> Water Resources in Korea > Introduction

The Korean Peninsula extends southward from the northeastern part of the Asian continent between 33 and 43 North Latitude and 124 and 132 degree East Longitude. The standard meridian of the peninsula is 135, nine hours ahead of GMT.

The Amnok and Tumen Rivers border both China and Russia to the north, and Japan is just across the East Sea. Since 1945, as a by-product of the Cold War, the peninsula has been divided at 38 North Latitude into the capitalist Republic of Korea (ROK), or South Korea, and the communist Democratic People's Republic of Korea, more commonly known as North Korea.

Areas, Topography and geology

The total area of the peninsula is 222,196 km2, similar in size to that of U.K, New Zealand, or Romania. South Korea possesses 99,434 km2 or 45% of the total land mass, and North Korea 122,762 km2, the remaining 55%.

About 70% of the land is mountainous, mainly to the north and east. Along the southern and western coasts the mountains descend gradually towards broad coastal plains. Most of the rivers have their tributaries on the north and east sides, and flow into the Yellow and South Seas. Concentrated for the most part off the southern coast are upwards of 3,200 islands of various sizes that provide scenery unparalleled in the world.
The eastern coast of the peninsula runs directly along the skirt of the steep mountain slope range, while the western and southern coast have curved shapes and have wide alluvial plains in places. It is presumed that this asymmetrical topography was caused by tilting movements, subsidence in the western coast and upheaval in the eastern coast, and thus, the ridge line of the watershed runs on the eastern side of the peninsula.

In general, rivers running to the eastern coast are short in their length and steep in their riverbed gradients. Long stretching rivers with gentle gradients such as the Han river, the Keum river, the Nakdong river and the Seomjin river flow into the Yellow and South Seas in Korea.

Population and Land Use

Koreans, like many other Asian peoples, are descendants of Mongolian Tungus stock. They differ from the neighboring Japanese and Chinese, however, in that Koreans are a homogeneous ethnic group with their own language, culture, and customs.
Korean people are characterized by their generosity, warmth, and kindness, and are renowned as one of the hardest working people in the world.
As of 2004, the population of Korea was estimated about 49 million with a population density of 492person/km2, which ranks as one of the highest countries in the world along with Bangladesh, the Netherlands, and Belgium.
The total land area is 99,601 km2. Farm land constitutes 20,263 km2 (20%), while forest covers 64,948 km2 (65%). Only 4 percent of the total land area is used for housing, public, and industrial land.

The Han-River basin with an area of 26,018 km2 (26 percent of the national land area) accommodates about 21 million persons, while the Nakdong-River Basin with an area of 23,817 km2 accommodates about 12 million persons.

Of the 99,408 km2 of land in Korea, about 20.8% (20,676 km2) is suitable for cultivation and most of the remainder is hilly or mountainous. Only about 5 percent of the area is used for building sites, roads and factories.

Climate and Vegetation

Korea is in the moderately humid zone of medium latitude. It has a distict seasonal climate which is greatly defined by dry, cold continental air masses during the winter and humid, warm air masses from the ocean during the summer. Temperature varies widely between summer and winter, and there is great regional diversity.

Distribution of precipitation is more varied than that of temperature. During the rainy season from June to September, Korea receives about 70% of its annual precipitation of 1,283mm. About 18% of the total annual precipitation falls during the dry season from October to March.
Two or three of the approximately 28 typhoons occurring in the vicinity of the northwestern Pacific Ocean every year, influence the Korean peninsula directly or indirectly. When a typhoon is located north of 20N and west of 140E and it is expected to influence the Korean peninsula.

The climate of Korea is suited for conifer and deciduous forests, though the relatively unequal distribution of rains have not allowed for very dense vegetation. At present, good forests can be found in mountain areas, where the forests have been protected and managed to a good degree, especially since the '60s.

Characteristics of the Rivers in Korea

The largest river in Korea from the viewpoint of basin area and river discharge is the Han River.
It has a basin area of 26,018 km2 and an annual runoff volume of 27.7 billion ?, which constitutes 26% and 28%, respectively, of the nation's total.
On the other hand, the longest river in Korea is the Nakdong River with a river length of 552km.

Major characteristics of rivers in Korea are as follows :

The river reaches are relatively short and channel slopes are relatively steep
The river reaches are short and drainage areas are small in Korea compared with other major continental rivers. The channel slopes are relatively steep upstream because of steep mountains and deep valleys in the uplands.

Floods occur quickly and peak flood discharges are enormous
Due to the topographical conditions and torrential rainfalls, the hydrographs of rivers in Korea are very sharp and peak flood discharges are enormous compared with other comparable rivers in the continent.

Flow variations are high
The coefficients of the river regime, expressed by maximum discharge over minimum discharge for rivers in Korea usually range from 100 up to 700. This large variation in the flow discharge causes serious problems in river management concerning flood control and water use.

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