Resolve physical-unit conversion and datum for WSE errors

Determine the physical-unit conversion and vertical datum corresponding to the native water-surface-elevation error measurements reported for KG-Chronos-2 and the comparison systems.

Background

The benchmark reports forecast errors in native water-surface-elevation units, but the manuscript does not establish the conversion of those values into physical units or identify the relevant vertical datum. Resolving these quantities is necessary for interpreting the absolute magnitude of the reported errors and for comparing them with physically meaningful hydraulic tolerances.

References

We retain native WSE units; the experimental record leaves the physical-unit conversion and datum unresolved.

— Knowledge-Graph-Augmented Chronos-2 for HEC-RAS Surrogate Forecasting  (2609.21381 - Holmberg et al., 18 Sep 2026) in Section 5.5, “Metrics and Paired Comparisons”