The principal river of southern Northeast China, the Liao River, historically
bifurcates into two
distributaries near the Liujianfang Hydrological Station (六间房水文站) at Xinkaihe Town (新开河镇) of
Anshan's
Tai'an County, forming the Liao River Delta. The eastern distributary, called the Wailiao River, was originally the larger one and the main body of lower Liao River. It travelled southwards to pick up two large
tributaries the Hun River and Taizi River, at a
confluence locally referred as the "Trident River" (三岔河). After the three rivers merged, the resultant large river then adopted the new name as Daliao River.
However, the low
elevation and the flat, waterway-rich (and often
rerouting) topography of the Liao River Delta region created a huge problem in
flood control. During
monsoon seasons the
storm surges from the
Bohai Sea could go as far inland as the Trident confluence, and when meeting the voluminous upstream water from the Liao River, would frequently exceed the capacity of river channels causing massive spill-over
flash floods. This flood risk particularly threatened the cities of
Yingkou (which is immediately adjacent to the Daliao River
mouth and home to 2 million people) and
Haicheng (which has over 1 million residents). In 1958, a
river engineering project was conducted, and the upriver of the Wailiao River at the Liao River bifurcation was blocked off, redirecting the Liao River flow entirely towards the Shuangtaizi River (双台子河), the originally smaller western distributary of the
river delta. This separated the Wailiao, Hun and Taizi Rivers from Liao River permanently, making the Daliao River an independent river system since 1958.
Tributaries
Wailiao River (外辽河, "outer Liao River"), was originally the main distributary of Liao River and the principal
headwaters of Daliao River, but only an often dry
streamchannel remains upriver after the 1958 project. However, numerous
canals draining the
rural area south of
Liaozhong between Liao River and Hun River had been rerouted to feed the river, and it does pick up more canals and old tributaries downstream, and winds southwards (serving as a border between
Panjin's
Panshan County and
Anshan's
Tai'an County) before draining merely 1.5 kilometres (0.93 mi) west of the confluence of Hun River and Taizi River. This 1.5 km confluence segment of the three rivers is locally known as the Trident River.
Hun River (浑河, "muddy river"), historically also known as Little Liao River (小辽水) or Shen River (沈水), was formally the second largest tributary of Liao River. Running 415 kilometres (258 mi) and draining a basin of 11,500 square kilometres (4,400 sq mi), the Hun River has numerous tributaries of its own, 31 of which has catchment area greater than 100 square kilometres (39 sq mi). It flows through the most populous area of Liaoning province, including the
provincial capital and largest city
Shenyang, as well as the 10th largest city
Fushun. The river got its current name from the fast flow speed and high sediment load, which leads to its muddy appearance.
The Hun River's headwaters arise from the
Qian Mountains, a branch of the
Changbai Mountains, where the river is also called Nalu River (纳噜水) or Red River (红河), and flows into the 5,437 cubic kilometres (1,304 cu mi) Dahuofang Reservoir (大伙房水库), which supplies drinking water to the surrounding cities of Shenyang, Fushun,
Liaoyang,
Anshan,
Panjin,
Yingkou and
Dalian. The river's middle section was also called Shen River, which gave name to the capital city Shenyang to its north, and the lower section is also called Clam River (蛤蜊河).
Taizi River (太子河, "crown prince river"), historically also known as Yan River (衍水) or Liang River (梁水), was formally the third largest tributary of the Liao River, running 413 kilometres (257 mi) and draining a basin of 13,900 square kilometres (5,400 sq mi). The river was named according to the legend that it was the last site of refuge for
Crown Prince Dan of
Yan, who fled to
Liaodong to resist
Qinconquest after the
failed assassination attempt on the
King of Qin.
Its headwaters arise from hill regions between
Benxi and
Fushun, and contains the famous
Benxi Water Caves. Like its sister Hun River running parallel north of it, Taizi River flows through some of the most important agricultural and industrial regions of southeastern Liaoning, including the cities of
Benxi, Anshan and Liaoyang.