粤港澳大湾区水生态状态演变及驱动机制研究

The evolution of water ecological state and driving mechanism in Guangdong-Hong Kong-Macao Greater Bay Area

以粤港澳大湾区为研究区域,考虑水生态与人类社会、内外环境变化之间的相互作用,构建能较为全面地反映粤港澳大湾区水生态状态的指标体系,量化2010—2019年粤港澳大湾区水生态状态及其演变趋势。根据大湾区面临的水生态风险,选取西江和北江年径流量、下游潮位、大湾区城市化率等7个驱动因子。以代表主要环境影响的驱动因子作为输入,以大湾区4个水生态状态指数作为输出,构建粤港澳大湾区河网城市群水生态状态反应器并研究其驱动机制。结果表明:粤港澳大湾区水生态状态近10年来不断向好;水生物状态受西江年径流量和下游盐度影响较大;生境指数在快速城市化影响下呈下降趋势,但下降速度逐年变缓;与此同时,快速城市化表现出对城市污水处理率的提高和对咸潮上溯的有效控制,为大湾区内主要河流水质改善做出贡献;在西北江分流比变化和自然灾害等影响下,大湾区水安全程度仍不断提高。

Taking the Guangdong-Hong Kong-Macao Greater Bay Area(GBA)as the research area,this study (1)considered the interaction between water ecology and human society,internal and external environmental changes,(2)constructed an index system that can reflect the water ecological state of the GBA more comprehensively,and (3)quantified the water ecological state of the GBA and its evolution trend from 2010 to 2019.Concerning the water ecology risks faced by the GBA,seven driving factors were selected,such as the annual runoff of the Xijiang River and the Beijiang River,the downstream tidal level,and the urbanization rate of the GBA.Taking the driving factors as the input and the four wa‐ter ecological state indices as the output,the water ecological state reactor of the river network urban ag‐glomeration in the GBA was constructed and its driving mechanism was studied.Results showed that (1)the water ecological state of the GBA has been improving in the past ten years;(2)the aquatic state was greatly affected by the annual runoff of the Xijiang River and downstream salinity;(3)the habitat index was under the rapid urbanization which shows a downward trend,but the rate of decline has slowed year by year;(4)meanwhile,rapid urbanization has shown an improvement of urban sewage treatment and effective control of the salt tidal upward,which has a positive impact on the improvement of the water quality in the GBA;(5)the water security of the GBA continues to improve despite the influence of changes in the diversion ratio and natural disasters.