Peak Flow Dataset
Peak Flow Dataset

On 12 May 2016 the National River Flow Archive (NRFA) released an update to the peak flows dataset. The new data includes Annual Maxima (AMAX) and Peaks over Threshold (POT) time-series data from gauging stations across England, Wales and Northern Ireland up to 30 September 2014. 

As well as adding two new water years to the dataset, five new stations have been included, and a whole host of associated metadata and station information has been updated. Metadata updates include station descriptions, ratings and datums, missing and rejected data, and FEH catchment descriptors, plus many more. These updates are available to view on the NRFA website.

Alongside the updates on the website a new set of data files have been produced for use in the WINFAP-FEH software. This software applies the latest Flood Estimation Handbook (FEH) statistical procedures and is widely used in flood risk strategy and planning activities, by regulators and environmental consultants, amongst others.

This was the first major update since the national peak flows dataset was transferred to the NRFA and the resulting data is a significant step in the right direction towards reliable flood data for the UK. The update has helped to provide a consistent approach to managing the UK’s hydrometric data, increasing reliability and usefulness. The peak flows dataset is thought to provide net economic benefits of more than £5m/year to regulators and consultants (Blackmore, 2015), boosting assistance to communities at risk of flooding.

During the update process the data provided by the Measuring Authorities is first automatically, then manually checked to ensure it is of the quality required to support important decisions and allow regulators and the private sector to predict, manage and mitigate the impact of flooding. It is these up-to-date accurate records of peak river flow which are vital for also developing the understanding of historical flood events and in turn the prediction of future events. This important part of the information provided by the NRFA allows users to make judgements on the usefulness of the data for their particular application.

A brief history of UK flood data

A brief history of UK flood data flow chart

  • 1975: Flood Studies Report (FSR) - Instantaneous flood peaks for over 550 gauging stations were published in Volume IV for the FSR (NERC, 1975) along with tabulated catchment characteristics and flood statistics.
  • 1978: Water Data Unit – A second phase began, updates were made to the existing stations published in the FSR, whilst a host of new stations were included.
  • 1991: Institute of Hydrology (IH) - Further major updates to both peaks-over-threshold and annual maximum flood peak data, begun at the IH. The database now contained over 77,000 peaks from 859 gauging stations throughout the UK, ending in or before 1990.
  • 1999: Flood Estimation Handbook (FEH) - Volume 3 of the FEH (IH, 1999), included v1.0 of the WINFAP-FEH program supplied by CEH and included flow data up to hydrometric year 1993/1994.
  • 2004 – 2014: HiFlows-UK - HiFlows-UK hosted on the Environment Agency’s website was a partnership between the UK Measuring Authorities. The data were an updated and enhanced version of the data contained in Volume 3 of the FEH. HiFlows-UK contained significantly more data than the FEH dataset, incorporating the results of subsequent data reviews to improve data quality, and additional information on each station, including the indicative suitability of the data.
  • 2014 – Present: NRFA - In April 2014, working with the EA, SEPA, NRW and the Rivers Agency, CEH launched a national peak river flow data service to replace HiFlows-UK. Responsibility for the provision of national data to support flood estimation was transferred from the HiFlows-UK initiative to the National River Flow Archive (NRFA). Provision of flood peak data is being fully integrated with the NRFA’s existing services for daily and monthly mean flow data. A minor update was made to the data in v3.3.4 in August 2014, whilst the first major update under the NRFA occurred in May 2016 with v4.

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