海河平原区地下水累计可恢复超采量评价

Evaluation of cumulative recoverable overexploitation of groundwater in Haihe Plain

地下水累计可恢复超采量评价对于地下水超采态势评判和超采综合治理实施都具有重要意义。本文以海河平原区为研究对象,提出超采量评价方法,旨在客观准确评价地下水累计可恢复超采量。针对浅层地下水超采量,提出生态临界水位作为传统“水位动态法”评价浅层地下水超采量的临界水位,据此得到研究区1959—2019年累计浅层超采量为869亿m^(3);针对深层地下水超采量,提出“不可恢复超采量”评价指标,采用地面沉降体积法评价深层地下水超采量,根据地面沉降体积计算深层承压含水层系统压密释水量体积,据此估算1970—2019年深层累计超采量为756亿m^(3);通过建立的一维非线性压密释水数值模型,模拟了深层承压含水层系统压密释水过程,计算得到非弹性压密释水量,评估研究区累计不可恢复超采量为558亿m^(3)。因此本文认为,自1960年代以来,海河平原区地下水浅层和深层累计超采量1625亿m^(3),其中可恢复的超采量仅为1067亿m^(3)。该研究结果可为未来地下水回补水量和南水北调规划调水量的确定提供参考。

The evaluation of groundwater overexploitation is of great significance for the evaluation of current groundwater overexploitation situation, the implementation of comprehensive treatment of overexploitation in the future, and water resources planning, and so on.Taking Haihe Plain as the study area, based on the existing research, this paper puts forward a new evaluation method of overexploitation, in order to evaluate the cumulative overexploitation of Haihe Plain more objectively and accurately.For shallow overexploitation, the “lower limit of healthy groundwater level” is proposed as the critical water level for calculating shallow overbreak by the traditional “water level dynamic method”.According to this method, the cumulative shallow overexploitation in the study area from 1959 to 2019 is 86.85 billion m^(3).For the deep overexploitation, the relationship between mining, overbreak, mining volume and overbreak is clarified.It is considered that “mining is over-exploiting, but the mining volume is not equal to the overexploitation”,and the “irrecoverable overexploitation” is proposed as the overexploitation evaluation index.According to the land subsidence volume, the cumulative overexploitation in the deep is estimated to be 75.61 billion m^(3) from 1970 to 2019.According to the “numerical model method”,the cumulative unrecoverable overexploitation is 55.8 billion m^(3).The cumulative overexploitation of shallow and deep layers is 162.5 billion m^(3),of which 106.7 billion m^(3) can be recovered.The research results can be used as important data support for groundwater recharge and planned water transfer of South-to-North Water Transfer in the future.