Sand and gravel mining in upstream of Yangtze River and its effects on the Three Gorges Reservoir

The sediment in river channel has long been one of the main resources for construction activities along the Yangtze River. As the Three Gorges Project was built and running, it is of great importance to make clear the characteristics of sand and gravel mining in upstream of the Yangtze River, which can be significant references for ensuring waterway stability and comprehensive management of the Three Gorges reservoir. In this research, sediment excavation activities along the Yangtze River were reviewed from a historical perspective. The mining activities has been documented as three specific stages: small scale mining from 1950s to 1970s, disordered massive development from 1970s to 2000s and the orderly mining according to related laws from 21th century to the present. The policies and rules for sand mining along the Yangtze River nowadays were introduced, including limits on annual total mining, permissible area, period, etc. Moreover, a management database under the framework of GIS, which based on field survey and official investigation, was established. Elaborate information was incorporated in the database, including the kind of sand mining location, annually exploitation quantity, type of the removal, etc. Then the type, size and distribution characteristics of in-channel mining points along the upper and middle reaches of the Yangtze River were analyzed. Finally, in conjunction with the hydrological data in recent years, the effects of the sand and gravel mining on the deposition of the reservoir were quantitative analyzed, particularly in terms of particle gradation and total amount of sediment.