Figure 1 8. Example of contours of sediment transport 



Example Application - East Pass Inlet 



Shoal classification at East Pass Inlet with the DMS-Manual prompted 

 investigation of the physical processes with two types of models that will become 

 available in the DMS-Analytical Toolbox. First, a hydrodynamic model 

 determines the magnitude and direction of the inlet's currents. Second, a wave- 

 refraction model characterizes the wave climate in the inlet throat. 



Inlet hydrodynamics 



As identified in Chapter 1, the maintained channels at East Pass Inlet contain 

 three channel shoaling hot spots (Figure 5). For two of the areas (Channel Bend 

 and Old Pass), the application of the DMS-Manual in Chapter 3 gave more than 

 one classification of shoal type. For both these areas, the physical processes 

 involved currents through the pass. This prompted the need to investigate the 

 inlet hydrodynamics. This section details the application of RMA2 (Thomas and 

 McAnally 1985) to resolve the current patterns at the shoaling areas. RMA2, a 

 2-D, depth-averaged, finite-element, hydrodynamic numerical model, computes 

 water-surface elevation and horizontal velocities for subcritical, free-surface 

 flows. The program computes a finite-element solution to the Reynold's form of 

 the Navier-Stokes equations. 



Figure 19 depicts the bathymetry input to RMA2. The constructed 

 bathymetry reflects a combination of the following hydrographic surveys, which 

 characterize the area given in parentheses: 



• 1997 US ACE SHOALS Lidar Survey (Inlet Vicinity) 



• 1996 US ACE SHOALS Lidar Survey (Inlet Vicinity) 



• 1987 NOAA Nautical Chart #1 1385 (Choctawhatchee Bay) 



• 1995 NOAA Nautical Chart #1 1388 (Gulf of Mexico) 



38 



Chapter 4 DMS-Analytical Toolbox 



