莫拉克颱風對鹿野溪集水區土砂生產之影響

The Influence of Sediment Yield Changed from Lu-Ye Creek Watershed after Typhoon Morakot

張瑜玲(Yu-Ling Chang) ； 許中立(Chung-Li Hsu) ； 戴欣怡(Shin-Yi Dai) ； 郭子銘(Jun-Ming Kuo) ； 許正葳(Cheng-Wei Hsu) ； 邱欣慰(Xin-Wei Giu) ； 張蘇能(Shu-Neng Chang)

《坡地防災學報》 15卷2期 (2016/12) Pp. 16-60

摘要

臺東縣鹿野溪集水區原本泥砂生產量就頗大，平時遇暴雨就造成溪水混濁而影響灌溉及民生用水之水質，再加上2009年莫拉克颱風災害影響，土砂產量更甚以往。本研究之主要目的在針對鹿野溪集水區進行土砂產量之相關調查及探討，期能提供作為臺東地區土砂災害防治方案研擬之參考依據。研究結果顯示，莫拉克風災前鹿野溪集水區總崩塌面積2,549.56ha，其中崩塌面積超過5ha約為1,135.10ha，佔全部崩塌面積44.52%；莫拉克風災後總崩塌面積增加至2,939.42ha，崩塌面積超過5ha約為1,644.92ha 佔全部崩塌面積55.96%。與災前崩塌面積之比對結果發現崩塌面積增加389.86ha，而依據陳樹群與賴益成所提出之泥砂遞移率公式計算結果，在災後土砂生產增加約2,955,800m^3，而Vanoni提出之公式計算結果呈相同趨勢。主要土砂生產來自於上游地區，主要原因為莫拉克颱風其降雨均集中在中央山脈南段之山區，在東部之平原地區年雨量並不多，因此下游地區土砂產量變化並不大。

關鍵字

鹿野溪 ； 莫拉克颱風 ； 土砂生產

並列摘要

Due to the typhoon effect and intensive rainfall, landslide and debris flow commonly occurred in river, especially on Lu-Ye creek watershed, which destroy the soil and water conservation facilities. It was not only caused Taitung's public construction damaged but also threats to the lives and properties of inhabitant. The main purpose of this study is selected mode of Lu-Ye creek watersheds sediment yield with related investigations as discussion issues, to serve a research reference and to provide a policy-based for government agencies developing Taitung sediment disaster prevention program. The results were showed that the landslide area of Lu-Ye creek watershed before influence of Morakot typhoon is 2,549.56 ha and landslide area over 5 ha is about 1,135.10 ha which occupied 44.52% of total area. The landslide area was increased 2,939.42 ha after influence of Morakot typhoon and landslide area over 5 ha is about 1,644.92 ha which occupied 55.96% of total area. Based on Su-Chin Chen and Yi-Cheng Lai put forward formula of Sediment Delivery Ratio, calculation results of sediment yield was increased to 2,955,800 m^3 as well as trend of Vanoni formula. This watershed sediment yield was mainly moving from upstream area. It was due to concentrated rainfall of Morakot typhoon and located in mountainous area of south Central Range and less precipitation in Plain of east area. Thus the variation of sediment yield in downstream area was not obviously.

並列關鍵字

Lu-Ye creek ； Morakot typhoon ； Sediment yield