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...