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Runoff Lab NX — User manual

Runoff Lab NX is the GeoStru web tool for extreme rainfall analysis and rainfall-runoff transformation. Starting from an annual maxima series of short-duration rainfall (60′, 3h, 6h, 12h, 24h) you get:

  • Probabilistic analyses (Gumbel, GEV, Pearson III, regional TCEV);
  • IDF rainfall curves \(h = a \cdot t^n\) for a given return period;
  • Synthetic hyetographs (Chicago design storm);
  • Flood hydrographs using the SCS-CN method.

Open Runoff Lab NX 5-minute quickstart

Who it's for

  • Hydraulic engineers sizing storm sewers, detention basins, spillways, road crossings.
  • Geologists producing hydraulic compatibility studies.
  • Designers preparing flow / return-period assessments for local authorities.

What you can do

Feature What it does
Station + series Station metadata + annual maxima by duration.
Analyses Parameter estimation for Gumbel, GEV, Pearson III, TCEV (4 levels).
Goodness-of-fit Automatic Kolmogorov-Smirnov and χ² tests.
Rainfall curves \(h = a \cdot t^n\) per \(T\), with log-log regression.
Hyetographs Chicago design storm from an IDF curve.
SCS-CN hydrograph Net rainfall + unit hydrograph + convolution.
AI Import Auto-extract a rainfall series from annual report PDFs or Excel tables.
Ready samples Three Calabria stations (Cosenza, Rende, Montalto) for exploration.
Save .hgstudy file (JSON), browser autosave.
Export Full PDF report with charts and tables.
Multilingual IT, EN, DE, ES, RO (TCEV analyses use the VA.PI. dataset and are available only in Italian).

Getting started

  1. Open nx.geostru.ai/runofflab/.
  2. Station: enter metadata and, for each duration, the annual maximum values (hmax in mm).
  3. Analyses: pick a family (Gumbel / GEV / Pearson III / TCEV) → get h(T) for T = 5, 10, 50, 100, 200 years.
  4. Curves: from an analysis + T, compute \(a\) and \(n\) of the law \(h = a t^n\).
  5. Hyetographs / Hydrographs: use the curve to build synthetic hyetographs and a flood hydrograph via SCS-CN.
  6. File → Export PDF report for documentation.

See the full workflow →

Manual chapters

Getting started

Method reference

Tools

  • AI Import — series extraction from PDF/Excel
  • FAQ — common gotchas

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