Slide 1

Tiffany L. Caudle, Thomas A. Tremblay, Jeffrey G. Paine, John R. Andrews, Kutalmis Saylam, and Aaron Averett Bureau of Economic Geology Jackson School of Geosciences The University of Texas at Austin American Shore and Beach Preservation Association National Coastal Conference October 2013 Tracking Shoreline and Geomorphic- Unit Change on South Padre Island, Texas Using Chiroptera Mapping System Slide 2 Project Acquire topographic and bathymetric lidar data and color infrared aerial imagery Tasks: Map 2013 shoreline, vegetation line and dune crest Update change rates of shoreline position Map geomorphic units Beach-dune system volume analysis Sediment budget Slide 3 BEGs Chiroptera Airborne Lidar System Laser System PRR, Topo: 400kHz PRR, Bathy: 36kHz 40 degree swath = 1m, 0.5 m Camera DigiCAM 50 MP 8176 x 6132 px RGB, Color IR Slide 4 Red laser Green laser 50 MP Camera (RGB), CIR) Cessna 206 Flight Direction BEGs Chiroptera Airborne Lidar System Slide 5 South Padre Island Survey Flown February 2013 (2 days) Beach, dune, and nearshore environments along 79 km of shoreline (to 1 km offshore) Topographic (200kHz) and bathymetric (36kHz)lidar data and hi-res Color I/R imagery 8-10 points per sq m Slide 6 Topo data and CIR images 500-m swath landward of the shoreline Bathy data collected 1000 m seaward of shoreline Intent to establish depth-penetration and water-clarity limits in Gulf of Mexico Slide 7 Topographic Lidar Point Cloud Elevation Intensity Slide 8 SHORELINE CHANGE Slide 9 2010-2013 Lidar Shoreline Positions Slide 10 Short-term Shoreline Change Rates 2010-2013 1348 Sites Max Erosion: -9.03 m/yr Max Accretion: 17.47 m/yr Average Rate: 1.75 m/yr 36% of sites eroding (483) 64% of sites accreting (865) Slide 11 Decade-scale Shoreline Change Rates 2000-2013 1346 Sites Max Erosion: -6.11 m/yr Max Accretion: 2.67 m/yr Average Rate: -1.12 m/yr 76% of sites eroding (1024) 24% of sites accreting (322) Slide 12 Long-term Shoreline Change Rates 1937-2013 1350 Sites Max Erosion: -7.12 m/yr Max Accretion: 4.48 m/yr Average Rate: -2.15 m/yr 84% of sites eroding (1134) 16% of sites accreting (216) Slide 13 1937-20132000-20132010-2013 Slide 14 GEOMORPHIC UNIT MAPPING Slide 15 Geoenvironments of South Padre Island Slide 16 Geoenvironments Mapping Methods Slide 17 Geoenvironments Washover Mapping Slide 18 Summary Topographic and bathymetric lidar survey of SPI flown in early February 2013 Comparison of 2013 lidar derived shoreline position with positions extracted from 2010-2012 data to determine short-term rates of shoreline change (ave. 1.75 m/yr accretion for SPI) Calculate decade-scale (-1.12 m/yr) and long-term (-2.15 m/yr) rates of shoreline change Lidar DEM beneficial for geoenvironments mapping Continue analysis of bathymetric lidar data to establish depth-penetration and water-clarity limits in Gulf of Mexico Slide 19 PRELIMINARY BATHYMETRIC RESULTS Slide 20 water surface bottom ground truth 0.8 m 2 m 2.2 m 1.4 m Slide 21 water surface bottom ground truth 3.3 m2.77 m3.5 m Slide 22 m m Slide 23 Tiffany L. Caudle tiffany.caudle@beg.utexas.edu Bureau of Economic Geology John A. and Katherine Jackson School of Geosciences The University of Texas at Austin Thank you!