An analytical solution for leakage rate and depletion of aquitard influenced by the delayed yield phenomenon

Abstract

Delayed yield phenomenon (DYP) occurs when the drawdown of an aquitard is no longer in equilibrium owing to previous changes in the level of water in adjacent aquifers. In this study, an analytical solution to determine the distribution of the drawdown at any time and at any point in an aquitard, in which the water level was not in equilibrium at the initial time, and the water level of the aquifers immediately above and below the aquitard was time dependent was developed. The analytical solution for the flow rate at any time and location was presented based on variations in drawdown in the aquitard. In addition, the effects of the DYP on the leakage rate and depletion of the aquitard were studied. Subsequent comparison of the proposed analytical and numerical solutions revealed that they were in good agreement. The results of this study will be useful to future studies of groundwater flow and environmental problems, such as water budgets, rising sea levels, solute transport, heat conduction and ground subsidence.

An Analytical Method to Calculate Groundwater Released From an Aquitard Undergoing Nonlinear Consolidation

“…Researchers have also investigated the groundwater dynamics and water balance in a linearly consolidated aquitard (Li & Zhou, 2015; Zhou, Guo, & Dou, 2013). For a nonlinearly consolidated aquitard (e.g., newly formed sedimentary soft soil), the variation of hydraulic properties varies nonlinearly due to the consolidation of the aquitard (Gibson et al, 1981; López‐Acosta et al, 2019; Müthing et al, 2018; Poskitt, 1969; Xie & Leo, 2004).…”

“…An analytical solution for drawdown variation in an aquitard was derived by Zhou, Guo, and Dou (2013), under the condition that the hydraulic head in the adjacent confined aquifer declines by a constant amount. An analytical approach was proposed by Li and Zhou (2015) to evaluate groundwater depletion in confining layers throughout the entire exploitation history or within limited periods, especially when there are few data on the drawdown history of pumped aquifers. Numerical models can also be used to analyze groundwater depletion in confining layers by providing information of aquitards (Huang et al, 2012).…”

Delayed Drainage of a Largely Deformed Aquitard due to Abrupt Water Head Decline in Adjacent Aquifer

“…The role of aquitards in the subsurface groundwater system has been increasingly recognized in many respects. The groundwater dynamics in the aquitard is closely related to the groundwater exploitation, groundwater contamination, underground storage utilization, and land subsidence [6,7].…”

“…Researchers have also investigated the groundwater dynamics and water balance in the small-strain consolidated aquitard [4,6]. For the large-strain consolidated aquitard (e.g., spatially the newly formed sedimentary soft soil), the variation of hydraulic properties is nonlinear during the consolidation of aquitard [24][25][26].…”

Contaminant transport in a small deformation aquitard affected by the delayed drainage phenomenon

“…The DDP of an aquitard was caused by a time lag between the drawdown in the aquifer and the subsequent drawdown change in the aquitard (resulting from change in pressure head). There are several studies about the DDP of the aquitard (Konikow & Neuzil, ; Li & Zhou, ; Neuman & Gardner, ). Zhou et al () defined the delay index (i.e., the delay time of hydraulic response in the aquitard).…”