| 摘要: |
| 赤水河作为长江上游珍稀特有鱼类国家级自然保护区的重要组成部分，其生态连通性对保护长江上游特有鱼类至关重要。但赤水河流域内广泛分布的小水电站严重影响了该区域的连通性。本研究收集了赤水河流域小水电站的空间位置、建设年份、装机容量等详细信息，并采用DCI(Dendritic Connectivity Index)、SCI(Stream Connectivity Index)、CAFI(Catchment Area Fragmentation Index)和新提出的CAFIM (Modified Catchment Area Fragmentation Index)四种连通性指数，全面评估了小水电站对赤水河流域水系连通性的时空变化。研究发现，赤水河流域几乎每条河流都建有小水电站，主要分布在低阶河流。DCI和SCI指数表明，随着电站数量的增加，赤水河流域的连通性显著下降，中下游地区连通性较上游地区更为恶化。CAFI和CAFIM指数揭示了类似趋势，河流破碎化程度不断加剧，特别是在习水河、大同河和桐梓河流域表现显著。创新提出的CAFIM指数将小水电站的装机容量因素纳入考虑，能够更加全面准确地评估小水电站的影响。CAFIM指数相较于传统指标，对装机容量变化更为敏感，能有效反映大型电站的影响。根据CAFIM等指数评估结果，研究评估了赤水河流域内各小水电站障碍物的优先级，提出应优先整改位于高阶河流且装机容量大的电站，以最大程度改善流域连通性。根据各指数评估结果，研究发现电站的位置和装机容量是决定其优先拆除顺序的关键因素，对位于高阶河流且装机容量大的电站(如金阳、圆满贯等)的拆除，对改善流域连通性效果最为显著。该研究全面评价了赤水河流域的连通性状况，提出了优化小水电站拆除的策略，为该流域生态修复提供决策依据，对保护长江上游特有鱼类具有重要意义。本研究为小水电站对流域河网连通性的评估及恢复对策提供了理论基础和方法支持。 |
| 关键词: 河流连通性 小水电站 riverconn 改进河流破碎化指数CAFIM 连通性指数 赤水河流域 |
| DOI： |
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| 基金项目:国家自然科学基金项目（面上项目，重点项目，重大项目） |
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| Assessment of the Impact of Small Hydropower Stations on the Connectivity of the Chishui River and Research on Restoration Strategies |
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Wentong Zhao,Wei He,Xianfu Zhao,Feng Chen,Jing Zhang,Xiaowei Jin,Feng Mao,Zhengfei Li
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1.Key Laboratory of Ecological Impacts of Hydraulic-Projects and Restoration of Aquatic Ecosystem of Ministry of Water Resources, Institute of Hydroecology, Ministry of Water Resources and Chinese Academy of Sciences;2.Institute for Global Sustainable Development, University of Warwick
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| Abstract: |
| The Chishui River, as an important component of the National Nature Reserve for rare and endemic fish species in the upper Yangtze River, has ecological connectivity that is crucial for protecting endemic fish species in the upper Yangtze River. However, the widespread distribution of small hydropower stations in the Chishui River basin has severely affected the connectivity of this region. This study collected detailed information on the spatial location, construction year, and installed capacity of small hydropower stations in the Chishui River basin. Four connectivity indices, namely the Dendritic Connectivity Index (DCI), Stream Connectivity Index (SCI), Catchment Area Fragmentation Index (CAFI), and the newly proposed Modified Catchment Area Fragmentation Index (CAFIM), were used to comprehensively assess the spatiotemporal changes in the connectivity of the Chishui River basin due to small hydropower stations. The study found that almost every river in the Chishui River basin has small hydropower stations, mainly distributed in low-order streams. The DCI and SCI indices showed that with the increase in the number of stations, the connectivity of the Chishui River basin significantly decreased, with the connectivity in the middle and lower reaches being more deteriorated than in the upper reaches. The CAFI and CAFIM indices revealed similar trends, with the degree of river fragmentation continuously increasing, particularly in the Xishui River, Datong River, and Tongzi River basins. The innovatively proposed CAFIM index incorporates the factor of installed capacity of small hydropower stations into consideration, enabling a more comprehensive and accurate assessment of the impact of small hydropower stations. Compared to traditional indicators, the CAFIM index is more sensitive to changes in installed capacity and can effectively reflect the impact of large-scale power stations. Based on the assessment results of the CAFIM and other indices, the study evaluated the priority of obstacles posed by each small hydropower station in the Chishui River basin and proposed that priority should be given to rectifying stations with large installed capacities located on high-order streams to maximize the improvement of basin connectivity. The study found that the location and installed capacity of the stations are the key factors determining the priority of their removal. The removal of stations located on high-order streams with large installed capacities (such as Jinyang and Yuanmanguan) has the most significant effect on improving basin connectivity. This study comprehensively evaluated the connectivity status of the Chishui River basin, proposed strategies for optimizing the removal of small hydropower stations, and provided a decision-making basis for ecological restoration in the basin, which is of great significance for protecting endemic fish species in the upper Yangtze River. This research provides theoretical foundations and methodological support for assessing the impact of small hydropower stations on watershed river network connectivity and developing restoration strategies. |
| Key words: River Connectivity Small Hydropower Stations riverconn Modified River Fragmentation Index CAFIM Connectivity Indices Chishui River Basin |
