極端水文事件土砂量對陳有蘭溪河川型態演變影響分析

The total sediment yield from the 1999 Chichi earthquake to Typhoon Morakot in 2009 in the Chenyoulan River watershed is around 158.1×106 m3. The excess sediment yield has resulted in serious sediment deposition, widening river width and river meandering in the Chenyoulan River. By comparison of DEMs from 2004 and 2010, sediment deposits are obvious at the convergences of the tributaries and the in main river. Especially apparent are the deposited depth of 2.9 m at the convergence of the Junkeng River and the main river and the deposited depth of 2.6 m at the convergence of the Shibachong River and the main river. The serious sediment deposition has also resulted in river meandering and serious scouring upstream from the convergence of the Shibachong River and the main river, and widening river width and scouring in the main channel downstream from the convergence of the Shibachong River and the main river.陳有蘭溪集水區由1999 年集集地震至2009 年莫拉克颱風約產生158.1×106 m3 土砂量，巨量土砂產出在主河段造成河段淤積、拓寬及擺盪；以2004 年及2010 年DEM 比較結果，支流匯入溪處是主要土砂堆積處，又以郡坑溪匯入處之淤積2.9 m 及十八重溪匯入處之淤積2.6m 為最；受土砂淤積影響，在十八重溪上游匯入處上游河段以河道擺盪及河岸淘刷為主，在十八重溪匯入處下游河段則以河道拓寬及主深槽刷深為主

地下水引發自由端順向坡土體滑動特性分析

Retrogressive sliding can be observed in groundwater-induced landslides. The major inducing factor of this phenomenon is the fluidization in the down-hillslope and the soil of the bottom-layers. Moreover, when the water content in the area around the groundwater input pipe surpasses 29%, sag in the upper soil layer can also occur. As the groundwater discharge increases in experiments with the same slope, the equilibrium time needed to achieve landslide equilibrium gets shorter and the durations of landslides also decrease. As the slope in experiments with the same level of groundwater discharge increases, the equilibrium time required to achieve landslide equilibrium gets shorter, the landsliding area in a specific time period gets larger and the total landsliding area also decreases.由地下水誘發自由端邊坡滑動現象，崩塌型態屬於後退型崩塌。主要誘發因子為滲透水分造成下層土壤流動化及地下水輸入管鄰近區域因土壤土體底層水分飽和度超過29%而產生土壤下陷現象。在相同坡度的邊坡滑動實驗中，地下水量越增加，達到邊坡滑動平衡的時間越短且發生滑動次數越少；而在相同輸入地下水量的邊坡滑動實驗中，坡度越增加則達邊坡滑動平衡時間越短、有越高比例的滑動面積集中在特定時段，且總滑動面積也會因此減少

巨額土砂匯入對和社溪河相演變之影響

Macro-sediment impulses induced by particular typhoons and rainstorms are the main reason for serious sediment disasters in the Heshe River. For example, the sediment input during Typhoon Morakot in 2009 which accounted for 95.8% of the annual sediment discharge is the most serious of these disasters. Since Typhoon Morakot, the sediment input has decreased, as there have been less serious typhoons and rainstorms, thus, transforming the river morphology from a braided river into meandering river. In addition, river bends and topographical notches restrain sediment from moving downstream and store it in these locations. These factors have indirectly increased the erosion density of the river banks by 2.5 to 10.5 times.特定之颱風及豪雨事件為和社溪集水區內巨額土砂進入河道造成相關土砂災害之主 要因素；尤以2009 年莫拉克颱風其間之輸砂量，佔該年總輸砂量之95.8％最為嚴重。然而，莫拉克颱風過後並無發生規模較大之颱風及豪雨事件，因此進入和社溪之土砂漸減，使得因土砂堆積造成之辮狀河川逐漸走向蜿蜒。此外，河川轉折點跟隘口處都會抑止土砂往下游運移並使土砂集中於此處，間接造成河岸淘刷密度增加2.5 至10.5 倍

