Two or more distinct phases of a compound or its breakdown products flowing through the subsurface at the same time.
In the unsaturated zone the contaminant transport includes 3 phases: solutes in the dissolved phase, vapour phase and an immiscible phase. In the saturated zone the contaminant transport includes 2 phases: solutes in the dissolved phase and an immiscible phase.
Why is a multiphase flow important?
Multiphase flow is important to consider when dealing with and assessing the movement of NAPL contaminants.