高強度降雨之坡地集流時間公式

The Time of Concentration under High Rainfall Intensity in Hillslope Area

陳樹群(Su-Chin Chen)

《中華水土保持學報》 30卷2期 (1999/06) Pp. 103-115

https://doi.org/10.29417/JCSWC.199906_30(2).0003

摘要

依水土保持規範之要求，任何與水土保持相關之開發行爲均需估算25年及50年之降雨強度及逕流量，其中首先觸及的即爲集流時間的長短，但由於各家公式所估計之値常差異極大，且又缺少實測資料可供佐證，因此常造成公式正確與否之爭議。有鑑於此，本研究收集約40組集流時間公式，其中可概分爲經驗公式及理論公式兩大類。經由分析發現不但各集流時間公式所估算之値差異極大，其所含蓋之因子亦多有不同。因此本研究經由理論分析，配合因子選定及敏感度分析，發現當降雨強度極大時，影響集流時間之因子，主要爲坡度S、地表覆蓋情形（以曼寧粗糙係數n代表）及坡長L等地文因子。由於運動波模式所建立之集流時間觀念具完整之水理基礎，再配合敏感度分析之結果，本研究推求之集流時間關係式爲方程式略。此式之特點在於能反應坡地開發所造成集流時間之變化，例如當開發前後，地表植生變化極大時，縱使坡度及坡長未改變，本式仍可因曼寧粗糙係數之改變而反應出集流時間之變化。本研究爲初步之成果，欲臻完善，仍須配合實測資料加以驗證。

關鍵字

集流時間 ； 高強度降雨 ； 運動波

並列摘要

The planning of soil and water conservation evaluate the recurrence interval of 25 and 50 years of rainfall intensity which is necessary for specifications. However, the time of concentration should be known before the runoff and rainfall intensity. For the purpose, about 40 time of concentration equations, including theoretical and empirical equations, were collected for research. The values have huge range in the same condition and the parameters are different in these equations. From the sensitivity analysis, three major parameters, namely slope, land-covered and slope length were found in the condition of high rainfall intensity. Therefore, according to the study, the time of concentration, The equation is abbreviated, which is developed from the concept of kinematic wave model. The characteristics of this equation can respond to the change in the time of concentration after the urbanization of hillslope. For example, the time of concentration is different because of the change in land-coverd, responding to Manning's n, although the length of slope is constant during the development of hillslope.

並列關鍵字

the time of concentration ； high rainfall intensity ； kinematic wave