Experimental Analysis of the Flow Field Influenced by Plant Distribution on the Floodplain

Abstract

河道植生雖有阻塞河道水流，抬高洪水位並造成下游淘刷的負面現象；卻亦有護堤固灘，減緩流速，促使深槽穩定的正面效果。因此本研究以單邊植生及單邊間隔植生之設計，分析植生對水流之阻礙束縮效應，並採用3 種不同流量來模擬不同植生覆蓋情況對水流之影響。研究結果顯示，採用單邊間隔植生，可較有效的達到減緩流速、穩定深槽 (導流)、保護下游裸露淤地、節省經費等效果。

The plant distribution on the floodplain can induce negative phenomena, such as blocking river flow, raising flood level, and scouring of the riverbed downstream of the plant region. However, if we construct efficiently plant distribution on the floodplain, it can also protect the dike, reduce flood velocity, and increase the stability of the channel. Therefore, we designed the unilateral plant and unilateral interval plant arrangement patterns combined three different discharges to simulate the flow effects of plant distribution on the floodplain. The experimental result showed the unilateral interval plant was a beneficial method to reduce flood velocity, increase the stability of the main channel and protect the riverbed.