Groundwater Resources of the Ordos Basin and Its Development and Utilization

The Ordos Basin is a large-scale sedimentary basin in Northwest China. From bottom up,the hydrostratigraphic units in the basin are pre-Cambrian metamorphic rocks,lower-Paleozoic carbonate rocks,upper-Paleozoic to Mesozoic elastic rocks and Cenozoic deposits. The total thickness is up to 6000m. Three groundwater systems are present in basin,based on the geological and hydrogeolgical settings,such as the karst groundwater system,the Cretaceous clasolite groundwater system and the Carbonate-Jurassic and Quaternary groundwater system. On the basis of the three groundwater systems, according to hydraulic connection and presence of uniform hyduaulic and hydrogeochemical fileds,the karst grounewater system is further divided into 10 flow systems and 22 sub-systems,the Cretaceous clasolite groundwater system can be 5 flow systems and 11 sub-systems, and the Carbonate-Jurassic and Quaternary groundwater system is 9 flow systems. The paper systematically discusses regional patterns of the aquifers,hydrogeochemistry and groundwater flow,presents a full assessment of groundwater resources,and puts forward suggestions on rational development of groundwater in the basin.