Variations of Groundwater Dynamics in Alluvial Aquifers with Reclaimed Water Restoring the Overlying River, Beijing, China

Some of the rivers in northern China are dried, and reclaimed water (RW) is used to restore these degraded river ecosystems, during which RW could recharge aquifer by bank infiltration. From 2007 2018, 2.78 × 108 m3 has been replenished dried Chaobai River (Shunyi reach), Beijing, China, located on edge one depression cone groundwater caused over-pumping. The hydrodynamic variations flow path were identified eight-year hydrological, hydrochemical, stable isotopic data, together with multivariate statistical analysis. infiltration drastically impacts dynamics a spatiotemporal variation. 30-m depth levels at Perennial intake reach increased quickly around 3 m after 2007, indicated that they dominated Other controlled precipitation from 2011, showing significant seasonal variations. In 2012, more transferred river, impact expanded downstream. However, 50-m 80-m showed decreasing trend variations, due pumping. was mainly recharged RW, being evidenced enriched δ2H δ18O. depleted δ18O regional meteoric origin. heterogenous properties multi-layer alluvial offer preferential for transport aquifers. proportion aquifers decreases calculated chloride conservative mixing model. lateral hydraulic gradient (0.43%) contributes aquifer. usage changed type Ca·Mg-HCO3 Na·Ca·Mg-HCO3·Cl. preferentially vertical leakage.