论我国水生态的保护与修复:任务与对策

本文聚焦我国水生态保护与修复工作,结合长期实践,分析当前的形势和任务,指出了当前要着力解决的水生态问题主要是:在大坝上游,河流变湖库,生境变化导致生物物种变化;水库水流流速变缓,水体自净能力降低,导致富营养化及藻类水华。在大坝下游,清水下泄,冲刷下游河道导致局部河道河势变化较大;水库蓄水使坝下游春季水温下降、秋季水温升高,水温变化过程滞后;水库蓄水导致大坝下游的水文过程改变,水的流量、流速、流态发生变化。在河道(航道)整治工程中,裁弯取直,缩短水流在河道中的停留时间,河岸衬砌和硬化,减少水向沿河堤岸的渗透,在大降水和洪水时易造成涝灾和洪灾。在涉湖工程中,阻隔河湖,填湖造地。在明确存在问题和迫切需求的基础上,提出了切实可行的对策建议。当前水生态保护与修复要围绕一条主线,即"人要发展,鱼要生存"的"人鱼线",要采取"调、控、退、通、改、拆"的综合措施,即生态调度,控制水污染,退建还水、退田还湖,河湖连通,对已建涉水工程进行生态化改造,对在保护区、重点风景名胜区、特有鱼类栖息地修建的小型工程要采取坚决措施拆除,恢复原貌。

Protection and Rehabilitation of Water Ecology in China: Task and Countermeasure

This paper focused on the water ecological protection and restoration in China,analyzed the current status and tasks based on long-term practice,and pointed out the main issues as follows.In the upstream of the dam,the river changes into a lakelike reservoir,and the habitat changes lead to the change of biological species;the flow velocity of the reservoir slows down,and the self purification capacity of the water body decreases,leading to eutrophication and algal bloom.In the downstream of the dam,water flows down and scours the downstream river,resulting in great changes in the local river regime;the reservoir impoundment makes the water temperature in the downstream of the dam to drop in spring and to rise in autumn,thus the water temperature change process lags behind;the reservoir impoundment results in changes in the hydrological process of the downstream of the dam,resulting in changes in water flow,flow rate and flow pattern.In the regulation project of river(channel),the measures of"cut the bend straight"shorten the stay time of water in the river,and the means of"lining and hardening the bank"reduce the water infiltration to the bank along the river,which is easy to cause waterlogging and flood disaster in heavy rainfall and flood.In the lake project,the river and lake are blocked;the land is built by filling the lake.On the basis of clarifying the existing problems and urgent needs,practical countermeasures and suggestions are put forward.At present,the water ecological protection and restoration should focus on the line of people-fish harmony,i.e.for people to develop and for fish to survive,and take the comprehensive measures of"dispatching,controlling,restoring,connecting,reforming and dismantling",that is,ecological dispatching,controlling water pollution,restoring construction to water and farmland to lake,connecting rivers and lakes,ecologically reforming of the existing wading projects,and dismantling small projects in the protected areas,key scenic spots,and special fish habitats to restore their original appearance with resolute measures.