碩士 / 國立成功大學 / 水利及海洋工程學系 / 87 / The objective of this thesis is to discuss the variation of river deltas in the eastern area in Taiwan by digitalized topographic maps and aerial photographs of past years. Analysis involves the following parameters: yearly variation of river delta in the eastern Taiwan area , longshore length and offshore length of river delta , the rate of change of longshore length and offshore length, the geometrical similarity of the coastline at river mouth region, and the rate of change of erosion and accumulation area. At last, one line model was used for numerical simulation to verify the present terrain data and to predict the evaluation of coastal terrain in the future.
Investigations show that river delta has smaller longshore length with the presence of sticking out terrain such as headland, and has larger longshore length with the absence of such terrain. The offshore length of river delta was related to terrain conditions at river outlet and the amount of suspended load of the river. Rivers across mountain region and flow directly into the sea in addition with larger suspended load have greater offshore length of river delta while those with huge downstream plain area of river delta have smaller offshore length of river delta. The rate of variation of longshore and offshore length of river delta depends on the discharge at river outlet region, the forming of spit at river mouth and the influence of headland. Furthermore, comparison of geometrical similarity of coastline indicates that coastline at Hua-Lien Chi river mouth region has the worst relativity with Gauss function, the Nan-Ao Chi river mouth region comes next, and the Ho-Ping Chi and the Li-Wu Chi region have the best agreement. Comparison of erosion/accumulation area ratio reveals that the Tai-Mar-Li Chi, the Li-Wu Chi and the Lan Yang Chi regions have the most potential of accumulation, then comes the Hua-Lien Chi and the Pei-Nan Chi regions. The Ho-Ping Chi and the Nan-Ao Chi regions have the least potential of accumulation. Numerical simulation also shows appropriate precision except at the Li-Wu Chi region with exceeding water depth and at the Lan Yang Chi region due to the change of southern coastline with variant discharge.
| Identifer | oai:union.ndltd.org:TW/087NCKU0083046 |
| Date | January 1999 |
| Creators | Jeng-Haw Huang, 黃振皓 |
| Contributors | Ching-Ton Kuo, 郭金棟 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 190 |
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