[Dec 05] YAN Hong: Water Allocation: Modelling and Simulation for Minjiang River Basin of China under Changing Climatic Conditions

The significant stress on development caused by unsustainable water resource allocation has been a perplexing problem for the Dujiangyan Administration Bureau of the Minjiang River Basin, at the upper Yangtze River in China. To tackle these regional water resources allocation issues at Sancha Lake, at the lower-right basin of the Dujiangyan Irrigation System, the local authority was seeking an optimal allocation strategy to ensure equitable and efficient water use for its subareas, from which the subareas would be able to provide reasonable reaction strategies. The authority dominates the water transactions between the subareas involved in water rights distribution, which shows a Stackelberg-Nash equilibrium, with the subareas playing a Cournot-Nash game to develop optimum strategies. Using a multi-objective multi-stage decision making process with an uncertain stream inflow, a multi-objective multi-stage Stackelberg-Nash-Cournot (m2SNC) game is modeled as a bi-level equilibrium optimization incorporating fuzzy random coefficients. An interactive-dynamic-programming-based genetic algorithm (IDP-GA) is designed to simulate the policies needed for the optimum allocation of water resources under various climatic scenarios. Specifically, a complete operational mechanism for the Sancha Lake area is presented to demonstrate the practicality and efficiency of the bi-level equilibrium model and the policy simulation procedure: (1) The bi-level equilibrium model, integrating the Stackelberg-Nash equilibrium and the Cournot-Nash equilibrium, is an efficient tool to determine optimal water resource allocation strategies. (2) Similar to the principles of an input-output system and the computable general equilibrium, the policy simulation system with an IDP-GA, an extension of principle of CGE, inputs scenario data and outputs an early-warning mechanism to inform the policy suggestions. (3) An emergency response cooperative mechanism based on allocation modes dominated by an authority is a relatively equitable and efficient method for developing countries which need to cope with uncertain situations under changing climatic conditions.