May was a changeable month – a warm, summery interlude aside, it was generally unsettled, often dull and a very wet month for much of the UK. Rainfall was occasionally intense, leading to numerous flood alerts. Localised surface water flooding occurred but peak river flows were rarely outside the normal range for May.
Substantial rainfall (concentrated towards the end of the month) caused notably low end of May soil moisture deficits (SMDs) in most areas, implying a heightened sensitivity to heavy rainfall in the early summer.
The assessment is contained in the latest monthly hydrological summary for the UK, the most authoritative analysis of water resources status in the country. The monthly summaries are produced by the National Hydrological Monitoring Programme, operated by the Centre for Ecology & Hydrology (CEH) in conjunction with the British Geological Survey.
There were marked spatial variations in rainfall; some of the highest rainfall anomalies were in eastern England, moderating deficiencies that had developed earlier in the spring. In contrast, north-east Scotland received below average rainfall, continuing the dry spell that has persisted through the spring.
Despite heavy rainfall at the end of the month, water levels continued to fall with a few exceptions. Provisionally, it was the third warmest spring on record for the UK (from 1910), but rainfall totals were moderately above average and near-normal spring river flows were characteristic of much of the UK.
Summary author, Simon Parry from the Centre for Ecology & Hydrology said, “With river flows and groundwater levels in the normal range or above (significantly so in areas where the wet winter of 2013/14 is still exerting an influence) and above average reservoir stocks in most impoundments, the water resources situation for the summer and early autumn is favourable.”
The monthly summary is a look back at hydrological events occurring in May 2014. For the latest information on flood warnings please visit the Environment Agency.
The Centre for Ecology & Hydrology jointly operates the National Hydrological Monitoring Programme (for the UK) in conjunction with the British Geological Survey. NHMP scientists produce the UK Monthly Hydrological Summary which assesses rainfall, river flows, groundwater and reservoir levels. They also operate the UK’s National River Flow archive. The NHMP also has a remit to analyse major flood and drought events in the UK and analyse long term trends in UK hydrological data. The UK Monthly Hydrological Summary is published on, or before, the tenth working day, of the following month. A Hydrological Outlook for the UK is also available.
Read the full May 2014 Hydrological Summary for the UK [PDF, 6.6mb]
Details of the National Hydrological Monitoring Programme
Media enquiries related to the Hydrological Summaries should be directed to the CEH Press Office. Our scientists can provide explanation and analysis of historic hydrological patterns, possible future scenarios under climate change and scientific understanding of the current situation. We are not able to comment on immediate operational issues.
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Key for river flows graphic: