Pond

A pond is an artificial pond of moderate depth with at least one inlet and an outlet, without formation of a stable temperature stratification. [ Evidence ?]

• 4.1 So-called tipping over a pond

Formation and characteristics

Ponds are considered historically significant development of hydraulic engineering. Only through the storage of potable and non-potable water, the expansion of settlements in the area of urban and rural areas was possible. This enormous importance of ponds for water storage was only recently lost gradually with the modern water supply from groundwater by deep wells and pressure lines ( waterworks ) - this is before the start of the growing use of steam power in the 19th century for the for more than 2,000 years highly significant function as a mill pond for the operation of water mills for the purpose of driving a wide variety of aggregates ( grinders, hammer mills, sawmills, etc.). While the cities were already partially equipped from the mid-19th century with new techniques of water (see Water Supply in Hamburg), one was in rural areas is still far rely on ponds.

Usually a flowing water ( stream, Landgraben ) is jammed and created by forming a Erdbeckens a storage volume, the pond bottom is formed with a slope so that the pond can be completely drained at the lowest point. There, the water level by means of a flow structure ( monk, Striegel investment in storage ponds ) is dammed and regulated, so that if necessary, the pond can be drained. The draining of a pond is performed as part of the use and conservation or recreation (eg pearling, cleaning or de-sludging ). Pond or ponds that have no outlet usually are colloquially sometimes referred to as ponds, but this is not correct.

Usually take with decreasing size and depth of a water body Still its stability and durability quickly, because with decreasing water volume, the relative proportion of the peripheral structural elements increases. The smaller the pond, the more material inputs affect the water body, as nutrients, biomass and mineral sediments accumulate constantly.

By entering and sedimentation of organic and mineral material it comes gradually to the growth of a solidifying by diagenesis layer of mud prevail in the anaerobic or at least low-oxygen conditions. Especially in times of high temperatures and falling water levels above the sediment can then occur to oxygen depletion. Perennial waters are often more affected by biogenic sedimentation as periodically dry, because in the latter case the biomass ventilated in the dry phase, oxidized and is finally made ​​as a plant nutrient in large parts of the environment is available again.

The anaerobic sludge at the bottom of a body of water still is, the better it can demobilize certain nutrients and evade the availability, which are only slight dry periods rather arises under water covering because of atmospheric oxygen statements. To minimize the formation of sediment therefore, longer dry periods can contribute ( " summer grazing " or " winter "). Achieved the accumulation of sediment near the water surface, vegetation, siltation, etc. can settle as reedbeds. The pond as still waters silted then little by little, so that he would disappear for lack of maintenance measures ( desludging = " Auslandung " ) over time and lose its function.

In the particular case of Auslandung ( desludging ) a pond of its actual Sohltiefe, the pond can not be drained completely, without informing the monk ( fish farming ) at the same time lower along with the end, so that maintenance measures will represent much more difficult by the depth pond bottom sediments may be released only under water or the jammed pond water must be pumped out along with the inflow of water. Although modern methods allow for site clearance under water ( mud pumps, etc. ) - for the treatment of the material ( transport, etc.) but are due to the process-related liquefaction complex measures required ( dry polder, etc.).

Importance

• Retention basins in the wake of flood protection in the derivation of receiving waters
• Rearing and keeping of fish ( aquaculture, eg carp )
• Near-natural attitude of ducks and geese ( poultry industry )
• Provision of drinking water for livestock ( livestock watering ) or people
• Provision of domestic water and fire water ( fire water pond )
• Water storage for energy by mill ponds, especially in the mining industry for example Upper Harz Water Regale (artificial pond )
• Beautification and revitalization of gardens, parks, golf courses ( village pond, jewelry, ornamental or garden pond )
• Swimming or water ( bathing or swimming pond )
• Impoundments for technical purposes ( raft pond, mill pond, dam pond )
• Purification of waste waters ( lagoons )
• Extraction of vegetable fibers from industrial hemp or flax fibers ( Rösteteich )
• Use as Horse Pond ( historical )

Ponds offer a variety of different plant and animal species habitat.

