Please use this identifier to cite or link to this item: `http://hdl.handle.net/11455/34289`
 標題: 應用逕流曲線指數法探討洪水歷線的變化Evaluating Changes in Flood Hydrographs with the Curve Number Method 作者: 王成ㄎㄨㄣ 關鍵字: stormflow hydrographs;暴雨逕流歷線;Pi-Lu-chi;runoff curve number method;non-unit hydrographs;畢祿溪;逕流曲線指數法;無因次單位歷線 出版社: 水土保持學系 摘要: 流量特性分析為集水區經營規劃的重要工作之一，本研究應用美國水土保持局（SCS）所發展出的逕流曲線指數（Curve Number）法來推估森林集水區單場暴雨所產生的洪水歷線變化，供水資源規劃、設計之用。逕流曲線指數法係美國水土保持局（SCS）所研發推導出的一種通用逕流推估法，如配合三角單位歷線或無因次單位歷線，可推算某次單場降雨所形成的流量歷線，本研究就以此逕流推估模式作為模擬水文歷線之工具，評估本模式應用在台灣上游森林試驗集水區之適用性，利用畢祿溪11號、12號集水區的水文氣象資料，分析比較模擬的暴雨逕流歷線跟實際觀測的暴雨逕流歷線是否有相同趨勢。 本研究之結果顯示逕流曲線指數法應用在模擬這二個集水區暴雨水文歷線時，效果尚可，所推估的和實際觀測的暴雨流量歷線其所表現的趨勢約略相同，但是實際觀測之流量歷線的退水段較模擬的退水段平緩;也就是實測的退水曲線斜率較模擬的退水曲線斜率小，這是因為暴雨發生時在森林集水區有極大之入滲率，這些入滲量形成了地下水之後再緩緩的流出，使地表下逕流成為溪流量的來源之一。但是，地表下逕流系統這方面的流出機制並不包含在逕流曲線指數法這個模式當中，因此造成此模式應用在森林集水區時應從逕流產生機制作必要的修正。Proper analysis of runoff characteristic is one of the primary works for watershed planning management. Runoff curve number method was originally developed by the U.S. Soil Conservation Service(SCS). It can be used to estimate stormflow hydrographs by calculating rainfall excess with triangular unit hydrograph or non-unit hydrograph method. This study evaluated changes in flood hydrographs of forested watersheds by calculating rainfall excess with SCS curve number method for hydrologic assessment, planning and designing. The applicability of SCS curve number method for headwaters forested watersheds in Taiwan was evaluated by comparing simulated and observed stormflow hydrographs of Pi-Lu-chi experimental watersheds No.11 and No.12. The results indicate good agreements between simulated and observed hydrographs for the two study watersheds. The estimated and observed hydrographs show similar trends. However the hydrographs simulated with the SCS curve number method have sharper peaks. The observed hydrographs were smoother and flatter, exhibiting long recession limbs. This was due to the slow and gradual withdrawal of water from storage, e.g., movement of water from subsurface storage and drainage systems. However, hydrologic functions by subsurface flows were not considered in the development of SCS curve number method. Therefore, SCS curve number method requires some modification based on streamflow generation mechanisms for application to forested watersheds. URI: http://hdl.handle.net/11455/34289 Appears in Collections: 水土保持學系