宁夏西部兴仁盆地地下水水化学特征

The Characteristic of Groundwater Quality of Xingren Basin in West of Ningxia

对宁夏西部兴仁盆地地下水水化学特征进行了研究.结果显示,地下水水质较差,由补给区的硫酸重碳酸型微咸水向排泄区过渡为卤化物硫酸型苦咸水,随深度的增加由苦咸水过渡为微咸水;溶滤与蒸发作用是导致地下水矿化度较高的主要原因,随矿化度的升高,SO42-,Cl-和Na+的含量迅速增加;水中F-质量浓度普遍偏高,NO3-质量浓度随含水层埋深的加大而减小,丰枯期变化明显.地下水同位素证明,研究区地下水主要来源为大气降水补给,浅层地下水的年龄低于深层地下水;在盆地灌区内,深层地下水的补给模式已发生改变,已接受上部潜水的越流补给.

The chemical characteristic of the groundwater in Xingren basin of Ningxia was studied. The result showed that the groundwater quality is worse, the chemical type of groundwater is transformed from sulphate and bicarbonate in recharge area into sulphate and halide in drainning area. The water quality in deep groundwater is better than that of the shallow. The main factors lead to the high total dissolved solids （TDS） is the dissolution of salts and evaporation, with the increase of salinity, SO4^2-, Cl^- and Na^＋ increase rapidly. F^- concentration is generally high in water, NO3^- concentration decreases with the increasing depth of the aquifer, and changes markedly in wet and dry period. Isotopic abundance of groundwater showed that the groundwater recharge is mainly from precipitation, the shallow groundwater is younger than that of the deep. The deep groundwater recharge patterns have been changed in basin irrigation district, it has accepted more recharge from shallow.