韓国琴湖江流域における堆積低地の地形特性
1984 年 39 巻 3 号 p. 131-142
詳細
1984 年 39 巻 3 号 p. 131-142
The writer has conducted research on the morphology, agents of the depositional landforms and the landform series in the Kumho-River Basin, Korea based on the geomorphologic land classification. The results are as follows: l . The geomorphology in the Kumho-River Basin consists of natural levees along the main stream and gentle slopes and hills. But there are few back-swamps. On account of the topography the extent of flooding is limited to the narrow area along the main stream course. The Kumho-River Basin is confined to a region the height of which is 100 m with a slope of less than 5°. 2. There are canyons (around A and D) and narrows (around B and C) along the Kumho-River. In flood times back water from the lower reaches to the upper reaches and overflowing from the main stream were seen in the upper parts of the canyons and narrows. Due to flooding natural levees were developed well along the main stream. 3. The piedmont gentle slopes of both banks, which occupy the spaces of the basins mostly, have been considered as erosional landforms in the past. However, these are confluent fans resulting from thin depositions consisting of new and older layers of sand and gravel. 4. The depositions in the confluent fans can be classified into the following geomorphologic elements, i.e., terraced older fluvial deposits (Fan I), which were inferred to be interglacial deposits, diluvium (Fan II), which was pushed out as debris flow in the last glacial stage, and younger fiuvial deposits (Fan 111), which are made up of the fine materials deposited on the layers (1 ) (2) by sheet flooding in the post-glacial stage. 5. The depositional landform series of the Kumho-River Basin is summarized in Fig. 9. The area upstream from Wepamree is characterized as the gravio-agency region and produced debris. The area between Wepamree and Jayang (Canyon D) is the storage region for the debris. From Jayang to the Iower reaches is a depositional lowland caused by the fluvial agency of the Kumho-River. The feature of the depositional landform series is that the series is divided into several parts by the canyons and narrows.
