Neighbors: Nature’s own hydrological models

This paper presents a generalization of the age-old paired catchment approach: it enables to simulate streamflow at the daily or hourly time-step, based on the observed streamflow at the outlet of one or several neighbor catchment(s). An extensive assessment is presented, based on a network of 1040 French catchments: it demonstrates that, alone, the proposed neighbor catchment (NC) model is as efficient as a rainfall–runoff model, and that when a rainfall–runoff model and the NC model are combined, an unprecedented level of efficiency is reached. Because it is nonlinear, the NC model holds a wide application spectrum: it can be useful for hydrological applications such as time series extension or reconstitution as well as trend assessment.