The interaction between surface water and groundwater significantly impacts the spatial distribution and evolution of water resources and hydrochemical components. Studying the exchange between groundwater and surface water is of great significance for watershed water resource protection, riparian ecosystem conservation, and water pollution prevention. This chapter focuses on three representative river systems in the northern Qinling Mountains: the Shidi River (Weinan City), the Xin River (Xi’an City), and the Qingshui River (Baoji City), and surface water–groundwater interactions in these three river basins were investigated using connectivity index, hydrochemistry, isotopes, and statistical analysis.