The National River Flow Archive (NRFA) has released an update to the Peak Flow Dataset including the files for use in the WINFAP software for flood estimation.
The dataset includes Annual Maxima (AMAX) and Peaks over Threshold (POT) data for 917 gauging stations of which 617 are in England, 168 are in Scotland, 94 are in Wales and 38 are in Northern Ireland. A total of 545 stations are recommended for use in pooling groups (‘Suitable for Pooling’), 349 stations are ‘Suitable for QMED’ and 23 stations are ‘Suitable for Neither’.
Version 12.1 contains:
- Correction at some sites to the catchment descriptor update which was applied in Version 12.
There are no other changes to the data files or flow data since Version 12. For changes between Version 11.1 (released in March 2023) and Version 12 (released in September 2023), users should refer to the release note for Version 12.
In Version 12, a new method was developed to snap points to their representative point in the digital terrain model (DTM) to better represent the real location of gauging stations on the digital drainage network. It is these locations on the digital drainage network which are used to compute FEH catchment descriptors. The new method led to updates which were overall, very minor and an improvement to what was held previously.
At a handful of gauging stations, manual interventions are required to best reflect what is happening on the ground, where the DTM does not perform appropriately.
In Version 12, several manual values were overwritten by automated values. In Version 12.1, catchment descriptor values at these sites have been reverted to the manual value.
The updated NRFA Peak Flow Dataset (Version 12.1) was released on 2nd November 2023 and reflects the NRFA data holdings at this time.
More information about the update can be found in the Version 12.1 release note.