A water grid for the UK

Abstract

The water supply infrastructure systems of the UK depend on a number of sources of water vulnerable to the impacts of climate change; however, the extents of these impacts on the performance of the water supply infrastructure systems are highly uncertain. While contemporary analyses exist, they are inappropriate for the projection of impacts and the supporting of decision-making at large spatiotemporal scales. This study appraises existing analyses of the impact of climate change on the water resources of the UK through a review of existing data and methods, addressing them via the development of a powerful probabilistic modelling framework. Consisting of models of climate variables, hydrology, and water supply infrastructure, the framework is suitable for the simulation of current and projected future water resource infrastructure systems under uncertain future conditions and at relevant strategic spatiotemporal scales. The study yields probabilistic projections of meteorological, hydrological and water resources drought severity, frequency and duration, and demonstrates the framework in a performance comparison between the existing configuration and the same system augmented with a ‘Water Grid’ facilitating the sharing of water resource. This study makes several conclusions. Firstly, that existing models of the impacts of climate change on the water supply infrastructure system of the UK are inadequate, restricted in their fitness for purpose by their roles within the prevailing regulatory framework and the data and methods available. Secondly, the UK is likely to experience progressively fewer meteorological drought events of shorter duration and increased severity, resulting in substantial reductions in river flows both on average and at the 5th percentile, and leading to substantial increases in water resources drought severity and duration over the 21st Century not wholly mitigable in the east and south of England via inter-basin transfers from Wales and the midlands.