Adapting to the effects of climate change on water supply reliability Nigel Arnell and Matt Charlton Walker Institute for Climate System Research, University of Reading School of Geography, University of Southampton Living with climate change: Are there limits to adaptation? London, February

Research questions Are there limits to our ability to adapt to climate change in a particular place? …and what controls those limits and barriers? Water supply reliability in southern England

Outline Water resources in southern England A conceptual framework The case study Potential adaptation options Barriers to implementation

Water resources in southern England Surplus or deficit in ? Environment Agency (2001) Increasing demands

…and add climate change Change in summer runoff, UKCIP02 medium- high scenario, 2020s

Adaptation options Eastern South East England Supply-side options Demand-side options

A conceptual framework Generic barriers apply to the adaptation challenge - is the need for adaptation recognised? - can the need for adaptation be defined? - can potential adaptation options be identified? - can adaptation options be evaluated? - can an option be selected? Specific barriersapply to individual options - are there physical limitations on the performance of the option? - are there financial constraints on the adoption of the option? - are there socio-political constraints on its adoption? - are there institutional factors within the organisation or its regulatory / market context that constrain the adoption of the option?

The case study catchment River Medway catchment, Kent Multiple ownership Complicated resource management

Multiple stakeholders Water supply companies Environment Agency Local councils SEERA CPRE Wildlife Trust Agriculture Water consumers

Change in the catchment Change by the 2020s

Potential adaptation options Supply sideDemand side Bulk transfersReduce leakage Effluent re-useMetering and tariffs Aquifer storage and recoveryWater efficiency DesalinationLicence trading Local resources - enlarge Bewl Bridge - new Broad Oak / Clay Hill - winter flood storages - new sources Public education Reduce rate of growth Increased connectivity No one option is likely to meet targets

Barriers to implementation Generic barriers Is the need recognised?Yes… Can the need be specified?Strategically - yes… Can potential options be identified?Yes… Can options be evaluated?Not sure yet… Can an option be selected?Not sure yet…

Specific barriers to individual options Supply side PhysicalFinancialSocio- political Institutional Bulk transfers Effluent re-use Aquifer storage and recovery Desalination Local resources - enlarge Bewl Bridge - new Broad Oak / Clay Hill - winter flood storages - new sources Increased connectivity Preliminary assessment StrongMediumWeak?

Specific barriers to individual options Demand side PhysicalFinancialSocio- political Institutional Reduce leakage Metering and tariffs Water efficiency Licence trading Public education Reduce rate of growth Preliminary assessment StrongMediumWeak?

Specific barriers Major physical barriers for most supply-side options (environmental constraints, reliable yield etc) Physical barriers for demand-side options relate to uncertainty over effectiveness Significant pressure-group objections to many supply-side options Significant customer barriers to many demand- side options

What next? Explore characteristics of different adaptation options with stakeholders How can portfolios of adaptation options be implemented? –Multiple ownership of the challenge of coping with water resources deficits

Thank you