https://doi.org/10.5194/hess-2019-238 Preprint. Discussion started: 24 July 2019 c Author(s) 2019. CC BY 4.0 License. Climate Change impacts the Water Highway project in Morocco Nabil El Moçayd1, Suchul Kang2, and Elfatih A. B. Eltahir2 1International Water Research Institute, University Mohammed 6 Polytechnic, Lot 660 Hay Moulay Rachid Benguerir 43150, Morocco 2Ralph M. Parsons Laboratory, Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA Correspondence: Nabil El Noçayd (
[email protected]) Abstract. The hydrology of Morocco is characterized by a significant spatial variability. Precipitation follows a sharp gradient decreasing from the North to the South. In order to redistribute water, a project is proposed to transfer 860 million m3 per year from the wet north to the arid southern regions, {Water Highway}. The present study aims to address the viability of the project including the effects of climate change in the watersheds located in the North. We perform Regional Climate Model 5 (RCMs) simulations over the study region using boundary conditions from five different global circulation models (GCMs) and following two emissions scenarios RCP4.5 (with mitigation) and RCP8.5 (business as usual). The impact on precipitation is assessed and the decrease of available water quantity is estimated. Under RCP 8.5 the project is likely unfeasible. However under the RCP 4.5 a rescaled version of this project may be feasible depending on how much water is allocated to satisfy the local water demand. 10 1 Introduction In many regions in the world, water scarcity is a critical issue that should be seriously addressed by stakeholders.