地理研究
Permanent URI for this collectionhttp://rportal.lib.ntnu.edu.tw/handle/20.500.12235/194
Browse
4 results
Search Results
Item 臺灣西南部河口地區之地形學研究(地理學系, 1995-03-??) 石再添; 張瑞津; 林雪美; 張政亮; 劉明錡; 陳政典The vincinity of the estuaries is one of the most populated area in the world. In order to ultilize the resource of this area more reasonably, the understanding of geomorphogical, hydrological and sedimentary characteristics becomes a main and basic task. Since estuary is located on the interface of river and sea, the morphology of estuary is influenced by the factors coming from both environments. The drainage basin area, shoreline length, shape factor, channel gradient, opening form, runoff, sediments, and monthly discharge etc. coming from the land. While the wind current, wave and tide etc. coming from the sea. This study area focuses on 20 estuaries of the south-western coast of Taiwan. The five of them are gravel estuaries and the rest are sandy. By correlation grain size of sandy estuaries has relationship with channel gradient below 100m, width of opening and shape factor. The forms of sand bar on estuaries are changed seasonly. Most of them has a tendency migrating southward due to northern moonsoon. The 20 estuaries can be classified into the wave dominated type, the tide dominated type and the runoff dominated type according average wave height, specific discharge and tidal range. Comparing the location of 20 estuaries during the period from 1904 to 1990(85 years). Most estuaries tend to migrate westward. The changes of estuaries are controlled by the intensity of wave and precipitation, the influence of reservior and hydraulic engineering and the changes of land use.Item 臺灣西南部嘉南平原的海岸變遷研究(地理學系, 1998-05-??) 張瑞津; 石再添; 陳翰霖嘉南海岸平原形成於晚更新世，海岸線的變遷與海水進退相對應，近三百多年來整體呈現向西推移的趨勢，古笨港、魍港（蚊港）及倒風內海已逐漸淤填，並被大量圍墾開發為魚塭或鹽田。濱外沙洲西側海岸除河口地區外，均向內侵蝕，在海汕洲及王爺港汕西側最大侵蝕率約達 12mn/yr。 外傘頂洲整體向東南方陸地漂移， 沙洲北段漂移速率甚至達58mn/yr。 沙丘主要分布於新港、鹿草一線以西，其中北港地區因濁水溪供沙充足，較嘉義沿海發達。 北港以西的海岸沙丘，大致分布在 7mn 以下，呈四列南北帶狀分布，隱示不同時期的海岸線位置， 應形成於大湖期海侵（ 3500-4000yr B.P. ）之後。 比較 1904-1926及 1990 年各時期之沙丘，其規模大致逐漸減小，係受人類開發利用影響所致。海岸平原地區向為人口稠密地帶，地形變遷常造成洪患威脅、丘沙漂移、土地利用改變、沿岸聚落興衰、土地權屬爭議及行政區劃定等之衝擊。相反的，人類擴張聚落、興建水庫、修築堤防、開鑿渠道、圍墾海埔地、取直河道等作為，也造成天然地形之改變，地形變遷與人類生活息息相關，其研究正可提供為土地規劃與開發利用的參考。Item 臺灣西南部臺南海岸平原地形變遷之研究(地理學系, 1996-11-??) 張瑞津; 石再添; 陳翰霖The Tainan coastal plain in southern Taiwan had been formed since late Pleistocene. The coast was marked by the offshore bars and lagoons, and have prograded to the west about 13 km since last three hundred years. The large lagoon was named as "paleo Taichiang Inland Sea" in Ching dynasty historical document had been filled up and reclaimed as fish ponds and salt pans due to the rapid sedimentation. However, the west coast of offshore bars have been eroded with a maxium rate about 14 m/yr in Tingtouerh bar in this century. The coastal dunes are distributed mainly in Salun, Tainan and Kunshen. Among them, Salun and Tainan dunes were deposited in Tahu Transgression stage (3500-4000 yr B.P.) where as the Kunshen dunes developed on offshore bars in last three centuries. Besides, a series of dunes is still exsited along the former Tsengwen River. Due to the expansions of the cultivated and built areas, all the dunes have decreased in magnitude. The river channel changed significantly both in hills and coastal plains. In the hills, 13 meander neck cutoffs can be observed in Erhjen River and Tsengwen River. On the coastal plain, river channel shifted by meandering and avulted suddenly in typhoon season because of epesodic sedimentation in the river bed. There were four big channel avulsions recorded since 19 century in Tsengwen River and the range of channel avulsion from north to south is about 25 km. However, the channel was confined after the dyke had been constructed in 1934. Overall, the geomorphological changes of Tainan coastal plain were caused by long term physical processes but modified strongly by human agency in the recent time. The geomorphological changes have induced some impacts on the human beings such as the decline of port, moving of village to prevent flooding, confusion of administrative boundary, etc.Item 臺灣西南部嘉南海岸平原河道變遷之研究(地理學系, 1997-11-??) 張瑞津; 石再添; 陳翰霖臺灣西南海岸平原各河流的河道變遷，主要導因於曲流作用、暴風雨後主流的迅速淤積，以及河口段的河道延長。八掌溪及曾文溪下游即分別發生過五次及四次的改道，河道擺幅達20公里以上，但自1920年代河堤興建後，河道便少有大幅改道現象。因海岸平原向西擴展，河流下游呈現延長河的特性，以急水溪為例，1904至1990年間河口每年平均向西推移43m。海岸平原地區向為人口稠密地帶，地形變遷常造成洪患威脅、土地利用改變、沿岸聚落興衰、土地權屬爭議及行政區劃定等之衝擊。相反的，人類興建水庫、修築堤防、開鑿渠道、河道截彎取直等作為，也造成天然地形之改變，地形變遷與人類生活息息相關，其研究正可提供為土地規劃與開發利用的參考。