Abstract:

Hydrogeological investigation in western Alxa in Inner Mongolia was very limited , which led to the controversy on the flow directions as well as on the origin of groundwater in the area. To verify the existing perspectives, it is necessary to obtain groundwater information in boreholes in the center of the desert area. In this investigation, four boreholes were drilled in the Badain Jaran Desert which provided key data for the aquifer-system and groundwater level. Based on the new data and results of previous investigation, the flow directions of groundwater were analyzed. It was found that the porous media aquifer of Quaternary is widely distributed in western Alxa with a thickness that is more than 50 m. The Quaternary aquifer and the sandstones in the Tertiary and Cretaceous formations compose the major permeable media for groundwater flow. As a result, groundwater flow is continuous in the study area. In general, the directions of groundwater flow are from east to west and from south to north under the hydraulic gradients between 0.8‰ and 7.9‰. On the regional scale, the influence of faults on shallow groundwater is not significant.

Key words: Badain Jaran Desert, borehole, hydrogeology, hydraulic gradient, Alxa