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Sediment Flushing from Sabo Dams and its Environmental Impact on River

萨博水坝冲沙及其对河流的环境影响

基本信息

批准号：
11660147
负责人：
FUJITA Masaharu
金额：
$ 2.18万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11660147/
关键词：
sediment flush river environment sabo dams fishes turbidity water riverbed variation sediment runoff control eco-system 階段状河床ハビタット土砂流出

项目摘要

The habitat of fishes and aquatic insects must deteriorate by passing of turbidity water and sediment when the deposit in sabo dams is released all at once to the river where the sediment transport becomes not active. ln this research, we have investigated the riverbed variation by a series of sabo dams and studied how they influence the habitat. Moreover, the impact that the artificial sediment flushing from sabo dams gives to the habitat in mountain streams is investigated from some field experiments and numerical simulations. The following results were obtained :1.Riverbed variation by a series of sabo dams(1)The effect of a series of sabo dams cannot be estimated by the addition of the effect of a single sabo dam.(2)Because much sediment would be flushed from slit sabo dams when the water discharge decreases at floods, the impact to the habitat might be severe.2.Movement of the sediment artificially flushed from sabo dams(1)The calculation program for analyzing the movement of the bed load was presented. The program could explain the deposition and erosion process in pools.3.Influence of sediment movement on the environment in habitat of fishes(1)The indices such as turbidity, dissolved oxygen, sediment storage capacity of pools, the space scale between gravels and cobbles, sediment deposition depth on riverbed, plane shape of streams are important in evaluation of the influence of sediment flushing.(2)The above-mentioned program was applicable to the evaluation of impacts by sediment flushing and recovering to the original riverbed.(3)The relation between the influence level and the stress index for char was experimentally clarified, and the sediment flushing condition with a little influence was presented.

当沙博坝的存款被释放到河流中的泥沙输运变得不活跃时，鱼类和水生昆虫的栖息地必然会因浊水和泥沙的通过而恶化。在本研究中，我们调查了一系列的萨博大坝河床变化，并研究了它们如何影响栖息地。此外，通过野外试验和数值模拟，研究了沙博坝人工排沙对山溪中小蠊栖息地的影响。结果表明：（1）多沙坝对河床的影响（1）多沙坝对河床的影响不能用单个沙坝的影响相加来估计。（2）由于洪水时泄流量减少，会有大量泥沙从窄缝沙坝中冲出来，对生境的影响可能会很大。（2）沙坝人工冲沙的运动（1）提出了分析推移质运动的计算程序。3.泥沙运动对鱼类栖息地环境的影响（1）水体浊度、溶解氧、池塘的泥沙贮量、卵石与卵石的空间尺度、河床泥沙淤积深度、河流平面形态等指标是评价泥沙冲刷影响的重要指标。（2）上述程序适用于冲沙和恢复原状影响的评价。（3）通过实验研究，明确了焦炭受影响程度与应力指数之间的关系，提出了影响较小的排沙条件。