Pond

From Wikipedia, the free encyclopedia

For other uses, see Pond (disambiguation).

A pond is typically a man made body of water smaller than a lake. However the difference between a pond and an artificial lake is subjective. They are both formed by ponding water. Ponds can be made by excavating a hollow in which water may lie, filling an existing depression with groundwater or water diverted from a stream, or by forming a dam to impound the water in a valley.

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. (Oxford English Dictionary)

Scientifically, a pond is any man made body of water where light is found in the entire pond body of water. A lake is any body of water that has a profundal zone; there is as limit of effective light penetration for organisms.

1 Nomenclature
2 Characteristics
3 See also
4 Gallery

[edit] Nomenclature

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. Much of this article is written on the basis of this American view.

A pond is 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.

Pond usually describes 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, 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 (40,000 m²).

Regional differences include the use of the word pond in New England, and Maine in particular, for relatively large waterbodies. For example, Great Pond, Maine, is over 10 square miles in area.

In areas which were covered by glaciers in the past, some ponds were created when the glaciers retreated. These ponds are knowns as 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 streams of more substantial means (creeks, rivers, etc.)

[edit] Characteristics

Typically, a pond has no surface outflow draining off water and ponds are often spring-fed. Hence, because of the closed environment of ponds, such small bodies of water normally develop self contained eco-systems. Ponds in heavily vegetated areas also display the formation of "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 eutrophic pond exposed to strong daylight. Decaying flora provide significant amounts of such nutrients.

In medieval times in Europe, it was typical for many monasteries and castles (small, partly self-sufficient communities) to have fish ponds. These are still common in the East Asia (notably Japan), where koi may be kept.

The term is also used for temporary accumulation of water from runoff (ponded water).

There are various regional names for naturally occurring ponds. In Scotland, one of the terms is lochan.

The word "pond" is sometimes also used to refer to the Atlantic Ocean in the expression "across the pond" (a deliberate idiomatic understatement).