EPANET 2.2 Engine Compatibility

The core numerical analysis within the WaterCAD and WaterGEMS applications is based on the hydraulic engine that was developed by the US EPA, called EPANET. Over the years, EPANET has undergone multiple iterations and revisions, though the most recognizable releases going back almost 20 years are version 2.00.10 and version 2.00.12, with the latter being in incremental update to the former, both worthy of consideration as canonical releases, both gaining acceptance and wide-spread usage in the hydraulics industry.

With the above in mind the previous WaterCAD and WaterGEMS releases have supported the concept of an Engine Compatibility mode, that exposes to the user an option to control the analysis engine to one of several different flavors.

EPANET 2.00.10
EPANET 2.00.12
WaterGEMS 2.00.10
WaterGEMS 2.00.12

The description for the Engine Compatibility mode from WaterCAD/GEMS describes the effect of these different settings as follows:

This field specifies which engine compatibility mode you wish to run in. Choose WaterGEMS 2.00.12 to get all the latest engine improvements and fixes made by Bentley and an engine mode that is based upon EPANET 2.00.12. This is the default choice for new models. Choose WaterGEMS 2.00.10 to maintain compatibility with previous versions of WaterGEMS (V8i SELECTseries 1 and earlier) where the computational engine is based upon EPANET 2.00.10. This is the default for upgraded models. If choosing a version of EPANET, any enhancements and calculation corrections and bug fixes made by Bentley will be disabled, in order to match the specific EPANET version results. Imported EPANET models will default to the appropriate EPANET version.

After the 2.00.12 release of EPANET had been out for some time, an open-source development effort was initiated to try to establish a community-based development paradigm for future EPANET releases. This open-source initiative delivered an EPANET update (version 2.1) some years ago, however, the nature of that release was that it delivered more for programmers and researchers, as opposed to hydraulics engineers. A more recent release, however, EPANET 2.2 delivers features that will be of interest to engineers and hydraulic modelers. This latest version of EPANET is also officially sanctioned by the US EPA, being available for download from the same location as the EPANET 2.0.x downloads, with major contributions towards the open-source project coming from the US EPA. It is set to be the next canonical release of EPANET, and as such, has been selected for inclusion within WaterCAD and WaterGEMS.

The latest releases of WaterCAD and WaterGEMS now include two additional Engine Compatibility modes.

EPANET 2.2.0
WaterGEMS 2.2.0

The updated description for the Engine Compatibility mode from the latest version of WaterCAD/GEMS describes the effect of these different settings as follows:

This field specifies which engine compatibility mode you wish to run in. Choose WaterGEMS 2.2.0 to get all the latest engine improvements and fixes made by Bentley and an engine mode that is based upon EPANET 2.2. This is the default choice for new models. Choose WaterGEMS 2.00.12 to get all the latest engine improvements and fixes made by Bentley and an engine mode that is based upon EPANET 2.00.12. Choose WaterGEMS 2.00.10 to maintain compatibility with previous versions of WaterGEMS (V8i SELECTseries 1 and earlier) where the computational engine is based upon EPANET 2.00.10. This is the default for upgraded models. If choosing a version of EPANET, any enhancements and calculation corrections and bug fixes made by Bentley will be disabled, in order to match the specific EPANET version results. Imported EPANET models will default to the appropriate EPANET version.