节水灌溉条件下宁夏银北灌区地下

根据灌区引水、排水、降水及蒸发等长观资料，分析讨论了宁夏银北引黄灌区大气降水、地表水、地下水相互转化规律及其时空分布状况。采用有限元法，建立了银北灌区地下水动态数值模型。在此基础上，研究了采取节水灌溉措施后，灌区地下水动态。首先按照优化后的灌区作物种植结构及相应的灌溉定额，反推灌区灌溉引水量。然后，通过相关分析，得到与灌溉引水量相对应的沟排量。最后，用反推所得数据及典型年份的降水和蒸发资料，进行了地下水动态趋势分析和数值模拟计算，给出了模型的预测结果，并将预测结果绘制成相应的地下水等水位线图。

Study on Ground Water Dynamics under Water-Saving Conditions in the Yinbei Irrigation District of Ningxia

The spatial and time distribution characters and the conversion rules among the atmospheric water, surface water, and ground water are analyzed and discussed based on the long-term observation data of irrigation water diversion, drainage discharge, precipitation and evaporation in the Yinbei Irrigation District. A numerical model for ground water dynamics of the Yinbei Irrigation District is established by FEM. On the basis of these researches, the ground water dynamic, which takes into account the effect of application of water-saving irrigation technique is studied in this paper. First, according to optimized structure of cropping pattern and corresponding irrigation water duties, the water diversion requirement of the irrigation district is calculated. Then, the corresponding drainage discharge is determined through correlation analysis. The data of the typical precipitation and evaporation are collected at the same time. Finally, the ground water change tendency a are analyzed with those data obtained, the numerical simulation forecasts the groundwater dynamics in the future, and the ground water table contour forecasted is illustrated with groundwater hydrograph.