Surfactant‐Induced Unsaturated Flow: Instrumented Horizontal Flow Experiment and Hysteretic Modeling

Organic compounds with surface‐active properties reduce the surface tension of water and can change soil water contact angles depending on their aqueous concentration. The presence of such compounds in the unsaturated zone affects soil moisture characteristics and unsaturated hydraulic conductivity relations, and can cause flow as a result of induced soil water pressure gradients. Some studies have used horizontal column experiments to measure …