Bureau of Economic GeologyThe University of Texas at Austin

GEOTUBES ALONG THE UPPER COAST

Preliminary Observations

James Gibeaut

Coastal Coordination CouncilExecutive Committee Special Meeting

November 12, 2001

0 20 40 60 80 100 120 140 160 180kilometers alongshore

-10

0

10

-5

5

re

trea

t

m

/yr

adv

ance

Freeportjetties

Brazos River

San LuisPass end of

seawall

GalvestonSeawall

East Beach

West Beach

BolivarRoads

Rollover PassHigh

Island

Follets Island Galveston Island Bolivar Peninsula

Sabine Pass

Long-term Average Annual Rate of Shoreline Change

Geotube Schematic

Approx. 30 ft

Approx.7 ft

Installation Covered and vegetated

Exposed Maintenance

Treasure IslandJuly 19, 2001

Geotube LocationsJuly 2001

Rollover Pass

San Luis Pass

Gilchrist East 6,200 feet

Gilchrist East

Total = 6.32 miles

Gilchrist West

Gilchrist West 14,400

Dellanera

Dellanera 1,590

Pocket Park 2

Pocket Park 2 380

Riviera

Riviera 590

Pirates Beach

Pirates Beach 8,540

Treasure Island, North, Middle, South

Treasure Island 1,650

2001July

1997Nov

1998Pre-Frances

1998Post-Frances

2000May

LIDAR Topographic ImagesGilchrist East Geotube Area

Rollover Pass Gulf of Mexico

1,000 ft

Pirates Beach on Galveston IslandJune 14, 2001

Exposed Geotubes June 13, 2001

Project Exposed (ft) % Exposed

Gilchrist, East 1,670 27

Gilchrist, West 10,630 74

Dellanera 413 26

Pocket Park 2 0 0

Riviera 0 0

Pirates Beach 850 10

Treasure Isl. 960 58

Total 14,520 43

Beach ProfileGilchrist West (GLO-021)

-1

0

1

2

3

4

5

0 20 40 60 80 100 120

9/23/1999

6/13/2001

7/18/2001

Heightin

meters

Distance in meters

geotube

GLO-021 Profile Location

Sept. 23, 1999

June 13, 2001

GLO-21 Profile Location

July 18, 2001

Website

www.beg.utexas.edu/coastal/coastal01.htm