DISCHARGE & NORMAL DEPTH

Manning: \( Q = A \cdot \frac{1}{n} R^{2/3} S^{1/2} \) SI (m·s)

Input parameters

Units

Affects inputs/outputs

Solve for

Forward or inverse

Channel type

Material preset

Sets n & τ_allow

Manning’s n (–)

—

Channel slope S (–)

Bottom width (b, m)

Flow depth (h, m)

Side slope (z:1)

For trapezoidal/triangular

Normal depth & hydraulics

Normal depth (h)

—

Area (A)

—

m²

Wetted perimeter (P)

—

Hydraulic radius (R = A/P)

—

Velocity (V)

—

m/s

Discharge (Q = A·V)

—

m³/s

Top width (T)

—

Froude number (Fr)

—

Bed shear (τ)

—

kPa —

Ensure consistent units. For triangular set b = 0 and use side slope z as “z:1”.