Use of Global Sensitivity and Data-Worth Analysis for an Efficient Estimation of Soil Hydraulic Properties

Anis Younes,Qian Shao,Husam Musa Baalousha,Marwan Fahs,Thierry Alex Mara

doi:10.3390/w12030736

Abstract

Accurate simulation of flow and contaminant transport processes through unsaturated soils requires adequate knowledge of the soil parameters. This study deals with the hydraulic characterization of soils using laboratory experiments. A new strategy is developed by combining global sensitivity analysis (GSA) and Bayesian data-worth analysis (DWA) to obtain efficient data that ensure a good estimation of the soil properties. The strategy is applied for the estimation of soil properties from a laboratory infiltration experiment. Results of this study show that GSA allows identification of regions and periods of high sensitivity of each parameter and thereby, the observations prone to contain information for a successful calibration. Further, the sensitivity depicts a nonlinear behavior with regions of high influence and regions of weak influence inside the parameter space. Bayesian DWA, performed a priori, allows to quantify the improvement of the posterior uncertainty of the estimated parameters when adding a type of measurement. The results reveal that an accurate estimation of the soil properties can be obtained if the target parameter values are located in the regions of high influence in the parameter space.

Highlights

Numerical models are essential tools for understanding the flow process through unsaturated soils, estimating subsurface recharge and/or prevent soil or water contamination
Bayesian data-worth analysis (DWA), performed a priori, allows to quantify the improvement of the posterior uncertainty of the estimated parameters when adding a type of measurement
The results reveal that an accurate estimation of the soil properties can be obtained if the target parameter values are located in the regions of high influence in the parameter space

Summary

Introduction

Numerical models are essential tools for understanding the flow process through unsaturated soils, estimating subsurface recharge and/or prevent soil or water contamination. The soil parameters are estimated by fitting model outputs to the laboratory observations. Several kinds of dynamic flow experiments, using different types of observations have been conducted to estimate the soil parameters. Among these experiments, one can mention one-step [1,2] and multistep [3,4,5,6,7] outflow experiments, infiltration experiments [8,9], extended multistep-outflow experiments [10], evaporation experiments [11,12], combined multistep-outflow

Methods

Results

Conclusion