臺東縱谷陡坡小集水面積之土石流潛勢溪流治理方式探討--以東縣DF020土石流特定水土保持區為例

臺東縣位於臺灣東部緊鄰中央山脈，全縣範圍中約占94％屬山坡地，截至2018年為止，共有166條土石流潛勢溪流，根據資料研判共有32條屬於陡坡小集水面積之土石流潛勢溪流之類型，若能建立良好的治理方式，將有益於減少政府資源浪費及維護人民權益。本研究藉由此類典型致災案例”臺東縣海端鄉廣原村東縣 DF020 土石流特定水土保持區長期水土保持計畫”進行案例探討，利用農地水土保持、崩塌地治理、安全排水、土石流潛勢溪流及既有設施及後續情形等五項主題進行探討，最終成果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；另土石流潛勢溪流之溪岸則主要以工程方式穩定，並維持足夠的通洪斷面，避免淘刷及溢流，其中於中上游設置沉砂空間尤為重要，而下游易淤積且保全對象處，需有安全排水及相關足量沉砂設施，且建議全區皆定期檢查並維持既有治理設施之效能。探討中得知臺東縱谷陡坡小集水面積之土石流潛勢溪流主要問題為下游土砂無法自然輸砂，而造成淤積情形，故建議利用中上游廣設沉砂池，將土砂滯留並配合下游沉砂池定期以人力清疏，維持效能，以沉砂分攤之觀點，應為一較佳之治理方式。

關鍵字

土石流潛勢溪流；特定水土保持區；沉砂池

並列摘要

Taitung County is located in eastern Taiwan close to the Central Mountain Range.The hillside occupies 94 percent of area. As of 2018, there are 166 the potential debris flow torrent. According to data analysis, there are 32 debris flow torrent types of potential debris flow torrent belonging to small and steep Watersted. Ifwe can establish a good governance approach,It will be beneficial to reduce the waste of government resources and safeguard the rights and interests of the people.In this case study, a case study was conducted using the standard disaster case “ the special soil and water conservation area in Taitung DF020 potential debris flow torrent”.Five themes are discussed includingSoil and Water Conservation in Agricultural and Forest Lands, Management of Landslide, Safe Drainage, Potential Debris Flow Torrent andExisting facility maintenance management.Discussion results mentioned the ways of hillside development and utilization to manage improvement and Suggestion of landslide control. In addition, the bank of the potential stream of the earth and rocky stream is mainly project-based, with the goal of stabilizing and maintaining adequate flood-cross sections.Avoid panning and overflowing. Among them, the establishment of a settling basin in the middle and lower reaches is particularly important.The downstream needs safe drainage and related enough settling basin.It is also recommended that all districts regularly check and maintain the effectiveness of existing governance facilities. During the discussion, it was learned that the main problem of protential debris flow torrentatof Small and Steep Waterstedin the Rift Valley in Taitung is that the downstream soil sand cannot be naturally transported, resulting in silting. Therefore, it is suggested to use multiple settling basin in the middle and upper reaches to keep the soil on the slopes.Downstream settling basin are regularly cleaned by human to maintain efficiency.The concept of soil amortization should be a better way of governance.