National River Flow Archive (NRFA) staff Catherine Sefton, Alannah Killeen and two NRFA area representatives Gianni Vesuviano and Eugene Magee carried out a one-day field visit to the Environment Agency’s Thames Area on Friday 5th August 2022. This followed on from an office meeting in February 2020, completing a liaison visit interrupted by the pandemic.
The field day consisted of visiting a number of gauging stations on the Thames and its tributaries, to discuss details of the stations, their operation and to capture whether updates and upgrades have been made in order to add to and improve the information provided by the NRFA.
The largest gauging station we visited was the 39046 Thames at Sutton Courtenay (left photo) which is an ultrasonic gauging station. The station was the first single-path ultrasonic site in the UK; however, the original equipment has since been replaced twice with multi-path ultrasonic transducers (the last update was in 2021). It was a helpful site visit to see the recent ultrasonic upgrades measuring the water velocity, as well as a radar sensor that was installed to measure the water level.
A smaller and different type of station we also visited was the 39065 Ewelme Brook at Ewelme, which is a Flat V weir located on a much smaller stream that flows into the River Thames at Benson. We also visited the 39027 Pang at Pangbourne (right photo), which is a Crump weir on a larger, mainly Chalk based catchment, which sometimes drowns at high flows due to backwater effects from the Thames.
Such visits allow the NRFA’s Regional Representatives to update their knowledge of current equipment, processes and problems at each site, giving them a better understanding of how the river flows are measured. This information underpins the quality control of data submitted to the archive and allows metadata updates to inform the user community of new and emerging issues which should be considered when analysing NRFA data. The NRFA aims to conduct between two and four measuring authority liaison visits a year across the UK’s 24 regional hydrometric data providers. However, with the COVID pandemic, the previous visit the NRFA team was able to carry out was in 2019, making this visit extra important! The NRFA team have since been busy quality controlling Version 11 of the Peak Flow Dataset which is due to be released in the second week of September.
Thank you to the Environment Agency Thames Area Hydrometry and Telemetry team who hosted the field visit, which proved very useful and will help inform and advance a large number of updates to the archive.