The Influence of Sediment Yield to the River Physical Habitats Restoration(1/2)

溪流整治工程為水庫集水區治理相當重要的一環，隨著人們對生態環境的重視，量化人為介入對水庫集水區溪流生態環境之影響性亦顯得重要。本研究主要探討土砂產量對河川集水區溪流物理棲地之變化，及採用人為工程對物理棲地之影響；本研究選定石門水庫集水區為分析對象，擬定調查作業程序，完成石門水庫集水區之十八條支流河川之現場調查，並分析彙整其調查成果。在本研究的分析過程中，本研究先針對18條河川進行河相五層分類分析，探討該河川河相特性及集水區內可能引發之土砂運移問題；而在土砂量估算上，本研究以1999年集集地震、2001年桃芝颱風及2004年艾利颱風為主要土砂災害事件，並估算屢次災害事件後之土砂總產量(包括崩塌量及土壤沖蝕量)，並利用現地勘查瞭解目前土砂在河道中堆積情況及對物理棲地造成影響。本研究採用河川物理棲地評估指標進一步瞭解目前18條河川物理棲地現況，主要探討泥沙堆積、地形、人為影響、植生復育及水流多樣性等，並以雷達圖表示目前河川物理棲地現況，比較自然棲地與人為工程介入棲地對棲地復育之影響，並提出未來復育方針及建議。此溪流物理棲地評估方法可量化工程對棲地之影響結果，對於石門水庫集水區之溪流物理棲地而言，人為干擾較少、流量越大、水流多樣性越好的集水區，溪流原始狀況佳。River training work is a considerably important link to reservoir watershed management. With people's focus on ecological environment, quantifying the influence of personal interference on the ecological environment of river in reservoir watershed shows significant accordingly. The study focuses the discussion of the influences of river physical habitats caused by sediment yield in the watershed and river engineering. This study chose Shihmen Reservoir watershed as analysis object. It drafted investigation operation procedures, completing on-site investigation of eighteen branches of Shihmen Reservoir watershed, collecting and analyzing the investigation results.The study analyze the river morphology characteristic and possible sediment transport questions of eighteen rivers by river morphology five-level classication method. The total sediment yield, including landslide and soil erosion, after Chichi earthquake in 1999, Typhoon Toraji in 2001 and Typhoon Aere in 2004 were estimated in the study. Field survey was proceeded to understand the sediment transport condition in eighteen watershed.The study uses the river physical habitat assessment index to analyze the physical habitat restoration condition of eighteen river watershed. The river physical habitat assessment index includes the sediment transport, topograph, river engineering, vegetation restoration and the diversity of flow. The radar graph which is calculated and built from the assessment by river physical habitat assessment index is used to show the river physical habitat condition and compare the difference between the natural river habitat and artificial river habitat. The study addresses the restoration direction of each river watershed and field survey point. This method quantifying the influence of artifical interference on habitat

