Flexibility: It provides a criteria for judging the behaviour of modules and semi-modules. It is generally denoted by letter 'F'. It is the ratio of the rate of change of outlet discharge to the rate of change of discharge of the parent channel.
2. If the straight sides of a triangular section of a lined canal with circular bottom of radius D, make an angle ? with horizontal, the hydraulic mean depth is
7. According to Lacey, depth of scour in a river depends upon the straightness of the reach. If D is the depth of scour in regime flow in a right angled bend, it is
times their heights
