Simulation of processes involved in soil salinization to guide soil remediation

The man-made development of lands for irrigated agriculture has provided benefits, but in some schemes has resulted in catastrophic problems arising from soil salinization including those in the Aral Sea Basin in central Asia and the Murray-Darling Basin in Australia. Soil salinization is, a gradual process and the impact of salt intrusion is noticeable after several years of development, typically ranging from 10 to 30 years. In central Asia salt water management has historically been based on rules of thumb with mixed results. A coupled surface and ground water model, HYDRO-GW, has been developed with the facilities to model the processes in the root zone and in the unsaturated and saturated subsurface system. The model is applied to the Kashkadarya irrigation area in Uzbekistan to assess the impact of various changes in land and water management practices on reducing salinity levels. Simplified equations have been presented which have potential application for assessing the salinization process and can be used as precursors to detailed assessment using a coupled surface and ground water model.