LIAO RIVER

Wade-Giles romanization Liao Ho, Pinyin Liao He, river in the southern Northeast (Manchuria) region in Liaoning province and Inner Mongolian autonomous region, China. The Liao River system drains the southern part of the Liao and Sungari plains of central Northeast China. Its drainage area is divided from the Sungari basin by a belt of land that has been subject to gentle uplift, while the plain area has in general been gently subsiding since the Mesozoic Era. The watershed area experienced intensified uplift in recent geological time, and this uplifting was accompanied by volcanic activity along the southern part of the divide. The plain as a whole is formed of thick sediments and is extremely flat and in parts swampy. In its upper reaches the Liao River divides into two main systems. The eastern Liao drains the foothills of the eastern mountains of the Northeast, while the western Liao, with its upper tributariesthe Lao-ha, the Ying-chin, and the Hsin-k'ai riversdrain the arid Jehol Uplands in southeastern Inner Mongolia. The volume of water varies greatly from season to season and has a marked summer maximum. The gradient in the plain is very low, and the lower Liao River valley has regularly suffered from summer flooding in spite of an extensive and long-established system of dikes. The river also carries a heavy load of silt. The area is icebound for about three months a year; extensive flooding often occurs during the spring thaw. The length of the Liao River is 836 miles (1,345 km), and its drainage basin is 83,000 square miles (215,000 square km). The Liao is not very important as a waterway; though its mouth, near the port of Ying-k'ou, is constantly silting up, it is navigable for small steamboats as far as San-chiang-k'ou, where the eastern and western Liao rivers diverge. Its principal tributary is the Hun River, which flows into the Liao not far above its mouth and drains the foothills of the Liaotung Peninsula and Ch'ang-pai Mountains, passing through Shen-yang (Mukden) in Liaoning province.