Towards adaptive and climate-resilient water management under deep uncertainty: lessons from Chile

Climate change is increasingly challenging water governance systems worldwide, particularly in countries with strong hydroclimatic gradients and complex institutional arrangements. In Chile, observed and projected changes in precipitation, temperature, snow accumulation, glacier mass balance and extreme events are already affecting water availability, ecosystem integrity, and the effectiveness of existing water management instruments. These changes occur in a context of deep uncertainty, where future hydroclimatic conditions cannot be reliably characterized using single deterministic projections, posing fundamental challenges for long-term planning and day-to-day water governance.

This study presents an integrated framework for adaptive and climate-resilient water management, developed in close collaboration with the Chilean Water Authority (Dirección General de Aguas, DGA). The framework combines advances in climate and hydrological science with institutional analysis and participatory processes, aiming to support decision-making across multiple spatial and temporal scales. First, we synthesize observed and projected climate change impacts on Chilean water resources at national and macro-regional scales, drawing on updated hydroclimatic datasets and distributed hydrological modelling based on the Variable Infiltration Capacity (VIC) model. This includes explicit consideration of surface water, groundwater, snow, and glacier contributions, as well as changes in drought and flood regimes.

Second, we conduct a comprehensive institutional diagnosis of water management functions and practices, identifying the key Functions and Tasks of Water Management (FLGH for its acronym in Spanish) performed by public agencies and other actors. Through interviews, workshops and macro-regional participatory processes, we assess how these functions depend on hydrological variables and how they are being affected by climate change. We then propose a classification of FLGH according to their climate sensitivity, decision horizon and flexibility, distinguishing between functions requiring methodological adaptation and those primarily affected through changes in frequency or operational intensity.

Third, building on this classification, we develop adaptive decision criteria and methodological proposals to explicitly incorporate future climate uncertainty into water management functions. The approach is inspired in adaptive planning approaches such as Adaptation Pathways to support climate scenario based decisions for long-term, high-commitment decisions, while strengthening monitoring, enforcement, and short-term operational capacities for highly climate-sensitive functions. The framework emphasizes the need to align institutional mandates associated with water security criteria, and territorial heterogeneity, recognizing that adaptive strategies must differ across Chile’s broad climatic zones.

The results provide a transferable approach for embedding climate change and uncertainty into water governance systems, highlighting the importance of linking hydroclimatic science, institutional analysis, and participatory processes. While developed for Chile, the proposed framework is relevant for other regions facing increasing water scarcity, institutional fragmentation, and deep climatic uncertainty.