Sustainable, Just, Equal, and Optimal Groundwater Management Strategies to Cope with Climate Change: Insights from Brazil

This paper applies optimal-control theory to develop groundwater exploitation strategies that account for potential climate change patterns in Brazil. Numerical experiments showed that whether climate change only affects groundwater quantity or whether it affects both groundwater quantity and quality, Brazilian water institutions will be able to implement optimal, equitable groundwater management strategies. However, they may be unable to achieve justice between current generations, while the economic, social, and environmental sustainability is likely to be favoured by a large regional groundwater availability. Institutional sustainability is ensured by the principles and institutions established by Brazil’s 1988 Constitution and by Law 9.433/97. Some sources of misunderstandings between managers and the research community are dealt with by suggesting directly applicable management strategies that accommodate stakeholder perceptions and desires. Some potential water policies based on the modelling results are discussed, with water conservation and water subsidies turning out to be beneficial for current and detrimental for future generations, respectively; in contrast, current generations paying for water at its social opportunity cost and being more concerned for future generations would benefit current generations.