闸坝调控对河流水生态环境影响特征分析

Analysis of the impact of dam operations on the river water ecological environment

为探讨闸坝工程对河流水生态环境的影响效应,进行实地闸坝调控实验,监测河流水质指标在不同调控(0m^3/s、20 m^3/s、40 m^3/s和60 m^3/s)方式下的空间变化,并调查水生态指标,探析长期和短期的调控干扰对河流水生态环境的影响特征。结果表明:60 m^3/s调控,有助于闸下污染物的氧化和分解,提高河流水体的自净作用;水体的强烈冲刷和扰动作用促进底泥中污染物向水体转化,极易造成闸下区域水体的突发性二次污染;短期频繁地开闸调控对浮游动植物的密度分布影响显著;长期的调控干扰导致水生生物群落和结构单一,水生态环境显著恶化,闸上区域负面影响更为严重。研究结果可为河流生态修护与可持续流域水环境管理提供科学依据。

Our field experiment made a thorough investigation of the influences of dam operations on the characteris- tics of the river water eco-environment, and studied the spatial variation of water quality at different control modes （0 m3/s, 20 m3/s, 40 m3/s and 60 m3/s）. We also monitored ecological indicators to allow us to analyze the long-and short-term effects of the dam on the river water eco-environment. The results showed that a flow of 60 m3/s benefitted oxidation and decomposition of water pollutants downstream of the dam, and improved river water self-purification. An increase in disturbance of water flow promoted pollutant transfer from the sediment into the water so that a sudden pol- lution accident resulting from sediment disturbance downstream of the dam could easily take place. Frequent operations occurring in a relatively short period of time significantly affected the density distribution of plankton. What＇s more, the long-term effects of dam operations led to the development of a very simple biological community and structure, the water eco-environment deteriorated markedly, and the negative effects on the river upstream of the dam were more se- rious than downstream. The results of this study are useful in providing reliable information for ecological river restora- tion and sustainable river basin management.