Study on Effective Utilization of Hydrological Information in Management of Flood and Low Flow

1. 利用运动波理论解析导出了非定常降雨作用下的流域集中时间，定量评价了降雨强度随时间的变化对流域集中时间和峰值流量的影响。基于这一理论考虑，提出了一种从观测到的流速图和水流图估计浓度时间的方法。将该方法应用于实测资料，明确地发现了集中时间与降雨强度和流域地形要素之间存在显著的统一关系，即坡面集中时间占总集中时间的优势，而河道集中时间远小于坡面集中时间。采用三维超声测速仪对实验室水槽和河道内的水流进行了测量。通过对实测数据的分析，得出了水流的水力特性，即各方向的平均流速、湍流强度、雷诺数应力和能谱，并揭示了实验室水槽与河道的水力特性之间的一些差异。实验结果表明，本研究所用的超声波测速仪在数小时的野外观测中运行稳定，对测量河道内三维水流具有实用价值。提出了评价今后水库运行中用于水资源利用的流入资料价值的程序。水库运行的数值模拟结果表明，获得干旱期开始和结束时间的提前信息是最有价值的，但随着信息误差的增大，这些时间的价值急剧下降。提出了一种利用这些信息对未来水流序列进行实时操作的方法。少

1. The concentration time of river basins subject to the unsteady rainfall was analytically derived from the kinematic wave theory, and the effect of variation of rainfall intensity in time on the concentration time and the peak discharge was quantitatively evaluated. Based on this theoretical consideration, the method to estimate the concentration time from observed hyetographs and hydrographs was proposed. As a result of applying this method to the observed data, the significant and unified relations of the concentration time to the rainfall intensity and to the topographical elements of the basin were definitely found out for such basins that the concentration time at the mountain slopes of is dominant over the total concentration time, while the one at the river channels is much short of the one at the slopes.2. The three-dimensional ultrasonic velocity meter was employed to measurement of the flows in a laboratory flume and in river channels. Analyses of the observed data yielded … More the hydraulic properties of flows, namely, the mean velocity, intensity of turbulence, Reynolds stress and energy spectrum in each direction, and revealed some differences between the properties for the laboratory flume and those for river channels. It has been confirmed that the ultrasonic velocity meter used in the present study operates stably during several hours of the field observation and therefore it has the practical usability to measurement of three-dimensional flows in the river channels.3. The procedures to evaluate the value of information on future inflows in operation of a reservoir for water utilizations were presented. Numerical simulations of reservoir operation showed that it is of most value to obtain the advanced information on the times when a drought period begins and ends, although the worth of these times sharply decreases as the errors in information increase. A method was also proposed to utilize such information on future streamflow sequences for real-time operation of a reservoir. Less