Two theories are given regarding the origin of the river's name. One theory is that the name derived from Yalu ula in the Manchu language. The Manchu word yalu means "the boundary between two countries". In Mandarin Chinese, yālù phonetically approximates the original Manchu word, but literally means "duck green", which was said to have been once the color of the river. The other theory is that the river was named after the combination of its two upper branches, which were called "" and "" ", respectively. Revised Romanization of Korean spelled it Amnokgang and Revised Romanization of Hangeul spelled it Aprokgang.
Geography
From 2500 m above sea level on Paektu Mountain on the China–North Korea border, the river flows south to Hyesan before sweeping 130 km northwest to Linjiang and then returning to a more southerly route for a further 300 km to empty into the Korea Bay between Dandong and Sinuiju. The bordering Chinese provinces are Jilin and Liaoning. The river is 795 km long and receives water from over 30,000 km² of land. The Yalu's most significant tributaries are the Changjin, the Hochon, the Tongro rivers from Korea and the Ai and the Hun from China. The river is not easily navigable for most of its length. Most of the river freezes during winter and can be crossed on foot. The depth of the Yalu River varies from some of the more shallow parts on the eastern side in Hyesan to the deeper parts of the river near the Yellow Sea. The estuary is the site of the Amrok River estuary Important Bird Area, identified as such by BirdLife International. About 205 islands are on the Yalu. A 1962 border treaty between North Korea and China split the islands according to which ethnic group was living on each island. North Korea possesses 127 and China 78. Due to the division criteria, some islands such as Hwanggumpyong Island belong to North Korea, but abut the Chinese side of the river.
History
The river basin is the site where the ancient Korean kingdom of Goguryeo rose to power. Many former fortresses are located along the river and the former capital of that kingdom was situated at what is now the medium-sized city ofJi'an, Jilin along the Yalu, a site rich in Goguryeo era relics. Wihwa Island on the river is historically famous as the place where, in 1388, General Yi Songgye decided to turn back his army southward to Kaesong in the first of a series of revolts that eventually led to the establishmentof the House of Yi. The river has been the site of several battles because of its strategic location between Korea and China, including:
The Korean side of the river was heavily industrialized during the period of Japanese rule, and by 1945 almost 20% of Japan's total industrial output originated in Korea. During the Korean War, the movement of United Nations troops approaching the river precipitated massive Chinese intervention from around Dandong. In the course of the conflict every bridge across the river except one was destroyed. The one remaining bridge was the Sino–Korean Friendship Bridge connecting Sinuiju, North Korea to Dandong, China. During the war the valley surrounding the western end of the river also became the focal point of a series of dogfights for air superiority over North Korea, earning the nickname "MiG Alley" in reference to the MiG-15fighters flown by the combined North Korean, Chinese and Soviet forces. It was the advance of UN forces during the Korean War toward the Yalu which allowed Chairman Mao Zedong to convince his people that China needed to intervene over fears of an US invasion, since toppling communism was one of America's stated goals and Douglas MacArthur had allegedly expressed his desire to expand the war into China. The river has frequently been crossed by North Koreans fleeing to China since the early 1990s, although the Tumen River is the most used way.
Economy
The river is important for hydroelectric power, and one of the largest hydroelectric dams in Asia is in Sup'ung Dam, 106 m high and over 850 m long, located upstream from Sinuiju, North Korea. The dam has created an artificial lake over a portion of the river, called Supung Lake. In addition, the river is used for transportation, particularly of lumber from its forested banks. The river provides fish for the local population. Downstream of Sup'ung is the Taipingwan Dam. Upstream of Sup'ung is the Unbong Dam. Both dams produce hydroelectric power, as well. In the river delta upstream from Dandong and adjacent to Hushan are several North Korean villages. Economic conditions in these villages have been described as poor, without access to electricity.
