A pond in central Europe
in
Udaipur,
India]]
Pond in winter
Artificial pond stocked with pond fish
A
pond is an inland
body of
standing water, either natural or man-made, that is usually smaller than a
lake. A wide variety of man-made bodies of water are classified as ponds, including
water gardens designed for aesthetic ornamentation,
fish ponds designed for commercial fish breeding, and
solar ponds designed to store thermal energy.
Ponds and lakes are distinguished from streams via
current speed. While currents in streams are easily observed, ponds and lakes possess thermally driven microcurrents and moderate wind driven currents. These features distinguish a pond from many other aquatic terrain features, such as
stream pools and
tide pools.
Technical definitions
The technical distinction between a pond and a lake has not been universally standardized.
Limnologists and
freshwater biologists have proposed formal definitions for
pond, in part to include 'bodies of water where light penetrates to the bottom of the waterbody,' 'bodies of water shallow enough for rooted water plants to grow throughout,' and 'bodies of water which lack wave action on the shoreline.' Each of these definitions have met with resistance or disapproval, as the defining characteristics are each difficult to measure or verify. Accordingly, some organizations and researchers have settled on technical definitions of
pond and
lake which rely on size alone.
Even among organizations and researchers who distinguish lakes from ponds by size alone, there is no universally recognised standard for the maximum size of a pond. The international
Ramsar wetland convention sets the upper limit for pond size as 8
hectares (19.768 acres), but biologists have not universally adopted this convention. Researchers for the British charity Pond Conservation have defined a
pond to be 'a man-made or natural waterbody which is between 1 m
2 and 20,000 m
2 in area (~2 ha or ~5
acres), which holds water for four months of the year or more.' Other European biologists have set the upper size limit at 5 ha (12.355 acres). In North America, even larger bodies of water have been called ponds; for example,
Walden Pond in
Concord, Massachusetts measures 62 acres (~25 ha).
Formation
Ponds can result from a wide range of natural processes, although in many parts of the world these are now severely constrained by human activity. Any depression in the ground which collects and retains a sufficient amount of precipitation can be considered a pond, and such depressions can be formed by a variety of geological and ecological events.
Artificial ponds can be constructed by excavating a hollow in which water may lie, by filling an existing depression with ground or surface water, by retaining water from a
stream, or by forming a
dam to impound the water in a
valley.
A pond construction
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.
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.
Pond usually implies a quite small body 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.
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 water bodies. For example a
Great Pond in Maine is considered to be at least 10 acres (41,240 m²) in area.
In areas which were covered by
glaciers in the past, some ponds were created when the glaciers retreated. These ponds are known 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 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
lochan, 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. These uses are deliberate
idiomatic
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
Some ponds have 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
ecosystems.
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
monasteries and
castles (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 ponds combined with irrigation
reservoirs are used as a
self-purifying irrigation reservoir to allow irrigation at times of drought.
Tobha is
Punjabi name for village pond. Every village in
Punjab (India) essentially has a pond, into which the drainage of village is forced.
Buffalos and other village animals take bath in village pond during summers. Tobha is really an object of entertainment for
village people, where children also learn to
swim and play.
The small pond in
bog or mountain is called in
Japan and is discriminate from the pond in the
plain and widely recognized by
mountaineers.
Examples
Thousands of examples worldwide are available to illustrate the pond; a few of these are:
See also
Gallery
