The groundwater motion under a geothermal condition is driven by the potential force originated from the water table gradient and by the buoyancy originated from the temperature distribution. Numerical experiments suggest that three types of groundwater flow system are possible; (1) the system in which potential and convective flows are balanced each other, (2) the system in which convective elements are transported to downstream by the potential flow, and (3) the system in which the potential flow is predominant. When the convective effect is relatively significant, such as systems of (1) and (2), some local flow systems are formed in the aquifer, and recharge and discharge areas of groundwater appear alternately along the surface of the aquifer. Thermal convection has an effect to narrow the area of heat distribution near by the heat source, while the potential flow can distribute heat over a wide area to downstream far from the heat source.
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