sentences:  Salt concentrations of outgoing water (either from one reservoir into the other or by subsurface drainage) are computed on the basis of salt balances, using different "leaching or salt mixing efficiencies" to be given with the input data.The effects of different leaching efficiencies can be simulated by varying their input value.If drain or well water is used for irrigation, the method computes the salt concentration of the mixed irrigation water in the course of the time and the subsequent effect on the soil and ground water salinities, which again influences the salt concentration of the drain and well water.