摘要
深层孔隙水的咸水下移是滨海地区普遍存在的环境地质问题,目前对其形成和循环运移机理争议较大,是当今水文地质理论研究的重要内容之一。作者通过地下水资源的系统调查研究,利用地下水同位素的采样测试成果并结合地下水含水层结构初步分析了深层水的补给运移,并根据地下水的历年开采量的调查和水位、水质的动态变化研究了地下水动力场、化学场的演化特征。作者认为,深层水氚含量较80年代含量高,绝大部分含量在4～10TU。在补给条件好的古河道上游地区,多在10～20TU。这表明深层地下水经过几十年的大规模开采,水动力条件改变,水平迳流和垂向越流均有所增强,促进了地下水循环,而以近50年来大气降水渗入补给的地下水占优势。由于几十年深层地下水的超量开采,天津市南部平原区已形成地下水位的常年漏斗区。由于浅、深层地下水巨大的水位差,深层淡水已受到上部咸水下移的影响。地下水的主要常量组分TDS、Cl-、SO42-在南部平原区表现为含量总体升高的趋势,在地下水的集中开采区表现的更为突出,已经导致了天津市中南部平原第Ⅱ含水组淡水水质的咸化,地下水环境正在不断恶化。
Based on the systematic survey of the groundwater resources and its annual pumping capacity, water level, dynamic variety, the study of the isotope and the structure of the water-bearing layers, it is discussed in this paper that the deep fresh water is turning into the salty water, because of downward movement of the shallow salty water in the plain area of Tianjin. The author thinks that the T (H^3) (about 4 ～ 10 TU, or about 10 ～ 20 TU in the old river beds under the good recharge conditions) is higher than that in 1980s, which means the water hydrodynamic field changed after the big scale pumping during the recent 50 years, and horizontal runoff and vertical down-flow all increased, and the recharge comes mainly from the rain water. Because of the over pumping of the deep groundwater, the subsiding center has been formed in the south plain of Tianjin. The difference between the shallow and deep groundwater levels made the upper salty water move downward, and the fresh water below was affected already. The normal contents TDS、Cl^-、SO4^(2-) tend to become higher, especially in the strongly pumping areas. The fresh water in the second water-bearing layer in the south and middle of the plain is turning to salinization, and the groundwater environment is deteriorating now.
出处
《地质调查与研究》
2004年第3期169-176,共8页
Geological Survey and Research
基金
中国地质调查局地质调查项目(200112400003)
关键词
天津市
地下水动力场
地下水化学场
成水下移
溶质运移
同位素分析
dynamic field of groundwater
chemical field of groundwater
downward movement of salty water
isotope analysis.
