断流河道复流对于河流生态环境质量提升和水资源调配具有重要意义。上游水库放水和跨流域调水等是复流的主要工程手段。不同于天然河道径流，这些通过工程补充到河道的水具有流量大、受人为控制影响和时间集中等特点，河水与地下水之间的相互作用因此也变得更加复杂。河道补水对河岸带地下水动态影响成为断流河道复流工程实施所关注的重点问题。本研究以永定河北京平原段生态补水工程为例，揭示河道生态补水工程对平原段河岸带地下水动态的影响。

本文对永定河北京平原段的水文气象、地质和水文地质条件进行了整理与分析。对于缺失资料部分，开展了水文地质钻孔勘探与野外渗水试验，对收集与实测资料进行了整合。通过资料对研究区水文地质单元进行了划分，确定了模型边界，并在此基础上建立了研究区数学模型和概念模型。根据研究区实际状况，对源汇项进行了概化计算。在模型建立后，选取已有地下水水位数据对模型参数进行了校正和检验，结果显示模型模拟结果准确，具有可靠性。使用校正后的模型对研究区地下水回补影响范围进行了确定，在影响范围内进行了适宜性控制分区划分，以用于指定针对性的回补方案。在上述工作的基础上，根据降水量、放水时间与回补地点不同，分别制定了全段连续、全段周期性、部分连续和部分周期性四种回补方案。同时设置了三种不同压采方案，研究了压采对地下水位的影响。最后，通过模拟结果和研究区实际条件，计算了永定河北京平原段最佳放水量。

结果表明，研究区北部位于山前地带，回补潜力大，含水层透水性强，赋水能力大，为宜补区；中部回补潜力小，为禁补区；南部回补潜力大但水文地质条件略差，为控制区。河流补水对地下水的影响具有迟滞性，影响范围以河道两侧4公里内最为明显。周期性回补下，地下水变化成脉冲式上升，一年内波动较大；而连续回补情境下地下水逐年提升，但对于两种回补方式，十年后地下水位总体变幅差距不大。相对于全段回补，部分回补并没能有效遏制禁补区地下水位上升，而严重影响到控制区地下水回补，因此回补地点应为河道全段回补。永定河北京平原段的最佳放水量为4.49-22亿m³，在此放水量下，2030年宜补区、禁补区和控制区平均地下水位分别较2020年回升5.43、9.01和4.37m。

The resumption of the river flow is of great significance to the restoration of groundwater head and the allocation of water resources. The release of upstream reservoirs and inter-basin water transfer are the main engineering means of reflow. Different from natural river runoff, these engineering replenishment rivers have the characteristics of large flow, artificial control and time instability, so the interaction between river and groundwater has become more complicated. The influence of river channel replenishment on the dynamics of groundwater in the riparian zone has become a key issue of concern for the implementation of the river resumption project. Based on the “Yongding River (Beijing Section) River Corridor Ecological Restoration Technology and Demonstration” project, this study reveals the impact of the ecological water replenishment project on the groundwater in the riparian zone of the plain section.

In this paper, the hydrometeorological, geological and hydrogeological conditions of the Beijing-Beijing Plain section of the Yongding River were organized and analyzed. For the missing data part, hydrogeological borehole exploration and field seepage tests were carried out, and the collected and measured data were integrated. Based on the data, the hydrogeological unit in the study area was divided, and the model boundary was determined. On this basis, the mathematical model and conceptual model of the study area were established. Based on the situation of the study area, the source and sink items were generalized. After the model is established, the existing groundwater head data was selected to correct and verify the model parameters. The results show that the model simulation results are accurate and reliable. The corrected model was used to determine the impact range of groundwater replenishment in the study area, and appropriate control zones were divided within the affected area to specify targeted recharge programs. On the basis of the above work, according to the different precipitation, discharge time and replenishment locations, four replenishment schemes of full-section continuous, full-period periodic, part-continuous and part-period were formulated respectively. At the same time, three different pressure recovery schemes were set up to study the impact of pressure recovery on groundwater head. Finally, through the simulation results and the actual conditions in the study area, the optimal water discharge of the Yongding River in Beijing Plain was calculated.

The results showed that the northern part of the study area is located in the piedmont zone, with high recharge potential, strong aquifer permeability, and high water supply capacity, which is a suitable replenishment area; The geological conditions are slightly worse and it is a control area. Under periodic replenishment, groundwater changes into a pulse-like rise, which fluctuates greatly within a year. Under continuous replenishment, groundwater increases year by year, but for the two replenishment methods, there is not much difference in the overall change in groundwater level after ten years. Compared with the full-stage replenishment, partial replenishment has not effectively restrained the rise of groundwater level in the forbidden recharge area, and seriously affected the recharge of groundwater in the control area. Therefore, the replenishment location should be the replenishment of the entire section of the river channel. The optimal water discharge volume of the Beijing Plain section of the Yongding River is 449-2200 million m³. Under this water discharge volume, the average groundwater head in the supplementary area, the forbidden area and the control area in 2030 will rise by 5.43, 9.01, and 4.37 m respectively from 2020.