किसी खुले चैनल (open channel) का सबसे कुशल या आर्थिक रूप से अनुकूलतम अनुप्रस्थ-काट (cross-section) वह होता है जिसमें:

For subcritical flow in an open channel, the control section for a gradually varied flow (GVF) profile is located:

Depth of the gradually varied flow in an open channel is determined by the method called:

Which of the following equations signifies that 'the free surface of water is parallel to the bed of the channel'? (where dh/dx represents the variation of water depth along the length of the channel)