Explanations:
The most economical section of a lined canal is a triangular section with circular bottom for small discharges and trapezoidal section with rounded corners for high discharges (canal). • When an impermeable layer is provided at bottom and sides of canal it is known as lining of canal. Lining of a canal is necessary when– • To minimize the seepage losses in canal • To prevent erosion of bed and sides due to high velocities. • To increase discharge in canal section by increasing the velocity.