Predictions in Ungaged Catchments: Favoring Hydro-diversity rather than Hydro-Eugenics

Eugenics' is a theory initiated and promoted by the famous statistician-geographer-meteorologist Francis Galton (1822-1911), mostly known among hydrologists for introducing in biometrics the Galton law (i.e. the log-normal distribution), the correlation and the standard variation measures. With eugenics, Galton was aiming at improving the qualities of a human population, by such means as discouraging reproduction by persons presumed to have undesirable inheritable traits and encouraging reproduction by persons presumed to have desirable inheritable traits. A hydrological equivalent to the eugenic controversy lies in regionalization studies, where modelers attempt to guess parameter values for their models at ungaged locations. In these studies, hydrological information (i.e. mean flow values, model parameter values, etc.) has to be transferred from 'donor' or 'reference' catchments to the ungaged ones. We propose to summarize the hydro-eugenic debate by the following question: should we keep poorly modeled catchments as potential donors in regionalization studies?