Standards of canal cross section

• Standards of canal cross section
  

• Usual dimensions of canal cross-section elements have been given here and there inappropriate articles.
• The standards as suggest by CWPC are given as follows.

1. General.

• A trapezoidal section is recommended for the canal.
• The longitudinal slope of the canal is determined depending upon the average slope.
• The natural ground along the proposed alignment.
• This is the maximum average slope that can be provided on the canal.

2. Side Slopes.

• These are dependent on the local soil characteristics and are designed to withstand.
• The following conditions during the operation of the canal.

(a) The sudden drawdown condition for inner slopes.(b) The canal running full with banks saturated due to rainfall.

• Canal in the filling will generally have side slopes of 1.5: 1.
• For canals in cutting, the side slope should be between 1: 1 and 1.5: 1 depending upon the type of soil.

3. Free Board.

• Freeboard in a canal is governed by consideration of the canal size and location, rainwater inflow, water surface.
• Fluctuations caused by regulators, wind action, soil characteristics, hydraulic gradients.
• Service road requirements, and availability of excavated material.
• A minimum freeboard of 0.5 m for discharge less than 10 cumecs and 0.75 m for discharge greater than 10 cumecs is recommend.
• The freeboard shall be measured from the FSL to the level of the top of the bank.
• The height of the dowel portion should not be used for freeboard purposes.

4. Bank Top Width.The minimum values recommended for top width of the bank are as follows.