A circular painted-steel channel, of radius 50 cm, is running half-full at 1.2 m3/s on a slope

Question:

A circular painted-steel channel, of radius 50 cm, is running half-full at 1.2 m3/s on a slope of 5 m/km. Determine
(a) Whether the slope is mild or steep; and
(b) What type of gradually-varied solution applies at this point?
(c) Use the approximate method of Eq. (10.52), and a single depth increment Δy = 5 cm, to calculate the estimated Δx for this new y.