The Wei River is the site of some of the earliest civilizations in China, including the Chou dynasty (1027-256 B.C). The Wei was the site of the first ambitious irrigation system built in China..the Paikung and Ch'eng-kung canal systems, built in the 3rd century BC. The river and it's tributaries were never used as major waterways for transportation, as they are heavily silt-laden and too shallow. This silt recently caused major flooding problems along the Wei. The Three Gate Gorge (Sanmenxia) Dam, located on the Yellow River was completed in the late 1950s. The Wei is the major tributary to the Yellow River. Within two years, sediment accumulation on the river bed behind the dam became very serious. At the confluence of the Wei and Yellow rivers, the build-up of sedimentation blocked the normal flow of Wei waters into the Yellow River causing the Wei to overrun its banks and threatening the city of Xi'an with serious flooding. The increased elevation of the river bed also made the underground water table rise, which caused increased salinization and alkalization of agricultural lands. These lands soon became useless for growing food. As the years passed, the sedimentation problem grew worse. By June 1991, the river bed at Tongguan pass had risen 4.6 meters. The Wei River was now higher than the surrounding lands, held in only by earthen dikes. The level of underground water in the Wei and Yellow river delta had also risen 2-3 meters, causing vast areas of land to be destroyed by salinization.
Another interesting feature of the Wei River area is the underground Army of Terracotta Warriors from the tomb of the first Chinese emperor, Qin Shi Huangdi. These are found in X'ian, a city in the Wei River Valley. In 1974, peasants digging a well uncovered these life-size horse and warrior figures. Approximately 7,000 figures from the tomb have been restored by archaeologists and are exhibited in a hall built above the excavation site. Several hundred thousand workers spent 36 years building the tomb which was destroyed and plundered by rebelling peasant shortly after the death of the emperor in 206 BC.
| 
