subsurface flow

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subsurface flow The flow of water at a shallow depth beneath the ground surface; it may be influenced by relatively impermeable layers which enlarge lateral flow. A temporary rise in the water-table can produce saturated interflow (saturated throughflow) analogous to saturated overland flow. The subsurface flow can re-emerge at the surface at or near the base of hill-slopes. Throughflow is flow through the soil, whereas interflow is flow through the rock above the water-table.