北京平原地下水可持续开采方案分析

Analysis of sustainable groundwater resources development scenarios in the Beijing Plain

地下水过量开采已经引起北京平原地下水位持续下降,降落漏斗逐年扩大以及一系列环境问题。控制地下水开采,增加地下水补给以达到地下水可持续开采应当成为北京市水资源管理的重要任务。本文根据北京市中长期供水规划、水资源特点和地下水开采现状设计了4种地下水开发利用开采方案:即维持现状开采、增加补给量、减少开采量以及联合方案。运用已建北京平原地下水数值模拟模型对4个方案进行了模拟,分析了地下水系统水均衡量变化,地下水流场变化以及地下水动态变化,以此确定可能的可持续开发方案。结果表明,维持现状开采必将使含水层地下水疏干;增补和减开单独实施虽能改善现状,但难以实现。只有应用增补和减开的联合方案,才有可能实现地下水可持续开发。其为北京平原地下水资源的合理开发提供重要的依据。

Over-exploitation of groundwater has caused continuous decline in groundwater levels, expansion of the cone of the depression and other environmental problems in the Beijing Plain. Control of groundwater abstraction and increase in groundwater recharge are important tasks for water managers in Beijing municipality. Based on long - term planning of water resources utilization, characteristics and groundwater conditions, four possible groundwater resources development scenarios are designed, including business as usual, reduced recharge, increased recharge and the joint scenario of reduced abstraction and increased recharge. The calibrated regional groundwater flow model of the Beijing Plain is used to simulate effects of each scenario on groundwater levels and balance components. The results show that the business as usual scenario will eventually lead to the depletion of groundwater resources. The reduced abstraction scenario could recover the depleted aquifer and establish a new equilibrium state; the remaining abstraction rate can not meet the water demand. The increased recharge scenario can sustain the present abstraction rate and recover the depleted aquifer, and the required artificial abstraction rate is very large and will be difficult to be implemented. The joint scenario consists of merits of reduced abstraction and increased recharge scenarios. It can sustain the required abstraction rate for water supply and recover the depleted aquifer, and eventually lead to a sustainable development of groundwater resources in the Beijing Plain.