The potential impacts of projected future climate change scenarios on the hydrologic response of a water-stressed Mediterranean river basin (Upper Litani River Basin in Lebanon) are quantified and assessed using the Water Evaluation and Planning (WEAP) model. Projected basin-level changes in water availability are then compared to multi-sector demands estimated under six basin-level develop- ment scenarios. The sustainability under these scenarios and the resilience of the system in the face of the projected climatic changes are then assessed in terms of a water resources index, demand reli- ability, demand satisfaction index, demand reliability index and the average duration of failure. The results reveal that the basin is expected to experience significant alteration in its hydrologic cycle and that current plans envisioning an increase in irrigated areas within the basin, is non-sustainable and will lead to a highly water stressed system. A conservative basin-level plan that integrates both supply- and demand-side measures is proposed in an effort to achieve a more sustainable system.
Climate Change, Water Stress Indices, Watershed Management, WEAP
 Frederick, K.D., Water resources and climate change Edward Elgar Publishing, 2002.
 Bates, B., et al., Climate change and water. Intergovernmental Panel on Climate Change (IPCC), 2008.
 Parry, M. L., Climate Change 2007: impacts, adaptation and vulnerability: contribution of Working Group II to the fourth assessment report of the Intergovernmental Panel on Climate Change. Vol. 4. Cambridge University Press, 2007.
 Rijsberman, F.R., Water scarcity: fact or fiction? Agricultural Water Management, 80(1), pp. 5–22, 2006. https://doi.org/10.1016/j.agwat.2005.07.001
 Smakhtin, V., Revenga, C. & Döll, P., A pilot global assessment of environmental water requirements and scarcity. Water International, 29(3), pp. 307–317, 2004. https://doi.org/10.1080/02508060408691785
 Engelman, R., Cincotta, R.P., Dye, B., Gardner-Outlaw, T. & Wisnewski, J., People in the Balance: population and natural resources at the turn of the millennium. Population Action International, Washington DC, 2000.
 Vedwan, N., Ahmad, S., Miralles-Wilhelm, F., Broad, K., Letson, D. & Podesta, G., Institutional evolution in Lake Okeechobee management in Florida: characteristics, impacts, and limitations. Water Resources Management, 22(6), pp. 699–718, 2008. https://doi.org/10.1007/s11269-007-9187-7
 Vörösmarty, C.J., Global water resources: vulnerability from climate change and pop- ulation growth. Science, 289(5477), p. 284, 2000. https://doi.org/10.1126/science.289.5477.284
 Moss, R.H., et al., The next generation of scenarios for climate change research and assessment. Nature, 463(7282), pp. 747–756. https://doi.org/10.1038/nature08823
 Cooley, H., et al., Understanding and reducing the risks of climate change for trans- boundary waters. Pacific Institute Oakland, 2009.
 Bazzani, G.M., Di Pasquale, S., Gallerani, V., Morganti, S., Raggi, M. & Viaggi, D., The sustainability of irrigated agricultural systems under the water framework directive: first results. Environmental Modelling & Software, 20(2), pp. 165–175, 2005. https://doi.org/10.1016/j.envsoft.2003.12.018
 Füssel, H.-M., Vulnerability: a generally applicable conceptual framework for climate change research. Global Environmental Change, 17(2), pp. 155–167, 2007. https://doi.org/10.1016/j.gloenvcha.2006.05.002
 Rosenzweig, C., Strzepek, K., Major, D., Iglesias, A., Yates, D., Mccluskey, A. & Hil- lel, D., Water resources for agriculture in a changing climate: international case studies. Global Environmental Change, 14(4), pp. 345–360, 2004. https://doi.org/10.1016/s0959-3780(04)00062-7
 Arnell, N.W., Climate change and global water resources: SRES emissions and socio- economic scenarios. Global Environmental Change, 14(1), pp. 31–52, 2004. https://doi.org/10.1016/j.gloenvcha.2003.10.006
 Alcamo, J., Flörke, M. & Märker, M., Future long-term changes in global water resources driven by socio-economic and climatic changes. Hydrological Sciences Journal, 52(2), pp. 247–275, 2007. https://doi.org/10.1623/hysj.52.2.247
 Ministry of Agriculture, Land use land cover map for Lebanon, Ministry of Agriculture: Beirut, Lebanon, 2002.
