香溪河梯级小水电站对河流生态系统功能的影响  

Impacts of Cascade Small Run-of-River Dams on River Ecosystem Functions in the Xiangxi River System

作　　者：吴乃成[1,2] 唐涛 周淑婵[1,2] 蒋万祥[1] 傅小城 李凤清[1] 蔡庆华[1] WU Nai-cheng;TANG Tao;ZHOU Shu-chan;JIANG Wan-xiang;FU Xiao-cheng;LI Feng-qing;CAI Qing-hua(Institute of Hydrobiology,Chinese Academy of Sciences,State Key Laboratory of Freshwater Ecology and Biotechnology,Wuhan 430072,China;Department of Geography and Spatial Information Techniques,Ningbo University,Ningbo 315211,China)

机构地区：[1]中国科学院水生生物研究所,淡水生态与生物技术国家重点实验室,湖北武汉430072 [2]宁波大学地理与空间信息技术系,浙江宁波315211

出　　处：《长江流域资源与环境》2021年第6期1458-1465,共8页Resources and Environment in the Yangtze Basin

基　　金：国家重点研发计划项目(2017YFC0506406);国家自然科学基金重点项目(30330140)。

摘　　要：香溪河是长江三峡水库湖北省最大且靠近坝首的支流,干流全长94 km,流域面积为3099 km^(2),其水能资源丰富,自然落差达1540 m。以香溪河流域内的18座小水电站为研究对象,于2005年10月20日至11月1日分别对河流主要理化指标及生态系统功能(以附石藻叶绿素a浓度为代表)进行测量,分析其对梯级水电站建设的响应。结果表明:5条河流(包括香溪河干流和4条主要支流)的空间异质性较大;从全流域来看,各主要理化因子如溶解氧、水深、浊度、流速等与附石藻叶绿素a含量相关性很高,但不同支流的主要影响因子各异,证明了流域空间异质性对研究小水电的影响具有重要作用;梯级小水电站建设对河流生态系统功能已产生显著影响,特别是在取水口下游的3号样点。由于取水造成的断流现象严重(采样时期,50%的电站出现断流,最长距离达3.2 km),因此在枯水期确定河流的最低生态需水量,是一个亟待解决的问题。从流域角度出发,通过多学科交叉手段研究小水电站建设如何与其他环境胁迫因子交互作用,如何共同影响河流生物多样性、生态系统结构、功能与服务。这将是流域水电站管理的重要抓手及解决途径,也是未来河流生态学的研究重点。Xiangxi River is the biggest tributary of the Three Gorges Reservoir in Hubei Province, which has a length of 94 km, a catchment area of 3 099 km^(2) and a natural fall of 1 540 m. There are many small run-of-river dams in the Xiangxi River system because of the high natural fall and their environmental consequences are worth paying more attention. From 20 October to 1 November in 2005, 18 small run-of river dam related segments were selected for measuring the main physicochemical variables and chlorophyll a concentrations(as a proxy of ecosystem function). The result showed that:(1) the main stream and the four tributaries demonstrated a high spatial heterogeneity in terms of environmental variables;(2) apparent impacts of cascade small run-of-river dams on chlorophyll a concentrations were found, particularly for the site just below the intake dam, where chlorophyll a concentrations increased significantly;(3) for the whole catchment, the main drivers of ecosystem function were DO, water depth, turbidity and flow velocity, however, different responses were found in distinct tributaries, indicating the potential effects of spatial heterogeneity;(4) almost 50% of the investigated river sections were dried out during the sampling period, and this implies that it’s urgent to quantify the minimum ecological water requirement to mitigate the negative effects of these dams. In addition, we advocate that understanding the interaction between run-of-river dams and other multiple stressors and their consequences on river biodiversity, ecosystem functions and services will be a core topic in river ecology, since this is essential for sustainable river basin management.

关 键 词：梯级小水电站 叶绿素A浓度 空间异质性 环境因子 流域水电管理 

分 类 号：X321[环境科学与工程—环境工程]