Water resilience or water security? Managing residual risk in urban water systems

A confluence of factors including population growth and climate change poses significant challenges to the sustainability of cities worldwide. A case study into climate change adaptation and urban water management was undertaken in Wellington, New Zealand, using resilience and complex systems science approaches. Climate change and water demand scenarios for 2040 and 2090 were generated using Greater Wellington’s ‘sustainable yield’ model and downscaled climate model data. Semi-structured interviews and a systems modelling workshop were conducted to gain an understanding of the local context for adaptation, resilience and response option selection. Analysis of modelled data indicates that with a 20% reduction in demand and additional storage, Wellington’s present supply capacity is sufficient to meet increased demand due to climate change and population growth, and cope with decreased supply due to climate change in all but the driest years to 2090. Analysis of workshops, interviews and literature indicates that enhancing community adaptive capacity to increase resilience to water shortages requires social learning, a process that could be facilitated through participative and collaborative approaches to water management. A pilot is proposed to initiate the processes of cross-scale experimentation, learning and adaptation – from end users, to water managers and government decision makers