Best Hydraulic Section Calculator

Calculate optimal channel dimensions for maximum hydraulic efficiency. Design channels with minimum excavation for a given discharge using rectangular, trapezoidal, or triangular sections.

Optimal Section Proportions

ShapeOptimal ProportionsR/y RatioEfficiency*
SemicircleTheoretical optimum0.500100%
Rectangularb = 2y (width = 2 x depth)0.5~95%
Trapezoidalz = 0.577, b = 1.15y (half-hexagon)0.5~97%
Triangularz = 1.0 (45-degree sides)0.3536~83%

* Efficiency compared to semicircular section for same flow area

Input Parameters

Design Configuration

Design Requirements

cfs

Design flow rate

ft/ft

Longitudinal slope

Roughness coefficient

Optional Parameters

ft

Additional depth above water surface

Ready to Calculate

Select a channel shape and design approach to find optimal dimensions.

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