Beach and Shoreline Changes Along the Upper Texas Coast: Recovery from Hurricane Ike Prepared for: 1700 N. Congress Avenue HDR Engineering, Inc. Austin, Texas 78701-1495 Texas Registration No. 754 555 N. Carancahua, Suite 1600 March 17, 2014 Corpus Christi, TX | 78401 HDR Project No. 166742 EXECUTIVE SUMMARY Hurricane Ike made landfall at Galveston Island on September 13, 2008 as a Category 2 hurricane. Its low rating on the Saffir-Simpson scale does not reflect its massive size, with tropical storm force or greater winds cutting a swath 400 miles wide. Ike’s storm surge reached 15 to 20 ft on Bolivar Peninsula and in parts of Chambers County with large waves present throughout the Gulf of Mexico. Large storm waves coupled with storm surge caused extreme erosion on the Texas coast. Peak shoreline erosion was over 400 ft with average values near 200 ft over much of the upper Texas coast. The storm, as reported by the National Oceanic and Atmospheric Administration (NOAA), is the second most costly in U.S. history (NOAA, 2011). Preliminary impact assessments from Hurricane Ike have been updated as part of this study, and recovery of the beach/dune system has been reviewed through the analysis of LIDAR data along the Upper Texas coast. Site visits and limited beach profile data were also utilized to compare with the LIDAR results and help provide a clearer picture of beach and dune recovery. Based on shoreline and volumetric change analyses performed by Harte Research Institute at Texas A&M University -- Corpus Christi, much of the upper Texas coast had not fully recovered by 2012, four years after the passage of Ike. Tables E1 through E3 document the shoreline and volumetric (beach and foredune) changes. Considering the significant redistribution of sediment along the coast, full recovery is not expected for some of these areas due to a lack of natural sediment input and significant transport of sand away from critically eroding areas, such as along West Galveston Island. The Sabine to High Island area prior to the storm consisted of a thin veneer of sand overlaying clay outcroppings. Much of that sand veneer is gone and is not expected to recover, leaving this section of shoreline more susceptible to ongoing erosion. Table E1 Average Shoreline Changes per Region (LIDAR Comparisons). Net Shoreline Movement (ft)* Region Epoch 1 Epoch 2 Epoch 3 Epoch 4 2005-2012 2005-2008 2008-2010 2010-2011 2011-2012 Sabine to High Island -90.2 -19.4 -11.7 -19.9 -141.1 Bolivar Peninsula -26.9 -12.5 9.6 -14.3 -44.0 East Galveston Island -53.7 72.2 60.0 8.5 87.0 West Galveston Island -51.0 40.2 50.3 -9.9 30.0 Follets Island 3.3 -10.2 55.2 -28.6 19.7 Quintana -68.2 29.0 57.6 -35.2 -16.9 * Negative values indicate shoreline recession and positive values indicate shoreline advance. Project No. 166742 i Table E2 Average Volume Change Results of Sub-aerial Beach per Region (LIDAR Comparisons) Net Volume Change per Alongshore Length (cy/ft) Region Impact of Ike Recovery Cumulative (2005-2008) (2008-2012) (2005-2012) Sabine to High Island -3.2 -0.6 -3.9 Bolivar Peninsula 0.3 -2.8 -2.5 East Galveston Island 2.2 -1.9 0.3 West Galveston Island -2.7 2.6 -0.1 Follets Island 1.6 -2.1 -0.5 Quintana -4.1 1.0 -3.1 Table E3 Average Volume Change Results of Foredune Zone – Dune Toe to 25 m landward, per Region (LIDAR Comparisons) Net Volume Change per Alongshore Length (cy/ft) Region Impact of Ike Recovery Cumulative (2005-2008) (2008-2012) (2005-2012) Sabine to High Island -8.5 -2.9 -11.4 Bolivar Peninsula -11.3 1.7 -9.6 East Galveston Island -3.2 1.5 -1.7 West Galveston Island -7.3 2.7 -4.5 Follets Island -4.7 -0.2 -4.9 Quintana -9.5 2.2 -7.3 Project No. 166742 ii ACKNOWLEDGEMENTS Detailed shoreline and volumetric changes analyses for this report were performed by Harte Research Institute at Texas A&M University -- Corpus Christi. Determination of preliminary shoreline changes after the passage of Hurricane Ike was performed under the supervision of Dr. James Gibeaut. Further review of the impacts from Hurricane Ike and associated recovery were performed by Diana del Angel (shoreline change analyses) and Dr. Michael Starek (volumetric changes). Their analyses and insight into the coastal processes along the upper Texas coast were invaluable. Project No. 166742 iii TABLE OF CONTENTS 1.0 Introduction ..............................................................................................................................1 1.1 Authorization .................................................................................................................1 1.2 Project Location and Purpose ........................................................................................1 1.3 Site Overview.................................................................................................................1 1.4 Previous Storms .............................................................................................................4 2.0 Hurricane Ike ...........................................................................................................................6 2.1 Formation and Development..........................................................................................6 2.2 Storm Conditions at Landfall .........................................................................................6 2.2.1 Winds..................................................................................................................6 2.2.2 Surge ..................................................................................................................7 2.2.3 Waves .................................................................................................................8 3.0 Preliminary Damage Assessment .........................................................................................10 3.1 Methodology ................................................................................................................10 3.1.1 Aerial Photography ..........................................................................................10 3.1.2 Beach Surveys ..................................................................................................10 3.1.3 LIDAR ..............................................................................................................11 3.1.4 Physical On-Site Investigations .......................................................................11 3.2 Upper Texas Coast Assessment ...................................................................................11 3.1.1 Sabine Pass to High Island ..............................................................................11 3.1.2 Bolivar Peninsula.............................................................................................13 3.1.3 East Beach .......................................................................................................17 3.1.4 Galveston Seawall ............................................................................................19 3.1.5 West Galveston Island......................................................................................19 3.1.6 Follets Island ...................................................................................................23 4.0 Texas Virtual Monument System .........................................................................................26 5.0 Shoreline Change Analysis of Upper Texas Coast - Impacts and Recovery ....................28 5.1 Methods........................................................................................................................28 5.1.1 Shoreline Mapping ...........................................................................................28 Shoreline Change Analysis ..........................................................................................29 5.1.3 Beach Survey Comparisons .............................................................................29 5.1.4 Site Visits ..........................................................................................................30 5.2 Results and Discussion ................................................................................................30 5.2.1 Sabine Pass to High Island ..............................................................................34 5.2.2 Bolivar Peninsula.............................................................................................37 5.2.3 East Beach .......................................................................................................40 5.2.4 Galveston Seawall ............................................................................................42 5.2.5 West Galveston Island......................................................................................43 5.2.6 Follets Island ...................................................................................................47 5.2.7 Quintana ..........................................................................................................49 6.0 Volumetric Change of Upper Texas Coast – Impacts and Recovery ................................52 6.1 Methods........................................................................................................................52 6.2 Volume Change Analysis ............................................................................................54 Project No. 166742 iv 6.2.1 Sub-aerial Beach ..............................................................................................54