生態農業：農業地景生態監測及復育【水土保持學系/陳樹群特聘教授】
| 論文篇名 | Determining transition reaches between torrents and downstream rivers using a valley morphology index in a mountainous landscape |
| 期刊名稱 | HYDROLOGICAL PROCESSES |
| 發表年份,卷數,起迄頁數 | 2021,35(11), e14393 |
| 作者 | Kuo, Cheng-Wei; Tfwala, Samkele; Chen, Su-Chin(陳樹群)*; An, Hsuan-Pei; Chu, Fang-Yi |
| DOI | 10.1002/hyp.14393 |
| 中文摘要 | 將河流劃分為同質河段是河流過程和流域管理的關鍵。與下游以河流為主的河流相比，上游以土石流為主的激流具有更陡峭的河道坡度和更小的河谷寬度/深度比。調查激流和河流之間的過渡河段，不僅可以探索景觀結構，還有助於災害管理。本研究提出了結合河道坡度和河谷寬度/深度比兩個變量的河谷形態指數，以確定激流和河流之間的過渡河段。使用基於地理信息系統 (GIS) 的地形分析將該方法應用於台灣的 41 條山區溪流。河谷寬度/深度比與河道坡度的關係圖用於確定將激流與河流分開的河谷形態指數 (Iv) 的邊界值。從圖中可以看出，約 80% 的流域呈現“L 形”曲線，這表明上游斷面坡度急劇下降，下游斷面河谷寬深比急劇增加。結果進一步證明了研究地點的平均值為 0.0047。地理區域之間的空間比較表明，東部河流的過渡河段往往發生在流域較低的地方，部分原因是地勢較高。支流匯合處和崩塌等局部因素促進了從洪流向河流為主的河流的轉變。衛星圖像驗證了該方法正確識別過渡河段，表明它可以為河流管理提供有用的參考。 |
| 英文摘要 | Dividing rivers into homogeneous reaches is key for river processes and watershed management. In contrast to downstream fluvially dominated rivers, upstream debrisflow dominated torrents have steeper channel slopes and smaller valley width/depth ratios. Investigating transition reaches between torrents and fluvially dominated rivers, not only explores the structure of the landscape, but also contributes to hazard management. This study proposed a valley morphology index combining two variables, channel slope and valley width/depth ratio, to determine transition reaches between torrents and rivers. The methodology was applied to 41 mountain streams in Taiwan using a Geographic Information System (GIS)-based topographic analysis. Plots of valley width/depth ratio versus channel slope were used to determine boundary values of the valley morphology index (Iv) separating torrents from rivers. The plots showed that about 80% of the river basins present “L-shaped” curves, which indicate sharp decreases in slope for upstream sections and dramatic increases of valley width/depth ratio for downstream sections. Results further demonstrated an average value of Iv 0.0047 across the study sites. Spatial comparison between geographic regions indicated that transition reaches in eastern rivers tend to occur lower in the drainage basin due, in part, to higher terrain. Local factors, such as tributary confluences and landslides promote the transition from torrents to fluvially dominated rivers. Satellite images verified that the approach correctly identified transition reaches, suggesting that it may provide a useful reference for river management. |
| 發表成果與本中心研究主題相關性 | 溪流型態分類以便於管理 |
