Wonderful Refreshing Springs

A spring is the result of an aquifer being filled to the point that the water overflows onto the land surface. They can range in size from intermittent seeps, which flow only after lots of rain, to huge pools with a flow of millions of gallons per day.

Jacob's Well, in Wimberley, Texas, is a VERY large spring.

A natural, vertical shaft over 300 feet deep flows constantly, forming Cypess Creek. Since the water is coming straight out of the aquifer, it is around 65° all year round.

The Well is a popular swimming hole, although I find it tough to stay in for very long.

Springs may be formed in any sort of rock, but are more common in limestone, which fractures easily and can be dissolved by weakly acidic rainfall.

As the rock dissolves and fractures, spaces can form that allow water to flow. If the flow is horizontal, it can reach the land surface, resulting in a spring.

Spring Water is Not Always Clear

Some springs, however, may have "tea-colored" water. The coloring comes from mineral enrichment caused by ground water coming in contact with naturally occurring minerals.

If surface water enters the aquifer near a spring, the water can move quickly through the aquifer and discharge at the spring vent. The discharge of highly colored water from springs can indicate that water is flowing quickly through large channels within the aquifer without being filtered through the limestone.

Thermal Springs

Thermal springs are ordinary springs except that the water is warm and, in some places, hot.

Many thermal springs occur in regions of recent volcanic activity and are fed by water heated by contact with hot rocks far below the surface. Even where there has been no recent volcanic action, rocks become warmer with increasing depth.

In these areas water may migrate slowly to considerable depth, warming as it descends through rocks deep in the Earth. If it then reaches a large crevice that offers a path of less resistance, it may rise more quickly than it descended.

Water that does not have time to cool before it emerges forms a thermal spring.

And, yes, warm springs can even coexist with glaciers, as many happy Greenlanders can testify.

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