河流健康理论初探

健康河流是指在相应一定时期其社会功能与自然功能和谐并能够均衡发挥的河流,其标志是具有良好的水质、水沙流畅的河床与可维系的河流生态系统。河流健康的指示性因子应是能够基本反映河流自然功能的因子,包括河床形态、水质、河流生态和河川基流,但因子的种类和数量因河而异,其量化标准的确定则要充分考虑河流自然功能和社会功能均衡发挥的需要和河流水情背景条件的变化。河流健康的核心是有相应足够而洁净的河川径流,因此保障河流一定的环境流量对维护河流健康十分重要。人类过多抽取河川径流和开发水电、不当地调控洪水和泥沙、过多向河流排污和过多改变关键物种栖息地水流环境的活动,均会对河流健康造成严重伤害。本文以黄河为例,对河流健康指标和低限健康指标的确定方法进行了阐述。

Healthy River: Essence and Indicators

Healthy river is a river whose social functions and natural functions can be balanced or compromised in corresponding periods. The symbols of healthy river should be favorable riverbed,acceptable water quality and favorable river ecosystem,when river's social functions and natural functions perform in a balanced way. The river health indicators should reflect the river's natural function status which includes the riverbed,water quality,river ecosystem and runoff. But,the variety and quantity would be different for different rivers because of different natural features and social background. The quantized indicators should be decided according to the requirement of maintaining river's normal natural functions and the extent whether the social functions and the natural functions could perform in the balanced way,and also the indicators should be adjusted according to the change of the natural features and social background. The key to river health is the abundant and clean flow,as the environmental flows are very important to safeguard the river health. The human activities would hurt the river health which include the over water diversion and over power generation from the river,improper regulation of flood and sediment,and over sewage discharge into the river and excessive change of the environmental flows relating to key species habitat. Taking the Yellow River as a case,this paper also explained the method to identify the river health indicators.