Protect The Natural Dune Seawall, Our First Line of Defense Against Hurricanes Richard L. Watson,...

Protect The Natural Dune

Seawall, Our First Line of

Defense Against

Hurricanes

Richard L. Watson, Ph.D.

TexasCoastGeology.com

(361) 749-4152

A River of Sand,A River of Sand,Sand Movement in the Surf ZoneSand Movement in the Surf Zone

• 700,000 to 800,000 cuyd/yr

• 250 Dump Trucks Per Day

• One Dump Truck Every 6 Minutes


Sabine


Central Padre Convergence, AccretionCentral Padre Convergence, Accretion

con

verg

ence

From GLO

MANSFIELDMANSFIELD PASSPASS


San Luis Pass Ebb DeltaTexasCoastGeology.com

Packery Channel, 11/27/2005Packery Channel, 11/27/2005


Galveston East JettyGalveston East Jetty


Dredging Rates

From Bales and Holley, 1989

The Breakers,1906


The Breakers, 1994

The Breakers, 1995


The Breakers, 1998


Freeport Jetties, Surfside

Old Delta

Location

New Delta

Freeport Channel


Brazos River Delta

1935

1954

NEW OLD

New Brazos River Delta

San Bernard River


Old

Del

ta

The Octagon, 1969

From Surfriders website

The Octagon, 2000From Surfriders website

From Surfriders website

Surfside before H. Rita


Surfside Village, TX after RitaSurfside Village, TX after Rita


Surfside Village after RitaSurfside Village after Rita


Holly Beach before RitaHolly Beach before Rita


Holly Beach After RitaHolly Beach After Rita


Holly Beach, LA after RitaHolly Beach, LA after Rita


Dauphin I., AL after KatrinaDauphin I., AL after Katrina


1912 to 1978 Hurricanes1912 to 1978 Hurricanes

USACE Texas Coast Hurricane Study, Corpus

Christi Bay Study Segment, 1979


All Storms Since 1851All Storms Since 1851


Hurricane Carla Wind Field, 1961Hurricane Carla Wind Field, 1961

Miles O. Hayes, 1967


Hurricane Carla Surge, 1961Hurricane Carla Surge, 1961



Celia Surge Flood, Port Aransas USACE, GALVESTON DIST.


Port Aransas, Early 60sPort Aransas, Early 60s


Pre-Jetty Foredune RidgePre-Jetty Foredune Ridge


Beach and Dune SystemBeach and Dune System

Texas General Land Office (GLO)


Private land boundarySeaward limit structures

Weak Area Natural Dune SeawallWeak Area Natural Dune Seawall



Natural Dune Seawall BreachedNatural Dune Seawall Breached



Beulah Opens Corpus Christi Pass, 1967Beulah Opens Corpus Christi Pass, 1967


Temporary Bridge after Celia, 1970Temporary Bridge after Celia, 1970


Island Road after Allen, 1980Island Road after Allen, 1980


Storm Erosion of DunesStorm Erosion of Dunes



Dune Erosion by Carla, 1961Dune Erosion by Carla, 1961



Multiple Buggy Cuts, 1970Multiple Buggy Cuts, 1970


Protect the Dune Seawall, 1970Protect the Dune Seawall, 1970


Poor Beach Management, 2005Poor Beach Management, 2005


Pure Sand Graded from RoadPure Sand Graded from Road


Removing Dune SandRemoving Dune Sand


Lost to the Natural Dune SeawallLost to the Natural Dune Seawall


Port Aransas Beach Regulations


The City of Port Aransas shall prohibit The City of Port Aransas shall prohibit beach maintenance activities which will beach maintenance activities which will

result in the SIGNIFICANT result in the SIGNIFICANT REDISTRIBUTION of sand or which will REDISTRIBUTION of sand or which will

SIGNIFICANTLY ALTER THE BEACH SIGNIFICANTLY ALTER THE BEACH PROFILE.PROFILE.




The City of Port Aransas shall prohibit The City of Port Aransas shall prohibit beach maintenance activities unless beach maintenance activities unless

maintenance activities will not maintenance activities will not materially weaken dunes or dune materially weaken dunes or dune

vegetation or reduce the protective vegetation or reduce the protective functions of the dunes.functions of the dunes.


