Understanding the influence of river-water infiltration on groundwater is essential for effective management of groundwater resources adjacent to a losing river. This study evaluates the influence of river-water infiltration in the alluvial fan of the Nalenggele River basin, northwest China, using (1) spectral analysis to analyze river discharges and groundwater levels, and (2) environmental tracers. The fluctuation period of groundwater levels was similar to that of river discharge. However, the time lag was about 50–150 days (increasing with distance from the channel), and the fluctuation period also increased with distance from the channel, from 297 to 990 days; this indicated a weakening influence towards the flanks of the alluvial fan. The total dissolved solids and δ¹⁸O values of the groundwater were close to those of the river water when the influence of river bank infiltration was strong. The spatial distribution of groundwater ¹⁴C activity reflected the influence of river bank infiltration and the groundwater residence time; ¹⁴C activities larger than 50 pMC in groundwater indicated a strong mixing with river water and fast groundwater flow, and reflected the strong influence of river bank infiltration. Data confirmed that the zone of strongest influence was near the river channel (horizontal distance ~5 km, maximum depth 150 m), whereas the zone of weakest influence was in areas far away from both sides of the river channel and near where groundwater seeps to the surface. River bank infiltration should be considered when developing groundwater resources to ensure the security of water supply.

了解河流水入渗对地下水的影响对于有效管理流失河流附近的地下水资源至关重要。这项研究使用（1）频谱分析来分析河流流量和地下水位，以及（2）环境示踪剂，评估西北纳伦格勒河流域冲积扇中河水入渗的影响。地下水位的波动期与河流流量相似。但是，时间间隔大约为50-150天（随着到通道的距离增加），并且波动周期也随着到通道的距离而增加，从297天增加到990天。这表明对冲积扇侧面的影响减弱。的总溶解固体和δ ¹⁸当河岸入渗的影响很大时，地下水的O值接近河水。地下水¹⁴ C活动的空间分布反映了河岸入渗和地下水停留时间的影响。¹⁴地下水中的C活度大于50 pMC表示与河水强烈混合并快速地流入地下水，并反映了河岸入渗的强烈影响。数据证实，影响力最大的区域在河道附近（水平距离〜5 km，最大深度150 m），而影响力最小的区域在远离河道两侧和地下水渗入的区域附近。表面。开发地下水资源时，应考虑河床入渗，以确保供水安全。