Flooding on the Thames at Wallingford
Flooding on the Exe at Dulverton. Photo Credit: Heather Lowther
Flooding on the Thames at Benson Weir
Peak Flow Data Overview
This page provides an overview of the peak flow data holdings on the NRFA and how to access them. Prior to April 2014, the data and information outlined on this page were provided by the HiFlows-UK initiative.
The NRFA’s peak flow data service provides flood data from river flow gauging stations around the UK. This includes both Annual Maxima and Peaks Over Threshold data at around 1000 river flow gauging stations throughout the UK. Additional information about the gauging stations is provided to allow hydrologists to make informed judgements regarding use of the data. A description of peak flow data holdings, describing data types, indicative suitability descriptions and useful definitions can be found here.
The data can be used with the statistical flood estimation methods set out in the Flood Estimation Handbook (FEH), which is the basis for most current flood estimation in the United Kingdom. This service is primarily aimed at experienced flood hydrologists and the web pages assume some knowledge of flood hydrology and the Flood Estimation Handbook.
As is the case with other NRFA data, the river flow data provided through this service originates from gauging stations operated by a range of UK organisations - including the extensive networks operated by the Environment Agency (England), Natural Resources Wales, the Scottish Environment Protection Agency and the Rivers Agency (Northern Ireland). Additional peak flow data and background information originates from the National River Flow Archive and the University of Dundee.
The provision of peak flow data by the NRFA commenced in April 2014. Prior to this date, this data and information was provided by other initiatives – most recently by the HiFlows-UK initiative. Further information about the history of this dataset can be found here.
The data currently provided via the NRFA’s Peak Flow data service are WINFAP-FEH files version 3.3.4. For more details of this version see here. Integration of the HiFlows-UK data into the NRFA is ongoing and users are warned that these data have been released prior to completion of the integration to prevent a loss of service during transition from the Environment Agency to CEH websites.
The process of harmonising the content of this dataset (both flow peaks and gauging station metadata) with information already held on the NRFA began in autumn 2013. The data harmonisation has been completed for key metadata, including: station numbers, river names, station names, geographical locations and station types. This resulted in a change of the stated NRFA station number for 12 stations.
Users should be aware however that substantial differences remain between the data and information originating from HiFlows-UK (now presented on the Peak Flow Data tab of NRFA station pages and in FEH data downloads) and that shown elsewhere on the NRFA. The programme of metadata harmonisation is expected to be complete in the next 18-24 months. Please contact the NRFA for more information or to highlight particular discrepancies.
Using the search facility, you can search for the required station using a geographical location, NRFA station number, river name, flow statistic or catchment characteristic. The search by maps function can also be used to locate gauging stations which hold peak flow data records.
Gauging station information that has been fully harmonised with the NRFA is provided on the 'Station Info' tab of an individual station page. The 'Peak flow data' tab of an individual station page provides the user with extra information not yet harmonised with the NRFA that should be taken into account when using the data. Using the drop down menu within the tab, the user can also find the AMAX and POT data, FEH catchment descriptors, rating and datums.
AMAX, POT and catchment descriptors can be downloaded from the website for use in WINFAP-FEH. Instructions for how to download the data can be found here.
Terms and Conditions
The terms and conditions of accessing and downloading the NRFA data holdings can be found here.
Further development of the peak flow service provided by the NRFA is planned for the future. The NRFA would welcome feedback or suggestions from users.