1. Texas Tidal Inlets Project: Depositional Environments and Morphodynamics of San Luis Pass
James C. Gibeaut1, Tiffany L. Hepner1, Rachel Waldinger1, John R. Andrews1, Thomas A. Tremblay1, and Thomas Ravens2
1Bureau of Economic Geology
John A. and Katherine G. Jackson School of Geosciences
The University of Texas at Austin
2Texas A&M University Galveston
Texas Coastal Erosion Technical Conference 2003
Galveston, Texas

2. Location Map

3. 1995 Color Infrared

4. Tide and Wave Energy Patterns

5. Tide Versus Wave Energy

6. Project Goals
Provide environmental information for understanding the dynamics of San Luis Pass.
Facilitate the management of the San Luis Pass tidal inlet system while addressing coastal erosion issues.
Establish a framework for conducting studies and presenting data for management of other Texas inlets.

7. Project Components Environments map
Topography/bathymetry digital elevation model
Tidal flow measurements
Geomorphic change analysis
Compilation of historic processes such as storm events
Morphodynamic model
Data availability and public awareness

8. Wetlands Map

9. Project Components Environments map
Topography/bathymetry digital elevation model
Tidal flow measurements
Geomorphic change analysis
Compilation of historic processes such as storm events
Morphodynamic model
Data availability and public awareness

10. Topo/Bathy Data Sources (summer/fall 2002)
Wave runner echo-sounder for bathymetry
Wading profiles for swash/breaker zone
Lidar for topography

11. Bathymetry and Wading Survey Lines

12. Onshore-Offshore Profile

13. Topo/Bathy Model (preliminary)

14. Ebb-Tidal Delta Sand Storage (thickness)
Volume= 3.13 million cubic yards

15. Project Components Environments map
Topography/bathymetry digital elevation model
Tidal flow measurements
Geomorphic change analysis
Compilation of historic processes such as storm events
Morphodynamic model
Data availability and public awareness

16. Tide Gauge Locations

17. Tide Curves (June 2003)

18. Spring Tide Lag Times

19. Inlet Flow
Ebb Tide Prism= 1.33 million cubic feet

20. Tidal Prism – Ebb Tidal Delta Storage Relationship, Low-Energy Coast
Boca Grande, FL
Aransas Pass, TX
San Luis Pass
Midnight Pass, FL
After Walton and Adams, 1976

21. Project Components Environments map
Topography/bathymetry digital elevation model
Tidal flow measurements
Geomorphic change analysis
Compilation of historic processes such as storm events
Morphodynamic model
Data availability and public awareness

22. Historical Surveys and Rectified Photography
1995 Digital Orthophoto Quarter Quads Serve as Base Maps
USGS/Tx Orthophoto Program
Scanned color IR film, 1-m resolution
Meet 1:12,000 map accuracy standards (90% of test points within10 m)
Our tests show typically within 5 m

23. Changes in Cross-Section
Compiled from
Mason, 1981

24. Changes in Cross-Section
Early data
from Mason, 1981

25. Throat Cross-Sectional Area and Width
Early data
from Mason, 1981

26. 1930 Channel

27. 1942 Channel

28. 1944 Channel

29. 1952 Channel

30. 1956 Channel

31. 1961 Channel

32. 1973 Channel

33. 1990 Channel

34. 1995 Channel

35. 1999 Channel

36. 2002 Channel

37. 1952

38. 1961

39. 1965

40. 1967

41. 1995

42. 1999

43. Project Components Environments map
Topography/bathymetry digital elevation model
Tidal flow measurements
Geomorphic change analysis
Compilation of historic processes such as storm events
Morphodynamic model
Data availability and public awareness

45. Summary San Luis Pass is a “mixed-energy” tidal inlet.
Ebb-tidal delta sand storage is small compared to other inlets.
Location of opening stable through time.
Channels not stable.
Adjacent shoreline change can be dramatic.
Distal shoreline change (1 to 3 miles away) is also affected by changes at the inlet.
Report and data available on the Website in February.