A Nationally Consistent Approach to Assessing Accumulated Rainfall Rarity

Accumulated rainfall totals are an important variable for a range of hydrological applications, including monitoring and forecasting, and long-term planning. A new report has been published which identifies the most appropriate, nationally consistent approach to quantifying return periods of long duration rainfall.

A comparison of the suitability of nine distribution families for estimating the relative rarity of accumulated rainfall periods across the UK provides opportunities to further improve the accuracy of return period estimation in many areas such as the water resource planning and the Hydrological Summary for the UK, and elsewhere.

Whilst distribution families that are commonly applied in extreme value estimation, such as the generalised extreme value, were demonstrated to be suitable in a lot of cases, overall Pearson Type III outperformed all other assessed distributions. Closer inspection of the performance on accumulation periods of 12 months or less provided further support for the suitability of Pearson Type III, as did the strong performance of Pearson Type III across accumulation periods, start months and regions.

Presentation of return level plots for two potentially appropriate distribution families demonstrated the sensitivity of return period estimates to distribution family, and thus the importance of this question. With this in mind, the approaches presented in Eastman et. al. (2021) provide opportunities to further improve the accuracy of return period estimation and uncertainty quantification.

The full report is now available

Figure 1 Northumbrian 12-month accumulation period beginning in October: return period plots for The Pearson Type III (pe3) and Generalised Extreme Value (GEV) distributions, with associated 95% confidence interval bands, and highlighted return periods corresponding to 48.09, 45.83, and 44.56 mm of rainfall per month. Points correspond to the Weibull plotting positions of the observed rainfall accumulation data.

REF: Eastman, MichaelParry, SimonSvensson, CeciliaHannaford, Jamie. 2021. A nationally consistent approach to assessing accumulated rainfall rarity. Wallingford, UK Centre for Ecology & Hydrology, 42pp.

About Drought briefing note: Drought monitoring and early warning

A new About Drought briefing note: Drought monitoring and early warning: new developments to meet user needs has been released. The note looks at the monitoring, forecasting and early warning needs for different sectors, the key new tools and strategies for monitoring and forecasting droughts, and highlights the ways that sectors such as water companies, regulatory bodies and the agricultural sector have used these tools so far. The note concludes by presenting applications for potential future uses.

The UK, while typically regarded as a wet country, is vulnerable to drought, particularly in some areas of the south and east. There is, therefore, a need for systems that contribute to robust decision-making relating to drought risk. Such systems need to cater for a diversity of sectoral needs. Based on recent drought research, a new suite of tools and approaches have been developed, leading to some advances in early warning capability in the UK of which the briefing note seeks to highlight.

This is the third of a series of briefs to support improved decision making concerning droughts and water scarcity. Click below to read the briefing note.

Front cover of drought monitoring and early warning brief
Drought monitoring and early warning: new developments to meet user needs – the third of a series of About Drought Briefing notes

Educational Resources

There are a number of educational resources developed through the DRY project and About Drought programme which span the breadth of the curriculum. For more information visit the DRY Utility Learning pages.

KS2 – DRY: The Diary of a Water Superhero

A bright, engaging story book has been produced for use in primary schools, with accompanying teacher’s notes and is due for publication later this year (2019). Designed to inform children to become champions to change behaviour, ‘DRY: Diary of a Water Superhero’ follows the story of an ordinary schoolgirl who becomes a water hero during a drought in the UK. The thought-provoking storyline encourages class discussions on how we treat water and how we can all save water as well as including activities.

The book, its concept and storyline were co-produced by Prof Lindsey McEwen, Luci Gorell Barnes, Verity Jones, Sarah Whitehouse and Sara Williams as part of About Drought, with illustrations by Luci Gorell Barnes.

Front cover of the book, DRY: the water diary of a superhero
Front cover of the book, DRY: the water diary of a superhero

The e-book, DRY: Diary of a Water Superhero is available to read online in English and Welsh

The book is also free to download in both English and Welsh.

The writing team have also run a couple of webinars to introduce the DRY Primary book resource – one for ‘educators’ and another for ‘parents and carers’.

Teachers’ Notes which accompany the DRY Primary Book were also developed.

KS3&4 – All About Drought Geographical Association resources

The DRY and About Drought programme have collaborated with the Geographical Association to develop research-informed resources that promote awareness of UK drought among young people. This includes creative thinking about positive water behaviours at home and in school, and adaptation to future drought.

We have worked with educational developer, Gemma Mawdsley to develop six lesson plans and learning resources for Key Stages 3 and 4 which are available from the Geographical Association.

