What are the effects of an increase in stream discharge on the velocity, capacity, depth, width, and gradient?

Answer 1

Go read your book!

It depends on the channel. Increasing the discharge increases the velocity, it also increases the amount of load the stream can carry. The relative depth increases i.e. the surface of the stream is at a higher elevation. Depending on the stream channel, more water volume can widen the stream. Unless there is erosive downcutting, the gradient should remain the same.