concept. The seawall was designed with guidance from the Shore Protection 

 Manual (SPM) (1984) which is based primarily on monochromatic wave theory. 

 Adequate storm protection was to be provided by the seawall without sacri- 

 ficing aesthetics of the ocean view. 



3. The proposed plan consists of constructing a new stepped-face sea- 

 wall with curved parapet located just seaward of the existing seawall (between 

 Rudee Inlet and 57th Street) . The existing dune field will be raised and 

 widened as necessary from 57th Street, north to 89th Street. Both structures 

 would be fronted by a continuously maintained beach berm. 



Study Background 



4. This report is second in a series of three reports on coastal engi- 

 neering studies conducted by the US Army Engineer Waterways Experiment 

 Station's Coastal Engineering Research Center (CERC) to assist NAO in advanced 

 engineering and design of the Virginia Beach, Virginia, Beach Erosion Control 

 and Hurricane Protection Project. The other two reports discuss physical 

 model studies and the beach and dune design. The overall study is divided 

 into two major sections consisting of the seawall design (i.e., physical 

 model, overtopping tests, and physical model pressure or wave loading tests) 

 and the beach and dune design evaluation. Figure 2 is a schematic presenta- 

 tion of the coastal engineering studies. This report presents selection of 

 the design parameters and an analysis of the results of the physical model 

 seawall overtopping tests (items 10-19). The other two reports deal with the 

 actual physical model tests for overtopping and measurements for wave loading 

 (items 15 and 20) and the beach and dune design (items 21-31). 



5. Selection of design waves, storm surge hydrographs, and runup- 

 overtopping rates was crucial to developing the most hydraulically efficient 

 seawall geometry and in analyzing short-term beach stability. Coastal engi- 

 neering studies in support of the seawall design consisted of selecting design 

 storms from the historical record, simulating the wave field for each of these 

 storms, establishing the design surge hydrographs, and developing a two- 

 dimensional hydrographic model to predict overtopping rates. 



6. Seawall overtopping tests involved hydraulically designing the most 

 efficient seawall plan and developing overtopping rates which could be used in 

 interior flooding design. The study used a two-dimensional physical model 



