Effects of solute concentration–dependent surface tension on unsaturated flow: Laboratory sand column experiments

Laboratory and numerical modeling studies were conducted to investigate the effects of solute concentration–dependent surface tension on unsaturated flow and transport of a dissolved organic compound. The laboratory experiments were conducted in a 2 m long unsaturated/saturated sand column with a water table at the bottom and butanol as the solute. Pressure head was measured with tensiometers connected to pressure transducers, and water content …