For supporting this idea, I divided my presentation in two parts. The first under the motto: the right numerics, for the right equations. There, I showed how Richards equation can be modified to account for transition to saturated conditions and for freezing soil. This last part has been largely derived from the work of Matteo Dall'Amico (here his Ph.D. thesis) and the subsequent paper on the Cryosphere journal. With the benefit of hindsight, I can tell that I could have been much more clear on the physics of the problem, but it was just doing the presentation that I realised it.
The second part is dedicated to justify the rational of what I called "The Geoframe project", which is an integrated system for doing hydrology by computer, completely open source, and which has a deployment in the JGrass-NewAGE system. Click on the painting above to see the presentation.