應用水文水理分析檢討野溪排洪效果

Applied Hydrology and Hydraulic Analysis Methods to Discuss the Mountain Stream Drainage Effect

陳德天(Der-Ten Chen) ； 許中立(Chung-Li Hsu)

《坡地防災學報》 2卷1期 (2003/09) Pp. 93-114

https://doi.org/10.29995/JSHR.200309.0006

摘要

在山坡地開發或集水區整體治理與評估工作中，頻率分析與水文演算是極為重要部份，為野溪整治規劃的主要參考指標之一，但卻往往為工程人員所忽略或不知應如何遵循使用。本文以草湖溪集水區之北坑溪與乾溪二條支流為主要分析對象，進行現場粒徑分析、集水區水文與河川水理的分析工作，並對既有的設施的排洪效果提出檢討，以便能規劃出整體性且適切的改善對策。經分析結果發現暴雨頻率分析方法以對數皮爾遜Ⅲ型分佈所推估之暴雨量與歷史資料最為吻合；由Horner公式所推估之不同重現期距暴雨量均較無因次公式之推估結果為大，採用Horner公式進行推估會使施設之水土保持工程較為保守而安全性較高；又經HEX-RAS分析顯示在北坑溪與乾溪各有44.4%與27.5%為流速較大者，應依實際情況規劃以防止河道淘刷。

關鍵字

野溪 ； 頻率分析 ； 粒徑分析 ； 水文演算

並列摘要

Frequency analysis and hydrologic routing are the important works on slopeland development or watershed protection works planning and evaluation. Although that are one of the principle index parameters for mountain stream control works planning, engineer always cannot understand how tocalculate it. This research used to assess flood depth profile and channel drainage capacity data from frequency analysis, grain size distribution analysis, hydrologic routing and HEX-RAS software to compare and criticize with field survey on, the tributary of Tsao-Hwu stream watershed, the parts of Beei-Keng mountain stream and Gan mountain stream. The results show that using the frequency analysis of Log-Pearson Type Ⅲ Distribution for assessment the storm rainfall were closely on the watershed, and the peak flood could be conservatively evaluated from Horner formula better than no-dimensional formula analysis. Therefore, there are 44.4% and 27.5% profiles runoff velocity so speedy individually, on Beei-Keng mountain stream and Gan mountain stream, need to planning the protect works in practical way.

並列關鍵字

Mountain stream ； Frequency analysis ； Grain-size analysis ； Hydrologic routing