- 期刊
農業非點源污染模式應用於河川保護帶配置上之探討
Application of AGNPS Model on the Configuration of Stream Buffer Zone
摘要
本文以農業非點源污染模式與地理資訊系統相結合應用於南投明湖水庫的四個子集水區，以協助集水區經營規畫時選擇適宜的方案。模式模擬不同寬度的保護帶與其配置對集水區泥砂輸出的效應顯示：雖然保護帶會減少集水區泥砂輸出，可是降低泥砂輸出效果在各個子集水區之間差異甚大。保護帶的寬度與其配置可能應視集水區的地形、水文與土地利用情況而定。緊臨河岸兩側的裸露地或崩塌地是最應優先處理的地區。以明湖水庫集水區而言，陡坡地的檳榔栽植是最主要的泥砂沖蝕來源之一。保護帶的設置對減少泥砂輸出的效果而言是低於陡坡地的檳榔栽植收回。明湖水庫上游的四個子集水區，若以改善集水區現況爲著眼，治理的順序爲4號、2號、3號、1號。但若依減低的泥砂輸出總量而言，則爲4號、3號、1號、2號。模式的模擬提供了集水區治理時分區優先順序決定的依據；決策時亦可考量當地社經條件做另外的選擇。
並列摘要
Watershed analysis is the first step in watershed management and planning. Models such as the Agricultural Non-point Source Pollution Model (AGNPS) in conjunction with a GIS constructed data base could tailor watershed's geological, soil, hydrological and land use characteristics to simulate the spatial effects of management operations, and could be a powerful tool in decision-making processes. The effectiveness of different widths and spatial arrangement of stream buffer strips on sediment yields were evaluated with the AGNPS model on the four sub-watersheds upstream of Ming-Hu reservoir, Nantou County. The result shows that stream buffer zones do reduce the sediment yield, but their effectiveness vary among four sub-watersheds. Treatments on bare land and landslides along streams are most critical in controlling the sediment yield. However, with extensive steep slope betel nut plantation cultivated in those watersheds, stream buffer zone alone could not reduce the sediment yield effectively. The effectiveness of reforestation of betel nut plantation on slopes steeper than 45% were simulated in those four sub-watersheds. Consideration of the restoration of watershed from current condition, priority of reforestation will be highest for No.4 sub-watershed, No.2 sub-watershed ranks second, NO.3 sub-watershed is the third, and least for No.1 sub-watershed. However, it changes to No.4, No.3, No.1 and No.2 in the decreasing order in terms of total sediment amount reduced by the-reforestation effort. Other evaluation criteria could readily be used with similar simulation schemes.