Movements of groundwater and transport in the subsurface are responsible for a variety of environmental, engineering, and geological processes of importance. This course targets students from various disciplines (geosciences, environmental engineering, agricultural engineering, civil engineering, chemical engineering, and applied mathematics) that work with physical and chemical processes in natural subsurface. The course will introduce the fundamental concepts that are important in understanding subsurface (reactive) transport processes, as well as their quantitative representation and application. Covered topics include, for example, effects of dispersion, transformation reactions, porous-media heterogeneity on transport, aqueous (dissolved) and multiphase (immiscible liquid, gas) systems, and interphase mass transfer. Depending on the students’ interests, the course will discuss the applications of the principles in understanding and quantifying chemical weathering processes, environmental (bio)remediation, geological carbon sequestration, and reservoir souring.