The transport of heat and fluids in soils and rocks can be affected by significant coupling between thermal, hydrological, mechanical, and chemical (THMC) processes. These include, but are not limited to, conductive, convective and radiative transport of heat, flow of liquids and gases under viscous, capillary and gravitational forces, stress-induced deformation and degradation, reactive transport, mineral precipitation/dissolution, and colloid transport. Understanding such processes is important for various applications, such as environmental remediation, nuclear waste disposal, CO2 geological sequestration, and oil, gas, and geothermal reservoir recovery. Hydrogeology Department scientists address the complex field of coupled processes analysis through an integrated experimental and modeling effort, combining laboratory experiments and in situ tests, using advanced monitoring methods with sophisticated modeling analysis. Powerful numerical simulators have been developed for flow and transport of multiphase, multicomponent fluids, capable of modeling TH processes (TOUGH2), THC processes (TOUGHREACT), and THM processes (TOUGH2-FLAC).