to pick up two large tributaries, the Hun River and Taizi River, at a confluence locally referred as the "Trident River" (三岔河), where it then adopted the new name Daliao River (大辽河, "Great Liao River") and drained into the Liaodong Bay just west of Yingkou. However, the Liao River Delta has a flat topography made up of soft sediment soil, with meandrous waterways that had a rich history of rerouting. This coupled with the risk of storm surges due to the region's low elevation, created a huge problem in flood control. This flood risk at the coastal section of the Liao River system was particularly threatening to Yingkou, a city immediately adjacent to the mouth of Daliao River and home to 2 million people. In 1958, the upriver of the Wailiao River at Liujianfang was blocked off via a river engineering project, redirecting the water flow from the Liao River proper entirely towards the Shuangtaizi River (which was renamed to simply the "Liao River" in 2011), effectively separating the Hun River and Taizi River from the Liao River system. Therefore, the Daliao River system is considered an independent water system of their own since 1958, and the Hun and Taizi River are no longer tributaries of the Liao River. Also, due to the Wailiao River's upstream flow being cut off, the Liao River no longer has any distributaries, therefore the Liao River Delta technically also ceased to exist from 1958 onwards, however the term remains in use to describe the area of Panjin between the Liao River's left bank and Wailiao/Daliao River's right bank. Tributaries Major tributaries Xiliao River (, "Western Liao River"), historically also known as Huang River (潢水), is the largest tributary of Liao River, running and draining a basin of . The Xiliao River is formed by the confluence of Laoha River (老哈河) flowing from the southwest, and Xar Moron River (西拉木伦河) flowing from the west, running its entire length eastwards within Inner Mongolia. It is joined at the lower course by a large tributary, the Xinkai River (新开河), which drains the southeast slopes of the Khingan Mountains and is dry in its upper reaches except after thunderstorms, north of the city of Shuangliao, before turning southeast to join the Dongliao River to form the Liao River proper near the common border of Liaoning, Jilin and Inner Mongolia. Dongliao River (, "Eastern Liao River")，is the other major