OR/15/007 Summary

Durant M. 2015. Description of groundwater droughts in the UK: 1890 to 2015. British Geological Survey Internal Report, OR/15/007.

The UK has experienced several, in some instances, prolonged drought episodes since 1890. This report summarises the major historical drought periods in the UK with respect to groundwater, from 1890 to 2012. The Standardised Groundwater level Index, SGI (Bloomfield and Marchant, 2013), for Chilgrove House (taken to broadly representative of groundwater droughts in southern UK) and Dalton Holme (taken to be broadly representative of northern UK) have been used to identify and characterise the drought episodes. The report consists of 9 descriptions of episodes of drought in a standard form, as well as a summary, and in some cases an analysis, of the literature available. Comparison of drought events is possible using the drought classification and summary found in each standardised description. Key sources of information include British Geological Survey (BGS) and Centre for Ecology and Hydrology (CEH) drought summaries post-1976, as well as long borehole records, meteorological and hydrological data and reports.

The compilation of the descriptions has highlighted discrepancies in the literature and data covering some periods, with a tendency for underreporting of earlier events, as well as those that displayed limited surface water impacts. In addition, a comparison between hydrological and meteorological reports and the SGI and groundwater data indicated differences in the reporting of the 2003–2006 drought and the 1988-1998 period. While general trends and characteristics are apparent for all the major UK droughts, each event typically exhibits unique features. In an attempt to develop a broad classification based on event characteristics, a matrix is presented based on parameters important to groundwater drought and this has enabled different drought patterns or typologies to be explored. For example, from the matrix it has been noted that, at least for the period under consideration, northerly groundwater droughts typically consist of a single winter event and tend to be underreported in the literature, despite relatively high intensity.