Under the action of gravity, surface water and groundwater always tend to W&;,7T8@
flow from higher to lower elevations. Surface water will flow over solid and oS#PBql4
through permeable formations, and its volume and velocity are a function of d9.~W5^fC
the available supply and the fluid head. Groundwater can move only +VRM:&
through a pervious material (fractured or fissured rock or soils with Ql{:H5
interconnected open voids), so its flow characteristic is also a function of q?bKh *48
formation permeability. Groundwater elevation varies as the supply source X.J$
5b
varies and can be raised or lowered locally by increasing or decreasing the Y3?)*kz%
local supply (naturally by precipitation or artificially by pumping a well or fW3NH7aUG
irrigating). In general, over a large surface area, groundwater surface is a aW;DfH
subdued replica of ground surface.
