Experimental Study of the Solute Transport towards Groundwater and Surface Water

The study of infiltrated solutes and their pathways toward the rivers is very important in water quality studies of rivers and groundwaters well as the management of fertilizers and pesticides in the farms. In this research, the transport of infiltrated solutes toward the connected groundwater and surface water was experimentally studied. The concentration of solutes and the discharges were measured separately in the groundwater and surface water, using a creative modification in the current experimental model of 150 cm length, 70 cm high and 20 cm width. Potassium permanganate was used to observe the pollutant cloud movement and sodium chloride was used to measure the amount of transported solute. Potassium permanganate was injected in places of 15, 35, and 55 cm far from the river while NaCl was injected in places of 15, 35, and 65 cm far from the river. In all experiments, the hydraulic head difference was 33 mm in the model. The tracer study showed that the capillary zone affects solute transport and the tracer starts to move horizontally above the groundwater table. When the NaCl injection starts, due to changes in the boundary condition, the river discharge decreases while the groundwater discharge increases. Continuous measurement of EC in groundwater and surface water showed that the river is affected more than the groundwater by receiving 60% of the injected salt.