The National River Flow Archive (NRFA) has released an update to the national Peak Flow Dataset. The dataset of peak river flow data and information consists of the files for use in the WINFAP software for flood estimation and updates to the accompanying metadata. The dataset includes Annual Maxima (AMAX) and Peaks Over Threshold (POT) data for 926 gauging stations of which 616 are in England, 178 are in Scotland, 94 are in Wales, and 38 are in Northern Ireland. The data from individual river flow gauging stations are categorised by their indicative suitability which relates to the hydrometric quality of flow data. A total of 552 stations are recommended for use in pooling groups (‘Suitable for Pooling’), 350 stations are ‘Suitable for QMED only’ and 24 stations are ‘Suitable for Neither’.
Version 14 contains:
• Network changes (addition, removal, and closure of gauging stations)
• An additional water year of data (updated to 30th September 2024) for all active peak flow stations in the UK
• Full period of record data and metadata review for a subset of stations in the dataset (81 stations)
• Modifications to existing time series
• Addition of new catchment descriptors:
SAAR9120
FARL2015
URBEXT2015
BFIHOST19SCALED
DRAINDENS
Amongst the changes, 10 new stations were added to the Version 14 Peak Flow Dataset:
• 3004 Cassley at Rosehall
• 6007 Ness at Ness-side
• 13012 South Esk at Gella Bridge
• 18008 Leny at Anie
• 21026 Tima Water at Deephope
• 21036 Whiteadder Water at Abbey St Bathans
• 39041 Lambourn at Shaw Ultrasonic
• 48013 Cober at Boscadjack
• 54090 Tanllwyth at Tanllwyth Flume
• 54097 Hore at Upper Hore flume
New AMAX records (AMAX 1, the highest ranking in the period of record) were established at 51 stations during water year 2023/2024 in Scotland, England and Northern Ireland. As well as the additional water year of data, an extensive review of period of record flow and stage data, gauging and rating data and associated metadata (e.g. POT threshold, station description, rating history, missing data periods, FEH Indicative Suitability, rejected years) was undertaken for 81 stations (11 stations in Scotland, 47 stations in England, 9 in Wales and 14 stations in Northern Ireland). In Wales, a review of bankfull and structurefull levels was undertaken, alongside an investigation into pre-digital rating holdings in the NRFA’s physical archive – results were fed back to NRW. For England, a review of AMAX comments for all Peak Flow stations was also undertaken.
During the Period of Record Review almost 3,371 years of data were reviewed!
A list of stations that were included in this year’s period of record data review can be found in the release note of the NRFA Peak Flow Dataset.
The NRFA’s Peak Flow Dataset provides flood data for 926 river flow gauging stations across the UK. The data can be used with the flood estimation methods set out in the Flood Estimation Handbook (FEH), which is the industry standard for current flood estimation in the UK. The Peak Flow Dataset has been shown to provide net economic benefits of almost £5.4 million per year in terms of costs saved by environmental consultants and regulators.
The peak flow data provided through this service originate from gauging stations operated by a range of UK hydrometric Measuring Authorities as is the case with other NRFA data. Maintenance of the NRFA Peak Flow Dataset, including the latest update, is carried out under a collaborative project between the UK Centre for Ecology & Hydrology, the Environment Agency, Natural Resources Wales, Northern Ireland’s Department for Infrastructure – Rivers Directorate, and the Scottish Environment Protection Agency.
The updated NRFA Peak Flow Dataset (Version 14) was released on 21st August 2025 and reflects the NRFA data holdings at this time. It is the eleventh version released since the NRFA took stewardship of the national Peak Flows database. Updated peak flow time series and metadata are now available to view on the NRFA website and can be found using the NRFA’s gauging station search tool. More information about the update can be found in the Version 14 release note.
