River Landform Changes of Mudstone Area in Southwestern Taiwan Based on Analysis of Topographic Maps

• Main Authors: YING CHIEH NIEH, 聶英潔
• Other Authors: Quo Chen Sung, Chun Lan Chang
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/89843474520319597822

碩士 === 國立高雄師範大學 === 地理學系 === 94 === The landforms of the mudstone area changed faster than the other geological areas because of its sensitivity and fragility, where the remains tended to be destroyed to vanish so that had not been unable to be searched out. However the pictorical mateials of different stages were suppoed to record the tracks of those landform changes. They are not as precise as field research, but can cross over the limits of space and time and help us observe the landform changes in a hundred years. Landform changes of different spacial scales can be discovered through different temporal scales, so this paper is going to discuss the river landform changes inclusive of meanders, terraces, the rate of denudation and valleys in a hundred years and the major process. Before that, map-overlap and the estimate the errors have to be done. The southern part of the upstream of the Erhjen River basin is chosen to be the study area , and the tpopgraphic maps of 1926 and 1957 and the DTM of 2003 are the media for this paper to discuss the landform changes. The datums of different stages have changed for several times, so it is important to overlap maps correctly as well as estimate the errors. Two tpyes of horizontal map-overlap were used for trail and error, and the two results were very closed. It is about 7~8. So the changes less than 8 meters were thought to be immovability. In addition, the evelation data were disturbed by surface plants and buildings. After correlating control points of different stages, it was estimated of 8-meter errors. With corrected maps, landform changes were calculated for understanding the procces of different scales which affected the landforms of different scales in a hundred years. The average rate of denudation coheres with the uplift in thousand years; the differenciation of rate of denudation of the basin and the bias of the moving bends reflect the control of the slope and the geomorphological trend; the smaller –scale changes of sinuosity and chute-cutoff is affected by human cultivation and climate changes in five years.