ERDC/CHL CETN-IV-22
December 1999
Improvements to Ocean City Inlet were monitored over 27 months from October 1986 through
January 1989. The monitoring program consisted of beach and offshore profile surveys, aerial
and ground photography, hydrographic surveys, wave gaging, and side-scan sonar surveys of the
scour protection area. Results of the monitoring program indicated that the rehabilitation effort
successfully met its goal of eliminating the sand source to the finger shoal, resulting in an
accretionary fillet on the downdrift shoreline.
Prevent transport by wind-blown sand
Sand shoals often appear inside of jetties adjacent to the beach berm or dry beach. These shoals
can be created by sand transported over the jetties during times of high water relative to the
elevation of the structures and by sand blown over the jetties, which occurs when the wind is
blowing with a longshore component and the beach is dry. Seelig and Sorensen (1976) describe
an example of shoaling by wind-blown sand transport at Penwater Inlet, located on Lake
Michigan, and discuss possible solutions to reduce shoaling (planting vegetation and placing
sand fences). For illustration herein, we consider the Mustang Island Fish Pass, Texas.
The Mustang Island Fish Pass was a 3.2-km-long channel dredged and opened in August 1972
by the Texas Parks and Wildlife Department to increase water exchange and fish migration
between Corpus Christi Bay and the Gulf of Mexico. It was never a Federal channel and was not
maintained once opened. The jetty spacing was 122 m, and the length (measured from the initial
shoreline) into the Gulf was 260 m (Behrens and Watson 1977, Kraus and Heilman 1997). By
March 1985, the pass had closed, primarily by shoaling near the Gulf entrance. Figure 5 shows
areas of shoaling on three dates. Tropical storms tended to open the pass, but the strong and
persistent wind blowing on the south Texas coast contributed to formation of the shoals. As
described previously, raising of jetties will reduce overtopping by water carrying sand during
times of high water. Similarly, higher jetty elevation and amenities such as walkways and
railings that increase effective elevation will reduce overtopping by wind-blown sand. At the
base of jetties, far from the beach, sand fencing and planting of vegetation can also reduce
infiltration by wind-blown sand.
7
Previous Page
