莱州湾南岸海水入侵变化趋势及成因分析

为了探讨滨海经济快速发展形势下莱州湾南岸海水入侵范围变化及其控制因素,利用2011—2015年4月份(枯水期)莱州湾南岸地下水潜水层TDS(可溶性固体总量)、Cl–质量浓度连续监测数据,结合历史资料,分析莱州湾南岸海水入侵分布特征。结果表明,近5年来研究区地下水Cl–质量浓度均值为13.4 g/L,呈由岸向内陆快速减小趋势;研究区海水入侵呈带状分布,2015年入侵线向内陆伸入超过45 km,入侵范围较1980年向陆扩张约11~30 km。通过对比分析得出,研究区年均降雨量、地下水位埋深及地下水超采面积与海水入侵面积呈显著线性相关,发现持续干旱气候、地下淡水超采是导致海水入侵扩张的主要因素,卤水开发、海水养殖及莱州湾沿岸河流拦蓄工程进一步导致海水入侵的加剧。

The trend and influencing factors of seawater intrusion in the south coast of the Laizhou Bay

This study aims to determine the extent and influencing factors of seawater intrusion in the coastal aquifer of the southern Laizhou Bay. In the recent five years, 15 groundwater samples per year were collected every April and analyzed for total dissolved solids (TDS) and Cl_- content. The results show that the average Cl_- concentration is 13.4 g/L, which rapidly decreases toward the mainland. According to historical data and Kriging interpolation calculation by logarithmic transformation, the salinization of the aquifer exceeded 45 km toward the mainland in 2015 and has expanded almost 30 km inland since 1980. In the comparative analysis, the annual rainfall, groundwater depth, and over extraction of groundwater show significant linear correlation with the seawater intrusion area. The seawater intrusion was mainly aggravated by the continual dry weather and over extraction of groundwater, and was further intensified by the unplanned salt production, aquaculture, and river reservoir.