Theory question 205
Underground Water and Karst(a) What is a spring? (b) With the aid of diagrams, describe three ways by which springs may be formed.
Show the model answer
Model answer
(a) A spring is a natural outflow of underground water at the earth's surface.
(b) Diagrams for any three: where a permeable rock lies on an impermeable rock and the junction meets the slope (scarp-foot / hillside spring); where the water table reaches the surface in a valley; along a fault that brings impermeable rock against permeable rock; where a dyke blocks the flow of groundwater; in limestone where an underground stream comes out at the base of the rock (vauclusian spring); hot springs in volcanic areas.
Explanation
Each diagram should show permeable and impermeable layers and the water table.