Modelling long-term effects of climate change and anthropogenic activities on water resources of the Moselle River basin.

Climate warming and evolution water demand for anthropogenic activities are two related ongoing changes that may increase existing pressure on water resources. Adaptation strategies are usually thought on the basis of hydrological projections. These projections, however, rarely incorporate changes in water and land management, issues that are then addressed by the adaptation plans within a sequential process. The objective of this study is to develop a modelling framework that incorporates water and land management evolution within a spatially distributed hydrological model in order to produce projections that are more realistic on the water resources shortages. We applied this methodology on the Moselle River (North-East France) basin using climate projections derived from various representative concentration pathway scenarios (RCPs), general circulation models (GCM), and regional climate models (RCM) in a multi-scenario multi-model approach. Hydrological projections are computed from a conceptual hydrological model, and a recent R package (airGRiwrm) was used to account for anthropogenic water withdrawals. Through contrasting scenarios of water use evolution built in partnership with the water stakeholders, we are able to explore different evolutions of water demand for each type of use present in the Moselle basin (withdrawals for domestic and industrial uses, energy production, and waterway navigation). These scenarios allow us to feed the hydrological model with different water withdrawals, in addition to the climate scenarios. The results of this multi-scenario and multi-model impact study on the water resources will be used to evaluate the water management sustainability and the adaptation levers.