Spring is a natural source of water that flows from the ground. Water from rain and melting snow seeps into the ground. It filters through the pores and cracks in the soil into the layers of rock. The water finally reaches a layer through which it cannot pass. This water held underground is called ground water. Gravity may force the water to rise until it finds a way out to the surface to form a spring.
Springs are found in mountains, hills, and valleys. They are often found at the foot of a cliff or slope or where a crack or fault reaches the surface. Hundreds of springs pour from walls of Idaho’s Snake River Canyon.
The largest springs are found in limestone regions where the water flows underground in cavelike channels. Where such channels reach the surface, great quantities of water may pour from the ground. Famous limestone springs are found in Florida and Missouri.
The temperature of a spring depends on the temperature of the soil or rocks through which its water flows. Ground water that travels close to the surface may produce springs that are warmer in summer than in winter. Springs that come from farther down are always cold. But deep down in the earth all rocks are hot. In volcanic regions hot rock may lie close to the surface. As a result, spring water that has traveled from deep in the earth, or has originated in volcanic regions, is often hot.
Many springs contain minerals dissolved from the rock by the moving water. They are known as mineral springs. The belief that these springs relieve ailments has popularized them as health resorts. Examples of such health springs can be found in Mount Clemens, Mich. ; Saratoga Springs, N.Y.; Hot Springs National Park, Ark. ; and in France.
