Insurance-Based Mitigation
• Accepting Failure
• Perverse Incentives
• Sprawling Development
• Stuck in Disaster-Recovery Cycle
• 100-Year Floodplain as Marker for Risk
• Rising Fiscal Debt
RECOVERY-BASED APPROACH TO MANAGEMENT
• Seeks to eliminate flood losses altogether
• Property damage considered failures in the system
• Incorporate contingencies if disaster occurs
• Avoidance balanced with resistance strategies
• Regional approach with local implementation
• Multi-functional solutions for flood mitigation
PROTECTION-BASED APPROACH TO MANAGEMENT
The overall strategy is to keep
the ocean surge out of
Galveston Bay by using a
coastal barrier (the Ike Dike)
Before
Ike
After
Ike
THANK YOU
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