LMNO Engineering logo LMNO Engineering, Research, and Software, Ltd.

Culvert Geometry

Compute Hydraulic Radius, Wetted Perimeter, and Area for Circular Culvert

Select calculation:
Diameter, d (L): 
  Depth, y (L): 
www.LMNOeng.com Top Width, T (L): 
  Area, A (L2): 
© LMNO Engineering, Wetted Perimeter, P (L): 
Research, and Software, Ltd. Hydraulic Radius, R (L): 
  Angle, θ (degrees): 

Units: (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). For instance, enter d, y, and T all in meters or all in inches or all in feet.


Open Channel Flow Culvert Geometry Diagram and Equations

Open Channel Flow Circular Culvert Geometry

Top width, T, is the top width of the water in the pipe. T=0 if the pipe is empty or full. T=d if the pipe is half full.

Open Channel Flow Culvert Geometry Equations

Open channel flow circular culvert geometry calculation does not check for unreasonable inputs. For open channel flow, please enter 0<y<d, 0<T<d, and d>0.

© 1998-2025 LMNO Engineering, Research, and Software, Ltd.  All rights reserved.

LMNO Engineering, Research, and Software, Ltd.
7860 Angel Ridge Rd.   Athens, Ohio  45701   USA   Phone: (740) 707‑2614
LMNO@LMNOeng.com    https://www.LMNOeng.com