FIELD-EVALUATION OF DESALINIZATION MODELS

Assessing the water quantities required for leaching salt-affected soi l is an important task in a reclamation programme. In Iraq, evaluation of leaching processes, in most reclamation projects, is achieved usin g empirical equations or by carrying out simple laboratory tests which can lead to error in estimating leaching requirements. In this study, five well-known mathematical models, each with a different theoretica l background, are chosen for evaluation against measured salt concentr ations within four test sites located in four major reclamation projec ts of different locations within the Mesopotamian Plain. The verificat ion of the single reservoir model with bypass, the theoretical plate t hickness scheme. the hydrodynamic convection-dispersion model and the transfer function models used against field data revealed significant agreement between the observed and predicted values of salinity during the leaching process within a certain depth of soil below surface. Bu t the model comprising a series of reservoirs provided a high degree o f correlation with the observed salinity within the whole profile of s oil. It was concluded that the selected mathematical models used for s tudying the leaching process lead to good correlations between predict ed and observed salinity values and these tend to improve with the inc rease of leaching water amounts.