Uncertainty propagation in a modelling chain of climate change impact for a representative French drainage site

Abstract

Analysis of the uncertainty propagation along a hydroclimatic modelling chain has been performed by few studies to date on subsurface drainage hydrology. We performed such an analysis in a representative French drainage site. A set of 30 climate projections provided future climatic conditions for three representative concentration pathways (RCPs): RCP2.6, RCP4.5, and RCP8.5. Three hydrological models for drainage systems, MACRO, DRAINMOD for DRAINage MODel, and SIDRA-RU for “SImulation du DRAinage - Réserve Utile” in French, on the three different parameter sets were used to quantify uncertainties from hydrological components. Results showed that the RCP contribution to total uncertainty reaches almost 40% for air temperature, does not exceed 15% for precipitation, and is almost negligible for hydrological indicators (HIs). The main source of uncertainty comes from the climate models, representing 50–90% of the total uncertainty. The contribution of the hydrological components (models and parameter sets) to the HI uncertainty is almost negligible too, not exceeding 5%.