An approach for assessing the vulnerability of the water resources of Yemen to climate change

This paper outlines the methodology followed in the study of climate change impact on water resources in Yemen and presents initial results on the vulnerability of the water resources system. The selected modeling strategy is used for the first time in climate change assessment studies and is briefly discussed, This strategy comprised 4 interacting models: a Rainfall-Runoff Model (RRM), an Irrigation Simulation Model (ISM), a Groundwater Simulation Model (GSM), and an Economic Policy Model (EPM). Adequate indication of the water system's sensitivity to climate change in arid and semiarid regions can only be achieved when appropriate temporal and spatial scales of the assessment are used. For instance, only hourly or daily time step models can capture climate impacts on floods of ephemeral wadis. The degree of accuracy required should also be determined by the scarcity/availability of the resources.