Garden ponds

A garden pond is a jewelry and ornamental lake, which is, however, not be described as Pond in the technical sense of the word. The sealing can be carried out with pond liner, a tone poem, with bentonite or concrete. There are also prefabricated pools of polyethylene or polyester. In most cases, the pond is used for beautification of the garden, but he is also applied for artistic or therapeutic purposes. In addition, a pond in a natural garden many animals provide habitat.

A garden pond can be constructed in various styles, such as natural as possible, modern or Asian koi. Ornamental ponds are becoming increasingly popular and have now even found in very small gardens. This is probably due to the high recreational value, the ornamental ponds distinguishes a small stream or fountain even increase this effect. Garden ponds are a comparatively clearer and more species-rich habitat, and that is why even for children to acquire an ideal setting, first note types to meet various adjustments and even different ecological strategies.

Ponds are in addition to other small standing water bodies can also be found in parks and on golf courses, where they serve as water reservoirs, game obstacles or design elements of the landscape.

In ponds and other water bodies often fish are exposed. The widely quoted waterfowl with fish spawning in the plumage are rarely cause for a spontaneous fish colonization, as the eggs are just extremely short way or viable.

Inhabitants of ponds

Biogeochemical Cycles

All forms of life in the pond hanging by biogeochemical cycles related. The plants take the water carbon dioxide and nutrients ( phosphates and nitrates and Others ) and form new biomass through photosynthesis. They differ from oxygen, which is initially dissolved in the water, but ultimately escapes, so far as it is not consumed by respiring organisms. At high oxygen concentration, it may be a gas supersaturation including the risk of gas bubble disease of fish. Then bubbles form, escape with which oxygen and nitrogen so long out of the water until a solution is reached equilibrium with the air.

The animals in the dark and the plants use up the oxygen dissolved in water for respiration and deposit for an equivalent amount of carbon dioxide from. Because the plants stop their photosynthesis in the dark, the carbon dioxide content increases at night, while the oxygen content decreases.

The increase of carbon dioxide (CO2 ) decreases the pH of the water. Thus one finds in the early morning hours the lowest pH and the lowest oxygen content. The highest values ​​are found, however, at sunset.

Through strong movement of the water surface ( stream, fountain) much CO2 will be expelled out of the water, while only little oxygen ( O2) is bound in the water. The most effective measure to increase the oxygen content is sufficient planting. Plant growth also reduces the available nutrients in the water and thereby regulates the growth of algae. The metabolic circuits underlying correspond to those in aquariums.

In water, dissolved carbon dioxide ( carbonic acid) is in equilibrium with bicarbonate, which is formed as a water hardness at the dissolution of limestone. Location and range of variation of the pH depend inextricably together with the hardness of water; with each doubling of hardness, the pH range is increased by the value of 0.3 ( = log 2).

Certain organisms ( snails) to escape the pond lime, for example, to build their case.

Due to the influx of " soft " rainwater, but especially by the so-called biogenic decalcification, the water hardness of the pond water will usually decrease over time. Have been used, however, calcareous stones in the construction or in the pond, the water hardness may also increase.

So-called tipping over a pond

Living in a pond plants and animals form a complex ecosystem with diverse relationships whose stability increases with the size and diversity of the water. Therefore particularly small ponds with few species often show up as relatively fragile and prone to failure, so regular cleaning is necessary.

If suddenly dies, a large proportion of the animals and plants in a pond, this is often incorrectly referred to as " tipping ". In a pond such a disaster usually goes back to an acute lack of oxygen. This is often caused by the oxygen consumption of a high biomass concentration (especially algae) cyclically and below sometime necessary for the survival minimum salary. An above-average proliferation of algae is caused mostly in an oversupply of nutrients in the pond. In the mud on the pond floor are organic remains of leaves, pollen and food residues, which release the bound nutrients with a rising water temperature. This results in an over-supply in the garden pond, which provides for fast -growing plants, such as algae, a niche for enhanced growth.

But sometimes dies even an algae population when their nutrients are exhausted. In other cases, an algae development follows the explosion of algae -eating zooplankton, which then eats the oxygen -producing algae and even the rest of the oxygen consumed by the exitus.

The hydrographic definition of tipping is not applicable in reality, ponds, because it requires a permanent stratification - see also eutrophication and sedimentation.