Design of Lined Canal and Canal Lining

Design of Lined Canal
Lining of canal
Canal Design

1. Ramanuj jaldhari Water Resource Engineering V Sem (CE)

2. CANAL IRRIGATION & DIVERSION HEAD WORK

3. Difference B/W Kennedy’s & Lacey’s Theory

4. Balancing Depth A canal section will be economical when the earth work involved at a particular section has an equal amount of cut and fill. If the amount of cut is equal to the amount of fill, it has to be paid for one only. More so, the necessity of a borrow pit or soil bank is entirely avoided. For a given cross section there is always only one depth of cutting for which the cutting and filling will be equal. The depth is known as balancing depth.

5. Lined Canal Lined canal means that canal is made of some material (such as brick, brick tile or cement concrete) which can block seepage of water into soil. In other words, make canal surface as rigid boundary.

6. NECESSITY OF CANAL LINING •To minimize seepage losses in canal •To increase the discharge in canal section by increasing the velocity •To prevent the erosion of bed and sides of canals •To reduce maintenance of canals •To protect the command area •To protect the canal from the damage by flood

7. ADVANTAGES OF CANAL LINING • Reduces the loss of water due to seepage. • Increases the duty of water. • Controls the water logging. • Provides the smooth surface & hence velocity of flow gets increased. • Due to increased velocity, discharge capacity of a canal is also Increased. • As a result, evaporation losses will be reduced. • Eliminates the effect of scouring in the canal bed. • Decreases the possibility of silting in the canal bed. • Provides the stable section of the canal. • Reduces the requirement of land width for the canal. • Reduces the maintenance cost for the canal.

8. DISADVANTAGES OF CANAL LINING • High initial cost • Difficulty for repairing the damaged section of lining • Long time to complete lining work • Changes in c/s are not easily possible

9. Design Principles of lined canal 1. Geometrical cross section of lined canal should be economical and at the same time it should be functionally efficient. 2. For Q ≤ 100 Cumec : Triangular section with sloping sides. For Q > 100 Cumec [ i.e , trapezoidal channel with rounded bottom corners]. 3. Side slope(n or θ) = 1 : 1 Side slope (n or θ)= 1.25:1 4. The side slope is selected in such away that it nearly equals the angle of response of the soil in the subgrade .

10. Design Principles of lined canal 5. Input data will be Discharge Q, Rugosity coefficient (N) side slope θ, longitudinal slope S & Maximum permissible velocity. 6. Output data will be Breadth (B) and Depth (d). 7. From the known values of v, n and s with the help of Manning’s equation R can be obtained V=R 2/3 S 1/2 /N

11. Design Principles of lined canal 8. Area of cross section A is given by Q=AV A = Q/V 9. Wetted perimeter is given by R= A/P P = R/A 10. For triangular channel section with rounded corners A = d 2 (θ + cot θ) P = 2d(θ + cot θ) d, θ can be obtained For trapezoidal channel with rounded corners A = Bd + d 2 [θ + cot θ] P = B + 2d[ θ+cot θ]

12. Any Query……???