Effect of multilayered groundwater mounds on water dynamics beneath a recharge basin: Numerical simulation and assessment of surface injection

Abstract

Interactions between groundwater mounds caused by a geologic layer contrast affect the efficiency of managed aquifer recharge in arid areas. However, research has rarely examined the roles of groundwater mounding size variations on soil water dynamics in a stratified vadose zone in response to a sustained infiltration source.Numerical experiments were conducted on a two-dimensional vertical-section domain using HYDRUS software to simulate the behaviours of two adjacent (upper and lower) groundwater mounds underlying an infiltration basin subjected to clay loam and sandy alternately-layered soil profiles. The model successfully predicted the volume and extent of perched water and approximated vertical travel times during events generating downward fluxes from the surface injection. The response time of the mounding width (lateral extension) to the surface injection was delayed as compared to that of the mounding height (vertical extension), especially for the lower water mound. The mounding heights and widths show a strongly positive correlation with the infiltration rates of both high-and low-permeability layers where the injected water mounded, while the water storage amounts in the high-and lowpermeability layers were governed by the mounding height and width, respectively. Exploratory simulations were then employed to assess the dependence of groundwater mounding behaviours and recharge performances on surface injection strategies.Results suggest that, by reducing injection rate or shortening injection duration, the near-term fraction of the surface injection converted to deep recharge is likely to be increased due to the narrowed groundwater mounding size, which would be limited by the water-retarding effect of layer contrasts. This study has important implications for predicting and understanding multilayered groundwater mounding behaviours and associated water mass balance under the geologic stratification, and is expected to aid in optimizing the infiltration basin operation for aquifer recharge.

Moisture Migration and Recharge Pattern of Low-Permeability Thick Cohesive Soil in Northern Margin of the Jianghan Plain

“…The initial values of the fitted parameters (Table 4) for each layer were estimated using the Neural Network Prediction embedded in the model, and then, the parameters were fitted by fitting the observations measured for this layer in the field test site. We compared observed field measurements with the results of the HYDRUS-1D simulations using the mean absolute errors (MAEs) and root mean square errors (RMSEs) shown in Table 5 [18,22]. The average value of the simulation data is very close to the average value of observed data at each layer.…”

“…Cohesive soil water and solute transport studies not only consume a great deal of time but are also hard to do [11]. Various studies have attempted to use technologies such as hydrological geochemistry, stable isotopes, in situ monitoring, and numerical simulations to reveal the migration of soil moisture and the conversion relationships among rainfall, soil moisture, and groundwater [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28]. But almost all of these studies were located in arid and semi-arid areas with unconfined groundwater aquifers.…”

Developments and applications of the HYDRUS computer software packages since 2016

“…HYDRUS has been used to evaluate many of these technologies. The most common application has been studies of the hydrological functioning of drywells (e.g., Glass et al, 2020;Helles & Mogheir, 2023;Moreno et al, 2023;Sasidharan et al, 2018Sasidharan et al, , 2019Sasidharan et al, , 2020Sasidharan et al, , 2021 and infiltration basins (e.g., Cannavo et al, 2018;Glass et al, 2020;Lu et al 2021;Nieec et al, 2021;Qi et al, 2021). The reservoir boundary condition in HYDRUS, for which the water level in a well or infiltration basin depends on the rate of water injection or pumping along with water infiltration or exfiltration, has most often been used in these applications (e.g., Glass et al, 2020;Sasidharan et al, 2018Sasidharan et al, , 2019.…”