지형학 관점에서의 영월댐 건설 타당성 평가 = Geomorphological Evaluation of the Construction Plan of Youngweol Dam

다국어 초록 (Multilingual Abstract)

In order to evaluate availability of a dam construction plan, it is inevitable to examinegeomorphological condition of the river and its basin. This work is a geomorphologist`scontribution to the evaluation of a great dam(98m in height) construction plan(Youngweol Dam construction plan) in a main upstream(local name `River Dong`)belonging to River Han. According to our survey, geomorphological situation related toRiver Dong in Yeongweol Area is unfavorable to the construction of the planned dam. Impounding reservoir valley behind the dam is too narrow and small(22.7㎢) comparing to the grandeur of river basin(2267㎢). With this low ratio(reservoir/drainage basin), one can`t expect flood control effect of the dam. Geomorphological situation of the river basin mainfest high-energy relief with low green dam effect, that prone to make fluviatile regime unstable. With this stiuation, stability of water reservation effect of the reservoir could not be assured. Besides, the drainage basin of River Dong correspond to the mountainous area where frost shattering and nival erosion are the most active in South Korea. Due to active slope erosion associated with these processes in mountainous area of high energy relief,sedimentation rate of the reservoir may be so high as to shorten remarkably longvity of th dam. Moreover, lithology of reservoir valley is limestone. more or less densely fractured by several tectonic accidents, ｉ.e. Mesozoic paroxysms. Plio-Quaternary orogeny of Mts Taebaek. These type of fragmented limestone is very susceptible to frost shattering as well as tokarstification, owing to easy circulation of water within the rock. After impounding related to dam construction, these phenomena will be so accelerated that may result in tremendous landslides, such as Vaiont Dam reservoir in Italy underwent in 1963.