Learning about climate change uncertainty enables flexible water infrastructure planning

Water resources planning requires making decisions about infrastructure development under substantial uncertainty in future regional climate conditions. However, uncertainty in climate change projections will evolve over the 100-year lifetime of a dam as new climate observations become available. Flexible strategies in which infrastructure is proactively designed to be changed in the future have the potential to meet water supply needs without over-building expensive infrastructure. Evaluating tradeoffs between flexible and traditional robust planning approaches requires extension of current scenario-based paradigms for water resources planning under climate uncertainty which take a static view of uncertainty. We develop a new dynamic planning framework that assesses the potential to learn about regional climate change over time and evaluates flexible approaches. We demonstrate it on a reservoir planning problem in Mombasa, Kenya. This approach identifies opportunities to reliably use flexible, incremental approaches, enabling climate adaptation investments to reach more vulnerable communities with fewer resources.