气候变化及南水北调中线工程对白洋淀流域水文的影响

本文从完整的水循环过程出发,将基于水文非线性理论的分布式时变增益模型(DTVGM)和以交替方向隐式差分法(ADI)求解的地下水模型(GWM)相耦合,建立了一种分布式的地表水地下水耦合模型,随后将其应用到南水北调中线典型受水区白洋淀流域,分析现状和未来气候下,调水对区域地表水与地下水可能产生的影响。模型识别结果表明:(1)DTVGM-GWM可较合理地反映河道流量和潜水位变化过程,模拟的浅层地下水流场基本上反映了地下水流动的趋势和规律;(2)南水北调工程的实施将大大缓解受水区特别是城市地区的地下水压力;在现状和未来气候条件下,调水后,平原区潜水位普遍抬升,流域地下水开采量明显减少,地下水蓄量、潜水蒸发明显增加,且春、秋季增加较多;流域径流量会有一定的减少,且夏、秋季减少较多;(3)在本文假定的水源配置方式下,未来实际蒸散发、潜水补给在调水影响下略有增加,在全年和各季节的变化主要受未来气候变化的影响。

Effects of climate change and the south-north water transfer project on hydrology in Baiyangdian basin

This paper presents a numerical model that integrates a distributed time-variant gain model(DTVGM) and a numerical groundwater model(GWM) of alternating direction implicit(ADI)difference and its application to the Baiyangdian basin to evaluate the impacts of climate change and the south-north water transfer(SNWT) project on the regional groundwater and surface water.A study case analysis shows that this integration model reasonably reflects the dynamics of river runoff and the temporal and spatial variations of groundwater table.By construction of the SNWT project,the annual groundwater exploitation under current and future climate scenarios is reduced,while the storage,evaporation and table of groundwater increases significantly and the annual runoff decreases,especially in spring and autumn.The actual annual evapotranspiration and groundwater recharge are mainly affected by climate change,and they increase a little in each season after the SNWT project.