地下水位对生态输水的响应过程模拟

Simulation of Response of Groundwater Level to Ecological Water Conveyance

生态输水补给地下水是干旱区水资源管理的重要组成部分。了解河流-含水层系统中的地表水-地下水相互作用对于可持续地管理含水层和获得预期的环境效益非常重要。利用拉普拉斯变换得到一维布森内斯克方程的解析解,基于扩散补给效应和延迟效应,建立改进的多级补给分析模型,模拟均质各向同性介质中的多年地下水位波动,间歇性生态输水补给条件下的无侧限含水层。为进一步验证该方法的有效性,将分析模型应用于塔里木河下游间歇性生态输水多年来的地下水位波动估计。结果表明:以地下水位变化为边界条件的解析解和改进的解析模型能较好地解释含水层地下水位的升降。通过与实测资料的对比,验证了模拟结果的准确性,该模型能有效地反映瞬时补给和多级补给条件下的地下水位波动。研究结果可为多年间歇性生态输水补给条件下地下水位变化的预测提供新模型,进而为地下水管理提供技术支撑。

Ecological water recharge to groundwater is important to water resources management in arid areas.Study of the surface watergroundwater interaction in a stream-aquifer system is essential for sustainability of aquifer management and generating the expected environmental benefits.In this study,the analytical solutions of the one-dimensional Boussinesq equation were obtained by the Laplace transform.Then,an improved analytical model of multistage recharge was constructed on the basis of the spreading recharge effect and delay effect to the multi-year groundwater fluctuations in the homogeneous,isotropic,unconfined aquifer under intermittent ecological water conveyance conditions.To further verify the proposed method,the analytical models were applied to estimate the fluctuation of water table in the lower reaches of Tarim River during the years of intermittent ecological water transport.The results show that the analytical solution and improved analytical model,which utilize the variation in the water table as a boundary condition,can well explain the rise and fall of the water table within the unconfined aquifer.The accuracy of the simulation results is verified by comparing with the measured data,and the results show that the model can effectively reflect the water table fluctuations under transient recharge and multistage recharge conditions.The results of this study could provide a new model for predicting groundwater level changes under the condition of multi-year intermittent ecological water supply,and then provide technical support for groundwater management.