Coupling Hydrological and Economic Model for the Analysis of Staged Growth in Water Management Systems

Planning and managing water resource systems with multipurpose surface reservoirs demand the careful consideration of several critical factors, including system longevity, multiple uses, phased development, substantial financial investments, complex management requirements, uncertainties in predicting future hydrological inputs, and the estimation of economic parameters. Despite the importance of these factors, recent research and software development efforts for water resource system planning and management have predominantly focused on hydrological models. Economic models that describe the phased growth of such systems are often either absent or not fully integrated into decision-making software. Well-established network-based decision support tools, such as MODSIM, AcquaNet, and SIMYLD-II, provide robust hydrological modeling but lack explicit economic sub-models to address the evolving nature of water resource systems over time. This paper introduces a novel approach that combines optimization and simulation techniques to evaluate the multi-year performance of a growing water resource system. By conducting multiple model runs for each phase of system development—each characterized by unique topologies, demand patterns, hydrological conditions, and water delivery preferences—economic analyses are suggested to complete the global evaluation of the system. This comprehensive approach provides valuable insights into long-term planning horizons. Research in this direction continues to evolve, aiming to bridge the gap between hydrological and economic modeling in decision support frameworks. To illustrate the proposed methodology, a test example is presented, showcasing the implementation of the economic calculations and computer routines described in the paper. This example serves as a foundational step toward more comprehensive tools for sustainable and economically viable water resource system planning and management.