大东湖水系连通工程生态风险评价及防控对策研究

开展河湖水系连通工程生态环境效应评价研究,对于揭示水文过程及其生态环境效应具有重要意义。目前侧重于探究连通后水文水动力、水质和水生生物等要素的变化,但对于连通工程实施中的生态风险及其防控对策研究较少。因此,针对大东湖水系连通工程,结合美国环境保护署的生态风险评价框架,构建了大东湖生态风险概念模型,以大东湖水系连通工程的各湖泊为风险小区,选取底泥悬浮、水位变动、引水水质和外来物种入侵作为风险源,水环境、浮游生物和底栖生物作为风险受体。利用相对风险模型对大东湖水系连通工程的湖泊生态风险进行评价。研究结果发现,大东湖水系连通工程中,杨春湖和沙湖的相对风险值较大,约为东湖的6倍,主要原因是杨春湖和沙湖的水位变动和底泥悬浮的风险较大。在此基础上,从开展湖泊底泥疏浚、恢复水体生态功能和优化涵闸工程布局等方面提出风险防控对策。研究结果可为大东湖水系连通工程的科学实施提供决策依据。

Ecological risk evaluation and countermeasures research of East Lake interconnecting river and lake system network

Research on the ecology and environmental impacts of interconnecting river and lake system network was important to reveal the hydrological processes changes and associated effects.Most researches focused on exploring the changes of hydrodynamics,water quality and aquatic organisms.However,ecological risk evaluation and countermeasures research of interconnecting river and lake system network was scarce.Therefore,this research taked the East Lake interconnecting river and lake system network as case study.Based on the ecological risk assessment framework of USEPA,an ecological risk concept model of East Lake interconnecting river and lake system network was built.Lakes in East Lake interconnecting river and lake system network were considered as risk districts.Sediment suspension,water level changes,water quality and biological invasion were selected as risk sources.Water environments,planktonic and benthic communities were selected as risk receptors.The relative risk model was used to evaluate the ecological risk in East Lake interconnecting river and lake system network.The results indicated that the relative risks of Yangchun Lake and Shahu Lake were 6 times that of East Lake,owing to the high risk level of water level fluctuation and sediment suspension in Yangchun Lake and Shahu Lake.Countermeasures such as sediment dredging,ecological restoration and culvert layout were put forward to reduce the ecological risk in East Lake interconnecting river and lake system network.This research results could provide decision-making basis for the implementation of East Lake interconnecting river and lake system network.