Unit 4-canal lining

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1. CANAL LINING

2. Canal Lining It is the treatment given to the canal bed and banks to make the canal section impervious. Canal lining is the process of during 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. Common lining materials include compacted earth, concrete, and plastic membranes.

3. Advantages of Lining Water Conservation : Lining a canal results in reduction in water losses, as water losses in unlined irrigation canals can be high. No seepage of water into adjacent land or roads : If canal banks are highly permeable, the seepage of water will cause very wet or waterlogged conditions, or even standing water on adjacent fields or roads. Lining of such a canal can solve this problem.

4. Advantages of Lining Canal linings improve command: Lining makes it possible to maintain high velocity in the canal. Generally lined canals are designed with normal value of silt factor (f= 1.2) and maximum permissible velocity (from 1.8 m/sec to 2.5 m/sec). For these values of f and V steepest practicable longitudinal slope may be adopted. Even then this slope will be flatter than the slope of unlined canal.

5. Advantages of Lining Thus this flat slope raises the FSL in general and brings the high area of land under command which have not been irrigated before. Another advantage of maintaining high velocities can be recognized from the fact that “lined canals require smaller sections to convey same amount of water as that carried by unlined canals”.

6. Advantages of Lining Canal linings increase available head for power generation.  Canal linings make the canal section stable. Canal linings prevent bank erosion and breaches. Canal linings assure economical water distribution Canal linings reduce maintenance costs

7. Types of Canal Lining

8. Types of Canal Lining Exposed and Hard Surface Linings Earth type canal lining. Buried Membrane Linings

9. Types of Canal Lining Exposed and Hard Surface Linings:- It includes all linings exposed to wear, erosion and deterioration effect of the flowing water, operation and maintenance equipment and other hazards. S u ch linings are constructed across of cement concrete and mortars, bricks , stones and exposed membranes. Although the initial cost of all these linings is generally high, the reinforced cement concrete linings are costliest and are usually recommended for use only where structural safety is the primary consideration

10. Types of Canal Lining Exposed and Hard Surface Linings:- 1 . Cast in situ cement concrete lining 2. Shotcrete or plastic lining. 3. Cement concrete tiles lining or Brick lining. 4. Asphalt concrete lining. 5. Boulder lining. 6. Exposed Membrane Linings.

11. Types of Canal Lining Earth type canal lining. Thick compacted earth lining is durable and can withstand considerable external hydrostatic pressure. Bentonite has shown considerable promise for use as a good lining material. Bentonite containing large percentage of montmorillonite , is characterised by high water absorption accompanied by swelling and imperviousness. It can be used as 5.0 cm thick membrane covered by protective blanket or as a mixed inplace layer of soil bentonite and well compacted.

12. Types of Canal Lining Buried Membrane Linings Hot-applied asphaltic, prefabricated asphalt materials, plastic film and a layer of bentonite or other types of clays protected by earth or gravel cover are cheap linings. These linings can be provided immediately after completion of excavation or even later. Membrane linings are susceptible to damage by weed root and permissible water velocity is limited to avoid erosion. The life of the lining is uncertain.

13. Cast In-situ Cement Concrete Lining

14. Shotcrete Lining

15. Canal Lining Concrete Lining

16. Canal Lining Concrete tiles canal lining

17. Canal Lining Brick Canal Lining Prefabricated Channel Section

18. Canal Lining GEOPOLYMER CANAL LINING