What is Rational Method Calculator?
Peak discharge from the rational formula Q = CiA with runoff coefficient guidance, design rainfall integration, and multi-return-period tables.
When would you use this?
- Small urban catchments where the rational method is still accepted by reviewers.
- Quick screening estimates before you invest in a full hydrological model.
- Teaching and peer checks against other estimation methods.
How Delta Hydro Studio handles it
- Runoff coefficient guidance aligned with South African practice.
- Ties into depth–duration–frequency rainfall where available.
- Tabulated results across multiple return periods for reporting.
How to use it
- 1
Open the Rational Method workspace in Delta Hydro Studio.
- 2
Define your catchment area and land use inputs (or pull from delineation).
- 3
Select rainfall intensities or IDF curves for your durations.
- 4
Review peak flows and export tables for your report pack.
Methodology & references
Full equations, assumptions, and literature references appear inside the in-app methodology panels for this tool, aligned with South African guidance (SANRAL TRH, SANCOLD, DWS technical manuals) and international references (USDA NRCS, FHWA HDS) where applicable.
Outputs & exports
Export professional Word and Excel report packs, tabulated results, and GIS-friendly layers depending on the tool. Screenshots in marketing materials are refreshed as the UI evolves — the studio always reflects the latest layout.
Ready to run Rational Method Calculator?
Free tier available — no credit card required to explore.