Groundwater contamination may occur as a result of spillages of hazardous chemicals, dumping of toxic waste, landfills, waste water, or industrial discharges. Contamination present within the ground has the potential to migrate or be transported by natural groundwater flow processes, and may ultimately enter the human food chain, either directly, or indirectly through agriculture.

NAMMU has the capability to model saturated and unsaturated groundwater flow in three dimensions. Transient contaminant transport may be modelled, including the effects of advection, diffusion, longitudinal and transverse dispersion, sorption and radioactive decay. In addition, fully coupled saline calculations are possible, modelling the process of salt intrusion to the water table.