The 2004/2006 drought had a strong regional focus and was generally most severe in the driest parts of the UK where groundwater is the major source of water supply and a combination of high population density, intensive agriculture and commercial activity generates the highest water demand. Careful management was required to reconcile the needs of a wide range of water users with the requirements of the aquatic environment.
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The summer of 2004 was indifferent, and August was particularly wet, followed by a notably wet October. However, there then followed a rather dry winter, particularly over England, and several months during 2005 were rather dry (although April and October were quite wet). A dry winter followed, leading into 2006, and, although May 2006 was notably wet, June was very dry and July was also drier than average. The last few months of 2006 were mostly rather wetter. The plot below shows the monthly North Atlantic Oscillation (NAO) Index for the periods before, during and after the drought. The NAO is a prominent teleconnection pattern in all seasons, and strong positive phases tend to be associationed with above-average temperatures in northern Europe, whilst negative phases of the NAO tend to be associated with below-average temperatures. There is more information available here.
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The drought began in the latter stages of 2003 in southern England, becoming more widespread within this region through 2004. The following year, drought spread to neighbouring regions in southern England and Wales, as well as Northern Ireland. The spatial extent of the drought was remarkably consistent, remaining restricted throughout 2005 and 2006 to southern England and Wales, and Northern Ireland. The highest severities were found in southern England around the midpoint of the drought and remained moderately high until diminishing quite quickly in all impacted catchments from December 2006 until concluding by February 2007. |
The duration of the 2004/2006 drought ranked amongst the top 10 in the period of record only in southern England and parts of south-west England and south Wales where durations exceeded two years. Durations were particularly notable in relation to historical records in Devon and Cornwall, ranking amongst the top three, and this was the longest event on record in three catchments. In contrast, the drought minimum was not that exceptional for this event, only within the Thames catchment ranking amongst the top 10 historical events. Mean deficits were also not that remarkable, owing to the moderate drought minima. Overall, the durations were sustained by two consecutive dry winters, whereas rainfall in between likely prevented drought minima from becoming exceptional. Nevertheless, this event is a good example of an event that causes management issues by its duration but not necessarily its severity.
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The 2003 and 2004/2006 droughts are described here as two separate droughts, however, due to the ‘memory’ of groundwater systems these two episodes are closely linked with respect to groundwater resources. The 2004/2006 groundwater drought was mainly focussed on the Chalk aquifer of the south of England but was characterised by significant local spatial variability. |
As a result of a series of weak recharge seasons between 2003/2004 and 2005/2006, the Chilterns were particularly impacted by the groundwater drought (Marsh, 2007): compare for example the Chalk groundwater level hydrograph for Stonor Park in the Chilterns with that of Dalton Holme in Yorkshire. The groundwater drought intensified in 2006 with the hottest July for the UK since records began, and ended with heavy rainfall in October 2006 that brought recovery for most groundwater levels by January 2007, although the recovery in groundwater levels was also highly spatially variable. Groundwater levels in the worst affected and/or more slowly responding areas of the Chalk and Permo-Triassic Sandstone aquifers took until March to return to seasonal averages (CEH, 2007).
The groundwater drought, although not as serious as previous droughts such as the droughts of 1975-76, 1988-93 and 1995-98 or the subsequent drought of 2011-12, led to the lowering of groundwater levels causing contraction of ephemeral groundwater-fed streams, particularly in the Chilterns, with evidence of migratory fish deaths, low oxygen levels and subsequent blue-green algal blooms (Marsh 2007; Marsh et al. 2007). Public understanding of groundwater drought was raised during this episode as part of the heightened social impact of the drought (Medd & Chappells, 2007; Medd & Chappells, 2008; Taylor et al. 2009; Dessai & Sims, 2010).
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Abstraction restrictions were imposed, mainly in the summer of 2006, affecting hundreds of farmers in East Anglia. According to NFU, those restrictions could cost the industry £300 million that year. This drought not only affected the UK but also continental Europe, yield reductions reported for many crops, as well as quality issues and grass shortages were reported in many locations, with hot weather reducing livestock grass intake. |
“The prolonged dry spell has been great for cereal harvest, but has put a lot of pressure on irrigators. Any root or vegetable crops unable to be watered will have suffered” 'Farmer Focus, Farmers Weekly, 19 August 2005, vol 143 (8), p64'
Extracts from the Historic droughts inventory of references from agricultural media 1975 to 2012
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A new economic regulator is established through the Water Act 2003 – Parliamentarians start to think of water resource management as a sustainability issue – the challenge of integrating environmental and economic objectives in the regulation of water resources starts to be recognised. |
In February 2003 Parliament started to discuss the introduction of the Water Bill 2003, which was passed later that year. The Water Act 2003 had a significant impact on the reorganisation of the water industry: it established the Water Services Regulation Authority as a principal economic regulator of the privatised water and sewerage industry in England and Wales. It grants increased powers to the Environment Agency in matters linked to water management, for example, when deciding upon applications for abstraction licences.
This legislative change is directly related to experienced and predicted environmental changes and periodic reduced rainfall. The Water Bill stresses the need to link water conservation and efficient water use. The government’s vision is also to better integrate economic and environmental regulation. Throughout the Parliamentary debate about the Water Bill, a new way of thinking about water management becomes apparent: Members of Parliament express concerns about the long-term sustainability of water resources, conservation and efficient water use, and the environmental impact of various phenomena such as droughts and floods.
Water and drought management start to be seen as environmental (or sometimes ‘sustainability’) issues, as well as an economic one.
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