基于Modflow的潜水位对气候变化和人类活动改变的响应

摘要

A model of the unconfined groundwater movement in the Wuqiao County,North China Plain,was developed based on GMS-Modflow.The calibrated model was then used to simulate the response of the shallow groundwater level（SGL） to the climate change（CC） and the human activities（HA） variability under three scenarios,namely the standard,CC and HA variability in the conning 40 years.The result shows that the SGL will decline at the speed of 19.3cm/a under current condition,thus the SGL will decrease by 7.74m from the beginning of 2011 to the beginning of 2050.Under emission circumstances of A1B,A2 and B1,though the average annual precipitation predicted by GCMs may increase by 4.1%,5.37% and 3.86% in the conning forty years,the SGL will decrease at 16.9cm/a,18.5cm/a and 19.3cm/a considering if direct and indirect influences of CC are considered simultaneously.This result indicates that the slight increase of the precipitation will not obviously slow down the drop of SGL in the future.Therefore,the artificial measures must be taken to retard the dropping of SGL.For relieving the dropping SGL water-saving technologies must be promoted,such as,using non-conventional water resources（e.g.the waste water） to substitute the conventional water and to raise the surface water supply.It will aggravate the SGL increase the water pumping from the confined aquifer and increase non-irrigation water.%采用GMS-Modflow软件构建了华北平原吴桥县的潜水运动模型,利用验证后的模型模拟了基准、气候变化和人类自主改变3种情景下未来40年该区潜水位对气候变化和人类活动的响应。结果表明：现状情景下,未来40年潜水位将以平均19.3cm/a的速度持续下降,从而导致2050年初潜水位较2011年初下降7.74m;综合考虑气候变化的直接和间接影响时,虽然A1B、A2和B1排放情景下利用GCM预估的未来40年平均年降雨量分别增加为4.1%、5.37%和3.86%,但潜水位仍然以16.9cm/a、18.5cm/a和19.3cm/a的速度下降,说明未来降雨的小幅增加对减缓潜水位降幅的效果微弱,人类必须采取自主措施才能应对潜水位持续下降;采取节水措施减少灌溉量对缓解潜水位下降效果最显著,其次为用非常规水源替代地下水抽水以及增加地表引水能力,而加大深层抽水量、增加非灌溉用水和地表引水量的减少都会导致潜水位下降态势进一步加剧。