Canal lining is the process of reducing seepage loss of irrigation water by adding an impermeable layer to the edges of the trench. Seepage can result in losses of 30 to 50 percent of irrigation water from canals, so adding lining can make irrigation systems more efficient.

Under-Drainage Arrangements in Canals:

Under-drainage arrangements in canals are necessary to prevent seepage losses due to the presence of high water tables and to maintain the stability of canal banks. These arrangements are made by providing a system of drains beneath the canal bed.

Types of Canals:

Canals can be broadly classified into two types based on the lining:

1. Unlined Canals: These canals are constructed without any lining. The water seeps into the soil through the canal bed and banks.

2. Lined Canals: These canals are constructed with a lining to prevent seepage losses.

Under-Drainage Arrangements in Unlined Canals:

Under-drainage arrangements are necessarily required in unlined canals to prevent seepage losses due to the presence of high water tables. These arrangements are made by providing a system of drains beneath the canal bed.

Under-Drainage Arrangements in Lined Canals:

Under-drainage arrangements are also required in lined canals to maintain the stability of canal banks. These arrangements are made by providing a system of drains beneath the canal bed. The drainage system consists of the following components:

1. Collector Drains: These drains are laid at the bottom of the canal bed and collect the seepage water from the soil.

2. Lateral Drains: These drains are laid at a certain interval along the length of the canal bed and collect the seepage water from the soil.

3. Cross Drains: These drains are laid perpendicular to the canal axis and connect the lateral drains to the collector drains.

4. Outlets: These are provided at suitable locations to discharge the seepage water collected by the collector drains.

Advantages of Under-Drainage Arrangements:

1. Prevents seepage losses and maintains the water level in the canal.

2. Maintains the stability of canal banks.

3. Improves the life of the canal.

Conclusion:

Under-drainage arrangements in canals are necessary to prevent seepage losses and maintain the stability of canal banks. These arrangements are made by providing a system of drains beneath the canal bed. Under-drainage arrangements are required in both unlined and lined canals.

Lined canals