A general particle tracking tool for arbitrary cell geometries with
Modflow-USG,
including nested grids, quadpatch grids, quadtree grids, and Voronoi tesselations.
(Developed by
S.S. Papadopulous and Associates, with Chris Muffels, Muhammad Ramadhan,
Xiaomin Wang, Matthew Tonkin, and Chris Neville). The Waterloo algorithm developed by M. Ramadhan in-house.