River Thames at Crowmarsh Gifford

ARCC-Water

Dr Mark New, Dr Suraje Dessai, Dr Julien Harou, UCL, Dr Will Medd, Dr Steven Wade & Prof Rob Wilby

University of Oxford, Exeter University, UCL, Lancaster University, HR Wallingford & Loughborough University

September 2009 to October 2012

The ARCC-Water project brings together a multi-disciplinary team of scientists, social scientists and engineers to develop new methods and tools to build adaptive and resilient water supply systems, and a comprehensive understanding of household water demand. The project aims to design robust water supply systems at regional and local scales to improve supply and demand system performance under future climate change.

Adaptive and resilient water systems

Reliable water supply is fundamental to human health and wellbeing – in the UK it is built on inter-linked infrastructure for abstraction, storage, treatment and conveyance of potable and wastewater. Climate change (CC) could affect the UK water system through:

  • changes in water availability for abstraction and storage, especially through altered drought frequency and intensity
  • changes in demand
  • changing risk of infrastructure failure.

Since 1997, water utilities have been obliged to include CC in long-term water resource plans for their Periodic Reviews (PRs). This analysis focuses on the effect of CC on average demand and deployable output on a Water Resource Zone (WRZ) basis, with limited consideration of effects on the entire water resource system. An integrated ‘whole system’ analysis would identify long-term water resource plans where a range of infrastructure and demand management options maintain secure supplies and enhance the environment.

Objectives:

The project will develop new methods and tools to:

  • assess the risk of climate change impacts on water infrastructure systems and improve the performance of the water supply / demand system under future extreme events that will drive system failure (floods, droughts, heat waves)
  • design robust water-supply infrastructure systems at regional and local scales by identifying packages of measures that guarantee reliable water supplies at competitive costs, meet carbon commitments and are socially and environmentally acceptable.

Features of the research project:

  • a ‘multi-criteria robust decision analysis’ framework for formulating and evaluating alternative water supply plans / policies that ensure security of supply and meet economic, environmental and social objectives
  • systematic treatment of uncertainties associated with future climate, hydrology, socio-economics, demand/behaviour, and technology
  • multi-scale, enabling regional integrated assessment across multiple Water Utility supply areas and local authority boundaries, as well as smaller-scale assessment within individual supply areas
  • new datasets and insights on future regional drought risk, critical infrastructure risk and demand-side adaptive capacity
  • build on, and add value to, existing research projects, methods and tools.

South-east focus with a national capability

The project will focus on southern England – this region is already affected by climate stress, and will be particularly vulnerable to climate change and demand growth. It covers Mid Kent Water, Southern, Sutton, East Surrey, Thames, Anglian Water, Essex and Suffolk, and Three Valleys supply areas. Many WRZs in these areas have an ‘unsustainable or unacceptable abstraction regime’ in one or more season according to the Environment Agency. ARCC Water tools and methods will be transferrable to other regions and the UK as a whole, eg. in support of the UK Climate Risk Assessment (CCRA).

This project is novel in scale (local to regional), methods (treatment of uncertainties in climate and demand drivers and the system itself; multi-criteria robust decision analysis), interdisciplinarity (natural, engineering, social, economic and computational science) and levels of engagement with a spectrum of stakeholders.

The research results will help to frame the terms of the next PR, and provide tools and data to better integrate climate change into the PRs. It will make use of the UK Climate Projections (UKCP09), and provide additional hydroclimatic scenarios not available directly from the projections.

Project concept

The ARCC Water Regional Water Systems Model (RWSM) will simulate supply intakes, demands and raw and potable water transfers within and between water service areas. Used within a Multi-criteria Robust Decision Analysis (MC-RDA), it will identify system vulnerabilities and help to design robust solutions.

Two baseline cases represent (i) the present-day regional water system for calibration, and (ii) the system as it would be in the 2030s under current 25-year water resource infrastructure plans.

Applying MC-RDA to the baseline will allow evaluation of the vulnerability of each system against hydroclimatic and demand projections from 2010 to 2050.

Based on these analyses, the project team will work with stakeholder partners to develop additional adaptation options to reduce system vulnerabilities. Alternatives will consist of a range of options including supply-side, demand-side and infrastructure/technology solutions. The RWSM model will be reconfigured to represent each adaptation alternative, and the MC-RDA repeated, identifying options that are (i) robust in the face of hydroclimatic and demand uncertainty and (ii) score highly for ecological sustainability, carbon reduction, economic cost, and public acceptability.

A final stage will assess changes in policy and regulatory standards needed to implement the best performing alternatives.

The project will include three case studies. Working with stakeholder partners, the WSM-MC-RDA will be applied to local water systems, enabling an evaluation of the approach at finer resolution, exploration of interactions between local and regional water systems, and testing RWSM simplifications in supply, outage and demand patterns against detailed local modelling results.