|Impact of Dam Construction on the Longitudinal Connectivity of the Lower Jinsha River
|中文关键词:树状水系 连通性指数DCI 修复次序 金沙江下游
|英文关键词:dendritic river systems dendritic connectivity index restoration sequencing Jinsha River
| The complex, diverse ecosystem of the lower Jinsha River makes it a center of aquatic biodiversity, inhabited by numerous protected, endangered, rare and endemic fish species. However, ecosystem health in the lower Jinsha River has significantly deteriorated in recent years due to fragmentation by high-density, high-intensity cascaded hydropower stations. In this study, the main stem and the tributaries of the lower Jinsha River were treated as individual watershed units, and we constructed a dendritic diagram of watershed unit connectivity, analyzed the effects of fragmentation caused by dams within the watersheds, and quantitatively assessed the longitudinal connectivity of the lower Jinsha River using the dendritic connectivity index (DCI). The study was based on digital elevation models (DEM) of the main stem and tributaries of the lower Jinsha River, along with data on reservoirs and hydropower station construction. Results show that dam passage capacity in the lower Jinsha River gradually increased, and the connectivity index of the lower Jinsha River trended upward as the passable capacity of the dams increased. More specifically, when the DCI reached 0.7, the overall connectivity of the watershed improved significantly. We then further analyzed the relationship of the watershed connectivity index in the lower Jinsha River with dam construction on the 14 tributaries and, based on the results, we recommend a three-phase sequence of watershed restoration: Phase 1 would restore watershed connectivity among the rivers most influencing watershed connectivity, including Heishui River, Xixi River, Niulan River; in Phase 2, connectivity of rivers with less influence would be restored, including Pudu River, Xining River, Longchuan River and Shenyu River; Phase 3 would involve longer term connectivity restoration of rivers of least influence, including Henghe River, Pulong River, Meigu River, Yili River, Mengguo River and Xiaojiang River. Our research provides base data to support planning and implementation for an effective connectivity restoration effort and the preservation of aquatic biodiversity.
|侯轶群,邹 曦,陈小娟,金 瑶,杨 志,刘宏高.2024.金沙江下游大坝建设对纵向连通性的影响研究[J].水生态学杂志,45(1):26-31.
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