The conditions required for maximum discharge through a triangular channel having a depth of flow y are:
1
each sloping side makes an angle of 30° with the vertical and hydraulic mean radius = \(\frac{y}{\sqrt{2}} \)
2
each sloping side makes an angle of 60° with the vertical and hydraulic mean radius = \(\frac{y}{\sqrt{2}} \)
3
each sloping side makes an angle of 45° with the vertical and hydraulic mean radius = \(\frac{y}{2 \sqrt{2}} \)
4
each sloping side makes an angle of 60° with the vertical and hydraulic mean radius = \(\frac{y \sqrt{2}}{2}\)