By Mandy Loeffler, P.E., M.ASCE
The Coasts, Oceans, Ports, and Rivers Institute (COPRI) of the American Society of Civil Engineers (ASCE) assembled two coastal field teams for a survey conducted Oct. 4-6, 2008 to examine, document, and report on the effects of Hurricane Ike in the Galveston area. The teams were directed to examine impacts to coastal landforms, buildings, coastal structures, infrastructure, and marinas.
Team members included experts in coastal engineering, hydrodynamics, wave run-up, surge, scour sediment dynamics, geomorphology, geotechnical engineering, and small structure damage assessment. The teams, led by Dr. Billy Edge of Texas A&M University and Spencer Rogers with the North Carolina Sea Grant, were divided into smaller investigative groups to accomodate the breadth of the mission and the time limits as well as to allow individuals to better examine areas within their field of expertise. My team specifically investigated coastal buildings and marinas, identified high water marks, and evaluated geotube performance. Our focus was to evaluate what construction methods worked or didn't to develop lessons learned. This article provides a brief synopsis of my experience with the post-storm survey. A survey team report will be published soon. Additional reports from the survey are posted on COPRI's Coastal Solutions Blog.
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Figure 1: Indication of depth of sand overwash in Beachtown subdivision, Galveston, TX |
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| Figure 2: Road failure behind west end of seawall, Galveston, TX. | |
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| Figure 3: Typical slab foundation failure at beachside residences. | |
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Figure 4: Remaining beach along Highway 87 near High Island, TX. Clay outcroppings exposed. |
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| Figure 5: Remains of residence near Gilchrist, TX. | |
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| Figure 6: Newer construction in Biscayne subdivision in Crystal Beach, TX. Many beachfront homes sustained damage but homes set back from the beach exhibited minor damage. | |
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| Figure 7: Damage at the Houston Yacht Club. |
Driving in Saturday morning, I noticed many boats still washed up along Highway 45 leading into Galveston. The primary damage I observed was due to flooding -- with the contents of homes and businesses, as well as insulation and sheet rock -- piled in heaps along the roads. However, the weight of the storm and my family’s own experience over the previous three weeks finally hit when I pulled into Moody Gardens. The survey team was staying at the Moody Gardens hotel in Galveston. My husband is a relief captain on the Colonel Paddlewheel at Moody Gardens and thus my family and I spent many afternoons enjoying its lush scenery and vegetation. Pulling in to the hotel parking lot, I estimated that 80+% of the landscaping was dead due to saltwater intrusion. In an article I read in the Galveston Daily News, the water in the parking lot was over chest deep at the height of the storm.
The first day was spent surveying coastal home construction along Galveston Island and a brief inspection of the Galveston Seawall. We began at the eastern end of Galveston Island in the new Beachtown subdivision. The subdivision was built using fortified construction techniques, including elevating the living quarters two to three feet above base-flood elevation. The ground level of most buildings had minor damage due to storm surge and wave action, but we witnessed little damage to the overall structures. The water did, however, push sand from the beach and dune area several feet into the subdivision. In some areas, it appeared the layer of sand overwash was approximately five feet (Figure 1).
From the east end of Galveston, we stopped at two locations along the Seawall. While the seawall overall appeared in good shape, we did find a few instances of sidewalk failure in the vicinity of a drain or other outflow structure. The worst damage to the seawall occurred at its west end where approximately 50 feet had collapsed (Figure 2).
From the end of the seawall we drove west on Route 3005 towards San Luis Pass. Along the beach side of the road, the most consistent damage was extensive scour underneath the concrete floors and around the piles, and the loss of most break-away walls (Figure 3). Sand overwash during the storm resulted in a layer of sand several inches to several feet in depth extending across Route 3005. During our visit the sand had been removed from the road and communities had begun stockpiling the sand for use on the beach or to replace the sand loss under residences.
In general, the first row or two of homes situated along the Gulf shoreline were the most heavily damaged, and some had collapsed or were moved from their pilings. Other homes sustained various levels of structural damage but were still standing. I had the opportunity to work along Spencer Rogers of the North Carolina Sea Grant who had over 30 years of evaluating coastal construction following major storm events.
On the way home that evening, I decided to check out the two houses I lived in when I was in college at Texas A&M University at Galveston. The first house was on Winnie Street, not far from the historic Strand District. I spoke with two women currently residing nearby and they said the water rose between 4 to 6 feet inside their homes. The other house on Ball Street, about three blocks southwest, did not appear from the outside to have sustained major water damage.
On day two the entire survey team traveled to High Island and Bolivar Peninsula. Since we were not allowed access to the Bolivar Ferry, which was only running one boat due to shoaling in the shipping channel and damage to the ferry landings, we departed Galveston at 5:30 am to make the drive around Galveston Bay through Winnie and down to High Island. Upon entering High Island, the beach erosion on Hwy 87 appeared quite severe, with exposed clay outcroppings and little sand remaining (Figure 4).
Several dozen cars were seen on the north side of the road, likely abandoned due to rising water during the evacuation. The right span of the Bolivar Bridge had collapsed and only one lane was open to traffic.
Upon crossing Bolivar Bridge it was immediately apparent the area suffered much more extensive damage than Galveston Island. The first several miles consisted of only skeletal remains of residences (Figure 5).
My guestimation is if your house was less than a decade old, you might have stood a chance. I’ve only been to Bolivar a handful of times, most recently for work in May, and the one thing I noticed was that the only older homes still standing were in pockets here and there, but most had some damage. Many miles of pilings, if that, were sticking out of the ground where the water took everything away. Little or no debris was left behind. The houses that survived appeared to be: newer; subject to more stringent building codes; further off the ground; and set back several rows from the beach (Figure 6).
The third and final day of the survey was spent in the Kemah area, north of Galveston, to inspect the Houston Yacht Club (HYC) and Seabrook Marina. The HYC sustained heavy damage and many sailboats broke loose from their moorings and washed onto the facility’s lawn. Many had been removed by the time of our visit; however, damage to the piers and walkways, breakwater, bulkheads, and roof structures were still evident (Figure 7).
Team members included: Robert G. Dean, University of Florida; Lesley Ewing, California Coastal Commission; Garry Gregory, Gregory Geotechnical - ASCE Geo Institute Liaison; Marie Horgan Garrett, Coastal Solutions, Inc.; James Kaihatu, Texas A&M; Mandy Loeffler, Moffatt & Nichol, Houston; Margery Overton, North Carolina State University; Donald Stauble, USACE/ERDC/CHL; Kojiro Suzuki, Port and Airport Research Institute, Japan; Jeffrey Waters, USACE/ERDC/CHL; Eddie Wiggins, USACE/JALBTCX; Paul Work, Georgia Tech.
