APPLICATION OF ISOTOPE TECHNIQUES IN THE RESEARCH OF THE GROUNDWATER CIRCULATION MODEL AND RENEWBILITY IN BAOTOU PLAIN
SU Xiaosi1,2,LIN Xueyu1,2 (1.Institute of Environmental Science,Beijing Normal University,Beijing100875,China;2.College of Environment and Resources, Jilin University,Changchun130026,China)
The isotopic evidence shows that the groundwater in the mountain apron and the Yellow River alluvial plain in Baotou plain has different groundwater circulation models. In the mountain apron, the phreatic water is recharged by local atmosphere precipitation and characterized by the typical hydrogeochemical zoning the same as that of the largescale alluvial and diluvial fan. The confined water is recharged by the fissured water with high recharge altitude. But in the cone of water table depression, the confined water has high δ18O and 3H,which shows that the leakage is from phreatic water to the confined aquifer. In the Yellow River lacustrine plain, the phreatic water is mainly recharged by the irrigated water diverted from the Yellow River. The isotope evidence shows that the shallow groundwater in mountain apron has the less mean residence time, higher circulating speed and larger renewability than the deep confined water formed in the pale-geological period.