Assessing the impact of projected climate change on drought vulnerability in Scotland

Although Scotland is relatively water resource rich in a UK and European context, water resource scarcity can occur during exceptional dry periods such as those experienced in North West Scotland during July 2012. Precipitation and flow anomaly indices have been recently developed and introduced operationally by the Scottish Environment Protection Agency, in order to assess the severity of dry episodes and use this information within the decision-making process when managing the ecological implications of measures required to ensure continuity of water supply. The latest projections of future climate in the UK (UKCP09) point to warmer, drier summers across much of Scotland and, as such, imply an increased frequency of periods of water shortage. This study makes use of the results from a collaborative project in which projected values of climate variables have been used to derive projected river flows at a number of catchments across the UK. These datasets have been used to evaluate the change in frequency of significant precipitation and flow deficits in Scotland. The findings suggest a marked increase in frequency of summer water resource scarcity across much of Scotland which has implications for water resource management, particularly where current storage is relatively low.