台湾地区水库集水区土地利用对水库淤砂之影响

The Influence of Land Use in Reservoir Sedimentation

本研究之目的即在整合及分析土地利用变迁对水库淤砂之影响 ,以了解各水库对开发之容忍度 ,选择翡翠、石门及德基三座水库资料较为完整的水库集水区进行流量与悬移质浓度之分析 ,分析土地利用变迁对水库淤积之影响。本文中将淤积量与搜集之基本资料进行分析 ,将分析步骤分为三部分 :一是淤积量与气象水文资料之关系 ,二是淤积量与水库集水区面积之关系 ,三是悬移质输砂率之关系 ,希望能从这部分找出与淤积量较相关之因子。

The purpose of this research is to analyze and integrate the influence of land- use change to the reservoir deposit,as well as understand the tolerance of reservoir to the water-shed developed.Three reservoirs,Feei- Tsuey,Shyr- Men,Der- Ji,from this ten were chose to do detail research,such as the relationship of discharge and suspended load,land- use change and sedimentation.Finally,simplified erosion model was developed.From this result,the trap efficiency of reservoir and sediment delivery ratio of watershed can be evaluated.From the data analysis and model evaluation,the ratios of forestland are mostly greater than80 % ,but Bair- Her reservoir is only 70 % in on- channel reservoirs.The landslide ratio of Wu- Sheh watershed, however,is 2 .44% thatis greatestone in ten reservoirs.As for sedimenttrap efficiency and de- livery ratio,sedimenttrap efficiency of Tzeng- Wen reservoiris greater than the others,and de- livery ratio of Shyr- Men reservoir is greatest in on- channel reservoirs.The sediment erosions of unit area of Wu- Sheh ,Bair- Her and Tzeng- Wen reservoirs are greater than the other on- channel reservoirs. From the result of the relationship of watershed area and averagereservoirs’sedimentation,the reservoirs ofsouth Taiwan have higher deposits than middle and north Taiwan.