1.

Function

:

To lower the groundwater table and control the irrigation induced salinity.

2.

Applicable areas

:

Inland and coastal command areas.
Vertisol areas in Parambikulam Aliyar project (550 ha)
Seasonal water logging in Aliyar head reaches of 2000 ha.
Lower Bhavani command (2000 ha)
Tambarani command (10000 ha)
Low-lying coastal regions of cauvery delta having seasonal water logging and salinity problem.

3.

Technique

:

At 1.2 to 1.5 m depth, 20-40 m spacing of perforated PVC pipes with coconut coir and gravel as envelope materials are to be laid with proper gradient to an outlet facility in accordance with the topography.
Diameter of pipes varies from 75 mm to 100 mm depending upon the quantity of water removed under normal field conditions.
80 to 100 perforations of 18 mm diameter per metre length are commonly recommended.

4.

Cost

:

Rs. 25000/- to Rs. 30000 per ha.

5.

Advantage

:

Improves crop yields by 50-80 % over non drained, waterlogged areas.