Development of hierarchical model of river ecosystem for its conservation and restoration-analyses on interrelations amongst sediment dynamism, channel geomorphology and ecological functions.

河流生态系统的层次结构：综述了河流系统中各层次的地貌特征。基于河流地貌和河岸植被格局，对鸡足河进行了河段划分。研究了京都市卡莫河沙洲浅埋带的理化结构，揭示了沙洲水质和水温的变化规律。开发了一种分布式降雨径流预测系统，用于评估巨岛河水系在大坝运行下的洪水衰减。泥沙动力与河流形态的相互关系：研究了奈良县吉野河河道泥沙蓄积量与地貌和微生境结构的关系。在黑部河和高原河研究了大坝冲沙对SS浓度和河流地貌的影响。研制了黑部大坝冲淤过程中水库河床冲淤过程监测系统。层次结构与生境功能的关系：研究了鱼类和水生昆虫产卵地点分布的决定因素是河段尺度特征，该特征是由水力梯度、弗劳德数、河床渗透性等一系列物理因素引起的供氧。层次结构与物质循环函数的关系：研究了乌济河和鸡祖河在不同流量条件下泥沙淤积物的大小和来源组成的纵向变化，结果表明，沙洲结构既是漂流泥沙淤积物的拦截者，也是河岸植被向河流生态系统提供泥沙淤积物的提供者。在17条河流中进行的藻藻生物测定的一系列野外试验结果表明，藻藻的生产更多地取决于有机质供应、流速和水温，而不是营养供应。河流生态系统恢复生态功能所需的输沙量：对比不同输沙量河流的底栖生物群落，发现输沙量中等的河流物种多样性最高。在Abukuma河和Kuzuryu河研究了水库大坝冲淤人工补沙的效果，泥沙运动恢复，促进了石质表面的更新。少

Hierarchical structure of river ecosystems : Geomorphological features of each hierarchy in the river systems were reviewed. Segment classification was conducted for the Kizu River based on stream geomorphology and riparian vegetation patterns. Physico-chemical structure of hyporheic zones in the sandy bar was studied in the Kamo River in Kyoto City and changing patterns of water quality and water temperature in the sandy bars were presented. A distributed rainfall-runoff prediction system was developed for assessing flood attenuation under the dam operation in the Yodo River system.Interrelations between sediment dynamism and river morphology : Sediment amount accumulated in the channel was investigated in relation to the geomorphology and microhabitat structure in the Yoshino River in Nara Prefecture. Effects of sediment flushing from dams on the SS concentration and stream geomorphology were studied in the Kurobe River and the Takahara River. Monitoring system for erosion process of … More sediment in the reservoir bed during the flushing work was developed in the Kurobe Dam.Relations of hierarchical structure to habitat function : Determinant factor for distribution of oviposition sites in fish and aquatic insects were investigated was elucidated to be a feature of reach scale which is caused by oxygen supply through a set or physical factors such as hydraulic gradient, Froude number, and permeability of the streambed.Relations of hierarchical structure to material cycling function : Longitudinal changes in size and source composition of SPOM were investigated in Uji River and Kizu River under different flow conditions and the results indicate that sandy bar structure functions as both fifterer of drifting SPOM and provider of SPOM derived from riparian vegetation to the river ecosystem. Results of a series of field experiments on bioassay of epilithon in seventeen rivers indicated that production of the epilithon depends more on supply of organic matter, current velocity and water temperature than on nutrient supply.Amount of sediment supply required for restoration of ecological function in the river ecosystems : Benthos community was compared among rivers different in sediment load and found that the species diversity was the highest in the rivers with intermediate sediment supply. Effects of artificial sediment supply with flushing flow from the reservoir dams were studied in the Abukuma River and the Kuzuryu River, resulted in recovery of sediment moving which promoted a renewal of epilithon on the stone surface. Less