Vadose zone modeling to identify controls on groundwater recharge in an unconfined granular aquifer in a cold and humid environment with different meteorological data sources

Abstract

Groundwater recharge (GR) is a complex process that is difficult to quantify. Increasing attention has been given to unsaturated zone modeling to estimate GR and better understand the processes controlling it. Continuous soil-moisture time series have been shown to provide valuable information in this regard. The objectives of this study were to (i) analyze the processes and factors controlling GR in an unconfined granular aquifer in a cold and humid environment and (ii) assess the uncertainties associated with the use of data from different sources. Soil moisture data monitored over three years at three experimental sites in southern Quebec (Canada) were used to calibrate the HYDRUS-1D model and to estimate ranges of possible GR in a region where groundwater is increasingly used as a source of fresh water. The simulations identified and quantified important factors responsible for the near-surface water balance that leads to GR. The resulting GR estimates from 2016 to 2018 showed marked differences between the three sites, with values ranging from 347 to 735 mm/y. Mean GR for the three sites was 517 mm/y for 2016–2018 and 455 mm/y for the previous 12-year period. GR was shown to depend on monthly variations in precipitation and on soil textural parameters in the root zone, both controlling soil-water retention and evapotranspiration. Monthly recharge patterns showed distinct preferential GR periods during the spring snowmelt (38–45% of precipitation) and in the fall (29% of precipitation). The use of different meteorological datasets was shown to influence the GR estimates.

Spatial datasets of 30-year (1991–2020) average monthly total precipitation and minimum/maximum temperature for Canada and the United States

“… These gridded temperature and precipitation datasets are commonly used to append historical climate estimates to remote locations for diverse applications, such as streamflow [ 3 ], groundwater recharge [ 4 ], droughts [ 5 ], heatwaves [ 6 ], flooding [ 7 ], river thermal regimes [ 8 , 9 ], frost [ 10 ], ecology [ 11 ], and other analyses. These datasets can be used as an average or baseline to evaluate trends, climate events, and provide context for year-to-year variability in temperature and precipitation.…”

“…These gridded temperature and precipitation datasets are commonly used to append historical climate estimates to remote locations for diverse applications, such as streamflow [ 3 ], groundwater recharge [ 4 ], droughts [ 5 ], heatwaves [ 6 ], flooding [ 7 ], river thermal regimes [ 8 , 9 ], frost [ 10 ], ecology [ 11 ], and other analyses.…”

Physical Soil Parameter and Resistivity Profile in the Vadose Zone: Preliminary Result of Groundwater Recharge Study

“…Since this process took a long journey, their occurrences in aquifers are prone to decrease due to natural and anthropogenic factors. Eventually, a comprehending groundwater recharge initiative becomes a fundamental task in managing groundwater resource sustainability on a watershed scale [11].…”

“…Tree roots also known as rhizosphere are part of the vadose zone, which has continuously been studied as a multi-disciplinary approach in hydro(geo)logy, ecohydrology, and soil-plant science due to its complexity and reclaimed status as the critical part that poses potential threats to the saturated or water table beneath [4,5,6]. Invasive methods such as Induced Polarization, Electrical Tomography, and Ground Penetrating Radar have been used to characterize spatial tree root zone distribution and also compare it with the soil's physical properties, notably soil water content, permeability, and total porosity [7,8,9], hence the evaporation and or percolation processes can be approached by simulating numerically the soil properties profile [10,11,12]. This paper describes the finding of an early result of electrical resistivity tomography measurement to map tree root zone combined with soil properties collected using core drilling at a surface area where two types of tree species were planted: Pinus merkusii and Melia azedarach, in volcanic environments.…”