Equity challenges in adaptive water supply investment and management pathways in The Federal District of Brazil

Adaptive planning and decision processes have proved to be important tools to identify robust policies for urban water supply systems facing climate, economic and social uncertainties. However, social and economic disparities need to be carefully reflected in adaptive plans and how they may shape conditions for the most vulnerable. In this study, we focus on the water supply system for the Federal District of Brazil (FDB), comprised of two major service areas (Descoberto and Santa Maria). The Federal District is home to more than 3- million people with strong inequities in the average incomes and water consumption patterns in the population its serves. This work aims to improve region’s adaptive urban water supply investment and management portfolio pathways. Our modeling formulation searches for alternative water supply management and investment policies to increase the reliability and financial stability of the water utility given a changing climate, increasing demand pressures and other deeply uncertain conditions. Results indicate that policies need to be carefully evaluated due to possible inequities they may promote between the service areas in terms of distributive costs and supply reliability performance benefits. We show asymmetries in how short-term actions benefit the two water service areas and influence the need of required infrastructure investments. These findings provide insights on how water policies and inequalities in socio-economic conditions may agravate disparities between service areas in urban water supply systems. Results of this study are broadly applicable to urban water supply planning problems globally in regions with high inequality.