Under the action of gravity, surface water and groundwater always tend to FJ?IUy 6
flow from higher to lower elevations. Surface water will flow over solid and Dv`c<+q(#
through permeable formations, and its volume and velocity are a function of 63 B?.
the available supply and the fluid head. Groundwater can move only ;i:d+!3XwC
through a pervious material (fractured or fissured rock or soils with Aq7osU1B
interconnected open voids), so its flow characteristic is also a function of >b4eL59
formation permeability. Groundwater elevation varies as the supply source II x#2r
varies and can be raised or lowered locally by increasing or decreasing the sCHJ&>m5-
local supply (naturally by precipitation or artificially by pumping a well or y:l\$ pGC%
irrigating). In general, over a large surface area, groundwater surface is a H}
g{Cr"Ex
subdued replica of ground surface.
