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：回顾了河流系统中各个层次的地貌特征。根据河流地貌和河岸植被格局对木津河进行了河段分类。对京都市鸭川沙坝潜流带的物理化学结构进行了研究，揭示了沙坝水质和水温的变化规律。开发了分布式降雨径流预测系统，用于评估淀川水系大坝运行下的洪水衰减。沉积物动力与河流形态之间的相互关系：研究了奈良县吉野河河道中累积的沉积物量与地貌和微生境结构的关系。研究了大坝冲沙对黑部河和高原河SS浓度和河流地貌的影响。黑部大坝开发了冲刷工程期间库床沉积物侵蚀过程的监测系统。分级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，阐明了河段尺度的特征，该特征是通过一组或物理因素（如河床的水力梯度、弗劳德数和渗透性）供氧引起的。分级结构与物质循环功能的关系：尺寸和来源的纵向变化对宇治川和木津川不同水流条件下SPOM的组成进行了研究，结果表明，沙坝结构既是漂流SPOM的过滤者，又是河岸植被对河流生态系统的SPOM的提供者。对17条河流进行的一系列底石生物测定的现场实验结果表明，底石的产生更多地取决于有机质的供应、流速和水温，而不是养分供应。河流生态系统恢复生态功能所需的底泥供给量：对不同输沙量河流的底栖生物群落进行比较，发现底泥供给量中等的河流物种多样性最高。在阿武隈河和九头龙河中，研究了水库大坝冲刷水流的人工沉积物供应的影响，导致沉积物移动恢复，促进了石头表面上的石碑更新。较少的

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