The core estimation methods in WINFAP 5 are:

  • Pooled & QMED analysis for ungauged catchments – most commonly used.
  • Pooled, QMED and Enhanced Single Site analysis for gauged catchments – use at-site data to improve your estimate.
  • Single Site Analysis – analyse at-site flood peak data in isolation of other catchments.
  • Historical Data Analysis  – extend at-site records with information on flood events that occurred before formal measurement began.

The package is linked to the FEH Peak Flow Annual Maximum (AM) and Peaks Over Threshold (POT) data, which can be downloaded from the NRFA.

The FEH is the industry standard for estimating peak flood flows from flood data in the UK.

The FEH statistical methods for flood estimation are based on flood frequency curves which define a relationship between the size of a flood (peak flow) and the return period (expected frequency of occurrence).

For further information, see our openly published online technical guide and supporting science reports here:

WINFAP 5 is complemented by ReFH 2, a rainfall-runoff modelling package for estimating design flood hydrographs and analysing observed events. This provides a temporally-varying design flood flow (rather than a single peak flow value), following guidance in the FEH Volume 4 and Supplementary Report No 1.