US Army Corps of Engineers
Hydrologic Engineering Center

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HEC-ResSim

Version 3.5 (September 2024) of the Reservoir System Simulation program (HEC-ResSim) is now available. This version supersedes Version 3.3 which was released to the general public in February 2021. Several new features, as well as enhancements to existing features, have been added to the program since that time. The new features to look for are listed in the Version 3.5 Release Notes.

Please refer to the HEC-ResSim User’s Manual for details regarding the new features, enhancements, and improvements.

We strongly recommend that before you start using HEC-ResSim 3.5:
  • make backup copies of your existing watersheds (and consider using separate modeling locations (folders) for your v3.3 and v3.5 watersheds)
As you use HEC-ResSim 3.5:
  • 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 ResSim 3.5, and
  • 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 3.5, the format of key model files is changed, thus making the watershed unable to be opened with older versions of ResSim.