https://scholars.lib.ntu.edu.tw/handle/123456789/167635
Title: | 關渡紅樹林植群變遷之衝擊評估 | Authors: | 施上粟 李鴻源 許志揚 游蕙綾 |
Keywords: | Guandu Nature Reserve, mangrove, wetland, hydraulic simulation, sediment routing, ecological impact | Issue Date: | Jun-2005 | Journal Volume: | Vol. 53 | Journal Issue: | No. 2 | Start page/Pages: | - | Source: | Journal of Taiwan Water conservancy | Abstract: | According to the analysis of cross-sectional elevation survey by Water Resources Agency form 1989 to 2000, authors found that the cross-section of K01, K02 and K03, which positions were around the Gunadu Nature Reserve, were deposited year by year. Furthermore, the coverage area of mangrove has increased form 10.5 ha in 1989 to 23.6 ha in 1994. It is found that mangrove can reduce the flow velocity and therefore speed up sediment deposition. The quasi-two-dimensional model, NETSTARS, was used to calculate the flooding impact around this region. The simulated results show that 5 year return period flood will bypass the dike after increasing 10% of Manning’s n. Moreover, 10 year and 20 year return period floods will also bypass the dike with mangrove spread effects. A horizontal two-dimensional model, TABS-2, was also applied in this study to simulate the sediment transport characteristics of this tidal wetland. The results reveal that significant sediment deposition occurs due to the extensive root network of mangrove. The deposition depth is about 1.3mm, 4.5mm and 2.7mm at node 1546, 1740 and 2090 during 2 year return period flood event. The increase of mangrove in this area has some adverse effects on the river hydraulic characteristics, including velocity retardation, increase of water surface elevation and sediment deposition. It is also found that mangrove spread threat Uca (Thalassuca) Formosensis Rathbun which is an endemic species of the fiddler crab in Taiwan and now disappeared in Guandu Nature Reserve. It was therefore suggested that we should take action to prevent this worse condition carry on as soon as possible. |
URI: | http://ntur.lib.ntu.edu.tw//handle/246246/64165 |
Appears in Collections: | 土木工程學系 |
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關渡紅樹林植群變遷之衝擊評估.pdf | 1.04 MB | Adobe PDF | View/Open |
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