Topography of Taiwan - Terrain

Terrain

See also: List of mountains in Taiwan and List of rivers of Taiwan

The terrain in Taiwan is divided into two parts: the flat to gently rolling plains in the west, where 90% of the population lives, and the mostly rugged forest-covered mountains in the eastern two-thirds.

The eastern part of the island is dominated by five mountain ranges, each running from north-northeast to south-southwest, roughly parallel to the east coast of the island. As a group, they extend 330 km (210 mi) from north to south and average about 80 kilometres (50 mi) from east to west. They include more than two hundred peaks with elevations of over 3,000 m (9,800 ft).

The Central Mountain Range extends from Su-ao in the northeast to Eluanbi at the southern tip of the island, forming a ridge of high mountains and serving as the island's principal watershed. The mountains are predominantly composed of hard rock formations resistant to weathering and erosion, although heavy rainfall has deeply scarred the sides with gorges and sharp valleys. The relative relief of the terrain is usually extensive, and the forest-clad mountains with their extreme ruggedness are almost impenetrable. The east side of the Central Mountain Range is the steepest mountain slope in Taiwan, with fault scarps ranging in height from 120 to 1,200 m (390 to 3,900 ft). Taroko National Park, on the steep eastern side of the range, has good examples of mountainous terrain, gorges and erosion caused by a swiftly flowing river.

The East Coast Mountain Range extends down the east coast of the island from the mouth of the Hualien River in the north to Taitung County in the south, and chiefly consist of sandstone and shale. It is separated from the Central Range by the narrow Huatung Valley, at an altitude of 120 m (390 ft). Although Hsinkangshan (新港山), the highest peak, reaches an elevation of 1,682 m (5,518 ft), most of the range is composed of large hills. Small streams have developed on the flanks, but only one large river cuts across the range. Badlands are located at the western foot of the range, where the ground water level is the lowest and rock formations are the least resistant to weathering. Raised coral reefs along the east coast and the frequent occurrences of earthquakes in the rift valley indicate that the fault block is still rising.

The ranges to the west of the Central range are divided into two groups separated by the Sun Moon Lake Basin in the centre of the island. The Dadu and Zhuoshui Rivers flow from the western slopes of the Central Range through the basin to the west coast of the island.

The Xueshan Range lies to the northwest of the Central Mountain Range, beginning at Sandiaojiao, the northeast tip of the island, and gaining elevation as it extends southwest towards Nantou County. Xueshan, the main peak, is 3,886 m (12,749 ft) high.

The Yushan Range runs along the southwestern flank of the Central Range. It includes the island's tallest peak, the 3,952 m (12,966 ft) Jade Mountain (Yu Shan), which makes Taiwan the world's fourth-highest island.

The Alishan Range lies west of the Yushan Range, across the valley of the south-flowing Kaoping River. The range has major elevations between 1,000 and 2,000 m (3,300 and 6,600 ft). The main peak, Data Mountain (大塔山), towers 2,663 m (8,737 ft).

Below the western foothills of the ranges, such as the Hsinchu Hills and the Miaoli Hills, lie raised terraces formed of material eroded from the ranges. These include the Linkou Plateau, the Taoyuan Plateau and the Dadu Plateau. About 23% of Taiwan's land area consists of fertile alluvial plains and basins watered by rivers running from the eastern mountains. Over half of this land lies in the Chianan Plain in southwest Taiwan, with lesser areas in the Pingtung Plain, Taichung Basin and Taipei Basin. The only sizable plain on the east coast is the Yilan Plain in the northeast.