The UK Surface and Groundwater Archives (SAGA) Committee convened for its 42nd Annual meeting held on the 5th March 2025.
The SAGA Committee comprises representatives of organisations from across the UK involved in the measurement, management or use of hydrometric data. This year's meeting was attended by members of the UK Centre for Ecology & Hydrology (UKCEH), the British Geological Survey (BGS), Natural Environment Research Council, Scottish Government, Environment Agency (EA), Scottish Environment Protection Agency, Natural Resources Wales, Department for Infrastructure – Rivers Directorate, the Met Office, Canal & River Trust, British Hydrological Society, Chartered Institution of Water and Environmental Management and representatives from the UK water industry (Thames Water). Amongst the items discussed at this year's meeting was a review of the activities of the National River Flow Archive (NRFA) over the last 12 months.
As custodians of the nation's central database for hydrometric data, the NRFA's activities have included updating and ongoing maintenance of its holdings. Ensuring that the Archive is up to date involves an intensive programme of year-round work to quality control new data before it is added to the Archive, as well as reviewing existing data.
The annual update to the Archive this year contained data for the water year 2022/2023. In summer 2022, a severe drought in the UK led to many new low flow records, and in this new water year, starting 1st October 2022, the lowest flows on record were captured at some sites nearing the end of the drought, particularly in northern and western areas. In this same water year, there were also new high flow records, with many being registered in eastern Scotland following the heavy rain on the 18th of November 2022.
Alongside the routine update to daily flow data, version 13 of the national Peak Flow Dataset was published on the 29th August 2024, which included an annual update to peak flow data as well as a period of record review of a subset of peak flow stations. Version 13 of the dataset provided flood data for 921 river flow gauging stations across the UK and during the review we looked at over 4,500 years of station data.
During 2024/2025, NRFA staff carried out two liaison visits, to the Hertfordshire and North London and Lincolnshire and Northamptonshire areas within the EA. In both cases, the visits began with an office meeting with the Hydrometry & Telemetry and Hydrology staff at which the EA's flow gauging network in the area was discussed. Updates to the supporting information were identified, resulting in improvements to the holdings of the NRFA. The office meetings were followed by a day of visits to gauging stations including the Beane at Hartham, the Lee at Feildes Weir and the Lee at Rye Bridge in the Thames catchment and to gauging stations including the Witham at Claypole Mill, the Gwash at Church Bridge and the Holywell Brook at Holywell on the Lincolnshire & Northamptonshire visit. The sites selected covered a range of different monitoring technologies.
NRFA staff continued to liaise and engage with key stakeholders and the user community, with activities including workshops on both peak flow data and network appraisal, presentations at the United Nations Drought Resilience +10 and the UK Environmental Observations Framework conferences, posters at two British Hydrological Society conferences and meetings with the Global Runoff Data Centre.
The NRFA website remains very popular and has seen further increases in the activity in 2024/2025. There were around 38,300 total downloads across river flow, spatial and metadata and about 840,000 page views by 90,700 users across all pages on the NRFA website. The most popular page was the search page, which received nearly 81,400 views and was then followed by the home page which gained over 81,200 views.
The National Hydrological Monitoring Programme (NHMP), operated jointly by UKCEH and the BGS has continued to publish the monthly Hydrological Summaries for the UK. In 2024/2025, the NHMP team responded to media requests, many of which were in January 2025 in response to the winter floods. The UK Water Resources Portal, a unique web-based system for tracking the hydrological situation in near-real-time, continued to be maintained with updates to river flows, rainfall, soil moisture and groundwater level data. In 2024 it received 9,760 views from across all continents.
Isabella Tindall, lead for the UK National Capability Theme on Understanding Extremes, commented that “2024/2025 was a successful year for the NRFA, with a number of important outputs and updates to our services including a redesigned website featuring a modern, clean look and a host of new features. At the SAGA Committee meeting our plans for the next 12 months were discussed. They comprise continued improvement to our data, website, and tools as well as plans to work with the Floods and Droughts Research Infrastructure Programme on digital systems.”