坡面型土石流特定水土保持區之治理問題檢討

The Discuss on Control Works Planning at Specific Soil and Water Conservation Area of Hillslope Type Debris Flow

許中立(Chung-Li Hsu) ； 陳淑慈(Shu-Tzu Chen) ； 劉承璋(Cheng-Chang Liu) ； 沈子祥(Zi-Hsiang Shen) ； 黃靚文(Gin-Wen Hwang) ； 高齊治(Chi-Zu Kou)

《坡地防災學報》 17卷1期 (2018/06) Pp. 1-19

摘要

臺灣的土石流潛勢溪流有一千七百多條，分析顯示其中將近半數是屬於上游陡坡而集水面積相對較小的坡面型土石流類型，其中頗多是下游沒有連接河流、較大的排水系統或腹地者，使得下移的土砂容易在其出口淤積，因不斷的堆淤而釀成災害。針對這種類型的土石流潛勢溪在劃定為特定水土保持後常礙於用地與現場條件嚴峻不易進行治理規劃，因此若能根據致災特性提出適切的治理方式，將有助於於減少公部門重複防災投資及維護人民權益。本研究藉由此類典型致災案例之臺東縣海端鄉廣原村東縣DF020土石流特定水土保持區進行治理方法探討，利用農地水土保持、崩塌地治理、安全排水、特定水土保持區既有設施及後續處理等五項主題進行探討，最終提出山坡地開發利用之管制精進方式與崩塌地治理之建議，並將土石流特定水土保持區之溪岸以工程方式穩定，並維持足夠的通洪斷面，避免淘刷及溢流，更於其中上游增設沉砂空間，提出泥砂分攤的觀念，避免全部流至下游淤積而有空間不足的問題，最後更建議全區皆應定期檢查並維持既有治理設施之效能。

關鍵字

坡面型土石流 ； 特定水土保持區 ； 治理工程 ； 泥砂分攤

並列摘要

There are more than 1,700 potential debris flow torrents in Taiwan, and the analysis shows that nearly half torrents of them are hillslope type debris flow which belong to the upstream steep slope and the watershed area is relatively small. Many of them are downstream without connecting rivers, larger drainage systems or hinterland so that the sediment moved down is easy to accumulate at its outlet and the disaster caused by it continuous siltation. For this type of potential debris flow torrents are often difficult to carry out governance planning due to the strict use of land and site conditions when them will plan specific soil and water conservation areas. Therefore, if we can propose appropriate treatment methods based on the characteristics of disasters, it will help reduce the repetitive disaster prevention investment and safeguard the people's rights and interests of the public sector. This study explores the treatment methods of the DF020 debris flow specific soil and water conservation area in the Dongyuan County, Haiduan Township, Taitung County, using five topics, such as agricultural land soil and water conservation, landslide control, safe drainage, potential debris flow torrent and existing facilities to discuss on follow-up treatment in the typical disaster-stricken case. Finally, it proposes the control methods of the hillslope development and utilization and landslide control, and to stabilize the river bank of the specific soil and water conservation area, and to maintain sufficient flooding section to avoid the brushing and overflowing. Adding a sedimentation weir, proposing the concept of sediment sharing, avoiding the problem of lack of space for the sediment all flow to the downstream. Finally, it is recommended that all districts should regularly check and maintain the effectiveness of existing treatment facilities.

並列關鍵字

Hillslope type debris flow ； Specific soil and water conservation area ； Control work ； Sediment sharing