1. Research Dep.; Israel Hydrological Service; P.O. Box 20365 Tel Aviv 61203 Israel
2. Ben-Gurion Univ. of the Negev, The Jacob Blaustein Institute for Desert Research; Dep. of Environmental Hydrology & Microbiology; Sde Boker Campus 84990 Israel
3. Institute of Soil, Water and Environmental Sciences; The Volcani Center; Agricultural Research Organization; P.O. Box 6 Bet-Dagan 50250 Israel
4. Institute of Soil, Water and Environmental Sciences; Newe-Ya'ar Research Center; Agricultural Research Organization; P.O. Box 1021 Ramat Yishay 30095 Israel