| Ponds
II types of ponds
(Robert of the Saint-Seine) For these times, much of artificial ponds have been created, that it is for the material extraction, the fish breeding or like water reserve.
The gravel pits of which the depth is often important are sometimes in communication by infiltration with a close waterway, to see with the water table. They are numerous and ask in end exploitation of the efforts of important installations in order to find their place in the and for if required becoming a place of pleasant fisheries. Apart from this type of specific lake, one can consider several types of ponds.
- Ponds of source
- Ponds of streaming
- Ponds in derivation
If I classify them thus, it is that each one with one to see several characteristics who to influence their destinations.
It is the case of the pond of source. The contribution of water is done by one or more sources, with in any case a primary source T the medium flow suffices for the lake.
If it is about a pond of barrage, the fact that he is fed by spring water has an unquestionable impact. The average overall temperature is generally lower, and often water is there of a stable quality.
It may be nevertheless that the sources are not permanent. In this case the pond will record variations as well on the level of the temperature as to that of oxygenation.
The pond of streaming depends closely on the relief in which it is located and of average precipitations recorded locally. If it can take the aspect of simple enough, a relief and a favorable level of precipitation to give this type of pond.
|
As for other types of pond, the nature of the catchment area is important for the biological balance of the lake. Thus, if the accesses are largely wooded, recovered water will have an unquestionable acidity, while if the mining areas slopes are occupied by meadows, the surface water will be neutral. In a case as in the other, if it is possible to establish fish to with it, the choice of the species will be different.
It is another type of pond, of which one of the characteristic is to be often very rich in fish. It is the pond in derivation.
That it is by using the secondary bed of a small river or by arranging channels for its fuel supply and its too full, the balance of this type of pond is very closely dependant during water on which it depends.
There in an overall way, summons us in the presence of what it is agreed to appoint of the Ponds of Barrages. The ones like the others make parties of a hydrological network, which in term of management requires a certain number of precautions in order not to disturb the receiving watery environment (river or brook).
That thus requires certain installations, such as grids or cages nettings, but also a method of adequate oil change. The owner of a pond, in addition to the authorization or the statement of oil change which is to be made or obtain, will have to take care not to force the oil change by too important . A pond is gradually emptied in order not to not too much charge the network downstream out of matters such as the mud or the suspended matter.
Example: A pond of 7 hectares having an average depth E 1, should not be to drain in less than 10 days.
Thereafter we will see what belongs to the wealth of a pond, the watery flora… Lire the continuation
|
