Interpretation of the environmental isotopes of groundwater in the middle-eastern part of the Hetao Plain

The Hetao Plain is covered by thick alluvial and lacustrine sediments deposited alternatively in the Quaternary Period.Because the ground surface is very flat,vertical recharge and discharge are main factors controlling groundwater refreshment in the Hetao Plain.（）3H and D-（）18O data of different water bodies show that in areas where there is no pumping,the irrigation recharge（using Yellow River water or groundwater） has limited impact on shallow groundwater.In areas near pumping wells,the irrigation recharge can reach deep aquifers which depends on the screen depth of the pumping wells and the pumping amount.