本研究主旨是結合地理資訊系統快速擷取資料及超強的處理運算能力，與適用於評估集水區沖蝕的農業非點源污染沖蝕模式，有效推估南投縣水里溪集水區的土壤流失量。利用地理資訊系統，分析及處理有關樣區的資料，以取得AGNPS模式中所需的參數，建立標準的輸入資料格式，估算分析泥砂量、逕流量與土壤流失量。推估結果顯示，此集水區沖蝕量每年平均每公頃流失量達29.5公噸，已超出美國及許多國家允許的每公頃11公噸的沖蝕容許上限。因此必須採用適當的水土保持措施，以控制土壤流失量在允許的範圍內。根據AGNPS的輸出資料，還可辨認出產生過量泥砂的小區，有助決策者判斷需要優先治理的地區，落實集水區管理策略與農地規劃。
The objective of this study is to integrate the effective and powerful tools of Geographic Information System (GIS) and the Agricultural Nonpoint Source Pollution Model (AGNPS) to quantify erosion problems in the Shuili River Basin. The AGNPS model input data were obtained by the GIS techniques. The estimated annual soil loss from this watershed is about 29.5 t/ha. It is, therefore, necessary to prescribe appropriate soil and water conservation practices to control the volume of soil loss within acceptable (or tolerable) limits. The model a1so has the capabi1ities of identifying areas with in the watershed with high erosion and sediment yield. This provides a guide in formulating policies and plans to counteract erosion effects, to optimize farm output and to stabilize economic development.
