Isotopic evidence of allogenic groundwater recharge in the Northern Ordos Basin

Large amount of groundwater recharge runs in opposite direction to the scarce surface water resources in the Northern Ordos Basin, and there are two controversial viewpoints. Hydrogen and oxygen stable isotopes are employed to identify the groundwater origin. Results show that surface water and soil water are mainly recharged by groundwater instead of local precipitation. The groundwater is not recharged by local rainfall, but is inferred to have originated from the Tibetan Plateau, based on isotopic (D, ¹⁸O, ³He/⁴He), hydraulics, geophysical, and geological evidence. It is consistent with the viewpoint of external groundwater recharging in North China. (author)