感潮部で湖沼と連結された水路の流れ特性に関する研究

摘要

Estuary sedimentation often blocks flood passage and navigation. This study was done to clear changes of flow condition by presence of a tidal pond (UTSURO), focused on a tide change. The results are summarized as follows: 1. As long as a tidal pond is located near a sea and its area is not so large, the water level in the pond almost corresponds to that in the sea, and the flow discharge into and out of the pond is proportional to the area of the pond. 2. When the length of a tidal channel is near a multiple of the odd quarter of wave length, resonance occurs in the tidal channel. 3. The Naka River estuary in Japan and the Huangpu River estuary in China satisfy the resonance condition, and their depths are kept deep. 4. Sedimentation at the Yellow River Estuary should be controlled by this method.%河口部には土砂が堆積しやすく，洪水の疎通障害や航行障害を生じていることが多い.本研究は感潮部で湖沼（以降，「感潮池(UTSURO)」または「感潮池」とする）の存在する河川河口部をモデル化し，水路内の流れを線形応答解析によって検討したもので，次のことが解明された.1.感潮池が外海に近く，その面積も小さい場合には，池の水位変化は外海のそれとほぼ等しく，池への流出入流量は池の面積に比例する.