A sacred spring
At Tampak Siring in Bali, Indonesia, spring water emerges into a temple. The water is thought to have healing powers. Many Hindu people come to the temple to emerge in the water and pray. They hope the water will cure their diseases.
The top of an aquifer may be high enough in some places to meet the surface of the ground. This often happens on a slope. The water flows out of the ground and creates a spring. A spring may be just a tiny trickle, or it may be a big gush of water.
Water flowing out of the ground at a spring may flow downhill and enter a stream. If the water from a spring can’t flow downhill, it may spread out to form a pond or lake instead. In the desert, the only reliable water may be from springs (Figure below). A spring may allow wildlife to inhabit an uninhabitable area.
A desert oasis is created by a spring in Nevada.
Sometimes an aquifer is confined. A confined aquifer is trapped between two impermeable rock layers. Pressure from the rock layer on top forces the water out where the aquifer reaches the ground surface. Water that flows up to the surface naturally is an artesian spring. If people drill a well into a confined aquifer, the water may flow to the surface without assistance. This is an artesian well (Figure below).
This artesian well supplies the water for Schönbrunn Palace in Germany.
Mineral Springs and Hot Springs
Some springs have water that contains minerals. Groundwater dissolves minerals out of the rock as it seeps through the pores. The water in some springs is hot because it is heated by hot magma. Many hot springs are also mineral springs. That’s because hot water can dissolve more minerals than cold water.
Springs in Yellowstone National Park are hot and contain dissolved minerals. Morning Glory Pool (Figure below) has a bright green color from dissolved minerals. Along the edge are thick orange mats of bacteria. The bacteria use the minerals in the hot water to make food.
Morning Glory Pool in Yellowstone National Park is a mineral spring.
Heated groundwater may become trapped in spaces within rocks. Pressure builds up as more water seeps into the spaces. When the pressure becomes great enough, the water bursts out of the ground at a crack or weak spot. This is called a geyser. When the water erupts from the ground, the pressure is released. Then more water collects and the pressure builds up again. This leads to another eruption.
Old Faithful (Figure below) is the best-known geyser in the world. The geyser erupts faithfully every 90 minutes, day after day. During each eruption, it may release as much as 30,000 liters of water!
Old Faithful in Yellowstone National Park is a geyser named for its regular cycle of eruptions.
- Earth's internal heat can create a hot spring.
- If hot water becomes trapped, pressure may build up. When the water breaks free, it creates a geyser.
Use the resource below to answer the questions that follow.
- Geysers and Hot Springs at http://library.thinkquest.org/17457/volcanoes/features.geysers.php
- What are geysers?
- Where does the heat for geysers come from?
- What are hot springs?
- What do hot springs contain?
- Where can hot springs be found?
- What causes a spring?
- Describe how a geyser erupts.
- Where do the minerals in mineral springs come from?