Experimental study of hydrodynamics of groundwater flow in karst aquifers

Abstract

A large-scale 3D laboratory model is constructed to simulate a karst aquifer. Three groups of experiments are conducted to study the flow exchange between matrix and conduit domains and investigate the effect of head difference, conduit size, and matrix/conduit gradients on matrix-conduit exchange. The findings of current study could be summarized as, 1) In experiments with higher matrix head, a counterintuitive head inversion, where conduit head becomes higher than matrix head, occurs when the head difference between matrix and conduit domains is small (less than 9.3 cm and 11.5 cm for the smaller 1-inch and larger 2-inch conduits, respectively). 2) Flow exchange is positively related to rescaled head difference (RSHD), a parameter combining the effect of matrix/conduit gradients and the head difference between conduit and matrix domains. 3) When the conduit has the higher hydraulic head, the flow exchange is on average 2.8 times higher than when the matrix has the higher hydraulic head. 4) Doubling the conduit size doubled the flow exchange and slightly increased the length of the head inversion.

Keywords:

• karst aquifers
• physical karst flow model
• matrix–conduit exchange
• groundwater dynamics

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Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Conflict of interest

The authors declare no competing interests.

Data availability statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.

CRediT author statement

Amin Hassan: Conceptualization, Methodology, Investigation, Writing - Original Draft, Ahmed M. Hedia: Conceptualization, Methodology, Investigation, Writing - Review & Editing, Hesham M. Bekhit: Conceptualization, Supervision, Ahmed E. Hassan: Conceptualization, Resources, Writing - Review & Editing, Supervision Mohamed A. Abd-Elmegeed: Conceptualization, Writing - Review & Editing, Supervision

Acknowledgments

The authors would like to acknowledge the efforts of the laboratory technicians at the Irrigation and Hydraulic Laboratory at Cairo University, Egypt, in setting up the laboratory model. The authors would also like to acknowledge the assistance of Prof. Ahmed Wagdy during the conceptualization phase and Eng. Ibrahim El Hefnawy for his helpful comments during the laboratory model setup.

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/02626667.2024.2376706.