NRFA Peak Flow Dataset Version 11 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 939 gauging stations which have been updated to include an additional water year of data (1 October 2020 to 30 September 2021) in England, Scotland, Wales and Northern Ireland.

Download Version 11 of the NRFA Peak Flow Dataset

Amongst the changes, six new stations were added to Version 11 Peak Flow Dataset including three which are completely new to the National River Flow Archive (*):

New AMAX1 records were established at 29 stations during water year 2020/2021 in northern England, eastern England and Wales.

As well as the additional water year of data, a Period of Record Review was undertaken for 100 stations across England and Scotland – which equates to around 4,600 years of data! In Wales, tasks were undertaken to review metadata, gaugings and ratings at 31 stations, plus an assessment of duplicate POTs in all sites in Wales.

The Period of Record 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 Review can be found in the release note.

The NRFA’s Peak Flow Dataset provides flood data for 939 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 11) was released on 7th September 2022 and reflects the NRFA data holdings at this time. It is the eighth 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 11 release note.