Representing Reservoir Water Storage in a Human-Earth Systems Model and its Role in Responding to Future Water Challenges
Water is essential for life, yet its availability varies greatly across regions and seasons. Over one-third of the global population experiences water shortages, especially during dry seasons. Reservoirs help manage temporal supply and demand mismatches by storing water when it's plentiful and releasing it when needed. However, understanding how reservoirs can help meet future water demands is complex. Our research introduced the GLObal Reservoir Yield (GLORY) model to enhance how reservoir water storage is represented in the Global Change Analysis Model (GCAM). This helps us better understand how reservoirs can meet water demands under changing climate and societal needs. We find that reservoirs' capacity expansion and water yield depend on many factors, such as seasonal climate variability, reservoir expansion potential and costs, and shifting water demands due to human-Earth interactions. This research explores the physical and economic aspects of reservoir water supply to better inform future water planning.
This research studies the challenge of managing water resources to meet human demands that will co-evolve in conjunction with climate and socioeconomic changes, particularly in water-scarce regions. It is the first to integrate reservoir water storage into the global multi-sector model GCAM that captures the interactions among climate, land, energy, and water systems. The GLORY model estimates the cost and water yield of various reservoir storage capacities, accounting for sub-annual climate variation, land-use feasibility, and economic factors. This advancement enables scientists to explore future water storage capacity expansion and its feedback on human-Earth systems, impacting fields such as environmental science, economics, and climate research.
Our research introduces GCAM–GLORY v1.0, an advanced framework designed to enhance the representation of global reservoir water storage within the GCAM. This model incorporates the GLORY model, which employs a linear programming-based optimization algorithm to simulate reservoir storage dynamics and their economic impacts. By dynamically linking GLORY with GCAM, we improve the understanding of reservoir water storage by evaluating the cost of water supply from reservoirs, taking into account regional physical and economic factors. This integration allows for the exploration of future regional reservoir expansion pathways and their interactions with climate, land, and energy systems.
Our findings emphasize the critical role reservoirs play in addressing human water demands and mitigating socioeconomic droughts, despite their relatively small physical footprint. The research underscores the necessity of considering sub-annual variations in climate conditions and human water demands for effective reservoir management. By incorporating these dynamics, we offer insights into the sensitivity of reservoir water supply across multiple dimensions and identify potential global reservoir expansion pathways. This work enhances our understanding of reservoirs' roles in the co-evolution of human-Earth systems and supports integrated, multi-sector strategic analysis for responding to future water resource challenges.