LNAPL transmissivity is the discharge of light non-aqueous phase liquid (LNAPL) through a unit width of aquifer for a unit gradient.
Scholars Alex Mayer and S. Majid Hassanizadeh define LNAPL transmissivity as the "product of the porous medium permeability and the LNAPL relative permeability, which in turn is a function of saturation, and the thickness of the LNAPL".
As a result, LNAPL transmissivity decreases in direct proportion to the decrease in LNAPL saturation achievable through liquid recovery technology.
LNAPL Transmissivity is not the only piece of data required when evaluating a site overall, because it requires a good LNAPL conceptual model in order to calculate.
However, it is a superior summary metric to gauged LNAPL thickness to represent LNAPL recoverability and migration risk (e.g., on site maps) and direct remediation efforts.