FLOW STRUCTURES DETERMINING RIVER LEVEL IN AN ESTUARY

必须找到流量和河流水位之间的正确关系，以便了解洪水期间的流量以及农业和水力发电等河流水的使用情况。通常情况下，河流流速被假定为通过经验H-Q方程的水平，其中H是水位（高度）和Q是流量，但在干旱期间，它变得非常困难，将这个表达式应用到河口比上游的位置。这是因为在潮汐、气压、风向和风速这四个关键因素的影响下，河流水位可以取很大的数值范围。在这项研究中，它试图推导出一种方法来定量估计潮汐，大气压，风向和风速对流量的影响，在石狩河河口，这四个因素显着降低水位（H）和河流流量（Q）之间的相关性。结果表明，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中。无风条件下的河流水位和稳定的河流流量的观测数据允许应用经验规则的河流上升纯粹是由于流量，提供了风和河流行为之间的关系的定量估计。其次，流量估计在一定的位置使用的四个因素和河流水位之间的定量关系，这被发现是几乎相同的观测流量。这证实了本研究的实际有效性。

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.