ground water

2.2 Ground water flow
2.2.1 Introduction
1- Ground water
• It is water that exists beneath the earth s surface in underground streams and aquifers.
• It is found that underground where part/entire حيث الفراغات تكون بشكل جزئي او كليvoid spaces between particles of rock and soil, or in crevices and cracks in rock are filled with water.

• Groundwater an important part of the hydrologic cycle
? Some of the water from melting snow/rainfall seeps into the soil and percolates into the saturated zone to become
Groundwater recharge.
? Eventually, groundwater reappears above the ground into streams, rivers, marshes, lakes and oceans or as springs and flowing wells discharge.


• ?Groundwater faces the threat of contamination from waste sites.
• ?Properties of subsurface govern both the rate and direction of groundwater flow.
2- Vertical distribution of groundwater
* Groundwater can be characterized according to its vertical distribution.
* Zone of aeration: consists of interstices فجوات occupied partially by water and partially by air.
? Soil water zone : extending from ground surface down through the major root zone
? Vadose zone : extending from lower edge of soil water zone to the upper limit of capillary zone
? Capillary zone: extending from the water table up to the limit of capillary rise.
* Zone of saturation: all interstices are filled with water under hydrostatic pressure.