A procedure for urban water supply system planning under climate variability and deep uncertainty conditions

Procedimento para o planejamento de sistemas de abastecimento de água urbana sob condições de variabilidade climática e incerteza profunda

ABSTRACT

This study developed a structured, easy-to-understand methodology for evaluating urban water supply system alternatives subject to climate variability and deep uncertainties. The water balance in all alternatives was computed from 2021 to 2060 using the Water Evaluation And Planning System (WEAP) platform and incorporating decision making under deep uncertainty (DMDU) techniques. A scenario ensemble of climate conditions and deep uncertainty factors was defined as a state of the world (SOW) for the comparison of performance among the alternatives. The procedure stablished system objectives (minimizing service failure, energy consumption and reservoir failures) and criteria to guide the evaluation among the alternatives. The methodology was applied to the urban water supply system (UWSS) in the Federal District of Brazil, revealing that one specific supply option demonstrated the best overall performance from a multi-objective perspective. However, if the goal is strictly to minimize the intensity of service failures, a different supply configuration emerges as the more effective choice. The methodology allows the selection of the condition that best meet the objectives and priorities of the water utility by choosing specific objective. It was possible to illustrate the tradeoffs that arise from the selection of specific objectives during the evaluation.

Keywords:
Deep uncertainties; Urban water supply system; Decision support system; WEAP