Mumbai University > Civil Engineering > Sem 7 > Irrigation Engineering

Marks: 4M

Year: Dec 2015

Causes of water logging:-

1. Inadequate surface drainage

   When the surface drainage is not adequate, the heavy precipitation in the area is not drained off quickly and the rain water remains stagnant over the area for considerable time. This gives rise to heavy percolation and water-table rises in the area.

2. Over-irrigation of field

   When the irrigation water applied to the field is in excess of the requirement of the crop, deep percolation takes place which is retained in the intermediate zone augmenting the ground water storage.

3. Obstruction of nature drainage

   If the nature drainage is obstructed by irrigation channel, rail or road embankments, it will not be able to pass the rain water of catchment. There will thus be flooding of land and consequent water logging.

4. Obliteration of natural drainage

   Sometime the cultivators plough up and obliterate an existing natural drainage. This results in to stoppage of storm water flow, consequent flooding and waterlogging.

Effects of water logging:-

1. Inhibiting activity of soil bacteria

   The liberation of plants food is dependents upon the activity of soil bacteria, which requires adequate amount of oxygen in the air for proper functioning. When the soil pores within the root zones of crops normally grown are so saturated as to effectively cut off the normal circulation of air, the land is said to be waterlogged.

2. Decrease in available capillary water

   Plant life draws its substance from the soil-solution round the soil particles which is drawn into the plants by capillary action and osmosis. If the water table is high, the roots of the plants are confirmed to the top layers of the soil above the water table while if the water table is lower, the root of plants have more room for growth.

3. Fall is soil temperature

   A waterlogged soil warms up slowly and due to lower temperature, action of soil bacteria is sluggish and plant food available is less.

4. Defective air circulation

   When the water-table is high, the drainage becomes impossible and the carbon dioxide liberated by plants root cannot be dissolved and taken away. Consequently fresh air containing oxygen is not drawn and activity of soil bacteria and plant growth suffers.