Analysis And Countermeasures On Water Supply And Demand Of Minqin Oasis

Water is the source of all lives on Earth. Water is not only a materialbasis, but also the strategic economic resource. Subjection to one of the NorthwestInland River Basin of Minqin is a typical resource-based and project-based dry areas,water supply and demand is one of the areas most arid region of sharp contradictions.Therefore, quantitative analysis of conflict situation and the status of water in Minqinoasis in Minqin major irrigated water supply and demand study have practicalsignificance for the sustainable development of regional coordination of water resources,ecological environment and the economy.The research in this paper are divided into4parts which are based on thehydrologic observation data and the characteristics of the of oasis and drainage systemin Minqin county. Firstly, we analyzed the seasonal and interannual variations ofhydrologic surface runoff according to the data of the hydrological stations on Caiqi andMount Red Cliff dam; Secondly, we calculated the vegetation area and estimate itswater consumption in the corresponding year in the irrigated area of oasis in Minqincounty on the basis of the remote sensing images in1991,1999,2003,2006,2009and2011; Then, we summarized the characteristic of variations of water resources supplyand demand in the two irrigated area mentioned above from the perspective of waterresources supply-demand balance. In the mean time，we estimated the loss ofgroundwater; In the last part of this paper we concluded the influence on groundwaterenvironment from groundwater loss, to provide a scientific basis for alleviating thecontradiction between supply and demand of water resources, protecting the ecologicalenvironment and the rational use of water resources in the irrigation area in Minqincounty. Main conclusions of this study are as follow: (1)The structure of water supply source changed after2001. Surface water sourceare supplied by single natural river water before2001, while inter-basin water transfer(Jingdian and Minqin Oases Water Diversion Project and XiYing river appropriativewater conveyance project) began to suplly water to oases after2001promoting thesurface water amount of Caiqi section from1.14×in2001to3.48×in2012,and Mount Red cliff reservoir inflow from0.85×in2001to2.48×in2011.(2)The contradiction between the supply and demand of water resources in MinqinDesert Oasis is prominent. According to the conclusion, the highest annual averagedifference between water supply and demand was about7.56×, and the lowestwas about2.29×in the main irrigation area over the past five years. The highestannual average gap between water supply and demand was7.70×in HongYashan Irrigation District and the lowest was2.46×in recent six years. Theannual average balance of supply and demand was3356.0×around riverirrigation area during five years.(3)Underground water in Minqin Desert Oasis totally presented a state of losing.But this situation has gradually eased since2006. The Water Diversion Project fromJingtai to Minqin and Water Project from Xi Ying River to Minqin as well as thegovernance of Shi Yang River have alleviated the shortage of water since2006. The lossof underground water in Minqin Desert Oasis reduced from8.12×(before2006)to6.33×(after2006). The contradiction between water supply and demand beganto ease up.(4)The water supply of Minqin Desert Oasis is mainly controlled by the amount ofsurface run-off. Water requirement is mainly affected by the evaporation from theground and transpires from plants. Before2006, the annual average surface run-off was1.21×. Since2006, it is about2.30×.The vegetation area usually decidesthe amount of water requirement if the annual evaporation amount changes less. Thelarger vegetation area is, the greater the amount of water needs. Taking Hong YashanIrrigation District as an example (in2001and2006), the evaporation differed by67mm,but the vegetation area increased53in2006. However, the vegetation waterconsumption only increased by1.34×.(5)In order to improve the groundwater environment, we should take measures toincrease the run-off supply, reduce the groundwater exploitation, and improve the water- saving irrigation technology. On the one hand, we should ensure to enlarge the surfacerun-off in Cai Qi Section and the water inflow in Hong Yashan Reservoir, assuring thatthe annual average surface run-off is not less than2.0×; on the other hand, weshould try to reduce the overload of irrigated area and change irrigation methods toreduce comprehensive irrigation water to a reasonable range of300-400m3/.