Isotope analyses of the interaction between the Anyang River and groundwater

The study of interaction between rivers and groundwater is a difficult and hot topic in hydrological researches. The interaction between the Anyang River and groundwater is of great significance for the scientific development and management of water resources in the city of Anyang. The conversion rate of surface water and groundwater in the Anyang River alluvial fan ranges in downstream from 17% to 27%, and the aquifer system changes from the phreatic aquifer with the highest water table of 80 m to a multi-layer aquifer with groundwater level of 40 m. The analysis of local precipitation monitoring data shows that the local meteoric water line is parallel to the global meteoric water line, indicating that the line represents the hydrogen and oxygen isotope characteristics of atmospheric precipitation in the region. The isotope values of the surface water are concentrated. In August 2016, the δ18O value ranged from -9‰ to -8.7‰, and the δD value ranged from -65‰ to -63‰. In January 2017, the δ18O value ranged from -8.5‰ to -8.2‰, the δD value varies from -63‰ to -61‰, and the hydrochemical type of the river water is of HCO3·SO4-Ca type, indicating that the watershed is less affected by the distance. The stable isotope values of groundwater varys greatly. In August 2016, the δ18O value ranged from -10.4‰ to -5.5‰, and the δD value, from -75‰ to -46‰. In January 2017, the δ18O value ranged from -10.2‰ to -5.4 ‰, and the value of δD, from -75‰ to -45‰, that is, an “evaporation” line is formed from the approaching precipitation value to the maximum value. The isotope values of groundwater in the middle reaches of the river (out of the mountain pass) shows the maximum evaporation value, indicating that surface water replenished to groundwater. Hydrochemical type of groundwater is of HCO3·SO4·Cl-Ca type, and there are obvious human pollution components. The shallow groundwater is recharged from infiltration of precipitation in downstream. The middle and deep groundwater mainly originates from the lateral flow in the middle reaches, and the hydrochemical type is mainly HCO3-CaoMg. type The comprehensive analysis shows that the “three waters” in the middle and lower reaches of the Anyang River (alluvial fan) have actively converted and affected its water quality and quantity.