The Role of Groundwater under a Large Irrigation-drainage System in Bameng Hetao Plain, China

摘要

The semi-closed geological and geographical characteristics are introduced as well as the framework of a large irrigation-drainage system in Bameng Hetao Plain, China. Yellow River is the key water resource for agriculture in this area. Under the irrigation-drainage system, groundwater is shallow buried, flowing slowly, and active in water cycling. The groundwater table and its seasonal variation have been adapted to the coupling of climate and irrigation activities of human. Fellow to the irrigation water from Yellow River, salts also is continuously imported to Bameng Hetao Plain without equal output. In current situations, the soil salt reduced by leaching function of irrigation water in farmlands. However, salt still accumulated in salinized wastelands by strong evaporation. At the same time, a large number of salt transports to groundwater, which normally has high salinity at present, from irrigation-drainage system and the farmlands. This kind of salt transport is an advantage to improve the irrigated soil but the long-term effect is a probable threat to the very limited fresh water resources in the aquifers and can make it more difficult to control the secondary salinization problem.