主管單位：台灣電力公司 Taiwan Power Company
執行單位：財團法人中興工程顧問社大地工程研究中心
主持人：鄭錦桐Chin-Tung Cheng
承辦人：林彥享Yen-Hsiang Lin
工作人員：鄭錦桐、林彥享、張玉粦、顧承宇、許世孟
C.T. Cheng, Y.H. Lin, Y.L. Chang, C.Y. Ku, S.S Hsu

摘要

大甲溪流域歷經88年921地震、90年桃芝颱風、93年的72水災與艾利颱風等重大震災與豪雨事件，於大甲溪兩岸自德基水庫以下至馬鞍調整池間造成山坡坍塌及土石流，並釀成衝毀路基、淤積河道、抬高洪水位等現象，致大甲溪發電廠各分廠遭受不同程度災害。為評估各事件所誘發的土石崩塌量以及土石搬運堆積情形，本計畫擬以五個時期的航照影像及近期的衛星影像資料，進行德基至馬鞍段集水區崩塌地變遷與土方估計研究。衡量災損之輕重緩急，本計畫擬採一次發包，分二階段進行，第一階段辦理德基壩至谷關壩間集水區，第二階段辦理谷關壩至馬鞍壩間集水區。其工作方法主要係利用921地震前、921地震後、桃芝颱風後、七二水災後及艾利颱風後等五期航照圖，分別獲得研究區域數值地形模型（DigitalTerrain Model,DTM）進行地形地貌的差異性分析，再利用航照圖及衛星影像進行德基至馬鞍段集水區內崩塌地、土石流與河床淤積判釋及分析，以瞭解各期間增加與潛在的崩塌地、土石流與河床淤積等範圍大小及體積，推估上述震災與各風災事件之集水區泥砂產量，並綜合評估其對集水區、水庫及電廠的影響；將相關調查與分析成果以地理資訊系統進行整合，供台電公司進行受損電廠復建評估之參考。

Abstract
The watershed of Dar-Chia River has a lot of disasters caused by Chi-Chi Earthquake (1999/09/21), Toraji Typhoon (2001/07/30), Mindulle Typhoon (2004/07/02), and Aere Typhoon (2004/08/23) in those years. The slopes along the Dar-Chia River have serious landslides and debris flows between the Der-Chi Dam and Ma-An Dam. The geo-hazards have destroyed the road, huge amount sediment yield bring to main river and raised the river bed. Therefore, the hydro-power stations along the Dar-Chia river suffer those disasters. We adopt five stages areophotos and satellite images to evaluate the volume and the migration of landslides and debris flows in the catchment of Dar-Chia River between Der-Chi dam and Ma-an dam. By considering the priority of reconstruction the hydro-power station facilities, we have divide into two phase to finish this project, phase one is from Der-Chi dam to Ku-kuan dam, and phase two is form Ku-kuan dam to Ma-an dam. This project are adopted five different stages of aerial photos for making digital terrain model (DTM) and ortho-areophotos. Those stages are before and after Chi-Chi earthquake, after Toraji typhoon, after Mindulle Typhoon, and after Aere Typhoon. We use DTMs to compare the differences of the landform and to compute the volume of landslide, debris flows and riverbed sedimentation between these different time periods. Meanwhile, the migration of landslide, terrace, and sediment deposits on the riverbed will also be investigated by interpreting color areophotos and SPOT satellite images. The future tendency and the potential volume of the landslides, debris flows, riverbed sedimentation will also be solved in this project. Finally, the influences of those geo-hazards will be summarized for Taipower to reconstruct the hydro-power stations and dams. The result of this project will also be integrated into GIS (geographic information system) for domestication and assisting analysis in this project.