RipRap Calculator

December 28, 2025

This tool turns the GSWCC chart into an interactive workflow: enter the discharge and pipe parameters, and the calculator highlights the relevant curve and returns the apron sizing outputs (La, W, and D50), along with supporting hydraulics data.

Riprap Calculator

Riprap-Lined Outlet Protection

Input

ON limits Q to gravity capacity (length, slope, material). OFF allows any Q input.
Tailwater condition
Tw ≥ 0.5·D0
Flow depth (in)
19.67
Velocity (ft/s)
8.21
La (ft)
16.00
3·D0 (ft)
6.00
W (ft)
12.40

Schematic

3·D0 = 6.00 ftTailwater: Tw ≥ 0.5·D0W = 3·D0 + 0.4·LaLa = 16.00 ftW = 12.40 ft

Full graph

Hover = tooltip · Click = set Q · Click to lock
05010015020000.511.522.533.541101001000Discharge, Q (cfs)Minimum Apron Length, La (ft)Median Riprap Diameter, D50 (ft)

Online summary

Current:Q (cfs): 22.62D0 (in): 24Length (ft): 50Slope (%): 1.00Flow depth (in): 19.67Velocity (ft/s): 8.21Material: RCPTailwater: Tw ≥ 0.5·D03D0 (ft): 6.00La (ft): 16.00W (ft): 12.40D50 (ft): 0.20
#Q (cfs)D0 (in)Length (ft)Slope (%)Flow depth (in)Velocity (ft/s)MaterialTailwater3D0 (ft)La (ft)W (ft)D50 (ft)
Add rows to build a multi-pipe summary table.
How to citeShow

Author ORCID: 0009-0000-1316-1362

DOI: 10.5281/zenodo.20974544

APA
Chernitsky, I. (2025). RipRap Calculator [Computer software]. Chernitsky.net. https://doi.org/10.5281/zenodo.20974544
IEEE
I. Chernitsky, "RipRap Calculator," Chernitsky.net, 2025. [Online]. Available: https://doi.org/10.5281/zenodo.20974544
BibTeX
@misc{chernitsky2025rip,
  author       = {Chernitsky, Ilia},
  title        = {RipRap Calculator},
  year         = {2025},
  doi          = {10.5281/zenodo.20974544},
  howpublished = {\url{https://doi.org/10.5281/zenodo.20974544}},
}