基于耗水均衡的东北水田灌区地下水数值模拟与水源配置

Groundwater Numerical Simulation and Water Source Allocation of Paddy Field Irrigation Area in Northeast China Based on Water Consumption Balance

【目的】缓解东北粮食主产区地下水超采压力,促进地表水、地下水资源科学配置。【方法】以黑龙江省庆安县和平灌区为研究区,基于耗水均衡的地下水数值模拟模型,采用实测资料对模型进行了验证与识别。在此基础上,应用该模型对2种灌溉模式下共22种情景进行了模拟。【结果】在常量灌溉模式下,地下水占比<66%时,灌区的地下水位有所抬升,能够得到恢复;等于66%时,灌区处于平衡状态;>66%时,灌区的地下水位持续下降。在节水灌溉模式下,地下水占比<68%时,灌区的地下水位有所抬升,能够得到恢复;等于68%时,灌区处于平衡状态;>68%时灌区的地下水位持续下降。各占比情景下节水灌溉模式较常量灌溉模式的地下水位波动小。【结论】地下水资源在灌溉用水中的占比对灌区的耗水均衡状态影响显著,随着地下水资源占比的增加,表现为灌区的20 a补排差总量逐渐减小为负值。

【Background】With the development of society and the increasing of global food demand,irrigation water for agricultural production plays a more important role.According to statistics,90%of the world’s freshwater resources are used for agricultural irrigation.At present,the supply and demand of surface water resources are unbalanced in many areas.Groundwater resources have become the main water source for agricultural water.With the increasing of grain production,the problem of overexploitation of groundwater is becoming more serious,which leads to over-exploitation of groundwater and huge underground funnel.【Objective】In order to alleviate groundwater overexploitation in the main grain production areas of Northeast China and promote scientific allocation of surface water and groundwater resources.【Method】Taked Qingan County and Heping Irrigation Area in Heilongjiang Province as typical irrigation areas,this paper used a groundwater numerical simulation model based on water consumption balance,and validated and identified the model with measured data.On this basis,22 scenarios under two irrigation modes were simulated with the model.【Result】①Under constant irrigation mode,when groundwater proportion is less than 66%,groundwater level in irrigation area rises and can be restored;when groundwater proportion equal to 66%,the irrigation area is in equilibrium;when it more than 66%,groundwater level in irrigation area keeps decreasing.②Under water-saving irrigation mode,when the groundwater proportion is less than 68%,the groundwater level in the irrigation area will rise and recover;when groundwater proportion equal to 68%,the irrigation area will be in equilibrium;when it more than 68%,the groundwater level in the irrigation area will decrease continuously.Water-saving irrigation mode is less fluctuation of groundwater level under each proportion scenario than constant irrigation mode.【Conclusion】The proportion of groundwater resources in irrigation water has a significant influence on the water consumption equilibrium state of the irrigation area.With the increasing of groundwater resources,the total amount of recharge and discharge difference in the irrigation area has gradually decreased to negative value in 20 years.Both irrigation modes can achieve water consumption equilibrium when groundwater accounts for 66%and 68%.