The quad2d tools can be used for setting up and running a parallel, quadtree-based, MODFLOW 6 model using refinement areas. Parallel pre-processing is supported using VRT and Ehdr raster tiles. For simulation, a new distributed memory parallel prototype of MODFLOW 6 is being used, that has been developed together with the United States Geological Survey (https://github.com/verkaik/modflow6-parallel.git, https://doi.org/10.5281/zenodo.5778658). The quad2d tools are recently applied to construct a prototype for the new Netherlands' National Flexible Groundwater Model:
Verkaik, J., Oude Essink, G.H.P., Bierkens, M.F.P., Lin, H.X. Construction of a national, flexible, groundwater model for the Netherlands using high performance computing: towards one unified model for national-scale and regional-scale modeling. In preparation.
The quad2d Fortran program requires compilation using e.g. Intel or GNU. Regarding dependencies, a makefile example is provided. The code should be linked with METIS that has to be compiled at 64-bit precision. For running the model, the parallel MODFLOW 6 code should be compiled with a Fortran compiler and linked with the Message Passing Interface library. The quad2d Python program uses Python 3 and requires the installation of the Jinja2 package. The pre-processing workflow is given below, where the command-line arguments and corresponding section of the INI input files are denoted for each step.
Quad2d is released under the GPL license v3.0 (see LICENSE). All data and software provided with this model come with ABSOLUTELY NO WARRANTY.