CHEN Jiji1, 2, WU Yue1, 2, TAO Lei1, 2, GUO Jing1, 2, XU Sushi1, 2, XI Yue1, 2, JING Hongwei1, 2
（1. Beijing Ecological Environment Monitoring Center, Beijing 100048, China;
2. State Environmental Protection Key Laboratory of All Materials Flux in Rivers, Beijing 100871, China）
Abstract： In order to study the influence of ecological water replenishment on groundwater level and water quality along the Yongding River, Yongding River plain was selected as a typical region to investigate the dynamic changes and influencing factors of groundwater level and water quality around river banks during thethree stages of ecological water replenishment. Results showed that the variation range of water level in the sampled wells ranged from -1.20 m to 2.29 m during the two water replenishment periods, and three water replenishment was the main control factor causing groundwater level recovery in the study area. During water replenishment period, the water level of monitoring wells in the upper reaches of Yongding River plain increased first and then decreased, while the water level of monitoring wells in the middle and lower reaches continued to rise, and the rise of water level in the middle reaches was significantly higher than that in the lower reaches. Under the influence of dilution and water quality of ecological water replenishment, the overall proportions of Cl-, Fe, Mn, CODMn, NH4+-N, and NO3--N decreased, especially for NH4+-N and NO3--N, which decreased by 63% and 59.1%, respectively. In contrast, SO42- and F- concentrations increased by 30.0% and 15.9%, respectively, after the ecological water replenishment. With the progress of water replenishment, the concentration of all groundwater compounds in the same river tended to be the same, and the peak value of pollutants disappeared. In conclusion, ecological water replenishment increased groundwater storage and effectively improved groundwater quality in the study area.
Key words：Yongding River plain; ecological water replenishment; groundwater quality ; water level
EARTH AND ENVIRONMENT Vol.51, No.3, Tot No.353, 2023, Page 266