For older students: Water Futures

Water Futures is an interactive visualisation tool stringing together several different models, which allows users – including students under guidance – to explore how water resources move throughout London. Models in general allow researchers, engineers and decision makers to envision different possible scenarios or outcomes. The models used in this tool are from Thames Water, a weather model from the University of Bristol and a water resources model from the University of Oxford called the WATHNET model. Water Futures was developed by the MaRIUS project working with Thames21, a community project that aims to provide education, improve rivers and improve the quality of life of people in the community by enhancing waterway environments.

Conversation starters: Understanding ‘Hidden’ or ‘Embedded’ Water

When thinking about personal water use, it is important to differentiate between direct water use and use of ‘virtual’, hidden or ‘embedded’ water in the growing and processing of the food we eat, the clothes we wear, and the items we use in our daily lives. The DRY project used the ‘hidden water’ quiz as a ‘conversation opener’ to engage children and adults about water behaviours – as a way in to talking about experiences of dryness and drought.

          Food water challenge questions

          Food water challenge answers

          Food water challenge teachers notes

The DRY project found that this quiz was particularly popular with school teachers and those running scout and brownie groups.

For more information about these materials and many more produced by the DRY project please visit the DRY Utility.

Far reaching influence of MaRIUS research into water risks

By Dr Helen Gavin, Project Manager for MaRIUS

Research from the MaRIUS project is widely recognised as having transformed how water risks are managed by the Government, water suppliers and regulators.

MaRIUS (Managing the risks, impacts and uncertainties of droughts and water scarcity) developed the first national-scale water resource model for England and Wales, triggering a transition in government policy and industry practice. Between 2014 and 2020 MaRIUS research involved new theory, the creation of new datasets and models, validation and demonstration in case studies of how the risk of droughts can be assessed and better managed through system modelling and ‘outcomes-based’ approaches to decision making. To date, four major reports have drawn on its work: ‘Water UK Long Term Planning Framework (2016); the National Infrastructure Commission’s ‘Preparing for a drier future, England’s water infrastructure needs’ (2018); the Committee on Climate Change’s CCRA3 Water Availability study (2018-19) and the Environment Agency’s report ‘Meeting our Future Water Needs: A National Framework for Water Resources’ (2020).

Prof Jim Hall, Principal Investigator (PI) of MaRIUS and Professor of Climate and Environmental Risks at the University of Oxford, is a member of the Prime Minister’s Council of Science and Technology and an Expert Advisor to the National Infrastructure Commission. The project was based at the Environmental Change Institute in Oxford.

“Our research has caused a transition in government policy and industry practice for water resource management in England. It has shown how drought risks can be assessed and better managed through system modelling and ‘outcomes-based’ approaches to decision making.

“We have achieved a significant shift in thinking and practice by the regulators, through interaction over eight years with water companies, the Environment Agency, Ofwat, Defra and the National Infrastructure Commission.”

Professor Jim Hall, University of Oxford

The increasing frequency of droughts and water scarcity in our warming climate, combined with our growing population and increasing demands for supply present huge challenges for national and local government, water suppliers, energy, agriculture, infrastructure, industry and communities.

MaRIUS’s work has provided conceptual frameworks and methodologies that have enabled government and its agencies to address these challenges and has provided data, systems models and other evidence that are transforming policy and practice. The new water resource system simulation model integrates public water supplies with use of water in agriculture, power generation and other industries. It has been used to explore different future scenarios of drought and assess the frequency, duration and severity of water shortages now and in the future. Tools have been developed to explore trade-offs between different aspects of risk and the cost of alternative management plans.

Key to the take-up of MaRIUS’s research was a series of well-managed and effective workshops where potential users sat down with the leading researchers to explore datasets, models and tools in development, sharing their real-world decision-making and communications processes.

“We are continuing to work very closely with the Environment Agency and Ofwat, at their request. We are undertaking joint resilience assessments and exploring the impacts on water resources. We continue to train Environment Agency staff on our model and will transfer this tool to them as they wish to use it to fulfil their regulatory responsibilities.”

Professor Jim Hall, University of Oxford

Groundwater management during droughts and future prospects

A new publication has been released today which explores how our essential groundwater resources are managed during droughts, and against a backdrop of environmental change, what future priorities should be.

The work reports the outputs from a meeting over 50 hydrogeologists from water companies, regulators, consultancies and academia that was held by About Drought in July 2019 in Birmingham. The aim of the meeting was to consider current groundwater drought management practices and identity research needs.

Four key themes are discussed throughout the paper:

  • Joined up definitions of drought
  • Enhanced monitoring
  • Improved modelling of groundwater during droughts
  • Better information sharing

“Managing groundwater supplies subject to drought: perspectives on current status and future priorities from England (UK)” has been published in Hydrogeology Journal and is available to all now.

Putting real-time data into the hands of water managers

A year on from the launch of the UK Water Resources Portal, it is being used as a valuable and reliable real-time water monitoring tool by environmental and water managers.

The web-based system tracks the latest hydrological situation across England, Wales and Scotland, allowing users to explore up-to-date data including rainfall, river flows, soil moisture and groundwater levels.

