TauDEM (Terrain Analysis Using Digital Elevation Models) is a suite of Digital
Elevation Model (DEM) tools for the extraction and analysis of hydrologic
information from topography as represented by a DEM. TauDEM provides the
following capability:

* Development of hydrologically correct (pit removed) DEMs using the flooding
  approach
* Calculates flow paths (directions) and slopes
* Calculates contributing area using single and multiple flow direction methods
* Multiple methods for the delineation of stream networks including topographic
  form-based methods sensitive to spatially variable drainage density
* Objective methods for determination of the channel network delineation
  threshold based on stream drops
* Delineation of watersheds and subwatersheds draining to each stream segment
  and association between watershed and segment attributes for setting up
  hydrologic models
* Specialized functions for terrain analysis

Note TauDEM also works fine with MPICH, so if you have it installed it is not
necessary to install OpenMPI.
