Effect of Shallow and Saline Groundwater on Drain Water Salt Loud in South Khuzestan

ABSTRACT Drainage water has to be disposed of, and in many cases they are disposed to rivers as a receiving water bodies. In order to attain sustainable river management, optimum use of water resources and reduction of the adverse effect of development, it is compulsory to prepare a plan for drain water management. In this research the mathematical model for forecasting the drain water quality in reclamation period is prepared based on water and salt mass balance in soil column. The control volume was between the drainage level and the soil surface and the soil condition was assumed saturated. Leaching experiment was executed in 10 hectare field in the south Khuzestan plain, SW Iran. Salinity and volume of the leaching water and drainage water during the experiments and soil before and after experiment were measured. Drain water salinity during the experiment was almost constant and very close to the groundwater salinity, and therefore there is no conformity with the mass balance model (between soil surface and drainage level). It shown that the shallow and saline groundwater table is highly affecting drain water salinity during initial leaching. So, as the main source of salt loud in drainage effluents, control of shallow and saline ground water must be more considered in design and operation steps. KEYWORDS: Groundwater, Impervious Layer, Leaching, Reclamation, Salinity