b. Computation of a variable velocity field across the cross 

 section. 



c. Optimization of the computational procedure by employing a 

 banded matrix solver in channel networks . 



d. Generalization of external and internal boundary conditions so 

 that a variety of channel networks can be described. 



e. Graphic display of the velocity field and stage 



40. The model presented in this study, DYNLETl, is very efficient and 

 unconditionally stable, permitting use of large time steps; it allows 

 flexible grid spacing and grid niimbering in the lateral and longitudinal 

 directions. The model also provides detailed two-dimensional velocity field 

 information in a system of interconnecting channels (each channel comprising a 

 one -dimensional calculation element) of different orientations. These 

 channels can represent actual channels, such as inlet throats, and bays. 

 Thus, the velocity at locations (called stations) that can be spaced irregu- 

 larly across the channel as governed by depth, roughness, and other physical 

 processes entering the full shallow-water equation set can be calculated. 

 Locations of stations along the particular cross section can be arbitrary, 

 allowing the velocity and stage at physically important locations of interest 

 to be readily obtained. The only capability lacking in DYNLETl in comparison 

 to complete two-dimensional models is that flow directions are constrained to 

 be along the specified channel axis. 



17 



