Understanding the interaction of surface water and groundwater affected by anthropogenic activities is of great importance for water resource and water quality management. The Xiong’an New Area, located in the North China Plain, has been designated a new building area by China’s government. Groundwater has been over pumped and artificial water was transferred to meet the water supply in this region. Therefore, the natural interaction of surface water and groundwater has been greatly changed and there has been a complex impact of the groundwater from anthropogenic activities. In this study, we used water chemical ions and stable isotopes of δ²H and δ¹⁸O to assess the interaction of surface water and groundwater in the Xiong’an New Area. We carried out field surveys and water sampling of the Fu River (domestic waste water discharge), Lake Baiyangdian (artificial water transfer), and the underlying groundwater along the water bodies. Results show that the artificial surface water (discharged and transferred) became the major recharge source for the local groundwater due to the decline of groundwater table. We used groundwater table observations, end-member mixing analysis of the stable isotopic composition and chloride tracers to estimate the contributions of different recharge sources to the local groundwater. Due to the over pumping of groundwater, the lateral groundwater recharge was dominant with a contribution ratio ranging from 12% to 78% in the upper reach of the river (Sections 1–3). However, the contribution of lateral groundwater recharge was estimated to be negligible with respect to the artificial water recharge from Lake Baiyangdian. Seepage from the Fu River contributed a significant amount of water to the connecting aquifer, with a contribution ranging from 14% to 75% along the river. The extent of the river influence into the aquifer ranges as far as 1400 m to the south and 400 m to the north of the Fu River. Estimations based on isotopic fractionation shows that about 22.3% of Lake Baiyangdian water was lost by evaporation. By using the stable isotopes of oxygen and hydrogen in the lake water, an influencing range of 16 km west of the lake was determined. The interaction of the surface water and groundwater is completely changed by anthropogenic activities, such as groundwater over pumping, waste water discharge and water transfer. The switched interaction of surface water and groundwater has a significant implication on water resources management.

Drylands cover over 40% of the global land area and are home to more than 2 billion humans. Here, we use the terrestrial water storage (TWS) anomaly data derived from GRACE satellites to assess water storage changes globally and find that drylands lost ~15.9 ± 9.1 mm of water between April 2002 and January 2017. The TWS trends are more significant and apparent in dry regions than in humid regions. The decrease in TWS occurred mainly in hyperarid and arid regions. Exact causes to the observed declines in TWS remain elusive due to anthropogenic water withdrawals, atmospheric demand (potential evapotranspiration,PET) in contrast to supply (precipitation,P) caused by the warming, and terrestrial ecohydrological responses. Therefore, we use a process‐based model forced by climate data to interpret the causes over three selected dryland regions showing the strongest drying trends. We find that the modeled TWS without considering anthropogenic water withdrawals explains most of the declining GRACE TWS over the southwestern North America (NA) and Middle East but underestimates the drying trend over North China. This suggests that TWS declines in the southwestern NA and the Middle East were primarily driven by the contrast between atmospheric demand and supply, whereas anthropogenic water withdrawals may have played a relatively more dominant role in TWS declines over North China. Additional model experiments indicate that terrestrial ecohydrological processes that help extract deep substrate water are critical for providing water supply additional to precipitation to sustainETin the drying drylands at decadal scales.