Quasi‐Saturated Layer: Implications for Estimating Recharge and Groundwater Modeling

• DOI: 10.1111/gwat.12916
• Publication Date: 2019-06-12T11:13:20Z
• Authors: Roger D. Gonçalves; Elias H. Teramoto; Bruno Z. Engelbrecht; Miguel A. Alfaro ...; Hung K. Chang; Martinus Th. van ...
• Keywords: Saturation (graph theory)

Abstract This study presents an extension of the concept “quasi‐saturation” to a quasi‐saturated layer, defined as uppermost dynamic portion saturated zone subject water table fluctuations. Entrapped air here may cause substantial reductions in hydraulic conductivity ( K ) and fillable pore water. Air entrapment is caused by rising table, usually result groundwater recharge. The most significant effects entrapped are recharge overestimation based on methods that use specific yield S y ), such fluctuation method (WTF), values. These impact estimation fluid flow velocities contaminant migration rates groundwater. In order quantify actual air, numerical simulations with FEFLOW (Version 7.0) model were carried out using layer for pilot area Rio Claro, Brazil. calculated rate represented 16% average precipitation over 8‐year period, approximately half estimates WTF method. amounted porosity 0.07, lower value 0.17 obtained experimentally . Numerical results showed volume can be very (0.58 fraction) hence significantly affect near table.