An analytical study on artesian flow conditions in unconfined‐aquifer drainage basins. Issue 10 (23rd October 2015)

• Record Type: Journal Article
• Authors: Wang, Jun‐Zhi; Jiang, Xiao‐Wei; Wan, Li; Wörman, Anders; Wang, Heng; Wang, Xu‐Sheng; Li, Hailong
• Is Part Of: Water resources research. Volume 51:Issue 10(2015:Oct.)
• Page Start: 8658
• Page End: 8667
• Publication Date: 2015-10-23
• Subjects: analytical solution -- flowing artesian wells -- artesian head -- artesian zone -- unit basin -- the Ordos Plateau; Hydrology -- Periodicals; 333.91
• DOI: 10.1002/2015WR017104
• Languages: English
• ISSNs: 0043-1397

Abstract

Abstract: 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. Key Points: The artesian head is rigorously defined and used to outline the artesian zone. The artesian head/zone changes with basin geometry and permeability properties. Theoretical findings on artesian head/zone are demonstrated in a field study.