邊區開發與環境衝擊：德基水庫集水區的環境變遷

Abstract

本文的目的在經由通用土壤沖蝕模型的建構，探究德基水庫集水區環境衝擊的發生因素，並分析不同時期引發環境衝擊因素的特性，進而討論本集水區環境衝擊發生與國家山地政策改變及颱風地震事件次數變化的關連性。 研究成果發現，德基水庫集水區在中部橫貫公路完工前後、蘋果開放進口政策之後，以及九二一地震之後的四個時期，由於面臨國家山地政策、以及地震颱風發生次數的改變，以致對環境造成衝擊的坡度、坡長、降雨、土壤沖蝕及植生覆蓋與管理因素，各自擁有不同權重。在中部橫貫公路完工前，自然因素扮演重要角色；同時，植生覆蓋與管理因素的影響力亦大。中部橫貫公路完工之後，受人為開發影響，植生覆蓋與管理因素所引致的環境衝擊程度更趨於提高。蘋果開放進口之後，環境衝擊程度再受到颱風次數提高、造成崩塌地增加影響，植生覆蓋與管理因素的影響力續增。九二一地震後，因為地震與颱風發生次數與規模暴增的影響，使得自然因素引致環境衝擊程度的影響力逐漸恢復。The paper focuses on constructing a soil erosion model to explore the causes of environmental impacts in Teh-Chi reservoir, and analyze their characteristics in different stages. Furthermore, to discuss the effect of national mountain policies and typhoon-earthquake numbers to environment impacts. The result shows that there are factors in different weights, the slope-gradient factor, the slope-length factor, the rainfall factor, the soil erodibility factor, and the cropping-management factor, in the four stages, separately before the completion of center cross-island highway, after the completion of center cross-island highway, after apple open-door policy, and after Chi-Chi earthquakes, when confronting different national mountain policies, and the increasing numbers and intensity of typhoons and earthquakes. Before the completion of center cross-island highway, the natural-induced factors played the most important roles, comparing with the latter stages, and cropping-management factor made much effects. After the completion of center cross-island highway, the cropping-management factor from human-induced factors increased their influences. After apple-open-door policy, the cropping-management factor increased their impacts continuously, due to the higher typhoon numbers and many landslides. Until the Chi-Chi earthquakes, owing to the abruptly increasing numbers and intensity of typhoons and earthquakes. The effects from natural-induced factors revived.