Although it has been reported that flowing artesian wells could be topographically controlled, there is no quantitative research on artesian flow conditions in unconfined aquifers. In this study, the water table, which has a lower amplitude than the land surface, is damped from the topography and used as the boundary condition to obtain the analytical solution of hydraulic head of a unit basin with a single flow system. The term artesian head is defined to characterize the condition of flowing artesian wells. The zone with positive artesian head is called artesian zone while with negative artesian head is nonartesian zone. The maximum artesian head and the size of artesian zones are found to increase with the damping factor and the anisotropy ratio, and decrease with the ratio of basin width to depth and the depth‐decay exponent of hydraulic conductivity. Moreover, the artesian head increases with depth nearby the valley and decreases with depth near by the divide, and the variation rates are influenced by the decay exponent and the anisotropy ratio. Finally, the distribution of flowing artesian wells and the artesian head measurements in different depths of a borehole in a small catchment in the Ordos Plateau, Northwestern China is used to illustrate the theoretical findings. The change in artesian head with depth was used to estimate the anisotropy ratio and the decay exponent. This study opens up a new door to analyze basin‐scale groundwater flow.

Groundwater flow systems and stagnant zones in drainage basins are critical to a series of geologic processes. Unfortunately, the difficulty of mapping flow system boundaries and no field example of detected stagnant zones restrict the application of the concept of nested flow systems. By assuming the variation in bulk resistivity of an aquifer with uniform porosity is mainly caused by groundwater salinity, the magnetotelluric technique is used to obtain the apparent resistivity of a profile across a groundwater‐fed river in the Ordos Plateau, China. Based on the variations in apparent resistivity of the Cretaceous sandstone aquifer, the basin‐bottom hydraulic trap below the river has been detected for the first time, and its size is found to be large enough for possible deposition of large ore bodies. The boundaries between local and regional flows have also been identified, which would be useful for groundwater exploration and calibration of large‐scale groundwater models.