NRFA Peak Flow Dataset Version 12 released

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 contains: 

- Network changes  

- An additional water year of data (updated to 30th September 2022) for all active peak flow stations in the UK 

- Full period of record data review for a subset of stations in the dataset (89 stations) plus other full network activities (see below) 

- Modifications to existing time series  

Amongst the changes, four new stations were added to the Version 12 Peak Flow Dataset: 

New AMAX1 records were established at 7 stations during water year 2021/2022 in northern England, eastern England and Wales. 

As well as the additional water year of data, a period of record data review was undertaken for 89 stations (19 stations in Scotland, 57 stations in England, and 13 stations in Northern Ireland). For Wales, tasks were undertaken to review metadata, gaugings and ratings at 27 stations including loading of the period of record gaugings and sense checking the datum histories. For England, a review of FEH Neither sites was also undertaken resulting in either an upgrade from FEH Neither to Suitable for QMED, or if no upgrade was viable, the removal of the site from the NRFA Peak Flow Dataset. 

Download Version 12 of the NRFA Peak Flow Dataset  

The period of record data review element provides an extensive check of the full record of data and associated metadata in the Peak Flow Dataset. It covers: 

Flow and stage data (including the extension of the dataset with recent and early records);  

Gaugings and ratings; 

Missing data periods;  

FEH Indicative Suitability; 

Metadata (station descriptions, station type, datum history, POT threshold, bankfull stage); 

Unrepresentative data periods;  

Rejected data. 

A list of stations that were included in this year’s period of record data review can be found in the release note.  

The NRFA’s Peak Flow Dataset provides flood data for 917 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, and the Scottish Environment Protection Agency. 

The updated NRFA Peak Flow Dataset (Version 12) was released on 13th September 2023 and reflects the NRFA data holdings at this time. It is the ninth 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 12 release note