THE BALANCE BETWEEN SUPPLY AND DEMAND OF WATER RESOURCES AND THE WATER—SAVING POTENTIAL FOR AGRICULTURE IN THE HEXI CORRIDOR

The Hexi Corridor is an important base of agriculture development in Northwest China.According to recent statistics,there are 65.94×10^8 m^3 of water resource available in the Hexi Corridor.At present,net consumption in development and utilization is 43.33×10^8m^3.Water supply and demand reach a balance on the recent level of production ,but loss of evaporation and evapotranspiration is as much as 25.69×10^8m^3.So net use efficiency of water resources is 59%.Based on analyzing balance between water and land considering ecological environment at present,there exists the serious water shortage in the Shiyang River system where irrigation land considering ecological environment at present,there exists the serious water shortage in the Shiyang River system where irrigation lands have overloaded.These is a comparative balance between supply and demand of water resource in the Heibe River system.and the Sule River system has some surplus water to extend irrigation land.Use of agriculture water accounts for 83.3% and ecological forest and grass for 6.9%.The Hexi Corridor still has a great potential for water saving in agriculture production.Water-saving efficiency of irrigation is about 10% by using such traditiona technologies as furrow and border-dike irrigation and small check irrigation,and water-saving wigh plastic film cover and techniques of advanced sprinkler and drip/micro irrigation ete.can save more than 60% of irrigated water.Incremental irrigation area for water-saving potential in the Hexi Corridor has been estimated as 56%-197% to original irrigation area.So the second water sources can be developed from water saving agriculture in the Hexi Corridor under Development of the Western Part of China in large scale .This potential can be realized step by step through developing the water-saving measures,improving the ecological condition of oasis agriculture,and optimizing allocation of water resources in there river systems.