北京平原地下水流数值模拟情景分析

在非稳定流模型(1995~2014年)基础上设计5个情景:现状(A)、回灌(B)、沉降中心停采(C)、沉降中心部分减采(D)及不同沉降中心不同减采比例(E),对北京平原2015~2030年地下水可持续利用进行分析。结果表明:(1)现状条件下,由于连续干旱及应急水源地的投入运行,北京平原地下水储存量被持续大量消耗,地下水位快速下降;(2)预测期内平均来说,A和B分别消耗1.16×108、0.28×108m3/a的地下水储存量,而C、D、E储存量分别恢复3.52×108、1.18×108、2.83×10~8m~3/a;(3)设计合理情景F:5区(八仙庄)、6区(天竺)和7区(王四营)的工业和城市生活用水分别减采0.51×108、0.12×108、1.76×108m3,总开采量19.28×10~8m~3,F是北京平原未来应采取的最优开采情景。

Numerical Simulation and Scenario Analysis of Groundwater Flow in Beijing Plain

In order to study the groundwater sustainable exploitation trend of Beijing Plain, this paper has set up the transient groundwater flow model (1995-2014) for Beijing Plain. A total of five exploitation scenarios have been designed based on this model: business as usual scenario(A), scenario with artificial recharge(B), scenario with pumping cessation in subsidence centers(C), scenario with the same pumping reduction percentage in subsidence centers (D), and scenario with different pumping reduction percentages in subsidence centers(E). The groundwater utilization of Beijing Plain from 2015 to 2030 was analyzed through the numerical simulation. The results showed: (1) under current condition, due to the continuous drought in recent years and emergency water source in operation, the groundwater storage of Beijing Plain was continually consumed to a large degree, resulting in the groundwater table falling fast; (2) on average for the prediction period, scenarios A and B will deplete 116 and 28 million m3 groundwater storage, respectively, while scenarios C, D and E will recover 352, 118 and 283 million m3 groundwater storage, respectively, indicating scenarios C and E are better than scenarios A, B and D; (3) a rational exploitation scenario F is designed through the analysis of the above scenarios: pumping reduction amounts in the subsidence centers are 0.051 billion m3/yr (100% reduction), 0.012 billion m3/yr (20% reduction) and 0.18 billion m3/yr (50% reduced) in zones 5 to 7, respectively. The total pumping reduction amount is 239 million m3/yr and the total pumping amount is 1928 million m3/yr. Scenario F is the reasonable pumping scenario for the Beijing Plain in the future.