沱江成都段河流生态健康评估研究

Health Assessment of the Tuojiang River in Chengdu Municipality

为摸清沱江流域成都段水生态系统健康状况,并探索有效的河流生态健康综合指数评估方法,文章以沱江流域成都段为研究对象,通过调查水文水质、生境、底栖动物、鱼类等环境生物要素,以水生态环境质量综合评价指数(WEQI_(river))法和河流健康指数(RHI)法进行评价对比分析。结果表明:基于水质、生境和底栖动物的WEQIriver综合指数法显示研究对象河流整体呈良好状态;基于岸线自然状况、违规开发利用岸线程度、生态流量满足程度、水质优劣程度、水体自净能力、鱼类保有指数和公众满意度的RHI综合指数法显示研究对象河流整体呈亚健康状态。2种评价结果均表现为干流和上游支流环境状况优于下游支流,部分点位结果差异较大,主要受不同方法侧重点不同影响,WEQI_(river)指数更侧重评价水生态系统的自身状况,RHI指数则更侧重评价人类活动对水生态系统的干扰程度。二者可以相互借鉴,综合用于河流生态系统健康评价。

This study evaluated the aquatic ecosystem health status of the Chengdu Section of Tuojiang River Basin and explored an effective index evaluation method to comprehensive measure ecological health of the river section.We investigat-ed the physical,chemical and biological factors such as hydrology,water quality,habitat,benthic invertebrates and fishes,and conducted a comparative analysis using the WEQIriver comprehensive index method and the RHI comprehensive index method.The WEQI_(river) comprehensive index method based on water quality,habitat and benthic invertebrates showed that the Chengdu section was in good condition.The results of RHI comprehensive index method based on the natural condition of the riverbank,degree of illegal exploitation and utilization of the riverbank,degree of ecological flow,degree of water pollu-tion,self-purification capacity of the water,fish retention index and public satisfaction showed that the whole basin was in a sub-health state.The results of the two methods showed that the environmental condition of the mainstream and upstream tributaries was better than the downstream tributaries.The environmental conditions of some sites were quite different be-cause they were influenced by the different focuses of the two methods.WEQI_(river) comprehensive index lays more emphasis on the state of water ecosystems itself,while RHI comprehensive index lays more emphasis on the interference level of hu-man activities to water ecosystems.The better effect is achieved by integrating the two methods in water ecosystem health as-sessment.