A system dynamics simulation approach for environmentally friendly operation of a reservoir system

Multipurpose reservoir operation is a very complex decision-making process because of its multiple and usually conflicting targets. A system view of the interactions between various reservoir purposes (like for example, hydropower production and environmental impacts such as fish habitats, sediment flushing, and landslide stability) is a prerequisite to attain the full benefits from reservoir operations. System dynamics simulation is a well suited approach for dealing with complex time-varying systems and is widely used in water resources management and analyses of global change. This paper presents the development of a generic system dynamics simulation approach (SDSA) for the analyses of interactions between reservoir’s various functions. The implementation of SDSA includes two steps. First, the causal diagram of the reservoir system is used to map and analyze the main interactions among reservoir system’s different components, identify driving feedback relationships and use the system structure to obtain insights’ into system behavior. In the second step, the stock and flow diagraming is used to quantify those feedbacks and interactions by introducing a set of physical and empirical relationships required to simulate the model. The developed SDSA is applied to the Three Gorges Reservoir in China. Scenario based simulation analyses are performed with the SDSA model to increase the understanding of placing different priorities on the interactions between hydropower production and environmental impacts of reservoir operations. Results from model validation and sensitivity analyses suggest that the developed SDSA model is capable of simulating interactions among reservoir’s various functions, and the case study application demonstrates the utility of the model for capturing the main characteristics of reservoir system dynamic behavior. The insights gained from model simulations can assist in environmentally friendly operations of the reservoir.