德州市浅层地下水水质演化

Shallow Groundwater Quality Evolution in Dezhou City

德州市属于典型的黄河下游冲积平原孔隙水水文地质区。该地区具有咸、淡两种水体共存的独特水环境特征,淡水天然的水环境条件非常敏感和脆弱。由于持续开采地下水,使该区域地下水的水动力场和水化学场发生了较大变化。根据德州市1996—2007年的地下水水质监测数据,论述了浅层地下水的水质特征,分析研究了浅层地下水的水质演化。结果表明:在开采条件和自然条件的共同作用下,浅层地下水水质不断演化,其中变化比较明显的水质指标是总硬度、矿化度和Cl-等。在区内齐河县、夏津县的苏留庄等一带,水动力场的变化导致地下水的矿化作用减弱,浅层地下水的矿化度、总硬度有所降低,水质趋向淡化。在宁津县、禹城市的张庄乡等一带,水动力场的变化导致地下水的矿化作用增强,浅层地下水的矿化度、总硬度明显升高,水质持续咸化。针对研究区地下水水质的演化趋势,提出了使微咸水逐渐向淡水方向演化的水质调控措施。

Dezhou City is in a typical Yellow River downstream alluvial plain pore water hydrogeology area where the distinct characteristics of water environment is comprised of salt water and fresh water,so that the natural aquatic environment condition of underground fresh water is rather sensitive and fragile.The continuous exploitation of the groundwater brings great changes in the hydrodynamic force field and hydrochemical field in this area.Based on the monitoring data of groundwater quality in Dezhou City from 1996 to 2007,the authors discuss water quality characteristic and analyze the water quality evolution of shallow groundwater.Results indicate that the water quality of shallow groundwater evolves constantly,in which the water quality index of total hardness,degree of mineralization and Cl-changes obviously.As diminished mineralization of groundwater caused by the change of the hydraulic force field,the total hardness and degree of mineralization decrease to some extent and the water quality has a tendency of desalinization in the area of Qihe County and Suliuzhuang Town of Xiajin County.Because of strengthening mineralization of groundwater caused by the change of the hydraulic force field,the total hardness and degree of mineralization increase to some extent and the water quality has a tendency of salinization in Ningjin County and Zhangzhuang Town of Yucheng City.According to the groundwater quality evolution tendency in study area,water adjustment measures have been put forward which may make the brackish water evolve into fresh water.