Environmental Isotopes profiles and Evaporation in shallow water Table soils

An estimated 0.66 of a billion cubic meters of water is lost each year from the Nile delta fallow soils using a physical model based on environmental isotopes profile data. Three times this amount is supplied to the root zone during the crop growing seasons through capillary rise. A modified water strategy should take into account this upward flow in order to optimize water management on the regional scale. The evaporation rate estimation and its extrapolation of capillary rise evaluation presented are subject to the working assumptions. Some factors lead to certain difficulties, namely: the presence of secondary evaporation planes, highly developed structure cracking at the soil surface, clay dispersion in the lower layers, sporadic winter rains, micro-climatic fluctuations, slight depletion in the inner water molecules compared to bulk pore water due to the history of soil material humidification and, finally bulk density errors due to shrinking and swelling of soils