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FLOW STRUCTURES DETERMINING RIVER LEVEL IN AN ESTUARY

决定河口河流水位的水流结构

基本信息

批准号：
13450199
负责人：
YOSHIDA Shizuo
金额：
$ 4.35万
依托单位：
Hokkaido University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2003
项目状态：
已结题

项目摘要

It is essential to find the correct relationship between flow rate and river level in order to have information about the flow rate during flood and about uses of the river water like agriculture and hydroelectric generation. Normally, the river flow rate is assumed to be given by the level through the empirical H-Q equation, where H is the water level (height) and Q is the flowrate, but during drought, it becomes extremely more difficult to apply this expression to the estuary than to locations upstream. This is because the river level can take a large range of values under the influence of the four key factors of tide, atmospheric pressure, wind direction and wind speed. In this study, it was attempted to derive a method for quantitative estimation of the effects of tide, atmospheric pressure, wind direction and wind speed on flowrate in the estuary of the Ishikari River, where these four factors dramatically lower the correlation between water level (H) and river flowrate (Q). It was found that the effect of tide and atmospheric pressure on sea level is almost exactly reflected in the fluctuations of river level. Data from observations of river level under windless conditions and steady river flowrate allowed application of empirical rules for river rise due purely to flowrate, providing a quantitative estimate of the relation between wind and river behavior. Next, the flowrate was estimated at a certain location using the obtained quantitative relation between the four factors and river level, and this was found to be nearly identical to the observed flowrate. This confirmed the practical validity of this study.

为了获得洪水期间的流量以及农业和水力发电等河水用途的信息，必须找到流量和河流水位之间的正确关系。通常情况下，河流流量被假定为通过经验 H-Q 方程由水位给出，其中 H 是水位（高度），Q 是流量，但在干旱期间，将该表达式应用于河口比应用于上游位置变得极其困难。这是因为在潮汐、气压、风向、风速四个关键因素的影响下，河流水位可以取较大范围的值。在本研究中，试图导出一种定量估计潮汐、气压、风向和风速对石狩川河口流量影响的方法，这四个因素显着降低了水位（H）和河流流量（Q）之间的相关性。研究发现，潮汐和气压对海平面的影响几乎完全反映在河流水位的波动上。在无风条件和稳定河流流量下对河流水位进行观测所得的数据允许应用纯粹由流量引起的河流上升的经验规则，从而提供风与河流行为之间关系的定量估计。接下来，利用获得的四个因素与河流水位之间的定量关系来估计某个位置的流量，发现这与观测流量几乎相同。这证实了本研究的实际有效性。