State Beach Regulations Add Further LimitationsState Beach Regulations Add Further Limitations

All sand moved or redistributed due to All sand moved or redistributed due to beach maintenance activities shall be beach maintenance activities shall be

returned to the area between the line of returned to the area between the line of vegetation and mean high tide.vegetation and mean high tide.


State Beach Regulations Add Further LimitationsState Beach Regulations Add Further Limitations

The General Land Office encourages The General Land Office encourages the removal of litter and other debris the removal of litter and other debris by handpicking or raking and strongly by handpicking or raking and strongly discourages the use of machines discourages the use of machines (except during peak visitation periods) (except during peak visitation periods) which disturb the natural balance of which disturb the natural balance of gains and losses in the sand budget gains and losses in the sand budget and the natural cycle of nutrients.and the natural cycle of nutrients.


Violation of Federal Regulations

Violation of Federal Regulations

The U.S. Army Corps of Engineers has The U.S. Army Corps of Engineers has requested that the City of Port Aransas requested that the City of Port Aransas cease dumping sand below the Mean cease dumping sand below the Mean High Water line. To do so, the City High Water line. To do so, the City needs a federal permit or it is in needs a federal permit or it is in violation of the Clean Water Act (CWA).violation of the Clean Water Act (CWA).


New Dune Ridge in 8 Years, 2005New Dune Ridge in 8 Years, 2005

High Dune, Wide Beach Best?High Dune, Wide Beach Best?High Dune, Wide Beach Best?High Dune, Wide Beach Best?

• Is a high dune and a wide beach the best protection?

• The most important part is the maximum volume, height and width of dunes.

• Hurricane surge will quickly cross any width beach and begin eroding the dunes.

• We MUST have the largest possible vegetated dune system to buy time for the storm to pass.

• Is a high dune and a wide beach the best protection?

• The most important part is the maximum volume, height and width of dunes.

• Hurricane surge will quickly cross any width beach and begin eroding the dunes.

• We MUST have the largest possible vegetated dune system to buy time for the storm to pass.

How Should We Manage the Beach?

How Should We Manage the Beach?

• Put a row of bollards in the center of the present road where the trash cans are now.

• Narrow the driving lane or move the present bollards seaward.

• This will maintain a pedestrian beach, a driving roadway, parking, and allow the dunes to grow.

• There is no downside. We maintain the full utility of the beach and get additional hurricane protection at no cost to the City

• Put a row of bollards in the center of the present road where the trash cans are now.

• Narrow the driving lane or move the present bollards seaward.

• This will maintain a pedestrian beach, a driving roadway, parking, and allow the dunes to grow.

• There is no downside. We maintain the full utility of the beach and get additional hurricane protection at no cost to the City


What about the future?What about the future?• Create a procedure to evaluate future needs,

including after a hurricane as well as after further dune growth.

• Require that the dunes be allowed to grow.• Create a permanent beach and dune

protection board staffed by local citizens and local scientists.

• Recognize that our beach is our most important tourist attraction and our dunes are our most important hurricane protection.

• Create a procedure to evaluate future needs, including after a hurricane as well as after further dune growth.

• Require that the dunes be allowed to grow.• Create a permanent beach and dune

protection board staffed by local citizens and local scientists.

• Recognize that our beach is our most important tourist attraction and our dunes are our most important hurricane protection.


Vegetated Coppice DuneVegetated Coppice Dune


Protect The Natural Dune Seawall, Our First Line of

Defense Against

Hurricanes

Richard L. Watson, Ph.D.


(361) 749-4152

•Our best storm Our best storm protection is a protection is a high and wide high and wide natural dune natural dune system.system.

•Let nature build it Let nature build it for us, it is free.for us, it is free.

•Our best storm Our best storm protection is a protection is a high and wide high and wide natural dune natural dune system.system.

•Let nature build it Let nature build it for us, it is free.for us, it is free.

Protect The Natural Dune Seawall, Our First Line of Defense Against Hurricanes Richard L. Watson,...

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