Catchment-scale hydrological studies on drylands are lacking because of the scarcity of consistent data: observations are often available at the plot scale, but their relevance for the catchment scale remains unclear. A database of 24 years of stream gauge discharge and homogeneous high-resolution radar data over the eastern Mediterranean allows us to describe the properties of floods over catchments spanning from desert to Mediterranean climates, and we note that the data set is mostly of moderate intensity floods. Comparing two climatic regions, desert and Mediterranean, we can better identify specific rainfall-runoff properties. Despite the large differences in rainfall forcing between the two regions, the resulting unit peak discharges and runoff coefficients are comparable. Rain depth and antecedent conditions are the most important properties to shape flood response in Mediterranean areas. In deserts, instead, storm core properties display a strong correlation with unit peak discharge and, to a lesser extent, with runoff coefficient. In this region, an inverse correlation with mean catchment annual precipitation suggests also a strong influence of local surface properties. Preliminary analyses suggest that floods in catchments with wet headwater and dry lower section are more similar to desert catchments, with a strong influence of storm core properties on runoff generation.
Bibliographical noteFunding Information:
Financial support. This research has been supported by the United
Acknowledgements. This study was funded by the NSF-BSF grant BSF 2016953, by the Israel Science Foundation (grant no. 1069/18), by the BARD project (IS-5124-18) and by a Google gift grant. This study is a contribution to the PALEX project Paleohydrology and Extreme Floods from the Dead Sea ICDP Core and is a contribution to the HyMeX program.
This research has been supported by the United States-Israel Binational Science Foundation (grant no. 2016953), the Israel Science Foundation (grant no. 1069/18), and the United States-Israel Binational Agricultural Research and Development Fund (grant no. 5124-18).
© Author(s) 2019.