抄録
Gravity-driven groundwater flow at the scale of drainage basins (basinal flow) is influenced by topography, which controls the water-table position and shape, and geological framework. The theory of groundwater flow systems was developed in the 1960's, in an effort to reconcile field observation with the theory of fluid potential, supported by mathematical analysis. Groundwater flow systems have a hierarchical structure comprising local, intermediate, and regional flow regimes; each having recharge, through-flow, and discharge zones. The presence of high- or low-permeability layers at depth can cause conspicuous spatial distribution of discharge or recharge areas on the surface. Owing to the in-situ interaction of groundwater and the surrounding environment, and the transport and accumulation processes, groundwater is considered a geologic agent. The concept of gravity-driven flow systems has provided a unifying theoretical background for understanding a diverse range of physical, chemical, and ecological phenomena. This article presents a brief overview of the theory of gravity-driven groundwater flow and its roles as a geologic agent, and also describes how the theory was introduced to and adopted by groundwater hydrologists in Japan.
