Canal lining

Canal Lining, advantages, disadvantages and types

1. UNIT- 5 Canal Lining Prof. Manjunath. B Assistant Professor Sanjivani College of Engineering Kopargaon

2. 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.

3. Reduced canal dimensions: The resistance to flow of a lined canal is less than that of an unlined canal, and thus the flow velocity will be higher in the lined canal . Therefore, with the higher velocity, the canal cross-section for a lined canal can be smaller than that of an unlined canal. Reduced maintenance : Maintenance costs for the following issues are eliminated using lining of canals. Periodical removal of silt deposited on the beds and sides of canals. Removal of weeds and water canals. Minor repairs like plugging of cracks, uneven settlements of banks, etc.

4. Advantages of Canal Lining Prevents water seepage through surface of the canal. Helps in preventing Water-Logging. Increases discharge carrying capacity of the channel. Increases channel life and reduce the maintenance cost. Increases Gross area under cultivation. Silting is prevented as velocity is increased. Prevents or Reduces Weed Growth. Increase available head for power generation due to flatter gradient.

5. Disadvantages of Canal Lining Heavy initial investment is required. Difficult to shift the outlets as lining is permanent. Difficult to repair the damaged lining. Berm is absent in Lined channels , so safety to vehicular and

6. Materials for Lining Main types of concrete lining used in India are : HARD SURFACE TYPE LINING: >> Cement concrete Lining >> Shotcrete Lining >>Precast concrete Lining >>Cement Mortar Lining >>Brick Lining >>Stone blocks Lining >>Asphaltic Lining EARTH TYPE LINING: >>Soil cement Lining >>Clay puddle Lining >>Sodium carbonate Lining

7. Cement Concrete Lining It has high initial cost so its use is limited. It has excellent hydraulic properties. Thickness varies from 5-10cm for M 15 concrete and 7.5 to 15cm for M 10 concrete. A subgrade is prepared and compacted. Subgrade is saturated to a depth of 30cm in sandy soil and 15cm in other soils. Lay a base coat of 1:4 cement and sand slurry on the subgrade. Spread oil paper/crude oil on the subgrade. The concrete is usually laid in alternate blocks.

8. SHOTCRETE LINING Shotcrete consumes large amount of cement. Cement and Sand in the ratio (1:4) is shot at the subgrade through a nozzle. Thickness of this type of lining varies from 2.5 to 6.5 cm. Shotcrete is also used for repair of old but sound concrete lining.

9. CEMENT MORTAR LINING It is usually used as sandwich material between brick layers. Thickness for this type of lining is kept from 1 to 4 cm. A large amount of cement is consumed in this type of lining and thus it is quite costly.

10. BRICK LINING It consists of a single or double layer of brick masonry. The size of brick is restricted to 30x15x5 cm for convenience of handling. This type of lining has been used in Punjab on Bhakra and Haveli canals. It is hydraulically as efficient as concrete lining. In case of failure repair can be done easily.