Manning — Rectangular & Trapezoidal Channel

1

Channel geometry, slope and discharge

Bottom width, side slope, bed slope, roughness and design discharge

Model: Q is the design discharge. The normal depth y_n is solved NUMERICALLY (by bisection) so that Manning's equation gives Q(y)=Q_design — a trapezoidal section has no closed-form solution for y. A rectangular section is the special case of side slope z=0.

2

Normal depth, velocity and Froude number

y_n, V, Fr — flow regime

3

Section properties

Area, wetted perimeter, hydraulic radius, top width

4

Formulas and substitution

Calculation steps ready to paste into a report