Abstract:

Based on the hydrochemical and isotopic data, this paper analyzes the hydrological geochemistry characteristics of Haiyuan basin combining with the existed geological and hydrogeological data of this area. As a whole, the chemical fields of local groundwater have the obvious zonation patterns from the recharge area to the runoff area,and to the discharge area, which are in conformity with the evolution law of water quality in arid basin. Geochemistry simulation shows that the local water-rock interaction changes gradually from the dissolution-mixture action in the recharge area into the dissolutionevaporation action in the discharge area, chemical compositions of the Tertiary strata and the circulation condition have a great influence on the groundwater quality. Isotopic features show that the Nanhua Mountain-Xihua Mountain fault controls the groundwater recharge of Haiyuan basin, so far, there is little impact of exploitation on the quality of deep groundwater. In some sites, the improved water quality with the exploitation of groundwater was observed, one explanation for this is that the increasing velocity of local water shortens the water-rock interaction time.
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Key words: groundwater, hydrogeological chemistry, isotope, characteristic, inverse modeling, Haiyuan, Ningxia