New Insights Into The Natural Variability of Water Resources in The Lower Jordan River Basin

Water availability is naturally low in the Lower Jordan River Basin (LJRB) extending from Lake Tiberias to the Dead Sea, whereas water demand is high. Still, no basin-wide overview of naturally available surface water resources exists up to now. The aim of this study is to estimate these water resources through application of the TRAIN-ZIN model. This hydrological model combines physically-based and conceptual approaches to incorporate dominant processes of (semi-)arid areas in adequate temporal and spatial scale. An adequate space-time resolution is achieved by using rainfall radar data as model input. Three rainfall seasons are simulated: a drought, an average season and a wet extreme. Simulation results emphasize the non-linear behaviour of (semi-)arid systems and resulting impacts on the spatial and temporal variability of water resources. Basin averages of seasonal water balance components ranged between 65 and 489 mm (rainfall), 53 and 270 mm (evapotranspiration), 7 and 87 mm (overland flow), 4 and 129 mm (percolation). However, all values comprise enormous spatial variability. It is concluded that space-time variability must be considered for water resources assessment in the LJRB in order to make accurate predictions of future water availability.