Culvert Capacity Calculator (Outlet Control)
Flow capacity of a circular culvert under head, outlet-control energy balance.
Outlet control governs when the barrel or tailwater limits flow (full-flowing culvert). Steep, short culverts flip to inlet control — check both.
Formula
Culvert Capacity Calculator (Outlet Control) is a free culvert capacity for process, mechanical and water engineers — instant, accurate and 100% client-side, with the governing formula and reference shown next to the result so the number can be defended, not just quoted.
About Culvert Capacity Calculator (Outlet Control)
Flow capacity of a circular culvert under head, outlet-control energy balance. The calculation implements HW − TW = (1 + K_e + 2gn²L/R^4/3)·V²/2g (FHWA HDS-5 — Hydraulic Design of Highway Culverts). Outlet control governs when the barrel or tailwater limits flow (full-flowing culvert). Steep, short culverts flip to inlet control — check both.
How to use Culvert Capacity Calculator (Outlet Control)
- 1Enter Culvert diameter in mm.
- 2Enter Culvert length in m.
- 3Enter Head (HW − TW) in m.
- 4Enter Manning n (Concrete 0.013 · CMP 0.024).
- 5Read Capacity, Barrel velocity instantly — no submit button needed.
- 6Need US units? Flip the SI/Imperial toggle and every field converts.
Why use Culvert Capacity Calculator (Outlet Control)?
- ✓Implements the standard formula — HW − TW = (1 + K_e + 2gn²L/R^4/3)·V²/2g
- ✓Reference cited on-page: FHWA HDS-5 — Hydraulic Design of Highway Culverts
- ✓One-click SI ⇄ Imperial toggle — values convert in place, physics stays in SI
- ✓Runs entirely in your browser — nothing uploaded, free forever
Frequently asked questions
What formula does the Culvert Capacity Calculator (Outlet Control) use?+
It computes HW − TW = (1 + K_e + 2gn²L/R^4/3)·V²/2g, per FHWA HDS-5 — Hydraulic Design of Highway Culverts. The formula is displayed under the result.
What should I keep in mind when using this calculator?+
Outlet control governs when the barrel or tailwater limits flow (full-flowing culvert). Steep, short culverts flip to inlet control — check both.
Does this work for any fluid?+
Yes — density and viscosity are inputs (with common fluids suggested in the field hints), so the same physics applies to water, oils, gases and process fluids. Compute always runs in SI internally, so unit mix-ups can't corrupt the result.
Is the Culvert Capacity Calculator (Outlet Control) free to use?+
Yes — completely free, no sign-up, no limits. It runs client-side in your browser, so inputs stay private and results are instant even on slow connections.
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