Changing water cycle: hydrological extremes and feedbacks

A consortium of Imperial College London, Reading University, University College London, and British Geological Survey funded under NERC’s Changing Water Cycle research programme The project progress can be followed using these links to Reports and Meetings

Society must face up to the implications of significant climate change, in particular increased risks from extreme floods and droughts. Management of these risks relies on scientific knowledge about future climate and its effects. However, the ability of scientists to predict the possible magnitudes of floods and droughts, and the frequency with which they are expected to occur, is very limited. In many locations, scientists cannot yet agree on whether local climate will become wetter or drier.

For example, drought planning is a particular concern in the UK. It requires rainfall and evaporation to be represented accurately at daily to annual time scales, however we do not yet know how this can be achieved using climate and hydrological science, and what new science and models are needed. In addition, in order to predict future climate, the energy and moisture movement (evaporation) from the land surface to the atmosphere and oceans needs to be estimated with sufficient accuracy; yet at the moment the methods used are very simplistic, for example they neglect or greatly simplify the role of groundwater.

This project is producing the science and models needed to address these and other questions, with climatologists, hydrologists, hydrogeologists, water resource planners and mathematicians working together to help develop a new generation of water cycle models. Specifically, the project is:

• Exploiting current generation climate science and statistical methods to improve and enhance projections of potential change;
• Developing innovative methods for the modelling of the hydrological response to climate variability and extremes under climate change;
• Seeking to improve the representation of hydrological processes in water cycle models, in particular, the enhanced modelling of the role of sub-surface processes. 

In addressing these gaps in knowledge, the project crosses all four themes of NERC’s Changing Water Cycle programme: land-atmosphere interactions; precipitation modelling; understanding of change; and innovative ways to assess consequences. Case studies will include the Thames catchment, the Eden catchment and the Isle of Wight, which represent the conditions over much of the UK.