# Hydrology Pro — Runoff and peak flow methods

> Runoff and peak flow methods (iPhone/iPad app by Alexius Academia.)

- Source: https://appshunter.io/ios/app/hydrology-pro/id6821024643 (this page in markdown: same URL + `.md`)
- Developer: [Alexius Academia](https://appshunter.io/developer/1209840214)
- Category: Productivity, Utilities
- Price: $2.99
- Age rating: 4+
- Requires: iOS 17.0 · 1 MB
- Languages: American English
- Released: 2026-10-31
- Data updated: 2026-11-04

## What is Hydrology Pro?

Hydrology Pro works out how much of a storm runs off a catchment, how fast it gathers and how high it peaks, and gives you the chart and a PDF report to go with it. It is made for civil, drainage and water resources engineers, and for students of hydrology.

EIGHT METHODS

• Rational method: peak discharge of a small catchment, with the frequency factor for rarer storms.
• Time of concentration: Kirpich, Kerby, the NRCS lag equation, the FAA equation and Bransby Williams.
• Runoff depth: the NRCS (SCS) curve number method, with the runoff volume, retention and initial abstraction.
• Unit hydrograph: the NRCS triangular and curvilinear hydrographs, with the peak, the time to peak and a table of ordinates.
• Rainfall intensity: an intensity-duration-frequency curve with your coefficients, with the intensity and depth at standard durations.
• Detention storage: a first estimate of the volume that holds an inflow peak back to an allowable release.
• Risk and return period: the chance of exceedance in a design life, or the return period for a risk you accept.
• Frequency analysis: the Gumbel distribution of annual maxima, with design values at standard return periods.

FEATURES

• Metric and English units: millimetres and hectares, or inches and acres. Switching converts what you typed.
• A chart with every result, with the solved state marked.
• Notes that say what each method was derived for, and when a result is outside that range.
• PDF reports with the inputs, results, notes, chart and tables.
• Save calculations by name and open them again later.
• Works offline. No account, no ads, no tracking.

The results are for preliminary design and checking. Coefficients and curve numbers depend on the catchment: confirm them from local data and standards, and have the design reviewed by a qualified engineer.

## Is Hydrology Pro safe?

Not enough ratings yet to assess Hydrology Pro.

## Is Hydrology Pro legit?

Hydrology Pro appears legitimate, with a few gaps. The AppsHunter Legitimacy Score for Hydrology Pro is 75 out of 100 points across 7 verification signals from App Store and developer data.


## Version history (last 1 release)

### 1.0 — 2026-10-31

No release notes.

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All apps by Alexius Academia: https://appshunter.io/developer/1209840214

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-11-04.*