Strategic planning for drought mitigation under climate change

Droughts continue to be a major natural hazard, and mounting evidence of global warming confronts society with a pressing question: Will climate change aggravate the risk of drought at the local scale? Are current infrastructures sufficient to mitigate the damage of future drought, or is in-advance infrastructure expansion needed for future drought preparedness? To address these questions, this study presents a decision-support framework based on a coupled simulation and stochastic optimization model through a case study area, the Frenchman Creek basin (FCB), part of the Republican River basin. A complex watershed simulation model is established and converted into a statistical surrogate model for computational feasibility. Decisions for drought preparedness include traditional short-term tactical measures (e.g., facility operation) and long-term or in-advance strategic measures, which require capital investment. A scenario-based, three-stage stochastic optimization model assesses the roles of strategic measures and tactical measures in drought preparedness and mitigation. Modeling scenarios of the future climate are developed from multiple general circulation models (GCMs) and regional climate models (RCMs) under different greenhouse gas emission scenarios to represent the various possible climatic conditions in the midterm (2040s) and long-term (2090s) time horizons. The result of the case study shows that current facilities are not enough to mitigate the damage under future climate conditions, indicating the requirement for infrastructure investment; meanwhile, socioeconomic factors (represented by the discount rate) complicate the decision along the planning horizon.