莫拉克颱風對臺東鹿野溪集水區土砂產量影響

The Influence of Sediment Yield Changed from Luye River Watershed at Taitung County after Typhoon Morakot

張瑜玲(Yu-Ling Chang)

指導教授 ： 許中立

國立屏東科技大學/農學院/森林系所/碩士(2012年)

https://doi.org/10.6346/NPUST.2012.00240

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鹿野溪集水區，因鹿野溪原本泥砂生產量頗大，造成溪水混濁，影響灌溉及民生用水之水質及水量，再加上2009年莫拉克颱風災害影響，土砂產量更甚以往，尤其鹿野溪等各重要治理集水區更因其地形地勢陡峭，降雨集中坡地遭受崩塌、沖蝕與土石流肆虐為害，危及臺東地區重大公共工程建設與居民生命財產安全更為顯鉅。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，俾期能提供相關單位作為臺東地區土砂災害防治方案研擬之重要參考依據。
研究結果顯示，莫拉克風災前鹿野溪集水區總崩塌面積2,549.56(ha)，其中崩塌面積超過5ha以上(含)約1,135.10(ha)，佔全部崩塌面積44.52(%)。莫拉克風災後總崩塌面積增加至2,939.42(ha)，崩塌面積超過5ha之面積約1,644.92(ha) 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389.86(ha)，崩塌之規模亦隨之擴大。而依據陳樹群與賴益成（1999）提出之泥砂遞移率公式計算結果，在災後土砂生產增加約2,955,800(m3)，而Vanoni提出之公式計算結果也呈現同樣之趨勢，主要土砂生產來至於上游地區，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，在東部地區之平原地區雨量並不多，因此土砂之生產均集中在鹿野溪之上游地區，下游地區土砂產量變化並不大。

關鍵字

莫拉克 ； 鹿野溪 ； 土砂產量

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. Due to the typhoon effect and intensive rainfall, landslide and debris flow commonly occurred in river, especially on Lu-Ye River watershed and 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 River 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 collapse area of Lu-Ye River watershed before influence of Morakot typoon is 2,549.56 ha and collapse area over 5 ha is about 1,135.10 ha which occupied 44.52 percentage of total area. The collapse area was increased 2,939.42 ha after influence of Morakot typoon and collapse area over 5 ha is about 1,644.92 ha which occupied 55.96 percentage of total area. According to calculation results which is based on Su-Chin Chen and Yi-Cheng Lai put forward formula of Sediment Delivery Ratio, sediment yield was increased to 2,955,800(m3) as well as trend of Vanoni formula. Sediment yield was mainly came from upstream area. It was due to concentrated rainfall of Morakot typoon is located in mountainous area of south Central Range and less precipitation in Plain of east area. As a result of sediment yield was concentrated upstream area of Luye River , the variation of sediment yield in downstream area was not obvious change.

並列關鍵字

Morakot ； Luye River ； Sediment yield

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