Delta Hydro Studio
FreemiumVerified
Browser-based hydrology and hydraulics calculators for practising engineers — no install, report-ready output.
PeakFQ
StableUSGS software for Bulletin 17C flood-frequency analysis of annual peak-flow records.
by US Geological Survey
- Pricing
- Gov-Public
- License
- US Government (public domain)
- Commercial use
- Permitted
- Ecosystem
- Standalone
- Platform
- Windows
About PeakFQ
PeakFQ is the USGS's reference implementation of Bulletin 17C — the US federal guideline for flood-frequency analysis. It fits the Log-Pearson Type III distribution to annual peak series using the Expected Moments Algorithm, handles historic and paleoflood information, censored data, Multiple Grubbs-Beck low-outlier screening and regional skew weighting.
If a US reviewer asks how your 1% AEP flow was computed, "PeakFQ per Bulletin 17C" ends the conversation. It reads USGS peak-flow files directly, so gauge-based frequency estimates take minutes. Outside the US the method still applies, though local guidance may prefer different distributions.
Where it fits in the workflow
TerrainCatchmentRainfallRunoffRoutingHydraulicsMappingReporting
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