SECTION OF A CANAL

The Canal section may be in Fully Cutting or Fully Banking or Partial Cutting and Partial Banking depending upon the natural ground surface and permissible bed slope of the canal

Terms Related to Canal Section1. Canal Bank 2. Berm 3. Hydraulic Gradient4. Counter Berm 5. Free Board 6. Side Slope7. Service Road or Inspection Road 8. Dowel 9. Borrowpit 10. Spoil Bank 11. Land Width

1. Canal BankNecessary to retain water in the canal.Three types of situation:

2. BERM

3. HYDRAULIC GRADIENTIt is line demarcating the saturated and dry portion of bank. It is actually parabolic in shape but for banks of less than 5 m height, we assume it as straight line.Depends on permeabilityOf soil.Clay 4:1 (H:V)AlluvialSandy

4. COUNTER BERMIt is provided when the H.G cuts the outer side of the bank. Minimum 0.5 m cover should be provided. The Width depends on

5. FREE BOARD

6. SIDE SLOPEThe side slope of the canal bank and canal section depends on the angle of repose of the soil existing on the site.

7. SERVICE ROADRoadway provided for inspection and maintenance work.Main canal, it is provided on both banks (4-6 m)Branch canal, one bank only (3 -4 m)

8. DOWELProtective small embankment for safety of the vehicles.

9. SPOIL BANKDumping of extra earth on the side of the main canal.

10. BORROWPITExtra earth is taken from this pits

11. LAND WIDTHTotal width of land required for construction of canal.The following dimension should be addedTop width of the canal Berm widthWidth of bankWidth of counter bermBorrowpitMargin of 1 m from the last section

Example

Solution