南通地区地下水咸化机理分析及改良措施

为了给南通地区地下水的合理开发和利用提供理论依据,利用各种水化学系数和变化图示对研究区内深层和浅层地下水的咸化机理进行了分析。结果表明:研究区内深层地下水中、西部水化学演化以正常的水-岩作用为主,东部沿海特别是寅阳镇一带深层地下水则主要因淋滤古海相地层盐分而使TDS增高;远离海边的大部分地区浅层地下水TDS增高主要与溶解地层盐分和蒸发作用有关,沿海地带尤其是东南角寅阳镇、海晏镇一带浅层地下水由于受到一定程度的现代海水入侵影响,其TDS显著增高。针对该区域地下水水化学变化特征,提出地下水系统改良措施:合理开发利用高TDS地下水可增加区域水资源量,增强调蓄能力,减轻对深层淡水资源的潜在威胁;逐渐增大地下咸水的开采量,从长远意义上逐步改良盐碱地,以利于水土资源利用及生态环境改善。

Analysis of salinization mechanism of groundwater in Nantong area and its improvement measures

In order to find out the salinization mechanism of shallow and deep groundwater in Nantong area, all sorts of hygro-chemical coefficients and variation diagrams were used to analyze the salinization mechanism of shallow and deep groundwater in the study area. The results show that, in the central and western parts of study area, the hydro-chemical evolution of deep groundwater is controlled by traditional water rock interaction, the increase of TDS in eastern coastal area, especially around the area of Yinyang Town, is the result of salt leaching from paleo marine strata. As for the shallow groundwater, the increase of TDS in the most areas far from the sea is mainly connected with the effects of dissolved salt and evaporation. Influenced at some degree by the modern seawater intrusion, the TDS in coastal area, especially in the Yinyang Town and Haiyan Town in the southeast corner, was significantly increased. According to these change characteristics of groundwater hydro-chemical in the study area, some measures of improving the groundwater system were put forward: develop and utilize high TDS groundwater reasonably to increase the amount of regional water resources and enhance the storage capacity, mitigating potential threats to deep fresh water resources; increase the exploitation amount of salt water gradually to improve saline and alkaline land step by step, having positive significance for soil and water resources utilization and ecological environment improvement in the long term.