18.1 2026.0 Release
Table 18.1 outlines the changes made to the default settings for the 2026.0 release and lists commands to revert the settings to those used by the prior major release group (2025). All default settings can be reverted to the prior release by using the command, “
2026.0 release upgrades the CUDA compiler (for GPU hardware) to CUDA version 12.9 and the Fortran compiler from the deprecated Intel ifort to the more modern Intel IFX Fortran. Due to this compiler update, even when switching defaults back to previous settings, the results are not guaranteed to match previous releases. It is recommended that when switching to this release with an established model, that test runs are carried out and comparisons made between the old and new releases to ensure that any changes are understood.
| Description | Backward Compatibility Command |
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| Reset all defaults to that used by the 2025 release. |
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| A new TIN triangulation method, Method B, has been implemented, which enforces breaklines, produces more balanced triangulations, and is more robust compared to the original Method A . |
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| A new HPC wetting and drying approach, Method C, has been implemented. The new approach computes infiltration for wet cells, and dry cells with positive rainfall rate until the depth reaches the drying depth. This method prevents cells from repeatedly alternating between dry and wet states, and is more robust compared to the previous default Method A (for non-SGS models) or Method B (for SGS models). See Section 8.2.2.4. |
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| Head loss due to the form loss defined by 2d_lfcsh and 2d_bg layers can become underestimated when the hydraulic structure is rotated against the 2D mesh. A new form loss adjustment approach has been implemented to solve the issue. |
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| Soil porosity has been removed from the horizontal groundwater flux calculation. Previously the horizontal groundwater flux was factored by soil porosity, which could lead to the selection of horizontal conductivity higher than industry standard range. |
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| A new option to reduce the groundwater flux based on the power function of relative saturation has been added to HPC. This feature is not applied by default to the vertical flux, and can be applied to the horizontal flux optionally. The primary reason to implement this feature to the vertical flux calculation is to improve the timing of vertical infiltration in multi-soil layered models. For backwards compatibility, set this exponent to zero. See Section 7.3.5.2.3. |
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