Shallow water equations

  The shallow water equations (also called Saint Venant equations after Adhémar Jean Claude Barré de Saint-Venant) are a set of equations that describe the flow below a horizontal pressure surface in a fluid. The flow these equations describe is the horizontal flow caused by changes in the height of the pressure surface of the fluid. Shallow water equations can be used in atmospheric and oceanic modelling, but are much simpler than the primitive equations. Shallow water equation models have only one vertical level, so they cannot encompass any factor that varies with height.