An analytical study on three‐dimensional versus two‐dimensional water table‐induced flow patterns in a Tóthian basin |
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| Authors: | Jun‐Zhi Wang Xiao‐Wei Jiang Zhi‐Yuan Zhang Li Wan Xu‐Sheng Wang Hailong Li |
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| Affiliation: | 1. Institute of Engineering Geology, Yellow River Engineering Consulting Co., Ltd. (YREC), Zhengzhou, Henan, China;2. School of Water Resources and Environment, China University of Geosciences, Beijing, China |
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| Abstract: | Although it has been increasingly acknowledged that groundwater flow pattern is complicated in the three‐dimensional (3‐D) domain, two‐dimensional (2‐D) water table‐induced flow models are still widely used to delineate basin‐scale groundwater circulation. However, the validity of 2‐D cross‐sectional flow field induced by water table has been seldom examined. Here, we derive the analytical solution of 3‐D water table‐induced hydraulic head in a Tóthian basin and then examine the validity of 2‐D cross‐sectional models by comparing the flow fields of selected cross sections calculated by the 2‐D cross‐sectional model with those by the 3‐D model, which represents the “true” cases. For cross sections in the recharge or discharge area of the 3‐D basin, even if head difference is not significant, the 2‐D cross‐sectional models result in flow patterns absolutely different from the true ones. For the cross section following the principal direction of groundwater flow, although 2‐D cross‐sectional models would overestimate the penetrating depth of local flow systems and underestimate the recharge/discharge flux, the flow pattern from the cross‐sectional model is similar to the true one and could be close enough to the true one by adjusting the decay exponent and anisotropy ratio of permeability. Consequently, to determine whether a 2‐D cross‐sectional model is applicable, a comparison of hydraulic head difference between 2‐D and 3‐D solutions is not enough. Instead, the similarity of flow pattern should be considered to determine whether a cross‐sectional model is applicable. This study improves understanding of groundwater flow induced by more natural water table undulations in the 3‐D domain and the limitations of 2‐D models accounting for cross‐sectional water table undulation only. |
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| Keywords: | analytical solution cross‐sectional model flow system three‐dimensional model Tó thian basin |
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