The World-Wide Water model (W3) and its Australian version, OzWALD, are two near-identical models for grid-based estimation of daily water balance dynamics and water-related vegetation dynamics. Both are evolutions of the original AWRA-L model. The example Matlab implementation of the models is freely available for download. You can find the code, relevant literature, and some course material via this link or the download button below.
(Note that this is not the AWRA Community Modelling System (AWRA CMS), which also an evolution of the original AWRA-L model but is maintained by the Bureau of Meteorology and can be found here: https://github.com/awracms/awra_cms)