Review article: Silt and the future development of China's Yellow River

Silt loading is a critical problem in the use of the Yellow River for irrigation, domestic, and industrial water supplies. Nearly all of the silt comes in runoff from the immense and highly erodible Loess Plateau. Salinity has a secondary but widespread effect on irrigation development and groundwater quality. Engineering structures and expanded irrigation have reduced the silt load in the lower reach of the river by half over the last 50 years. Still, the level of the river bed continues to rise higher above the surrounding North China Plain. Millions of rural and urban lives are threatened by the possibility that an embankment will break and unleash a horrendous flood, as had happened numerous times prior to 1949. Earthquakes could cause similar castrophes. Increased populations in cities, expansion of irrigated land, and rapid industrialization have brought about locally severe water shortages. This, in turn, has led to surface and groundwater pollution by salt and heavy metals, lowering of groundwater levels, land subsidence, and salt water intrusion from the Bo Sea. Interbasin water transfers from the Yangtze River in the south to relieve water shortages in the north have been proposed for decades but remain controversial. The high cost of dams, canals, tunnels, pumping, and water control systems needed for the transfer has been a major objection. Other factors have been the adverse environmental impact in both the Yellow and Yangtze river watersheds of transfers and, importantly, the questionable need of the transfers if water conservation practices were used widely and effectively.