Under the action of gravity, surface water and groundwater always tend to _[OEE<(
flow from higher to lower elevations. Surface water will flow over solid and VrGb;L'[
through permeable formations, and its volume and velocity are a function of FUqhSW
the available supply and the fluid head. Groundwater can move only rd 35)
through a pervious material (fractured or fissured rock or soils with G|G?h
interconnected open voids), so its flow characteristic is also a function of c7nk~K[6
formation permeability. Groundwater elevation varies as the supply source E=1/
varies and can be raised or lowered locally by increasing or decreasing the l#vw
L15
local supply (naturally by precipitation or artificially by pumping a well or u.L8tR:(
irrigating). In general, over a large surface area, groundwater surface is a a@=36gx)
subdued replica of ground surface.