We have always recommended that users zip backup copies of their watershed before opening them in a new version of HEC-ResSim.  This becomes even more important when upgrading to HEC-ResSim 4.0.  There have been major changes to the underlying watershed file structure between version 3.5 and version 4.0, making the incompatibility absolute.

Occasionally, there are reasons to not move forward to the latest version or reasons one might venture forward, only to find the need to go back to an earlier version.  Therefore we have added an extra warning to help users identify the risk taken when upgrading. 

There are at least three ways in which version compatibility comes up -

  • Watershed
  • Network 
  • Simulation

Before Upgrading to a new version of HEC-ResSim

We strongly recommend that before you start using any new version of HEC-ResSim:

  • make backup copies of your existing watersheds
  • consider using separate modeling locations (folders) for your watersheds that are used with different versions of ResSim
    • for example you can have directories for groups of watersheds that are
      • compatible with v3.3
      • compatible with v3.5
      • compatible with v4.0
      • compatible with v4.1-Beta

As you use the new version:

  • check the data in all elements of your model, being especially vigilant in reviewing your operation rules
  • verify the operation of your current models with the prior version
  • once satisfied with the results produced by the new version for each of your current models, make another set of backup copies. This second backup copy is suggested because when you open a watershed in ResSim 4.0, the format of key model files is changed, thus making the watershed unable to be opened with older versions of ResSim.