Pond
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2008-07-13T13:10:49Z
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[[Image:Staw naturalny.JPG|thumb|250px|A pond in central Europe]]
[[Image:Niagara Falls and Garden Pond.JPG|thumb|250px|Garden pond near [[Niagara Falls]].]]
[[Image:Niagara Falls Garden 2005.JPG|thumb|250px|Formal [[rock garden]] pond with [[waterfall]].]]
[[Image:Pond02.jpg|thumb|250px|This could be a pond in any wooded [[landscape]] perhaps satisfying all the older biological sciences based definitions.]]
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{{left60|57}}A '''pond''' is a body of water smaller than a [[lake]], both being examples of [[terrain feature]]s. Although the term pond is universally used to describe waterbodies that are smaller than lakes, an internationally recognised size cutoff has not yet been agreed, with values ranging from 2 [[hectare]]s (~5 [[acre]]s, 20,000 square metres) to 8 hectares (19.768 acres, 80,000 m<sup>2</sup>) used to distinguish the smaller from the larger waterbody. </div>
In the United Kingdom, where the charity Pond Conservation [http://www.pondconservation.org.uk] has made some of the most extensive studies of ponds, the now widely adopted definition of a pond is 'A man-made or natural waterbody which is between 1m<sup>2</sup> and 2 [[hectare]]s (~5 [[acre]]s or 20,000 m²) in area, which ''holds water for four months'' of the year or more'.<ref
>Biggs J., Williams P., Whitfield M., Nicolet P. and Weatherby, A. (2005). 15 years of pond assessment in Britain: results and lessons learned from the work of Pond Conservation. Aquatic Conservation: Marine and Freshwater Ecosystems 15: 693-714.</ref
>
{{TOCnestright}}In other parts of Europe some biologists prefer to set the upper size limit at 5 ha (12.355 acres)<ref
>Céréghino, R., J. Biggs, B. Oertli, and S. Declerck. 2008. The ecology of European ponds: Defining the characteristics of a neglected freshwater habitat. Hydrobiologia 597:1-6.</ref
>, and in North America even larger waterbodies are often called ponds. For example, Walden Pond in Concord, MA messures 62 acres. The international Ramsar wetland convention sets the upper size limit for ponds as 8 ha (19.768 acres). Although the size cutoff between ponds and lakes is partly subjective both are formed by ponding (standing) water.
Ponds may be man-made or natural in origin and can be made by excavating a hollow in which water may lie, filling an existing depression with ground or surface water or by retaining water from a [[stream]], or by forming a [[dam]] to impound the water in a [[valley]]. Ponds can be made by a very wide range of natural processes, although in many parts of the world these are now severely constrained by human activity. In some countries [[backyard pond]]s or [[garden pond]]s are popular and common.
The techniques may be combined to form a [[reservoir]] in flat country by enclosing an area with an embankment. Such a pond, unless very small, is usually called a reservoir. In some cultures, the meaning has been extended to include small bodies of water impounded naturally. <ref>[[Oxford English Dictionary]]</ref>
The many different definitions ''traditionally applied by freshwater [[biologist]]s'' to ponds such as: {{I}}a body of water where light penetrates to the bottom of the waterbody, {{I}}a waterbody shallow enough for rooted water plants to grow throughout its area, {{I}}a water body which lacks wave action on the shoreline <br/>
are very difficult to apply in practice, and may vary according to season, pollution or the presence of trees around the waterbody. For example, when a pond is too heavily shaded by trees for plants to grow throughout, does it cease to be a pond? If the waterbody is polluted, light may be prevented from penetrating to the bottom of even quite shallow ponds by dense blooms of algae - and if so, is the waterbody still a pond?
For this reason more practical definitions based on size, which can be easily measured at all times and change only if the pond is physically modified, are now widely used. In the same way, lakes can simply be defined as waterbodies which are larger than ponds. A review of old definitions of ponds is provided by Biggs et al (2005) in the book ''15 years of pond assessment in Britain''.
==Nomenclature==
[[Image:Winter December 2007 with Pond.jpg|200px|thumb|Pond in winter]]
In origin, pond is a variant form of the word pound, meaning a confining enclosure. As straying cattle are enclosed in a pound so water is enclosed in a pond. In earlier times, ponds were man-made and utilitarian; as stew ponds, mill ponds and so on. The significance of this feature seems in some cases, to have been lost when the word was carried abroad with emigrants so that in places like the United States, natural pools are often called ponds. <ref>Oxford English Dictionary</ref>
[[Image:2007 0731klklk0039.JPG|thumb|right|200px|An Australian rock pond. [[Heathcote National Park]]]]
[[Image:Photo of two people reflected in a fish pond.JPG|right|thumb|200px|Two people [[reflection (physics)|reflected]] in a [[fish pond]] ]]
A pond is sometimes characterized as being a small body of water that is shallow enough for sunlight to reach the bottom, permitting the growth of rooted plants at its deepest point. <ref> But [[Mere (lake)|mere]] may be thought a better term for this.</ref>
''Pond'' usually implies quite small bodies of water, generally smaller than one would require a boat to cross. Another definition is that a pond is a body of water where even its deepest areas are reached by sunlight or where a human can walk across the entire body of water without being submerged. In some dialects of [[English language|English]], pond normally refers to small artificially created bodies of water.
Though not generally accepted, some regions of the [[United States]] define a pond as a body of water with a surface area of less than 10 acres {{fact|date=June 2008| This definition must be peculiar to the United States because of the use of 'acre'. A brief web search found no source for the definition. A source should be cited or the definition removed }} (40,000 m²).
