本文係透過水工模型試驗，針對基隆河截彎取直及員山子分洪前後之水位與流速等水力參數變化進行探討，以瞭解流場機制，作爲基隆河工程治理之參考。研究結果顯示，基隆河經截彎取直後，因底床坡度增加導致上游河段流速加快，水位明顯下降；然而下游坡度未變，流速漸緩無法迅速將上游流量排除，以致水位稍微抬升。未來於上游需注意河床刷深造成堤防基礎破壞問題，因此需考量加深堤防基礎；下游則需注意河床淤積造成洪水位抬升問題，因此需考量增加通水斷面。整體而言，員山子分洪後，可有效降低洪水位而減輕洪水威脅。

The main purpose of this study is to discover the water level and velocity hydraulic parameters before and after the short cut and Yuanshantze flood diversion of the Kee-Lung River to understand the hydraulic characteristics by channel tests. It is hoped that the result of this experiment can be served as a reference for the Keelung River Yuanshantze Flood Diversion Project in the future. The results showed that the upstream flow velocity increased with slope increased and the water level had dropped clearly after short cut of the Keelung River. However, the downstream slope was almost constant and the velocity decreased that caused a rise of water level slightly. The upstream scour trend and downstream water rises trend after short cut of the Keelung River need to be taken care in the future. Therefore, the suggested regulation methods are to deepen the foundation of levee upstream, and to increase the cross sectional areas for the downstream reach. In general, flood disaster will mitigate because the water level decreases after the Yuanshantze flood diversion.