A simple model for the simulation of the flow behavior in unconfined double porosity aquifers

• Published in: Journal of hydrology (Amsterdam) 2021-05, Vol.596, p.126076, Article 126076
• Main Author: Moutsopoulos, Konstantinos N.
• Format: Article
• Language: English
• Subjects: Analytical solutions; Depth-integrated approach; Dual continuum approach; Dupuit assumption; Fractures; Numerical solutions; Porous matrix
• ISSN: 0022-1694; 1879-2707
• DOI: 10.1016/j.jhydrol.2021.126076

[Display omitted] •A simple simulation formulation is possible only for the discharging aquifer case.•A system of partial differential equations is proposed involving only 4–6 parameters.•The exchange term in equations derived using a depth-averaged approach is non-linear.•Both analytical and numerical solutions are proposed. The flow processes in unconfined double porosity aquifers consisting of a porous matrix and a dense network of fractures are investigated using the equivalent continuum approach, the Dupuit assumption and a depth-integrated formulation. We show that, unlike in the case of confined double porosity aquifers, in the case we investigate the term describing the internal flux between the two equivalent continua is non-linear. For the case of dewatering processes, a system of Partial Differential Equations, which involves only four parameters is developed. It is demonstrated that for the opposite case of recharging aquifer, at least for some cases, a much more complicated mathematical description is necessary. For the dewatering aquifer case fully explicit analytical solutions for both the variations of water table and discharge to an adjacent water body are developed. We verified the accuracy of the solutions for the head by comparison against numerical results.