Historical Shoreline Change Through Texas Gulf
A Publication of the Gulf Coast Association of Geological Societies www.gcags.org HISTORICAL SHORELINE CHANGE THROUGH 2007, TEXAS GULF COAST: RATES, CONTRIBUTING CAUSES, AND HOLOCENE CONTEXT Jeffrey G. Paine, Sojan Mathew, and Tiffany Caudle Bureau of Economic Geology, Jackson School of Geosciences, University of Texas at Austin, University Station, Box X, Austin, Texas 78713, U.S.A. ABSTRACT Long-term historical rates of Gulf shoreline change along the Texas coast have been determined through 2007 (the latest imagery that predates Hurricane Ike) from a series of shoreline positions that includes those depicted on 1800s charts and mapped from aerial photographs, ground GPS surveys, and airborne lidar surveys. Net rates measured at 11,731 sites spaced at 164 ft (50 m) along the 332 mi (535 km) of Texas Gulf shoreline average 4.1 ft/yr (1.2 m/yr) of retreat, significantly lower than late Pleistocene to early-Holocene retreat rates of 8 to 181 ft/yr (2.4 to 55 m/yr) and similar to mid- to late Holocene rates estimated using past sea-level positions and shelf bathymetric contours as a shoreline proxy. Net shoreline retreat occurred along 84 percent of the Texas Gulf shoreline, resulting in an estimated land loss of 13,890 ac (5621 ha) since 1930 at an average rate of 180 ac/yr (73 ha/yr). Rates of change are more recessional on the upper Texas coast (-5.3 ft/yr [-1.6 m/yr] east of the Colorado River) than they are on the central and lower coast (-3.3 ft/yr [-1.0 m/yr] from the Colorado River to the Rio Grande).
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