南化及乌山头水库集水区土壤冲蚀抑制量评估 - 中华水土保持学会.pdf

2015 年中華水土保持學會年會及學術研討會論文摘要集 1 南化及烏山頭水庫集水區土壤沖蝕抑制量評估 [1*] [1] [2] 賴承農 許振崑 林伯勳 摘 要 本研究重點為估計2012 至2013 年發生於南化及烏山頭水庫集水區治理區域的土壤沖蝕抑制量 ，並透 過沖蝕針量測數據為基礎以評估土壤沖蝕抑制量 。土壤沖蝕抑制量亦是目前集水區保育治理成效評估的最重要的指 標之一 。為求量化人為復育後邊坡之土壤沖蝕抑制量與呈現出南化及烏山頭水庫減淤效益，本研究利用整治邊坡與 裸露邊坡上的沖蝕針所量測得之土壤沖蝕深度資料 。透過沖蝕針量測紀錄，南化與烏山頭水庫集水區的土壤沖蝕抑 制量至少可達43.92% ，顯示以人為復育後邊坡確實有效抑制土壤沖蝕。 關鍵詞：南化及烏山頭水庫集水區、整治邊坡、土壤沖蝕抑制量 。 Evaluation of Soil Erosion Suppression Rate for Nanhua and Wusanto Reservoir Watersheds Cheng-Nung Lai[1*] Chen-Kun Hsu[1] Bor-Shiun Lin[2] ABSTRACT This study focuses on the soil erosion suppression rate of remediated areas in Nanhua and Wusanto reservoir watersheds during 2012 to 2013 and evaluates the soil erosion suppression rate based on erosion pin data. The soil erosion suppression rate is also one of the most important indicators of remediation effectiveness. To quantify the suppressed rate of soil erosion on remediated hillslopes and to represent the effectiveness of sedimentation reduction of Nanhua and Wusanto reservoir watersheds, this study utilizes measured soil erosion depth of several erosion pins embedded in remediated and non-remediated hillslopes. Through monitoring data, soil erosion suppression rate averaged over 43.92% in Nanhua and Wusanto reservoir watersheds, respectively. These results also demonstrate that the remediated hillslopes are reliable, valid and cost-effective in suppressing soil erosion. Key Words: Nanhua and Wusanto reservoir watersheds, remediated hillslopes, soil erosion suppression rate. 一、前 言 臺灣地形、地質及氣候環境特殊，使得集水區砂源供應十分豐沛；以流域而言，土砂生產、運移及堆積等三項 機制，從上游至下游屬於一貫性連續運動；若屬正常供砂，可適時補注河道，維持河道穩定性及保持水路不變；反 之，屬於異常供砂，將造成河相及深槽改變、河道嚴重淤積，亦使原有生態棲地喪失或縮減，危及人類居住安全； 另更直接成為公共給水、灌溉、發電、防洪及觀光功能之水庫之重大威脅。然而，水庫集水區內土砂淤積係屬無法 避免之自