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spring

 
Britannica Concise Encyclopedia: spring
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In hydrology, an opening at or near the Earth's surface where water from underground sources is discharged. Springs discharge either at ground level or directly into the bed of a stream, lake, or sea. Water that emerges at the surface without a perceptible current is called a seep.

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Sci-Tech Encyclopedia: Spring
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A place where groundwater discharges upon the land surface because the natural flow of groundwater to the place exceeds the flow from it. Springs are ephemeral, discharging intermittently, or permanent, discharging constantly. Springs are usually at mean annual air temperatures. The less the discharge, the more the temperature reflects seasonal temperatures. Spring water usually originates as rain or snow (meteoric water).

Hot-spring water may differ in composition from meteoric water through exchange between the water and rocks. Common minerals consist of component oxides. Oxygen of minerals has more 18O than meteoric water. Upon exchange, the water is enriched in 18O. Most minerals contain little deuterium, so that slight deuterium changes occur. Some hot-spring waters are acid from the oxidation of hydrogen sulfide to sulfate.

Mineral spring waters have high concentrations of solutes and wide ranges in chemistry and temperatures; hot mineral springs may be classified as hot springs as well as mineral springs. Most mineral springs are high either in sodium chloride or sodium bicarbonate (soda springs) or both; other compositions are found, such as a high percentage of calcium sulfate from the solution of gypsum.

The chemical compositions of spring waters are seldom in chemical equilibrium with the air. Groundwaters whose recharge is through grasslands may contain a thousand times as much CO2 as would be in equilibrium with air, and those whose recharge is through forests may contain a hundred times as much as would be in equilibrium with air. Sulfate in groundwater may be reduced in the presence of organic matter to H2S, giving some springs the odor of rotten eggs. See also Geyser; Ground-water hydrology.

 
Columbia Encyclopedia: spring
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spring, in geology, natural flow of water from the ground or from rocks, representing an outlet for the water that has accumulated in permeable rock strata underground. Some of the water that falls as rain soaks into the soil and is drawn downward by gravity to a depth where all openings and pore spaces in the rock or soil have become completely saturated with water. This region is called the zone of saturation, and the water it holds, groundwater. The upper surface of the zone of saturation is called the water table. Above the water table lies the zone of aeration, where the pore spaces in the soil are quite dry and are filled with air. When the upper surface of the groundwater (water table) intersects a sloping land surface, a spring appears. The occurrence of springs is closely related to the geology of an area. If an impervious layer of rock, such as a clay deposit, underlies a layer of saturated soil or rock, then a line of springs will tend to appear on a slope where the clay layer outcrops. Igneous rocks are also impervious to water, yet they are often extensively fractured, and springs commonly appear where these fractures come to the surface. Fractures in limestone are often enlarged by the dissolving action of groundwater, forming small underground channels and caves. Where these channels outcrop, springs are likely to be found. Springs are common along major faults because groundwater reaches the surface along the fault plane. Lines of springs help locate the position of faults such as the San Andreas of California. Springs can be a valuable water resource, and improvement in flow can often be accomplished simply by driving a pipe into the ground at the point where water seeps from the ground. Sometimes it is advisable to divert the spring water into a cistern or other storage reservoir from which the water can be pumped at will. When the water, because of the geological structure of the strata, issues under pressure, the spring is called artesian (see artesian well). Another type of spring is the geyser. Hot springs occur when the water issues from great depths or is heated by near-surface hot volcanic rock, as in Yellowstone National Park, Iceland, and New Zealand. Mineral springs are those with a high mineral content, usually silica or lime, dissolved from the rocks through which the water has passed (see mineral water). Many ancient city-states, such as Troy, had their sites determined by springs. Pioneer farmhouses often were located in the same way.

Wikipedia: Spring (hydrosphere)
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On an average day nearly 300 million gallons of water issue from Big Spring in Missouri at a rate of 465 cfs.

A spring is any natural occurrence where water flows on to the surface of the earth from below the surface, and is thus where the aquifer surface meets the ground surface.

Contents

Formation

A spring may be the result of karst topography where surface water has infiltrated the Earth's surface (recharge area), becoming part of the area groundwater. The groundwater then travels though a network of cracks and fissures - openings ranging from intergranular spaces to large caves. The water eventually emerges from below the surface, in the form of a spring.

The forcing of the spring to the surface can be the result of a confined aquifer in which the recharge area of the spring water table rests at a higher elevation than that of the outlet. Spring water forced to the surface by elevated sources are artesian wells. This is possible even if the outlet is in the form of a 300-foot deep cave. In this case the cave is used like a hose by the higher elevated recharge area of groundwater to exit through the lower elevation opening.

Nonartesian springs may simply flow from a higher elevation through the earth to a lower elevation and exit in the form of a spring, using the ground like a drainage pipe.

Still other springs are the result of pressure from an underground source in the earth, in the form of volcanic activity. The result can be water at elevated temperature as a hot spring.

The action of the groundwater continually dissolves permeable bedrock such as limestone and dolmite creating vast cave systems[1].

