Hydrogeology Part – 4 SPRINGS A spring is a concentrated discharge of groundwater appearing at the ground surface as a current of flowing water. Springs occur in many forms and have been classified as to cause, rock structure, discharge, temperature, and variability.  Bryan divided all springs into       those resulting from nongravitational forces and      those resulting from gravitational forces.  Under the former category are included volcanic springs, associated with volcanic rocks, and fissure springs, resulting from fractures extending to great depths in the earth's crust. Such springs are usually thermal (fig above).  Gravity springs result from water flowing under hydrostatic pressure. the following general types are recognized: 1. Depression Springs-Formed where the ground surface intersects the water table. 2. Contact Springs-Created by a permeable water-bearing formation overlying a less permeable formation that inte...

Hydrogeology Part – 2   Darcy’s law and hydraulic conductivity           Water contained within the interconnected voids of soils and rocks is capable of moving, and the ability of a rock to store and transmit water constitutes its hydraulic properties.      The laws that govern the behaviour of groundwater flow in saturated material is that formulated empirically by the French municipal engineer for Dijon, Henry Darcy, in 1856.      Darcy studied the flow of water through porous material contained in a column and found that the      T otal flow - Q, is proportional - difference in water level, h1 − h2, the cross-sectional area of flow, A, and inversely proportional to the column length, L. proportionality constant - K      where dh/dl represents the hydraulic gradient, with the negative sign indicating flow in the direction of decreasing hydraulic head. Limitations:      D...

 Hydrogeology Part – 2  Vertical distribution of Ground water Zone of aeration  Consists of interstices occupied partially by water and partially by air. Sub divided into the soil water zone, the intermediate vadose zone, and the capillary zone Zone of saturation        All interstices are filled with water under hydrostatic pressure. The saturated zone extends from the upper surface of saturation down to underlying impermeable rock. phreatic surface - is defined as the surface of atmospheric pressure and appears as the level at which water stands in a well penetrating the aquifer.      Saturation extends slightly above the water table due to capillary attraction; however, water is held there at less than atmospheric pressure. Water occurring in the zone of saturation is in commonly referred to simply as groundwater, but the term phreatic water is also employed. Types of Aquifers      Aquifers may be classed as unconfined ...