Deformation of the clay layer and Fluxes at the bottom of the clay layer

<p>A physical model test has been carried out to study the groundwater dynamics, water balance, and deformation characteristics of the aquitard in response to an abrupt hydraulic head decline in the adjacent confined aquifer. The hydraulic head in the clay layer is initially constant. The hydraulic head in the lower sand layer declines suddenly by <i>φ</i>  at the beginning and then remains unchanged during testing. We measured the drainage flux at the bottom of the aquifer and the subsidence of the clay layer.This supporting information document provides: (1)Supplementary Table 1 (Table S1), which presents time series data of the deformation of the clay layer (mm); (2) Supplementary Table 2 (Table S2), which gives time series data of the fluxes at the bottom of the clay layer (cm³/s).</p>