1 Introduction 



The Prototype 



Sargent Beach, Texas, is located on the Gulf coast about 60 miles 1 south- 

 west of Galveston, TX (Figure 1). The beach, which provides protection for 

 the Gulf Intercoastal Waterway (GIWW), is experiencing an average erosion 

 rate of 30 ft per year. Left unchecked, the beach will be breached in a few 

 years and the GIWW will be directly exposed to Gulf waves. A revetment, 

 approximately 8 miles long, has been proposed to protect the eroding 

 shoreline. 



Purpose of Model Investigation 



The objective of this study was to investigate, via a two-dimensional coastal 

 model, alternate designs for the proposed revetment. The first two designs 

 investigated were similar except that one plan used 5-ton stone armor, whereas 

 the other was protected by 6.2-ton concrete blocks. When the stability of the 

 first concrete block design proved to be marginal, block shape and, thus, gross 

 porosity of the armor layer were modified in an effort to achieve satisfactory 

 stability. Finally, the shape of the concrete blocks was optimized and wave 

 overtopping rates were determined for the recommended section. 



1 A table of factors for converting non-SI units of measurement to SI units is presented on 

 page vi. 



Chapter 1 Introduction 



