A Coastal Barrier Protecting the

Houston/Galveston Region from Hurricane Storm

Surge

Center for Texas Beaches and Shores

Texas A& M University at Galveston

The Ike Dike

The Houston/Galveston RegionIs home to about 2 Million people and

may double by 2050Galveston Bay provides valuable

ecosystem services and supports a vast petrochemical complex

Port of Houston alone generates over $117 Billion in economic activity annually

Is affected by a major storm about every 15 years

Full evacuations are increasing difficult for Hurricanes that quickly increase in intensity and/or change direction

On Sept. 13, Ike passed over Galveston IslandKilling over 80 peopleCausing $32 Billion dollars in damageDamaging sensitive ecosystems and

wildlife habitatsDevastating our vulnerable (poor,

elderly) populations much more than others

Had it hit farther west (more towards San Luis Pass)

its impacts would have been much more severe

Hundreds of lives lostMany more billions in damages

But Even with a “Favorable” Path

81,000 homes205,000 residents5,000 businesses99,000 jobs42 schools41 electrical substations131 wastewater treatment plants13 hospitals

Received a surge of 10 Feet or more

To date, surge reduction strategies have been local:

Circling DikesCoastal RevetmentsHardening of PropertiesRaising Individual Structures

But Each Approach has Limitations

A Better Strategy

Protect the entire Houston/Galveston Region including Galveston Bay from hurricane surge using a coastal barrier (the Ike Dike) similar to the Dutch Delta Works

Components of the Ike DikeExtension of the existing Galveston

Seawall out to the West End (San Luis Pass)

Covering a total distance of 18 milesAddition of a seawall on Bolivar

Peninsula from Bolivar roads to High Island Covering a total distance of 35 miles

Construction of inland “wrap-arounds” or extensions to the Dike at both ends

Construction of floodgates at Bolivar Roads, San Luis Pass, and on the Intracoastal Waterway

Galveston Island

Bolivar Peninsula

Bolivar Roads

San Luis Pass

Intracoastal WaterwayExisting Seawall

Proposed Galveston Bay Enclosure

The Dike protects all of GalvestonBay including ship channels

The Galveston GatesGalveston gates will be the costliest

component of the Ike Dike and its biggest tourist attraction

Must allow water circulation into the bay under normal conditions

But close quickly when a hurricane approaches to provide a 17ft higher-than-sea-level barrier across Bolivar Roads

Based on flood gates now operating near Rotterdam

Rotterdam Flood Gates protect a channel 1181 ft wide and 75 ft deep

Houston Ship Channel Specificationsmain channel dredged to project depth

of 45 feet and width of 530 feet; 35-foot wide transition slopes on

either side of the main channel, measuring 45 feet deep at their

innermost point, and 12 feet deep at their outermost point;

200-foot wide barge lanes outside of the transition slopes, measuring 12 feet deep; and,

width of the entire channel is 1000 feet

Bolivar Roads

Animation of the flood gates closing

When the gates have closed, they are flooded and drop down and seal the barrier.

Closed Flood Gates

Elsewhere - Can use other flood gate designs – Japanese example

San Luis Pass

Intracoastal Waterway

Rough CostsSeawall Extension:~$1,000,000,000

Bolivar Roads Floodgate:~$ 1,000,000,000

San Luis Pass Floodgate:~$ 50,000,000

Intracoastal Floodgates:~$ 100,000,000

Total Building Cost: ~$ 2,150,000,000

Additional costs will incur if purchase of land is required and there will always be inflation

Sand Re-Nourishment

Seawalls can cause beaches to lose sand

The Ike Dike Design should include a system to continually re-nourish the beach in front of the seawalls

The Ike DikeProvides Comprehensive Regional

Protection from Storm SurgeProtects Both Properties and

EcosystemsHelps Less Resilient Populations (Poor

and Elderly)Costs Much Less than a Single

Hurricane RecoveryAnd We Face Recurring (15 yr Interval)

HurricanesProtects Against Hurricanes that

Quickly Change Path or IntensityIs Less Costly and More

Environmentally Sound than Armoring the Entire Bay System

Center for Texas Beaches and Shores at

http://www.tamug.edu/ctbs/