 Ministry of Environment, State of the Environment Report. Beirut, Lebanon, 2001.
 Ministry of Energy and Water, National Water Sector Strategy. Beirut, Lebanon, 2010.
 Mitchell, T.D., et al., A comprehensive set of high-resolution grids of monthly climate for Europe and the globe: the observed record (1901–2000) and 16 scenarios (2001– 2100). Tyndall Centre for Climate Change Research Working Paper, 55: p. 25, 2004.
 Fayad, A., Watershed modeling using integrated hydrologic information system, in Department of Civil and Environmental Engineeering. American University of Beirut: Beirut, Lebanon, 2012.
 Kyselý, J. & Beranová, R., Climate-change effects on extreme precipitation in central Europe: uncertainties of scenarios based on regional climate models. Theoretical and Applied Climatology, 95(3–4), pp. 361–374, 2009. https://doi.org/10.1007/s00704-008-0014-8
 Maurer, E., Adam, J. & Wood, A., Climate model based consensus on the hydrologic impacts of climate change to the Rio Lempa basin of Central America. Hydrology & Earth System Sciences Discussions, 5(6), pp. 3099–3128, 2008. https://doi.org/10.5194/hessd-5-3099-2008
 Semenov, M.A. & Stratonovitch, P., Use of multi-model ensembles from global climate models for assessment of climate change impacts. Climate Research (Open Access for articles 4 years old and older), 41(1), p. 1, 2010. https://doi.org/10.3354/cr00836
 Tao, F., Zhang, Z., Liu, J. & Yokozawa, M., Modelling the impacts of weather and climate variability on crop productivity over a large area: A new super-ensemble-based probabilistic projection. Agricultural and Forest Meteorology, 149(8), pp. 1266–1278, 2009. https://doi.org/10.1016/j.agrformet.2009.02.015
 Yates, D., Purkey, D., Sieber, J., Huber-Lee, A. & Galbraith, H., WEAP21—A demand-, prior- ity-, and preference-driven water planning model part 2: aiding freshwater ecosystem service evaluation. Water International, 30(4), pp. 501–512, 2005. https://doi.org/10.1080/02508060508691894
 Yates, D., Sieber, J., Purkey, D. & Huber-Lee, A., WEAP21—A demand-, priority-, and preference-driven water planning model: part 1: model characteristics. Water International, 30(4), pp. 487–500, 2005. https://doi.org/10.1080/02508060508691893
 Hashimoto, T., Stedinger, J.R. & Loucks, D.P., Reliability, resiliency, and vulnerability criteria for water resource system performance evaluation. Water Resources Research, 18(1), pp. 14–20, 1982. https://doi.org/10.1029/wr018i001p00014
 Zongxue, X., Jinno, K., Kawamura, A., Takesaki, S. & Ito, K., Performance risk analysis for Fukuoka water supply system. Water Resources Management, 12(1), pp. 13–30, 1998. https://doi.org/10.1023/a:1007951806144
 Fowler, H., Kilsby, C. & O’Connell, P., Modeling the impacts of climatic change and variability on the reliability, resilience, and vulnerability of a water resource system. Water Resources Research, 39(8), 2003. https://doi.org/10.1029/2002wr001778
 Martin-Carrasco, F.J. & Garrote, L., Drought-induced water scarcity in water resources systems, in Extreme hydrological events: new concepts for security. In: O.F. Vasiliev, et al., Editors, Springer Netherlands. pp. 301–311, 2007.
 Pulido-Velazquez, D., Garrote, L., Andreu, J., Martin-Carrasco, F-J. & Iglesias, A., A methodology to diagnose the effect of climate change and to identify adaptive strategies to reduce its impacts in conjunctive-use systems at basin scale. Journal of Hydrology, 405(1), pp. 110–122, 2011. https://doi.org/10.1016/j.jhydrol.2011.05.014