Current water infrastructure designs and design processes are ill-suited to address deep uncertainties related to climate variability and change. Water systems increasingly exhibit fragility to extreme weather events and changing climate conditions. The concept of resilience offers a framework to improve water system design for uncertain futures by incorporating capabilities such as persistence, adaptability and transformability. Resilience by Design is based on decision making under deep uncertainty and systems analysis. The formulation generates water system design options that provide resilience capabilities at least cost and specify the optimal choices for persistence, adaptability and transformability for performance over a wide range of possible futures. Resilience by Design is a generalizable approach offering important new methods of planning and managing for the resilience of critical infrastructure. The full methodology is described here: Brown, C., Boltz, F., Freeman, S., Tront, J. and Rodriguez, D., 2020. Resilience by design: a deep uncertainty approach for water systems in a changing world. Water Security, 9, p.100051.
The methodology is divided into four phases:
Phase 1 – Define
The first step is to convene stakeholders to establish local perspectives on the objectives and priorities for undertaking this analysis. These objectives become the basis upon which investment portfolios are assessed. The scope of analysis is set by working with stakeholders to establish the boundary of the system, which parts of the system must be represented in the model and the most important risks and uncertainties facing the system. Lastly, this stage of analysis defines a preliminary set of interventions with stakeholders to improve the resilience of the system.
Phase 2 – Collaborative modeling
Technical team of analysts and local partners collaboratively model the system of interest. Model components typically include a weather generator (to create stochastic sequences of possible future climate), hydrology module, water system infrastructure module, demand module, water quality module and finance module. Many scenarios of climate and demand are used to stress test the system and identify key system vulnerabilities.
Phase 3 – Analyze
Identify the optimal portfolios of interventions to improve resilience based on stakeholder identified metrics. Interventions include both infrastructure and policy options such as demand management and implementation of environmental regulation.
Phase 4 – Align
Translate the results of the optimisation process into an investment and policy implementation roadmap that stages decisions such that adaptations are implemented based monitoring of how the future actually unfolds.
Applications to date
There are currently several ongoing examples of implementing Resilience by Design into water system planning and management strategies, in Mexico City, San Francisco and Tanzania.
Application of RbD to Mexico City and three supply basins in collaboration with the World Bank. Models of urban flooding and household water supply (for households not connected to the distribution system) have also been developed.
San Francisco Public Utilities Commission
Long Term Vulnerability Assessment to understand the impact of climate change in combination with and in comparison to other factors vulnerabilities. Dynamic adaptive pathways will establish staged investments in order to build the resilience of their system.
In collaboration with the World Bank, this project focuses on designing water, food and energy investments that are resilient to both future uncertainties and the trade-offs between competing water interests. Our analysis has focused on the Rufiji, Pangani and Wami-Ruvu basins.
Funding for Resilience by Design is provided by the Rockefeller Foundation.