BLUE 3D: source code, benchmark inputs and model outputs

Source code, benchmark input files, model outputs, and figure scripts for the manuscript "BLUE 3D: a mass-conservative quasi-three-dimensional model of variably saturated flow with the water table as a free boundary, tested against full three-dimensional Richards solutions" by H.T.T. Nguyen and G.L. Song (submitted to Journal of Hydrology). BLUE 3D couples vertical Richards columns, in which the water table is an explicit free boundary found from the mass balance of the saturated zone, with a Dupuit aquifer layer and a diffusion-wave overland layer. The archive contains: (1) the BLUE 3D model (soil.py, column.py, blue3d.py); (2) the fully coupled 2D and 3D Richards-overland reference model (ref2d.py, ref3d.py) and the Hantush (1967) solution (hantush.py); (3) the scripts that run every test in the paper (t0_save.py to t9_het.py: column, Dupuit, overland, Vauclin, Hantush mound, heterogeneous mound, hillslope, cost and scale tests); (4) the saved model outputs (.npy) and timing files; and (5) the scripts that produce all figures (fig*.py) and the figures themselves. Requirements: Python 3.10 or later with NumPy, SciPy, Numba, Matplotlib, and PyAMG. Each test script is run from the archive directory, e.g. "python t7_hantush.py blue 5 20"; the figure scripts read the saved outputs.