RAINFALL DURING MODERN AND HOLOCENE DEAD SEA LAKE-LEVEL CHANGES AND WATER RESOURCES DURING LONG-TERM DROUGHTS IN THE MIDDLE EAST

Recently constructed chronologies of Dead Sea levels over the last 3000 years will be presented. To quantify these changing levels in terms of precipitation and water resources in the basin and the severity of Middle East droughts, we construct an analogue for lake level changes in terms of 19th and 20th centuries rainfall fluctuations of Jerusalem; the longest rainfall record in the region. By that we overcome the complexity of the hydrologic system of the Dead Sea and the sparsely rainfall data synchronous with modern natural Dead Sea levels. We show that fluctuations in Jerusalem rainfall represent large areas in Israel and neighboring countries. The historic lake curve of the Dead Sea and rainfall data since 1880s are utilized to calculate the mean and standard deviation of Jerusalem rainfall during rise (648 mm/yr, sd=122 mm), fall (445 mm/yr, sd=117 mm), and stable (553 mm/yr, sd=120 mm) lake levels of the Dead Sea prior to the artificial diversions of water from its drainage basin. We suggest that these values characterize Holocene rains during the various modes of Dead Sea lake-level changes. If this is accepted, the association between Jerusalem and northern Israel rainfall and the Dead Sea level variations point at the severity of past regional droughts. The simple relationship between Galilee rainfall and available water for consumption in the Sea of Galilee were demonstrated before. This relationship indicates that during late Holocene Dead Sea level falls only little (if at all) volume of water was available annually. The prevailing climatic conditions during these multi-year episodes were severe droughts that in modern times will be a disaster for the Middle East water resources.