| dc.description.abstract | The storm surge from Hurricane Ike inundated Bolivar Peninsula as well as
pooled up (~4 meters above sea level) in the Galveston Bay System behind Bolivar.
After the hurricane passed, this water flowed back over the peninsula for about 19 hours,
causing a great deal of coastal destruction. Analysis of post-Hurricane Ike aerial
photography and Lidar data revealed the development of dramatically different scour
and backflow features in the beach and dune environments along Bolivar Peninsula,
Texas. Using Ward's cluster analysis, the 454 identified features were grouped
according to shape and size characteristics generated by an object-oriented shape
analysis program. Five distinct groups of features emerged from the cluster analysis.
Group 1 features were small and compact, distributed mostly in the west; Group 2
features were large and dendritic in nature, distributed where the peninsula was narrow.
Group 3 features had a longshore orientation with many of them resembling piano keys,
distributed in the east. Group 4 features were oriented longshore and ornate in shape.
Many of them were similar in shape to Group 2 or 3 features though statistically different enough to be grouped alone; they were distributed mostly in the eastern half of
the study area. Group 5 features tended to be elongated, oriented cross-shore, nonbranching,
and distributed mostly in the east.
At least four flow environments caused characteristic forms. The first flow
environment is typified by seaward flowing water encountering a road parallel with the
coastline. The water flowing over the road scours deeply on the leeward side (seaward
side), denuding beach sediments down to the resistant mud layer (Groups 3 and 4). The
second flow environment was caused by a geotube, which breached during the storm and
channelized flow through the breaches (Groups 2 and 5). The third flow environment
had a comparatively high elevation, high development, and shore-perpendicular roads
(Group 2). The fourth flow environment was typified by wide beaches backed by dunes
(lost in the storm) as well as flat vegetated areas. Water flowing seaward over the
vegetation scoured deeply into troughs after it came off the vegetation (Groups 1, 3, and
4). | en |
