圖書典藏及影音數位平台

台北水源特定區位於大台北地區之東南隅，本區域之地質、地形等環境條件不佳，且近年颱風降雨集中，影響本轄區之水土保持甚鉅，遇暴雨時易沖刷表土砂石進而進入河川水庫水體，進而造成泥水挾帶氮、磷等營養源，導致水質污染，故此問題為水源集水區內亟待解決之課題。 為避免特定區之水源、水質、水量因自然及人為破壞而日趨惡劣，本研究以監測、診斷、處理三大步驟來建立土砂保育健康診斷模式。監測之第一步為進行集水區特性、河溪特性、災害歷史等分析，以瞭解集水區整體特性並作為健康診斷指標訂定之參考，第二步為由集水區地面水文資料觀測、坡面土砂資料監測及空中航照衛星影像以獲得集水區之相關資料，從而建立逕流率、崩蝕率、綠覆率、水質指標、泥砂濃度等健康診斷指標。 診斷是指利用健康診斷指標來分析集水區之土壤泥砂流失問題、水文流量問題及水質污染問題，其中，逕流率可評估集水區水源涵養情形，崩蝕率評估集水區年土砂流失情形，綠覆率評估集水區植生所佔比例，水質指標評估集水區水質之良窳，泥砂濃度評估集水區表土流失問題；並瞭解其主要原因為何，亦即區分為三種驅力，即地文等內在條件、降雨等外在環境及人為開發等後天影響。 處理則是針對不同驅力所造成集水區問題之對應策略，第一步為選定集水區管理目標；第二步為以子集水區為單元進行降低洪峰、減少泥砂、水土林資源保育等策略規劃及方案擬定；第三步為經由土砂整治率、綠覆率改善比、水質改善比等效益分析選定適合之策略方案。追蹤是指方案完成後之維護管理情形，並利用整治成效追蹤指標來進行定期及不定期追蹤考核。 本研究除完成土砂保育健康診斷模式之建構外，並建立適用本區之產砂模式，以推估區內之土壤沖蝕量及崩塌量，並以北勢溪之翡翠水庫泥砂淤積量資料及南、北勢溪之河道輸砂量來作為檢定驗證，可得此產砂模式之適用性。

Taipei Water Source Domain is located at the southeast of Taipei Metropolis with steep topography and fragile geological conditions. The centralized rainfalls in past years affected seriously the soil and water conservation in this area. The eroded soils carrying nitrogen and phosphorus went into water bodies and resulted in water pollution; this is the urgent challenge to be dealt with in water source domains. In order to avoid degradation of water quality due to the natural and human-made damages, health diagnosis model of soil conservation is established under the framework of monitoring, diagnosis and treatment processes. First step at monitoring process is to analyse the watershed characteristic, river characteristic and disaster records for understanding whole watershed characteristic and being references when health diagnosis indicators were set up. Second step at monitoring process is to obtain the watershed related data from hydrology observations at the ground, sediment recorders on the slope and air photos or satellite images. Subsequently, the health diagnosis indicators such as runoff ratio, denudation ratio, ratio of green cover, water quality indicator and sediment concentration were set up. The diagnosis process is using health diagnosis indicators to analyse soil conservation related problems such as soil loss, discharge and water quality. The water resource conservation of a watershed could be evaluated by the runoff ratio; the soil losses of a watershed could be evaluated by the denudation ratio; the plant cover of a watershed could be evaluated by the ratio of green cover; the water quality of a watershed could be evaluated by the water quality indicator and the fine-grained soil losses of a watershed could be evaluated by the sediment concentration. The causes of these problems aboved were also appreciated and were divided into three kinds of driving force, such as watershed inherent conditions, the external environment and human development effects. The treatment process is selecting according management plans for different driving force. First step is to decide the management object; second step is to draft strategic planning such as cutting down peak discharge, decreasing soil losses, and conserving soil-water resource for the sub-watershed; third step is to select suitable programs through analysing sediment completeness ratio, green cover completeness ratio and water quality completeness ratio. Besides health diagnosis model of soil conservation, the sediment yield model suitable for water source domain was established to estimate the soil erosion and landslide volume amount. The model passed verification based on sediment deposit data from Feitsui Reservoir and sediment transport capacity of Nan-Shih Stream and Pei-Shih Stream.