人文型瞬時單位歷線之建構及應用

Abstract

台灣年平均降雨量高達2500公厘，且於時間與空間之分布上皆極不均勻。晚近三十年間，台灣地區隨著都市化之演變、人口集中與土地利用改變等因素影響下，許多暴雨所造成之災害更甚以往。 在過去研究中，水文模式之主要考慮因子為地文因子或水文因子，尚無詳細探討人文因子所造成模式之影響。由都市化現象造成環境變遷可歸納出地文因子與人文因子之變化。因此，本研究採用分析階層程序法將人文因子包括國民所得與人口密度等納入長短程通用水筒模式中予以考慮，以建立蘊含人文因子之瞬時單位歷線，並藉以評估集水區因土地利用改變所導致逕流歷線特性變化之因果關係。 本研究以基隆河上游五堵集水區為研究區域，探討都市化之水文環境改變對不同時期之降雨－逕流事件之影響，由結果可知都市化程度之多寡對於集水區逕流量之形成有顯著之影響。本研究提出建構人文型瞬時單位歷線之構想，可提供未來都會區水文規劃之參考。

The average annual rainfall in Taiwan is 2,500 mm. Rainfall is temporally and spatially non-uniform. In the recent 30 years, typhoon-related damages have exacerbated due to development of urbanization, population concentration, and the change of land use. The calamity that a lot of storms cause is more serious than in the past. Previous studies have explored the geographic factor or hydrologic parameter mainly related to hydrologic models. However, no previous research has been undertaken into the influence that the humane factor. The results cause environmental changes by urbanization can sum up with the increase of impermeable area and improve the density of population. This research uses the Analytic Hierarchy Process to consider the humane factor in the hydrologic models. The analytical results achieved in this study can be applied for urban watershed management in Taiwan. The model is calibrated and validated by the rainfall-runoff records of selected typhoon events occurred at the upstream watershed of Wu-tu, Keelung River Basin. The results suggest the effect of urbanization will advance the time of concentration and grow in quantity of flood peak indeed. Flow peak is underestimated by using parameters calibrated from earlier stages of urbanization. It implies degree of urbanization will effect basin’s runoff remarkably.