本研究主要目的在於探討不同季節時蓮華池集水區水文敏感區之動態變化,應用土壤水份演算模式估算土壤潤濕程度與地表逕流生成機率,並分析地形指標與逕流生成機率之關係,再據此設定門檻值劃設3、6、9及12月時之水文敏感區範圍。結果顯示,蓮華池4號與5號集水區地形指標分級多介於2-15間,邊坡地帶之地形指標值與地表逕流生成機率則呈線性正相關。而透過土壤水份演算模式估算出之平均土壤潤濕程度,則以6月份最高,12月份最低,明顯地隨季節而變化。此外,蓮華池4號與5號集水區於夏天雨季時,擁有較高的逕流生成機率,冬天旱季時逕流生成機率則最低。最後,在相同地形指標下,蓮華池4號集水區之地表逕流生成機率略高於5號集水區。
The purpose of this research is to study the dynamic change of hydrologically sensitive areas in the Lien-Hwa-Chi watersheds during different seasons. We apply the soil moisture routing model (SMR) to estimate soil saturation degree and probability of runoff generation in the study area, and to analyze the relationship between topographic index and probability of runoff generation. Based on the relationship, we identify the hydrologically sensitive areas in March, June, September, and December. Results show that the topographic indices in Lien-Hwa-Chi watershed No. 4 and No. 5 range from 2 to 15, and have a positive linear relationship with probability of runoff generation. Through the application of SMR, the soil saturation degree is properly estimated. The highest value of soil saturation degree is in June, and the lowest value is in December. It is obvious that soil saturation degree varies with different seasons. In addition, the probabilities of runoff generation in Lien-Hwa-Chi watershed No. 4 and No. 5 are highest in the summer-wet season, and are lowest in the winter-dry season. Finally, based on the same value of topographic index, the probability of runoff generation in Lien-Hwa-Chi watershed No. 4 is higher than that in watershed No. 5.