A natural spring on Mackinac Island in Michigan.

Types of spring outlets

  • Seepage or filtration spring. The term seep refers to springs with small flow rates in which the source water has filtered into permeable earth.
  • Fracture springs, discharge from faults, joints, or fissures in the earth, in which springs have followed a natural course of voids or weaknesses in the bedrock.
  • Tubular springs are essentially water dissolved and create underground channels, basically cave systems.

Spring flow

The stream flowing into this cave at the bottom of Grand Gulf, a huge sinkhole in Missouri, resurfaces at Mammoth Spring in Arkansas.

Spring discharge, or resurgence, is determined by the "spring's" recharge basin. Factors include the size of the area in which groundwater is captured, the amount of precipitation, the size of capture points, and the size of the spring outlet. Water may leak into the underground system from many sources including permeable earth, sinkholes, and losing streams. In some cases entire creeks seemingly disappear as the water sinks into the ground via the stream bed. Grand Gulf State Park in Missouri is an example of an entire creek vanishing into the groundwater system. The water emerges nine miles away, forming some of the discharge of Mammoth Spring in Arkansas.

Classification

Springs are often classified by the volume of the water they discharge. The largest springs are called "first-magnitude," defined as springs that discharge water at a rate of at least 2800 liters or 100 cubic feet (2.8 m3) of water per second. Some locations contain many first-magnitude springs, such as Central Florida where there are 33[2] known to be that size, the southern Missouri Ozarks (11 known of first-magnitude), and 11[3] more in the Thousand Springs area along the Snake River in Idaho. The scale for spring flow is as follows:

Magnitude Flow (ft³/s, gal/min, pint/min) Flow (L/s)
1st Magnitude > 100 ft³/s 2800 L/s
2nd Magnitude 10 to 100 ft³/s 280 to 2800 L/s
3rd Magnitude 1 to 10 ft³/s 28 to 280 L/s
4th Magnitude 100 US gal/min to 1 ft³/s (448 US gal/min) 6.3 to 28 L/s
5th Magnitude 10 to 100 gal/min 0.63 to 6.3 L/s
6th Magnitude 1 to 10 gal/min 63 to 630 mL/s
7th Magnitude 1 pint to 1 gal/min 8 to 63 mL/s
8th Magnitude Less than 1 pint/min 8 mL/s
0 Magnitude no flow (sites of past/historic flow)
Fontaine de Vaucluse or Spring of Vaucluse in France discharges about 470 million gallons (1.8 billion liters) of water per day at a rate of 727 cubic feet (21 m3) per second.

Spring water content

Main article: Mineral spring

Minerals become dissolved in the water as it moves through the underground rocks. This may give the water flavor and even carbon dioxide bubbles, depending on the nature of the geology through which it passes. This is why spring water is often bottled and sold as mineral water, although the term is often the subject of deceptive advertising. Springs that contain significant amounts of minerals are sometimes called 'mineral springs'. Springs that contain large amounts of dissolved sodium salts, mostly sodium carbonate, are called 'soda springs'. Many resorts have developed around mineral springs and are known as spa towns.

Trout fishing on Maramec Spring in Missouri.

A stream carrying the outflow of a spring to a nearby primary stream is called a spring branch or run. Groundwater tends to maintain a relatively long-term average temperature of its aquifer; so flow from a spring may be cooler than a summer day, but remain unfrozen in the winter. The cool water of a spring and its branch may harbor species such as certain trout that are otherwise ill-suited to a warmer local climate.

Historic uses

Springs have been used for a variety of human needs including drinking water, powering of mills, and navigation, and more recently some have been used for electricity generation.

Modern uses

Present-day uses include recreational activities, such as trout-fishing, swimming, and floating. The water is also used for livestock and fish hatcheries.

Notable springs

See also

Drinking water.jpg Water portal

References

  1. ^ http://ga.water.usgs.gov/edu/watercyclesprings.html
  2. ^ http://www.tfn.net/springs/Springbook/FirstMagnitude.htm
  3. ^ http://www.if.uidaho.edu/~johnson/ifiwrri/1000spgs.html
  • Springs of Missouri, Vineyard and Feder, Missouri Department of Natural Resources, Devision of Geology and Land Survey in cooperation with U.S. Geological Survey and Missouri Department of Conservation, 1982

External links


This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)

 
 

 

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Britannica Concise Encyclopedia. Britannica Concise Encyclopedia. © 2006 Encyclopædia Britannica, Inc. All rights reserved.  Read more
Sci-Tech Encyclopedia. McGraw-Hill Encyclopedia of Science and Technology. Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved.  Read more
Columbia Encyclopedia. The Columbia Electronic Encyclopedia, Sixth Edition Copyright © 2003, Columbia University Press. Licensed from Columbia University Press. All rights reserved. www.cc.columbia.edu/cu/cup/.  Read more
Wikipedia. This article is licensed under the Creative Commons Attribution/Share-Alike License. It uses material from the Wikipedia article "Spring (hydrosphere)".  Read more