利用定量模型推估花蓮縣銅門村土石流發生處之尖峰逕流量

本文的主要目的在於研究花蓮縣秀林鄉銅門村土石流發生處的設計雨型及推估土石流發生時的逕流歷線，並探討其與土石流發生的關係。本研究在設計雨型方面是採用台灣省水利局銅門雨量站的時雨量資料，利用組合法、無因次法、位序法、三角形法來計算設計雨型，同時經過各種不同誤差計算的比較結果，以位序法最具代表性，因此以位序法所得的設計雨型來代表銅門地區26小時設計雨型。在定量模型的研究方面，本研究藉著銅門地區集水區模型試驗，求出試驗逕流歷線，並與現地所量測到的逕流歷線比較，求出其關係式；再以土石流發生時的降雨資料來進行模型試驗，求得模型逕流歷線，利用模型與現地之間的關係式推求土石流發生時的尖峰逕流量爲7.36 c.m.s，尖峰流量發生時間爲降雨開始後30.58小時。另以位序法設計雨型代入十年頻率的降雨量490.80 mm來進行模型試驗，所推估的現尖峰流量爲4.67 c.m.s，尖峰流量發生時間爲降雨開始後18.36小時。

關鍵字

土石流；設計雨型；尖峰逕流量；自動化人工降雨機

並列摘要

The main purpose of this study is aimed at the design hyetograph and the runoff hydrograph at Toun-Men, Hua-Lien, where debris flows had occurred. In regard to design hyetograph, the rainfall data were obtained from Toun-Men. The design hyetograph were then computed by using Composite Method, Non-Dimensional Method, Rank Method and Triangular Hyetograph Method. After comparison of the results obtained from different bias calculating, it was found that the Rank Method was most suitable for the 26-hour design hyetograph at Toun-Men. As for the watershed model analysis, runoff hydrographs obtained from the watershed model tests were compared with those obtained in the field, and accordingly their relationships were found. Then, a runoff hydrograph was measured from a watershed model test using the modified rainfall data which was observed during the occurrence of the debris flow. Using the runoff hydrograph and the aforementioned relationship, the peak runoff in the field during the occurrence of the debris flow was found to be 7.36 c.m.s. and the time of the occurrence of the peak runoff was found to be 30.8 hours after it began to rain. Aside from these, a rainfall amount of 490.80 mm with the return period of 10 years was substituted by a design hyetograph obtained by using the Rank Method to run the model test. It was estimated that the peak runoff was 4.67 c.m.s. and the peak runoff took place 18.36 hours after it began to rain.

並列關鍵字

Debris flow ； Design hyetograph ； Peak flow ； Automatical rainfall simulator

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