PrintUnderstanding flow and transport processes in the natural subsurface are important for a wide range of applications and disciplines. Flow and transport processes play a critical role in ground water and surface water management and environmental protection, energy extraction from deep hydrocarbon reservoirs, chemical weathering, and soil management. Here we primarily discuss fundamental flow and transport processes in natural subsurface systems.
For a conservative tracer that does not participate in reactions, advection, dispersion and diffusion are the major transport processes that control its transport. Advection, also called convection in some disciplines, determines how fast a tracer moves with the fluid flow; dispersion and diffusion processes are driven by concentration gradients and/or the spatial variation of flow velocities and therefore determine the extent of spreading.