Peak Flow Dataset

The NRFA provides access to its peak flow data holdings in a format suitable for direct use in WINFAP software. The ZIP file linked below contains files for AMAX, POT and catchment descriptors.

Please be aware that data contained in these files may differ from those data which are displayed on the station pages on the NRFA website. The NRFA Peak Flow Dataset is updated when a significant number of changes have been applied to the dataset. Find out when new files are available by subscribing to our newsletter and following us on Twitter and LinkedIn.

There are separate files for each data type:

• .am Annual maxima (AMAX)
• .pt Peaks over Threshold (POT)
• .xml Catchment Descriptors (for WINFAP 5 software)
• .cd3 Catchment Descriptors (for WINFAP 3 software and WINFAP 4 software)
• .cd2 Catchment Descriptors (for WINFAP 2 software)

• Version 14: NRFA Peak Flow Dataset - note on version 14 [PDF, 1.46 MB]

Version 14 of the NRFA Peak Flow Dataset marks the eleventh major update to the dataset under the National River Flow Archive. This release includes an additional water year for all active peak flow stations across England, Scotland, Wales, and Northern Ireland, extending coverage up to the end of September 2024. It also incorporates a comprehensive Period of Record Review for 81 UK stations, updating both data and metadata. The dataset was officially released on 21st August 2025.

View information on previous versions of the NRFA Peak Flow Dataset.

All data download files are zipped and will require extraction. When you extract the zipped files, we suggest you preserve the file paths (ensure the "Use folder names" option is ticked in Winzip). The .zip files then extract into three folders:

• Suitable for Neither
• Suitable for QMED
• Suitable for Pooling

These three folders are based on the Indicative Suitability of each station. Users may wish to create other folders - e.g. for all stations or station from both the 'OK for QMED' and 'OK for pooling' folders.

You will need to register the new NRFA Peak Flow Dataset in WINFAP 5 software. To do this, run WINFAP 5:

1. Go to Options > Peak Flow Datasets...
2. Browse to the new folder 'NRFAPeakFlow_v#.#' and click 'select' (Note you need to select the folder that contains the manifest.xml file)
3. A 'default' dataset can be identified for use in the current and subsequent projects

You will need to tell the WINFAP 4 software where to find the new files. To do this, run WINFAP 4:

1. Close any existing project file
2. Open a new project file
3. Go to Options > Project file options > Load Options
4. Browse to the new folder 'NRFAPeakFlow_v#.#' and click 'select' (Note that WINFAP 4 accesses all sub-folder files)

You will need to tell the WINFAP 3 software where to find the new files. To do this, run WINFAP 3:

1. Close any existing project file
2. Open a new project file
3. Go to Options > Project file options > Load Options
4. Browse to the new folder 'OK for pooling' (or as appropriate) and click 'select'

Read the terms and conditions of accessing and downloading the NRFA data holdings.