Swale (grass-lined channel)
Swales and grass channels, solved the 8.05 way
The workbench runs the manual's permissible-velocity procedure exactly as written — capacity at high retardance, stability at low — but iterates the depth solution for you instead of the manual's trial-and-error tables, and cites Figure 8.05c for every Manning's n it interpolates.
What the workbench does
- V-shape and trapezoidal sections with automatic depth iteration at both design stages
- Manning's n interpolated from the Figure 8.05c vegetal-retardance curves (classes A–E)
- Capacity check (uncut, high retardance) and stability check (mowed, low retardance) in one pass
- Permissible-velocity comparison by soil and lining, with 0.5 ft freeboard
- Establishment-phase liner suggestion when bare-soil velocities govern
Sources it answers to
NC E&SC Manual, Appendix 8.05 — Design of Stable Channels and Diversions
design procedure, retardance classes, permissible velocities
Figure 8.05c — Manning's n vs. VR by retardance
roughness interpolation
What you walk away with
Output- Two-stage results table showing both retardance checks side by side
- Pass/fail against permissible velocity with the governing value flagged
- Calc-sheet PDF with the full iteration trace
Explore the other modules: Skimmer basin design · Outlet protection / riprap aprons