Drainage has its purpose in ameliorating the water balance in the soil. The need of a drainage application in a wet area under Middle-European conditions depends beside others on the quality of land as e.g. water permeability, structure, porosity, area position, climate, agricultural use, depth of the underground water etc.
Irrigated areas in arid climate zones tend to be oversalted. Due to the high evaporation the saliferous water is guided to the soil surface with the ascending water stream. The salt washed out is deposited onto the soil. This leads to desolation and unfertility. The application of the drainage avoids this reaction as the ascending saliferous water is lead off.
A further use of the drainage is to be found in the field of underground and surface engineering in order to protect against backwater. The aim and purpose of the drainage is to lead off the surplus of rain in winter and spring as also the abundant heavy rains in the summertime.
The surface of the soil can now dry equally and can be cultivated without any damage. Moreover you achieve an increased earning and a decreased soil erosion. Plastic drainpipes wrapped with natural or synthetic fibres have been highly approved by long experience.
These pipes, composed of suckers (50 - 65 mm) and collectors (80-200 mm) are laid about 0.80-1.20 m beyond the soil with an incline of about 0.25 -1.0 per cent.