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Vadose zone lag time effect on groundwater drought in a temperate climate

Journal Contribution - Journal Article

An essential factor in the propagation of drought, from meteorological drought to groundwater drought, is the delay between a precipitation event and the groundwater recharge reaching the groundwater table. This delay, which mainly occurs in the vadose zone of the hydrological cycle, is often poorly studied. Therefore, this paper proposes a method for estimating the spatially distributed delay in the vadose zone using the kinematic wave approximation of Richards' equation combined with the van Genuchten-Burdine and Brooks-Corey parametric model. The modeling was approached (1) using a detailed parametrization of soil and geological layers and (2) using lumped hydraulic and physical properties of geological layers. The results of both approaches were compared against the physically based flow model Hydrus-1D. This analysis shows that using a detailed parametrization of soil and geological layers results in good comparison, with a Nash-Sutcliffe efficiency of 0.89 for Brooks-Corey and 0.80 for van Genuchten-Burdine. The delay result of the Brooks-Corey model was incorporated into the groundwater recharge time series from 1980 to 2013 to analyze the effect of this delay on groundwater drought. The results show that the delay in the vadose zone influences groundwater drought characterization features such as the number, duration, and intensity of drought events.

Journal: Water (Switzerland)
ISSN: 2073-4441
Issue: 8
Volume: 12
Publication year:2020
Keywords:Drought propagation, Groundwater drought, Groundwater recharge delay, Kinematic wave approximation, Vadose zone
CSS-citation score:1
Accessibility:Open