Impact of Fractured Aquitards on Solute Transport in an Aquifer-Aquitard System

Author

Zanjan Center for Research in Climate Change and Global Warming (CRCC), Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan

Abstract

     The fractured aquitards not only protects the aquifers from contamination but also acts as a pathway to transport solute into them. Here, we investigate the influence of a fractured aquitard in moving the solute from a contaminated upper aquifer into the clean lower aquifer by applying analytical models. In this work, the one-dimensional advection-dispersion equations of solute transport, considering horizontal flow in the aquifers and vertical flow through the aquitard, is applied in a 3-layer aquifer-aquitard-aquifer system. The governing equations were analytically solved in the Laplace domain and then numerically inverted into the real time domain using de Hoog algorithm. The results reveal that the transported amount of solute from the polluted upper aquifer into the lower aquifer is increased by adding fractures in the aquitard intervened between the upper and lower aquifers. In addition, the transported amount of solute is enhanced by increasing elapsed-time. The condition of the denser network of fractures within the aquitard is caused to (1) reduction of the solute concentration in both the contaminated upper aquifer and aquitard (matrix and fracture parts) and (2) the shorter solute plume through the contaminated aquifer. The findings of this model can be applied for exploring the safety of the deep aquifers for burring dangerous industrial and hospital wastes as well as for investigation of the influence of the oil reservoirs on the contamination of the adjacent aquifers.
 

Keywords

References

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Advanced Applied Geology
Volume 7, Issue 1
April 2017
Pages 96-105

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