1. The Texas Shoreline Change Project: The Texas Shoreline Change Project: Combining Lidar, Historical Photography, and Ground Surveys to Measure Shoreline Change Rates along Bay and Gulf of Mexico Shorelines James C. Gibeaut, William A. White, Roberto Gutierrez, Rachel Waldinger, John R. Andrews, Tiffany L. Hepner, Rebecca C. Smyth, and Thomas A. Tremblay Bureau of Economic Geology John A. and Katherine G. Jackson School of Geosciences The University of Texas at Austin

2. Shoreline Length Gulf = 600 km Bays = 9,400 km

3. Mapping past and current shorelines – Aerial photography – Ground kinematic GPS – Airborne lidar – shoreline plus beach and dune topographic mapping Calculating “average annual rate of change” and projecting future shoreline position – GIS-based Shoreline Shape and Projection Program (SSAPP) Beach profile ground surveys Data availability and public awareness – Online reports – Web-based GIS using ArcIMS software Project Components

4. Data Sources Before 1930: Maps from the mid to late 1800’s produced by the U.S. Coast Survey – “high-water line mapped.” Generally not used: Engineering structures altered sediment budget since 1900.

5. Sand Trapped by Jetty, Southwest end of Bolivar Peninsula (08/07/98)

6. Data Sources 1930’s to 1990’s - Vertical Aerial Photographs

7. Digital Photo Rectification 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

8. Shoreline Interpretation Wet/Dry Line Gulf of Mexico Matagorda Bay

9. Shoreline Interpretation Shoreline and Vegetation Line

10. Project Components Mapping shorelines – Aerial photography – Ground kinematic GPS – Airborne lidar – shoreline plus beach and dune topographic mapping Calculating “average annual rate of change” and projecting future shoreline position – GIS-based Shoreline Shape and Projection Program (SSAPP) Beach profile ground surveys Data availability and public awareness – Online reports – Web-based GIS using ArcIMS software

11. 1990’s – Kinematic GPS Surveys Data Sources

12. Project Components Mapping shorelines – Aerial photography – Ground kinematic GPS – Airborne lidar – shoreline plus beach and dune topographic mapping Calculating “average annual rate of change” and projecting future shoreline position – GIS-based Shoreline Shape and Projection Program (SSAPP) Beach profile ground surveys Data availability and public awareness – Online reports – Web-based GIS using ArcIMS software

13. Mirror sweeps laser beam across the ground. Range to target is determined by measuring time interval between outgoing and return of reflected laser pulse. Aircraft position is determined using GPS phase differencing techniques. Pointing direction of laser determined with Inertial Measuring Unit (IMU) and recording of mirror position. Data streams recorded and synchronized for post processing. Airborne Topographic Lidar

14. GPS Coastal Network

15. Lidar Instrument in Cessna 206 Optech ALTM 1225

16. MHHW+0.6 m msl Geotube Landward boundary BEG-02 Beach profile QAd496Gibeaut_CCC_Jan31_2002 Lidar Digital Elevation Model 1 - m grid Ellipsoidal heights converted to orthometric heights (NAVD 88) using GEOID99 gravity model. Local mean sea level (MSL) correction applied.

17. Calibration Target

18. Calibration Flight Lines

19. Lidar Survey Video

20. Galveston Beach Wet/Dry Line

22. Galveston Island Profile

23. Representative Wet/Dry Elevation 0.6 m along Upper Tx Gulf Coast 0 1 2 3 -2 0.6 MHHW 0 100 Height relative to MSL (m) Distance (m) 50 upper berm crest vegetation line

24. Why Use a Wet/Dry Elevation? Consistent with historical photography. Consistent with 2d ground GPS surveys. Lidar can measure reliably even during elevated water levels. Geomorphologically significant elevation not as susceptible to short-term erosion/depositional cycles compared to lower elevations.

25. Hand-Smoothed Shoreline

26. Project Components Mapping shorelines – Aerial photography – Ground kinematic GPS – Airborne lidar – shoreline plus beach and dune topographic mapping Calculating “average annual rate of change” and projecting future shoreline position – GIS-based Shoreline Shape and Projection Program (SSAPP) Beach profile ground surveys Data availability and public awareness – Online reports – Web-based GIS using ArcIMS software

27. Shoreline Shape and Projection Program ArcView Interface

28. Shoreline Change Rate

29. Projected Shoreline Galveston Island

30. Project Components Mapping shorelines – Aerial photography – Ground kinematic GPS – Airborne lidar – shoreline plus beach and dune topographic mapping Calculating “average annual rate of change” and projecting future shoreline position – GIS-based Shoreline Shape and Projection Program (SSAPP) Beach profile ground surveys Data availability and public awareness – Online reports – Web-based GIS using ArcIMS software

31. Ground Survey

32. Beach Profile Annotated

33. Project Components Mapping shorelines – Aerial photography – Ground kinematic GPS – Airborne lidar – shoreline plus beach and dune topographic mapping Calculating “average annual rate of change” and projecting future shoreline position – GIS-based Shoreline Shape and Projection Program (SSAPP) Beach profile ground surveys Data availability and public awareness – Online reports – Web-based GIS using ArcIMS software

34. www.beg.utexas.edu/coastalwww.beg.utexas.edu/coastal