Chapter 2 : Terrain


        Terrain is the physical character of the earth’s surface. Although the total area of Taiwan is only 36,000 square kilometers, its terrain is quite varied.

 

Terrain Types

        Taiwan has the following types of terrain: mountains, foothills, terraces, basins, and plains. The drainage area of the Dajia River (Figure 2-1) includes all five types. The Dajia River starts high in the Central Mountains. It slices west through the Syue Mountains, creating steep gorges. It then runs through the foothills and the Taichung Basin. Then it cuts across the Houli Terrace, forms an alluvial plain at its estuary—the place where it meets the sea—and finally flows into the Taiwan Strait.

Figure 2-1 The Drainage Area of the Dajia River

 

Terrain Distribution

        Geologically, Taiwan is located at the edge of Asia, facing the Pacific Ocean. Taiwan’s mountains rose up millions of years ago, when two of the earth’s plates pushed up against each another. The mountains run north-south along the entire length of the island. The main range is the steep central mountain range. As you go west or east from this range, you move downhill: the elevation steadily decreases. Mountainous terrain gradually yields to foothills or terraces, and, finally, to low and flat alluvial plains. Basins are scattered among mountains, hills, and terraces.

        In Figure 2-2, you can see that the most extensive type of terrain is mountainous. All the mountain ranges roughly run north south. The five main mountain ranges are the Coastal Range, the Central Range, the Sheshan Range, the Yushan Range, and the Alishan Range. The Central Range extends from Suao in the north to Eluanbi in the south. They form the central ridge of the island. This ridge is the watershed of the eastern and western rivers. The main peak of the Yushan Range is Jade Mountain, which at 3,952 meters is the highest mountain in Taiwan.

 

Figure 2-2 Terrain Map of Taiwan

 

        Taiwan has some volcanic terrain because of its location on the circum-Pacific volcanic and seismic belt. There are three main volcano groups: Keelung, Datun, and Penghu.

        A low, flat center surrounded by mountains is called a basin. The major basins in Taiwan are the Taipei Basin, the Taichung Basin, the Taiyuan Basin, and the Puli Basin.

        Taiwan’s plains, terraces, and foothills are mainly located in the west. Plains account for 30% of the island’s total area. The largest plain is the Jianan Plain. Other larger plains include the Yilan Plain, the Pingtung Plain and the East Rift Valley. A plain at higher elevation is called a terrace. Examples of this type of terrain include the Linkou Terrace, the Taoyuan Terrace, the Dadu Terrace and the Bagua Terrace. Foothills are distributed among the periphery of mountains. In other words, foothills lie between mountains and plains. Foothills are only several hundred meters high, and the rise and fall in elevation is not as dramatic as in mountainous terrain.