降雨引發邊坡崩塌潛勢評估模式之建構

The study focuses on establishing the assessment model for the landslide potential caused by rainfall events. The study suggests to assess the initiating causes and the inherent causes individually during the landslide potential assessment. During the research process, the study assesses the landslide potential values without considering the rainfall and earthquake impacts, and combines the landslide potential values with the rainfall impact as the landslide potential value under rainfall events. The study selects eight assessment factors as the landslide potential basis. The weight of the assessment factors is obtained by using Analytic Hierarchy Process (AHP) and the assessment standard is based on the landslide cases in serious disaster region, includes Nantou County, Wanrung Township in Hualien County, Heping Township in Taichung County, and Alisan Township in Chiayi County, caused by the Typhoon Toraij in 2001. The study use the rainfall quantity to quantify the influence of the rainfall on landslide. Based on the 175 landslide cases from the 7th, 8th, 14th,and 20th Province Highway, the minimum threshold value to induce the landslide under rainfall event is 8.93. The mean value and the standard deviation of the 175 landslide cases assessment value are 12.97 and 1.77 respectively. According to the the geology, terrain, rainfall characteristic of the landside cases, the assessment value of the landslide cases is zoned for different landslide types. The landslide cases from Mingder reservoir watershed and serious disaster region during Typhoon toraji and Shihmen reservoir watershed during Typhoon Aere are the verification cases. The study use kriging method to simulate the rainfall distribution during rainfall event. According the minimum threshold value to induce the landslide under rainfall event, the correctness of the landslide potential model on serious disaster region exceeds 80%. But the correctness of the landslide potential model on Shihmen reservoir watershed is approximate 60%. According to the 10058 landslide cases during Typhoon Toraji and Typhoon Aere, 75.2% of the landslide potential values centralizes in 8.93 to 12.本研究主旨在建構降雨情況之崩塌潛勢評估模式，本模式在建構過程中將降雨誘發因子與崩塌相關之環境潛在因子分離，並建議採用兩段式評估法進行建構，先評估未降雨未地震自然情況下之邊坡崩塌潛勢，再將自然情況崩塌評估值與降雨事件對邊坡崩塌之影響結合，方為降雨情況下之崩塌潛勢評估值。 於模式建構過程中，本研究將崩塌現象分為六評估面八細部評估因子進行評估，並以多評準決策層級分析法評定各評估面之權重，以2001年桃芝颱風於南投縣、台中縣和平鄉、花蓮縣萬榮鄉及嘉義縣阿里山鄉之崩塌案例為依據，給定細部評估因子之評分方式，至此建立自然情況崩塌潛勢評估模式。 在降雨對邊坡影響之量化上，本研究考量降雨事件代表性及實用性，以臨前降雨量及降雨事件降雨累積量為主要考量，並以北橫公路、中橫公路、台14線及南橫公路等共175處邊坡崩塌案例進行模式建構，模式估算結果發現降雨情況下引發邊坡崩塌之最小崩塌門檻值為8.93，平均崩塌門檻值為12.97，標準偏差值為1.77，本研究並以過往崩塌案例分佈特性區分為崩塌頻發區、崩塌集中區及邊坡暫態穩定區而新竹縣五峰鄉桃山村土場部落及民都有部落於艾利颱風所引發之崩塌案例，以本研究之降雨情況崩塌模式評估值亦落於崩塌集中區之內。 在案例驗證上，本研究採用克力金法模擬研究區於桃芝颱風時之降雨分佈， 並在研究區中崩塌率差異大之村落及土石流多之村落進行驗證，桃芝颱風事件於南投縣及台中縣挑選八個村落共1103處崩塌案例，艾利颱風於石門水庫集水區挑選五個村落共909處崩塌案例，經以本研究所建構之模式評定降雨情況崩塌潛勢評估值分佈，若以降雨情況最小崩塌門檻值8.93為界，則本研究對南投縣及台中縣八個村落之預測準確率約可達80%以上，而在石門水庫集水區之預測準確率則在60%左右，預測準確率下降之原因在於本研究對石門水庫集水區之坡腳掏刷崩塌現象預測率不足。 相較於過往崩塌潛勢評估模式之建構，本模式對降雨誘發因子對邊坡崩塌之影響深入探討，本研究認為過往崩塌潛勢評估模式未能在崩塌時間點上突破，主因在於誘發因子在崩塌潛勢評估模式中之角色混淆所導致，本研究採用兩段式評估法及點對點評估方式嘗試獲得降雨情況邊坡可能發生崩塌現象之最小門檻值及可能發生之時間點。中文摘要II AbstractIII 目錄IV 圖目錄VI 表目錄XI 第一章緒論1 第二章崩塌之成因與型態分類4 第三章邊坡穩定評估文獻回顧15 第四章崩塌地潛勢評估模式之建構26 第五章自然情況之崩塌潛勢模式建構52 第六章明德水庫案例分析107 第七章桃芝颱風及艾利颱風之崩塌案例驗證142 第八章結果與討論82 第九章結論191 參考文獻19