2/20/2017

1

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

2/20/2017

2

INSURED FLOOD LOSS, 1972-2015

2/20/2017

3

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.

2/20/2017

4

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)

2/20/2017

5

PROPERTY VALUE (2010)POPULATION DENSITY

SOCIAL VULNERABILITY INDEX (1980) SOCIAL VULNERABILITY INDEX (1990)

2/20/2017

6

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

lio

ns

of

21

01

2 U

.S.

Do

lla

rs

SFHA-OUT V Zone A Zone

2/20/2017

7

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

2/20/2017

8

INSURED FLOOD CLAIMS, 1972-2014 INSURED FLOOD CLAIMS BY YEAR 1972-2013

CHANGING FLOODPLAIN BOUNDARIES CHANGING FLOODPLAIN BOUNDARIES

CHANGING FLOODPLAIN BOUNDARIES CHANGING FLOODPLAIN BOUNDARIES

2/20/2017

9

CHANGING FLOODPLAIN BOUNDARIES CHANGING FLOODPLAIN BOUNDARIES

CHANGING FLOODPLAIN BOUNDARIES FLOOD DAMAGE AND ELEVATION

Before

Ike

After

Ike

2/20/2017

10

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

2/20/2017

11

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

2/20/2017

12

• 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.

2/20/2017

13

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

2/20/2017

14

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

2/20/2017

15

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

2/20/2017

16

2/20/2017

17

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

2/20/2017

18

1978197819781978 INCREASING DEVELOPMENT 1989198919891989 INCREASING DEVELOPMENT

1995199519951995

1995199519951995 INCREASING DEVELOPMENT 2005200520052005 INCREASING DEVELOPMENT

2010201020102010 INCREASING DEVELOPMENT FLOODPLAIN ENCROACHMENT

2/20/2017

19

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

2/20/2017

20

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

2/20/2017

21

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

2/20/2017

22

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

2/20/2017

23

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

2/20/2017

24

RESIDENTIAL CONNECTION OPTIONS RESIDENTIAL CONNECTION OPTIONS

PATH OF SYNTHETIC STORM

2/20/2017

25

FLOOD LOSS REDUCTION FROM PER STORM SCENARIO($, MILLION)

2/20/2017

26

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

www.tamug.edu/CTBS