Land-Water Interface Modeling Using a Two- Dimensional Shallow Water Model

In this paper the H2D shallow water model is developed which employs terms like atmospheric pressure, wind stresses, tidal forces, and boundry friction status. Adding the algorithm of wetting and drying in boundry cells, along with the changing wind and pressure fields, a new model called Surge2D is developed. The numerical 2D model developed in this study estimates the shallow water currents. The landwater interface is treated as a moving boundary in which the flooding and draining rate depend on the both simulated current and the height of water in adjacent ‘wet’ cells. This ensures realistic and smoothly varying results. In this approach for the status of a boundary cell to change from dry to wet or wet to dry, the water level should become greater or less than a specified stage, respectivly. Furthermore the fluid must cross the length of the boundary cell according to the flow velocity in the adjacent cell. The results of this model were compared to both analytical solutions and MIKE21 results. The result of the 2D model indicated an excellent agreement with the analytical solutions (differences less than 0.1%). This model is used to study the effects of Shahid Kalantary causeway on the current pattern and characteristcs in Urmia Lake, in north-western Iran.