臺東安朔溪土砂生產及現地應用之探討

A Study of the Sediment Yield and Field Engineering Methods in Taitung-Ansowshi Watershed

張蘇能(Chang-Su Neng)

指導教授 ： 許中立 博士

國立屏東科技大學/工學院/水土保持系所/碩士(2013年)

https://doi.org/10.6346/NPUST.2013.00003

摘要

臺東地區地形東西短南北長，地勢陡急狹長，常受颱風豪雨影響甚大，且近年來降雨量屢創新高，土砂災害問題頻傳，威脅居民生命財產之安全甚鉅。本研究調查範圍為臺東縣安朔溪集水區，莫拉克風災後安朔溪產生大量土砂，造成河工構造物之損毀或埋沒，危及下游地區居民生命財產及省道臺九線之橋樑安全。
研究結果顯示，安朔溪受2005年海棠颱風侵襲影響，造成集水區河道兩側邊坡裸露災害明顯擴增；2009年莫拉克颱風挾帶的超大豪雨於8月7、8、9日三天降下臺灣山區半年平均雨量，而就安朔地區而言，單日降雨則已超過過去歷史雨量200年頻率年之降雨量值。顯示安朔溪土砂產量最主要之影響因素為高強度長延時特性之降雨。
安朔溪河道產砂部分，依據Khazai and Sitar法所推估結果，集水區總產生土砂量約為160萬立方公尺。由於土砂運送之遞移特性，透過泥砂遞移經驗公式換算於中上游區域推估可能輸出之土方量約為100萬立方公尺。
莫拉克風災之後，造成研究區內大量之土砂堆積並埋沒或損毀既有之工程構造物，大量之土砂如未能有效整治將可能對下游地區造成嚴重之災害，如能有效的應用現地土砂進行現地拌合利用，做為河川整治工程之材料，不但能減少災害之發生，且能節省治理工程之經費，亦能達到節能省碳之效果。

關鍵字

莫拉克颱風 ； 安朔溪 ； 土砂產量 ； 現地拌合

並列摘要

The topography of hillslopes located at Taitung County is quite steep with fragile geological structure. It was frequency affected by typhoon flood and causes critical harm. This study is to investigate the area of Ansowshi watershed in Taitung County. Typoon Morakot caused a large amount of sediment production in Ansowshi and ruined construction of river. It not only endangers the safety of bridges in Highway No. 9 but also threats to the lives and properties of inhabitant.

The results show that Ansowshi was affected by super Typhoon Haitang (2005) and caused damages of the foot of the two side’s slopes in watershed. Typhoon Morakot (2009) dumped heavy rains on August 7 to 9. It is equivalent to an average rainfall for 6 months on mountain site in Taiwan. The value of maximum 1-day rainfall in Ansowshi is over frequency of 200 years in history. It shows that the main factors of sediment yield in Ansowshi are affected by high intense and long period of rainfall.
According to Khazai and Sitar formula, Ansowshi watershed sediment yield is 1.6 million (m3). Due to the characteristic curve of sediment, sediment in the area of upper river was estimated 1 million(m3) by conversion of Sediment Delivery Ratio empirical formula.

Typhoon Morakot disaster produced a number of sediments in Ansowshi area and caused great damage or covered up with sediment to river construction. It could cause great damage in downstream if sediment has not effect improvement. It was expected that use local sediment as materials to river improvement could reduce disaster and save funds, even achieve the funtion of enviroment protection of saving energy and reduce the carbon dioxide.

並列關鍵字

Morakot Typhoon ； Ansowshi ； Sediment yield ； In-situ Mixing

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