Transposing measured discharge time-series: large-scale comparison of top-kriging to geomorphology-based inverse modeling

Few methods transpose streamflow measurements for continuous prediction of ungauged catchments. Top-kriging has been used mainly to predict the statistical properties of runoff, but has been shown to outperform traditional regionalization approaches of rainfall-runoff models. We applied the top-kriging approach across the Loire river basin and compared predictions to a geomorphology-based transposition approach. Whereas top-kriging uses spatial correlation, the other approach has the advantage of being more naturalistic by using a well-known geomorphology-based component of a hydrological model and its inversion. Both approaches require an equal degree of calibration and provide similar performances. We also demonstrate that the Ghosh distance can be used efficiently to calculate weights and to identify the ability of gauged catchments for use as donor catchments. This result is particularly relevant for catchments with Strahler orders above five, i.e., where nested structures of catchments are more significantJRC.E.1-Disaster Risk Managemen