Assessment of groundwater resources based on AutoCAD technique

The catchment areas with the hydrological data in the southern region of the Cretaceous system are divided into seven categories according to the distribution characteristics of physical geographic conditions, watershed, lithology and geological structure. River baseflow of the Cretaceous system in the Ordos Basin is 1.143 billion m3/a. Baseflow of the Jing River drainage area is 538 million m3/a, which accounts for 47.0 % of the total, and baseflow of the Wuding River drainage area is 352 million m3/a, which accounts for 30.8 %. The AutoCAD technique of baseflow separation is chosen for two reasons. Firstly, the automated technique neither has the true physical basis, nor the relation to groundwater movement. Selection of $$ \alpha $$ value must refer to manual method for baseflow separation. Each pass will result in less baseflow as a percentage of total flow. Secondly, it is always thought that the manual method for baseflow separation is based on physical reasoning. The AutoCAD technique is essentially manual baseflow separation using the drafting tools available in AutoCAD. During the manual baseflow separation process, it makes the calculation workload substantial. The greatest benefits of using AutoCAD for calculation are to reduce the workload, enhance the efficiency, and provide more precise results. Hence, the AutoCAD technique provides a new way for baseflow separation.