It makes use of very recently published real-time river flow data from the Environment Agency (EA) and puts it in the context of longer term water availability, using data from the National River Flow Archive based at the UK Centre for Ecology & Hydrology (UKCEH), including knowledge about drought indicators that have been developed through the About Drought programme.

It includes standardised indicators for rainfall (Standardised Precipitation Index), river flows (Standardised Streamflow Index) and groundwater (Standardised Groundwater Index), but allows users to switch to actual values, which can make them easier to understand. Indices can be compared between locations with very different rainfall and between times of year or be calculated over different time frames, depending on the user’s requirements.

Matt Fry, Environmental Informatics Manager at the (UKCEH), manages the data workstream of the About Drought knowledge exchange project. His focus has been on co-designing the tools to put the research programme’s data into the hands of users in an accessible and meaningful way. He says:

You do not need technical skills to use the UK Water Resources Portal. Anyone with an interest in current water resources or drought conditions can use it – from policymakers to members of the public, businesses to farmers and regulators to consultants. It really helps to raise awareness of the status of river flows and rainfall, particularly during drought episodes, and we believe it is an excellent communications tool for all sorts of end users and decision makers

Jamie Hannaford, Principal Investigator of About Drought and Principal Hydrologist at UKCEH, adds:

“The UK Water Resources Portal is a big advance in real-time data availability.”

The UK Water Resources Portal is just one of the many user-friendly data products from About Drought.

Explore the data platforms here.

Read more in the online About Drought Handbook.

Historic Droughts: Using the past to inform the future

Lucy Barker (UK Centre for Ecology & Hydrology) presents on a number of cutting edge aspects of drought science.

Climate change projections indicate that extreme events will increase in their frequency and severity in the future.  An improved understanding of the drought events of the past can inform current and future management. In this talk, Lucy demonstrates how reconstructed river flows have enabled consistent, national scale characterisation of historic hydrological droughts and how access to current and historic data can support ongoing drought monitoring activities.

The work originates from a number of projects including Historic Droughts and the About Drought programme and you can view the talk below.

This talk is part of the British Hydrological Society webinar series, “Future Hydrology in a Changing Environment”. You can view past webinars on their YouTube channel.

Ecosystem report cards

The environment work stream has developed five ecosystem-based report cards to communicate the effects of drought in an accessible way. The report cards are a synthesis of existing knowledge and new research within the programme. The ecosystems are:

The report cards capture the latest, cutting edge data from the programme and designed to be used by all, including the general public. The series summarises current and future aspects of water scarcity in the main ecosystems of the UK and cover the ecosystem responses, future scenarios and potential for drought management.

Experts from About Drought discuss the past few months remarkable weather

Experts from the About Drought project have given updates on the recent changeable weather we’ve been seeing in the UK and further afield.

The team at the UK Centre for Ecology & Hydrology (UKCEH) released a blog post which focused on the hydrological transformation following the wettest February on record, which soon turned into one of the driest springs on record. Low soil moisture and river flows at the end of May have resulted in impacts on agriculture and the environment, and heightened concerns over water resources over the longer term.

“There is now an increasing risk of reduced crop yields and potential water use restrictions.”

Katie Muchan, Hydrologist at UK Centre for Ecology & Hydrology

Find out more by visiting the UKCEH blog post which also highlights the UK Water Resources Portal, one of the outputs from About Drought.

Adding to the debate, Professor Len Shaffrey at the University of Reading contributed to a blog post exploring the reasons as to why we are seeing such changeable weather.

The article explores whether the persistent high-pressure “blocking” weather systems which bring clear, dry conditions for many days or weeks, are becoming more frequent. These systems are particularly synonymous with heatwaves and drought in summer and bitterly cold conditions in winter.

Len explains that changes in the Arctic, “might influence the frequency of blocking events”:

“The theories suggest that as the Arctic warms, changes in the strength and position of the northern hemisphere jet stream will allow blocking events to become more frequent.” 

Professor Len Shaffrey, professor of climate science at University of Reading

Find out more by visiting the Carbon Brief blog post.

Interested in the UK water resources situation?

Following the wettest February on record earlier this year, last month is set to be declared the driest May in England for 124 years with some water regions warning of potential drought conditions.

The UK Water Resources Portal allows anyone with an interest in current water resources or drought conditions to explore the data both nationally and locally. The portal makes use of very recently published river flow data from the Environment Agency and rainfall data from the Met Office to show the situation across the UK. Alongside historical data and standardised indices, the Portal allows users to put the current situation into a historical context.

Check out the UK Water Resources Portal

For help using the Portal we have created a YouTube User Guide

The UK Water Resources Portal is one of the outputs from About Drought project. More information and further outputs can be found in the About Drought Handbook.