Flow of ground water through porous medium is governed by well-known Darcy's law which states that the rate of flow, Q through a saturated porous medium is: (i) Proportional to the difference in hydraulic head Ah between the two flow sections, (ii) Proportional to the area of flow cross-section A, and (iii) Inversely proportional to the length, L between the [...]
This article provides a paragraph on well irrigation. The amount of water stored in the earth's crust is estimated to be around 8 billion cubic kilometres, half of which is at depths less than 800 metres. This volume of water is about 35 times the combined storage of all the world's rivers, fresh water lakes, reservoirs and inland seas. Ground [...]
The subsurface occurrence of ground water can be divided into two zones (Fig. 4.1): (i) Vadose zone or unsaturated zone or zone of aeration, and (ii) Phreatic zone or saturated zone or zone of saturation. In the saturated zone, all pores or voids are filled with water, whereas in the unsaturated zone, pores contain gases (mainly air and water vapours) [...]