# Application of CLAWPACK to Richards' equation

I'm looking to solve the Richards' equation. This models water flow in porous media and is a nonlinear, possibly degenerative, parabolic differential equation that takes the form

$\partial_t \Theta(\psi) - \nabla \cdot (K(\Theta)\nabla(\psi+z))=0$

where $\psi$ is pressure head, $\Theta$ is the water content, $K$ is the conductivity and $z$ is a vertical height. Pressure is the primary unknown.

This is a 'famous' equation and further information can be found on scholar [1,2].

I would like to calculate a 3D solution, and I am looking into possible solvers.

1. Is Clawpack applicable to this type of equation?

2. Is it possible to use Clawpack with an 3D unstructured mesh such as those that are generated from CGAL (currently I have a surface mesh defined using CGAL).

Any insight is much appreciated.