基于水经济价值的长江口环境流量探讨

适宜的环境流量对于维持河口生态系统稳定以及保障区域社会经济用水需求有着重要意义。论文以探讨水资源优化配置条件下长江口适宜环境流量为目的,基于水经济价值分析构建了长江中下游水资源优化配置模型,分析了区域缺水量以及环境流量约束的影子成本随长江口环境流量约束的变化。结果表明：当环境流量约束超过临界值后,区域缺水量不断增加,且环境流量约束产生非零影子成本;通过区域供水目标和环境流量约束的影子成本图确定长江口适宜环境流量的上限和下限,得到20%、50%、75%及95%水资源保证率下,长江口适宜环境流量分别为27.10×10⁹~29.65×10⁹、25.50×10⁹~27.12×10⁹、23.08×10⁹~24.62×10⁹及17.72×10⁹~19.65×10⁹ m³/月;该环境流量标准可以满足一定目标下长江口的生态需求。

Study on Environmental Flow in Yangtze River Estuary Based on Hydro-economic Analysis

Suitable environmental flow requirements are important for maintaining stability of ecosystem in estuary area as well as satisfying social and economic demands for water in upstream area. The aim of this research is to discuss suitable environmental flow in Yangtze River Estuary on the basis of regional water resources allocation. Based on the analysis of economic value of water, a hydro-economic optimization model is built for the middle and lower reaches of the Yangtze River Basin with minimum environmental flow constraint in Yangtze River Estuary. By changing the environmental flow constraint in Yangtze River Estuary, variations of regional water shortages and shadow costs with the environmental flow constraints are discussed. The results show that the regional water shortage begins to increase and the shadow cost of the environmental flow constraint becomes positive when the environmental flow constraint exceeds a certain critical value. Upper and lower limits of suitable environmental flow are obtained according to regional water supply target and shadow costs of the environmental flow constraints. Suitable environmental flows in Yangtze River Estuary at water resources guarantee rates of 20%, 50%, 75% and 95% are 27.10 billion-29.65 billion m³/month, 25.50 billion-27.12 billion m³/month, 23.08 billion-24.62 billion m³/month and 17.72 billion-19.65 billion m³/month, respectively. With these environmental flows, the water demands in upstream area can be satisfied and ecological objectives in Yangtze River Estuary can be realized.