Groundwater System And Recharge From The Remote River In Southwestern Margin Of The Jungger Basin

Author smmarized the rescareh contents and methodology of groundwater formation, environmental and hydrogeological characteristics in arid zone all over the world, reviewing and analyzing the—state—of—the—art of groundwatcr research and some subjects to be dealt with in study area—upper and middle reaches of Kuitun stream in the Western margin of the Zhunger Basin. On the basis of study of components, texturc, boundary conditions of groundwater syste m, influence of active faults and flods on the system, through studying about hydrochemistry, tempcrrure, pH and Eh value, environmental isotope components and their changes of environmental isotopes, author studies formation conditions of groundwater, such as origin, elevation of recharge, etc., found that anion favces evolution arc as following:HCO₃→HCO₃·SO₄→SO₄·HCO₃→SO4·Cl→Cl·SO₄→Cl and cation facics evolve as:Ca→Ca·Mg(Na)→Ca·Na→Na·Ca→Na·Mg→NaGroundwaters originated from presipitation and snowmelt (surface water component), Recharge altitude is higher than 3200m as, and formation temperatues range from 1～5℃.Conceptual models of groundwater system were developed in south basin of Dudhanzi and Sarlong wellfield. Local, tronsitional and regional groundwater flow system are determined in the cross—section from south to north where through flow velocity is at about 100m/a in the Local, system, turnover time about 50—100 a; 1.6—4.8m/a in the regional system, and turnover time more than 50000 a. Groundwater in the deeper system is formed older than 50000 a,and in stagnant state.Author divided the types of remote river, exploring formation conditions, recharge mechanism. On the basis of the data of measured discharge at upstream and downstream of Kui tun stream, author computed the recharge from the riverbed using the modified Green—Ampt flow equationmand commenting the effect of anisotropy, water content deficit on recharge amount q (t) and elevation of mound Z.,(t).Ground water is specially stored in" River-Aquifer" system in the arid zone, and "xuanhe" rivers occur widespreadly in the piedmont,being a source of change in time and space, forming local groundwater flow system. So called" Xuanhe" means separation of water ruble from the river level, or remote from (high above) the regional water table,goundwater mound is beneath the riverbed and recbarge adjacent aquifers. Recharge from the "Xuanhe" is controlled by river flow, river bae and unsaturated zone below the river (media grain, ahisotropic, hydrolic conductivity, etc. and aquifer (depth, scope, boundary andpermeability).Infiltration of surface water in the unsaturated zone, insisted of interbedded of coast—graind and fine Myers, can be described as" saturated then inflitrate layer by layer" for those coast, permeable layer and in the zone of poorly sorted nedia as" movement of liquid—gas facies interface". Under the interaction of gravitation and capillary attracion, water moves preferantiallly down through fine interstices, then through rough ones. This course. is not continuous due to pluse recharge rfom ephemeral rive.Morever, influence of groundwater exploitation on bioenvironments and oasis zone are discussed. Regulation of water use in agriculture and industry, up and lower reaches, and attention to economic profit are suggested.