Causes, preventive and curative measures of water logging
Answers
Answer:
Causes of Waterlogging:
After studying the phenomenon of waterlogging in the light of hydrologic equation main factors which help in raising the water-table may be recognised correctly.
They are:
i. Inadequate drainage of over-land run-off increases the rate of percolation and in turn helps in raising the water table.
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ii. The water from rivers may infiltrate into the soil.
iii. Seepage of water from earthen canals also adds significant quantity of water to the underground reservoir continuously.
iv. Sometimes subsoil does not permit free flow of subsoil water which may accentuate the process of raising the water table.
v. Irrigation water is used to flood the fields. If it is used in excess it may help appreciably in raising the water table. Good drainage facility is very essential.
Preventive Measures:
Preventive measures include the following:
(a) Controlling the loss of water due to seepage from the canals:
The seepage loss may be reduced by adopting various measures for example
i. By lowering the FSL of the canal:
Loss may be due to percolation or absorption but when FSL is lowered the loss is reduced to sufficient extent. It is course essential to see that while lowering the FSL command is not sacrificed.
ii. By lining the canal section:
When the canal section is made fairly watertight by providing lining the seepage loss is reduced to quite a good extent.
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iii. By introducing intercepting drains:
They are generally constructed parallel to the canal. They give exceptionally good results for the reach where the canal runs in high embankments.