The month of September 2014 was the driest September on record for the UK (in a series of records from 1910) and also registered as the equal fifth driest in the England & Wales Precipitation series from 1766. The exceptionally low rainfall triggered river flow recessions and, around month-end, river flow runoff from the UK closely approached the lowest on record for late September.
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 in conjunction with the British Geological Survey.
During September the majority of the western UK received less than 20% of the long‑term average rainfall, with Wales recording 15% and 11% in Northern Ireland. For only the third time in the last 100 years, September was warmer than the preceding August in the Central England Temperature series from 1659.
Soil moisture deficits (SMDs) increased throughout the UK from August to September, the largest such increases on record for many regions and stocks in the majority of reservoirs declined by 10% or more in September. Groundwater levels declined through September (with little sign of the commencement of recharge) although they mostly remained within the normal range or higher.
Summary author, Simon Parry from the Centre for Ecology & Hydrology said, “Despite the dry September, given the status of groundwater and the wet weather during the first half of October, the water resources situation remains healthy for the UK, although the longer-term outlook is sensitive to the rainfall received in autumn and winter.”
The monthly summary is a look back at hydrological events occurring in September 2014. Latest information on flood warnings is provided by the Environment Agency, Natural Resources Wales and Scottish Environment Protection Agency (flood warnings for Northern Ireland are not available).
The latest Hydrological Outlook for the UK was also issued this week. It states, “The one month outlook for October is for both river flows and groundwater levels to be within the normal range, with some localised exceptions. The three month outlook is suggestive of a similar pattern, with normal conditions most likely for the next few months.”
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.
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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