The idea for the General Estuarine Transport Model (GETM) was born in May 1997 in Arcachon, France, during a workshop of the PhaSe project, which was sponsored by the European Community in the framework of the MAST-III-programme. It was planned to set up an idealized 3D numerical model for the Eastern Scheldt, The Netherlands, for simulating the effect of vertical mixing of nutrients on benthic filter feeders growth rates. However, at that time the Public Domain models did not allow drying and flooding or used the inflexible step-like vertical coordinates (z). Therefore, Hans Burchard wrote a new 3D numerical hydrodynamic model including flooding/drying, a k-ε turbulence closure model, momentum advection, mass conservation and the general vertical coordinates. Later in May 1998, Karsten Bolding fully rewrote this model from a one-file FORTRAN77 code to a modular FORTRAN90/95 code, made the interface to the General Ocean Turbulence Model (GOTM), integrated the netCDF-library into the model, and prepared the parallelisation of the model. During 2001, GETM was extended to be a fully baroclinic model with transport of active and passive tracers, calculation of density, internal pressure gradients and stratification, surface heat and momentum fluxes and high-order advection schemes. The horizontal curvi-linear coordinates were also implemented to simulate, for example, the long, narrow and bended tidal Elbe River. 

In the near future, GETM will be extended with adaptive grids, two-way nesting, improved open and cyclic boundary conditions, a surface wave module, a thermo-dynamic ice model, a better source documentation and a coupling to benthic and pelagic ecosystems. For a more detailed description of the features of GETM have a look here.