SoWat stands for Sodium chloride-Water and is a model (almost an equation of state) for the properties of fluids in the H2O-NaCl system.
It has just been published in two parts in Geochimica et Cosmochimica Acta.
Computational geochemistry, molecular geochemistry, thermodynamics of fluids and minerals. Interplay between geochemistry and modern physical-chemistry.