2024 – Groundwater famine and feast. Quantifying future groundwater extremes
The IAH GB Chapter / Hydrogeological Group Ineson 2024 meeting was held on 19th November 2024 on the subject of “Groundwater famine and feast. Quantifying future groundwater extremes”. Over 130 people attended, hearing 7 presentations including the Ineson Lecture by John Bloomfield (BGS) and a keynote talk by David Macdonald (BGS), as well as 18 posters and a panel debate. The event this year was sponsored by the FCRIP-funded Project Groundwater Northumbria.
David Macdonald provided a systematic overview of recent international literature in the context of an extended definition of groundwater flooding and groundwater flood settings. Despite this body of work, it was later noted that groundwater is represented by only a tiny proportion (~1%) of recent global publications into floods and droughts.
Will Rust showed intriguing evidence of an approximate 7-year cycle in long-term historic UK records of streamflow, rainfall, and groundwater levels which are linked to +positive (wet and warm) and negative (blocking pattern) periods of the North Atlantic Oscillation (NAO) index. Wilco Klutman presented time-series analysis forecast modelling for the 2018 extreme drought in the Netherlands, highlighting how computational models need to be appropriate for processes that become active under extreme conditions. This was also emphasised by Gemma Coxon, who demonstrated the need for a new generation of hydrological models that take account of human interventions such as abstractions, inter-basin transfers, reservoirs, and wastewater returns, and called for open collaboration and sharing of data, modelling and platforms within the context of the current UK flood and drought research infrastructure plans and investments.
Ilias Karapanos presented a water company perspective, outlining issues in developing Water Resources Management Plans (WRMPs) and Drought Management Plans (DMPs), advocating the benefits of conjunctive use of groundwater and surface water, but noting that this would require a move towards more flexible abstraction licensing. Concerns about unforeseen consequences of water management were also raised in discussions, including the potential impacts of abstractions on heightened groundwater flood risk. Representing the event sponsors, Geoff Parkin and Rhiannon Marchi-Smith presented and discussed approaches to understanding and managing groundwater flood risk and resilience in the legacy mine workings in NE England which are representative of other similar post-industrial regions, using a systems approach to illustrate the complexity of flow pathways. Mark Fermor highlighted the generally unrecognised scale of the economic impact of groundwater flooding, particularly as fluvial flood response in permeable catchments is affected by the joint probability of occurrence of high baseflow and relatively low return period runoff events; he advocated that groundwater flooding be part of the National Risk Register, and changes to the organisational responsibilities set out in the 2010 Flood and Water Management Act to give the Environment Agency national jurisdiction for groundwater flooding.
In his Ineson Lecture 2024, John Bloomfield reflected on the evolution of groundwater drought research since a more systematic approach was taken to examining long term records by BGS scientists based at Wallingford. He used a helpful spatio-temporal framework for groundwater behaviour and highlighted (at least) 5 research ideas which can be taken forward by the wider research community. His talk focussed on the phenomenology of groundwater level behaviour using standardised indices and time-series analysis methods, both within the UK and across Europe. Results of this work included demonstration of the effects of different periods of antecedent rainfall, links between groundwater response and streamflow, and how climate change atmospheric warming can amplify groundwater droughts. Following a suggestion to extend historical groundwater flood records using citizen science, it was noted in discussion that this could take an approach to that already used successfully by hydrologists for rapid response catchments.
Some key take-home message which emerged during the day included:
• a general lack of awareness of the significance of groundwater flooding in relation to other forms of flooding;
• the need to better integrate groundwater with surface water and human activity in our conceptual thinking, data analyses, modelling, and in national and local regulatory and governance approaches; closer links between the hydrogeological and hydrological communities would help to facilitate this.
• there is potential to improve flood forecasting from all sources including groundwater through a combination of NAO cycle predictions, historical time-series analysis, improved integrated hydro(geo)logical modelling, and recognition of the essential role of groundwater in river flood levels.
• theinter-related nature of floods and droughts and potentially unforeseen consequences in water management, leading to the need to take wider systems approaches in our thinking.
The speakers have kindly agreed to make their presentation available: Slides-Ineson-2024
