Rainfall

Design Rainfall — IDF & depth–duration–frequency online

Depth–duration–frequency (DDF) estimates and IDF-style curves from regional models and international datasets, plus user data import where needed.

What is Design Rainfall?

Depth–duration–frequency (DDF) estimates and IDF-style curves from regional models and international datasets, plus user data import where needed.

When would you use this?

  • Any study that needs consistent design storm depths across durations.
  • Comparing published regional models with local observations.

How Delta Hydro Studio handles it

  • Supports South African regional models alongside global references.
  • Outputs structured for direct use in hydrology and hydraulic tools.

How to use it

  1. 1

    Pick your location or catchment centroid.

  2. 2

    Select the rainfall model source appropriate to the study.

  3. 3

    Generate depth–duration tables and curves for your return periods.

  4. 4

    Push results into rational, TR-55, or storm generator workflows.

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 Design Rainfall?

Free tier available — no credit card required to explore.

FAQ

Do I need a desktop GIS install to use Design Rainfall? +
No. Delta Hydro Studio runs in the browser — upload inputs, run calculations, and export professional outputs without local GIS installs for most workflows.
Is there a free tier? +
You can start free on the Stream plan with credits to explore tools. Several hydraulic and delineation tools remain accessible without a paid subscription.
Where are my data and calculations stored? +
Projects live in your Delta Hydro Studio workspace. Export Word, Excel, and GIS formats when you need offline archives or submittals.

Related tools

Ship compliant studies faster

Create your workspace on the Stream plan, then open Design Rainfall when you are ready to run production calculations.