Research Of The Influence Of Water Saving Irrigation On Wuliangsuhai Lake Of Hetao Irrigation Area In Inner Mongolia

Since 1990s, with the global water crisis, the problems of the relationship between water and ecology has been regarded intensively. This problem is more important in arid and semi-arid areas. The Inner Mongolia Hetao irrigation area is the biggest gravity irrigation area in Asia, where the agricultural water was mainly diverted from the Yellow River. At present, the effective way of reducing the water use quantity is to reduce the transfer water quantity from the Yellow River and to develop water saving engineering.As an important part of the drainage system in Hetao irrigation area, Wuliangsuhai lake, which is located in the east-south of Hetao plain, is the biggest lake marshland in the irrigation area. The supplementary water of Wuliangsuhai lake is mainly from the draining water of the farmland irrigation in the Hetao irrigation area. The water saving projects in the irrigation area will greatly reduce both the divertion water form the Yellow River and the irrigation drainage water, and there will be a large influence on the supplementary water and the ecology system of Wuliangsuhai lake. Therefore, the research of the influence of water saving projects in Hetao irrigation area no Wuliangsuhai lake is important and practical.This paper studied the factors which effected the water level of Wuliangsuhai mainly, and established a model to analyse the relationship of the supplementary water from the irrigation area to Wuliangsuhai lake, the drainage water from Wuliangsuhai to the Yellow River and the water level of Wuliangsuhai lake, and analyzed the changes of water level in Wuliangsuhai lake before and after the water saving projects. The results indicate that: irrigation drainage water of Hetao irrigation area effeted the water level in Wuliangsuhai lake chiefly. After the implementation of water saving projects, the water level of Wuliangsuhai lake will decrease by 0.1m and the water area will reduce 10 km2. The paper revealed that water saving will lead to the increasing of salt content of Wuliangsuhai lake and the aggravating eutrophication.The paper has some innoventions: under the foundation of the water level model of Wuliangsuhai lake, the influence of water saving and the relationship of water saving in the irrigation area, water level, water quantity and quality in Wuliangsuhai marshland are important in Wuliangsuhai marshland protections.