Geometric Calculations for Non-Circular Open Channels

Compute hydraulic radius, wetted perimeter, and area for trapezoidal, rectangular, and triangular open channels


Non-circular open channel geometry calculation is mobile-device-friendly as of September 2, 2014

Select calculation: 
Depth, y (L): 
© 2014 LMNO Engineering, Bottom Width, b (L): 
Research, and Software, Ltd. Side Slope, z (H:V): Area, A (L2): 
Wetted Perimeter, P (L): 
Hydraulic Radius, R (L): 
Top Width, T (L): 

Units in open channel geometry calculator: You may enter numbers in any units, so long as you are consistent. (L) means that the variable has units of length (e.g. meters). (L2) means that the variable has units of length squared (e.g. m2).

Diagram and Equations for open channel geometry calculator:

Open Channel Cross-Sections

z is side slope of trapezoidal and triangular channels, defined as horizontal to vertical ratio. Both sides of the channel are assumed to have the same side slope.

Equations (note that R=A/P):
Open Channel Geometry Equations

The non-circular open channel geometry calculation does not check for unreasonable inputs. Please enter positive values.


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Please contact us for consulting or other questions.

LMNO Engineering, Research, and Software, Ltd.
7860 Angel Ridge Rd.   Athens, Ohio 45701  USA   Phone and fax: (740) 592-1890


LMNO Engineering home page (more calculations)  

Manning Equation Calculator

Design of Trapezoidal Open Channels Calculator

Design of Rectangular Open Channels Calculation

Unit Conversions

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