Regional differences include the use of the word pond in New England, and Maine in particular, for relatively large water bodies. For example, [[Great Pond]], Maine is over 10 square miles (26 km²) in area.<ref
>This appears to be, in its present form at least, artificially dammed. It is therefore a pond in the original sense of the word.</ref
>
In areas which were covered by [[glacier]]s in the past, some ponds were created when the glaciers retreated. These ponds are known as [[Kettle (geology)|kettle ponds]]. [[Walden Pond]] in Concord, Massachusetts is a well known example. Kettle ponds are usually quite deep and clean because they are fed by underground aquifers rather than surface streams.
The term is also used for temporary accumulation of water from [[surface runoff]] (''ponded'' water).
There are various regional names for naturally occurring ponds. In [[Scotland]], one of the terms is [[loch]]an, which may also apply to a large body of water such as a lake.
The word "pond" is sometimes also used to refer to the [[Atlantic Ocean]] in the expression "across the pond", and the expression "big pond" similarly is sometimes used for the [[Pacific Ocean|Pacific]]. These uses are deliberate [[idiom]]atic [[understatement|understatements]]).
Ponds' calm waters are ideal for [[insects]] and other water dwelling [[invertebrates]]. This includes the [[pondskater]], the [[water boatman]], the [[diving beetle]], the [[whirligig beetle]] and the [[water scorpion]].
==Characteristics==
Typically, a pond has no surface outflow draining off water and ponds are often [[spring (hydrosphere)|spring]]-fed. Hence, because of the closed environment of ponds, such small bodies of water normally develop self contained [[eco-system]]s. Ponds in heavily vegetated areas also display the formation of "[[wiktionary:scum|scum]]", which is a common term for dead and decaying [[vegetation]] condensing on top of the water. A contributor to this is the presence of [[algae]], which multiply quickly in a nutrient-rich [[Eutrophication|eutrophic]] pond exposed to strong daylight. Decaying flora provide significant amounts of such nutrients.
==Uses==
In the Indian subcontinent, [[Hindu]] [[temples]] usually have a pond nearby so that pilgrims can take baths. These ponds are considered sacred. In [[medieval]] times in [[Europe]], it was typical for many [[monastery|monasteries]] and [[castle]]s (small, partly self-sufficient communities) to have fish ponds. These are still common in Europe and in [[East Asia]] (notably [[Japan]]), where [[koi]] may be kept.
Another use is in agriculture. In agriculture, [[treatment pond]]s combined with irrigation [[reservoir]]s are used as a [[Water purification|self-purifying]] irrigation reservoir to allow irrigation at times of drought.
==Examples==
Thousands of examples worldwide are available to illustrate the pond; a few of these are:
*[[Antonelli Pond]], [[California]], [[USA]]
*[[Big Pond, Nova Scotia]]
*[[Christian Pond]], [[Wyoming]], [[USA]]
*[[Hampstead Ponds]], [[England]]
*[[Oguni-numa Pond]], [[Japan]]
*[[Pete's Pond]], [[Botswana]]
*[[Rožmberk Pond]], [[Czech Republic]]
*[[Houghton's Pond]], [[Massachusetts]], [[USA]] —just barely over the lake lower size limit
*[[Walden Pond]], [[Massachusetts]], [[USA]] —famous, but well over the lake lower size limit
==See also==
*[[Chemical pond]]
*[[Duck pond]]
*[[Cooling pond]]
*[[Solar pond]]
*[[Fountain]]
*[[Pond Aeration]]
*[[Lentic System Ecology|Pond Ecology]]
*[[Tarn (lake)|Tarn]]
*[[Treatment pond]]
*[[Tide pool]]
*[[Water garden]]
== Gallery ==
<gallery>
Image:University Hills Park3.jpg|A pond located at "University Hills Park", [[College Park, Maryland]] USA
Image:Petershof Bolshoy Palace 2005.jpg|A pond in [[Peterhof]] formal [[garden]]. In a baroque garden such as this, it would normally be called a basin, following French practice.
Image:pond.jpg|A garden pond.
Image:Samothraki-pond-red-layers.jpg|Close-up of pond in the forests of [[Samothraki]] island. The colors of the rocks are due to deposition of minerals.
Image:Garden pond_3.jpg|A garden pond.
Image:Temple pond kerala.jpg|A typical Kerala pond. Every major Hindu temple has a sacred pond near to it, used by the pilgrims to take a holy bath.
Image:Chosen5.jpg|A small rock pond. [[Heathcote National Park]].
Image:Long Pond - St Regis.jpg|338-acre Long Pond in the [[Saint Regis Canoe Area]] in the [[Adirondacks]].
</gallery>
<br>
==References==
<div class="references-small">
<references/>
</div>
== External links ==
* [http://www.pondconservation.org.uk/ Pond Conservation]
{{Commonscat|Ponds}}
[[Category:Wetlands]]
[[Category:Bodies of water]]
[[Category:Fluvial landforms]]
[[cs:Rybník]]
[[da:Dam]]
[[de:Teich]]
[[et:Tiik]]
[[es:Estanque]]
[[eo:Lageto]]
[[fr:Étang]]
[[it:Stagno (acqua)]]
[[he:בריכה]]
[[nl:Vijver]]
[[ja:池]]
[[nrm:Mare]]
[[pl:Staw (geografia)]]
[[pt:Lagoa]]
[[ro:Baltă]]
[[ru:Пруд]]
[[fi:Lampi]]
[[zh:池塘]]