April was a mild month of sunshine and showers in many areas of the UK. In a series from 1910, only two previous Aprils have been warmer, and the Central England Temperature series indicates that 2014 marks the third warmest beginning to a year since 1659.
Below average rainfall across a large area of England & Wales in April caused flows in many rivers to decline rapidly and fall below average, although most remained within the normal range. The exception to this is an area of groundwater-influenced catchments in central southern England that continue to register notably high flows in response to unprecedented winter rainfall.
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.
Near-average rainfall was registered at the national scale, but the underlying spatial variability was considerable as rainfall anomalies varied by an order of magnitude. Whilst parts of central southern England received more than 200% of the long-term average rainfall, areas of East Anglia recorded less than 20%.
Moderate river flow deficiencies have become established in areas of Yorkshire, Lincolnshire and the north-east of Scotland. Although late-April rainfall temporarily reversed the normal seasonal drying trend, soil moisture deficits continued to track near average at the national scale, with the exception of Northern Ireland which was dry in April.
Summary author, Simon Parry from the Centre for Ecology & Hydrology said, “Despite falling groundwater levels, ten Environment Agency groundwater flood alerts remained in effect at the end of April in central southern England. There were continued local impacts on property and sewerage systems, but it is unlikely that additional areas will be affected by groundwater flooding. With reservoir stocks mostly above average and the majority of groundwater levels within the normal range or higher, the water resources outlook remains healthy.”
The summary reports:
- Following the unprecedentedly wet winter of 2013/14, the last two months have been notably dry for much of the UK, particularly so in Northern Ireland and eastern parts of Great Britain.
- Accumulated river flows over March-April illustrate how quickly rivers have returned to the normal range across Northern Ireland, Wales and England (with the exception of groundwater-influenced catchments in central southern England) since the wettest winter on record.
- Despite heavy late-April rainfall across southern England, water levels in the Chalk mostly fell back towards their normal range. Conversely, levels in the Chalk in Yorkshire remain below average and are also low in Northern Ireland. An index of total storage in the Chalk aquifer indicates that, although peak levels were similar, they were much less sustained through 2013/14 than in 2000/01.
The monthly summary is a look back at hydrological events occurring in April 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 April 2014 Hydrological Summary for the UK. [PDF, 1.84MB]
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: