Efficient estimation of effective hydraulic properties of stratal undulating surface layer using time-lapse multi-channel GPR

Xicai Pan,Jiabao Zhang,Kurt Roth,Stefan Jaumann

doi:10.5194/hess-23-3653-2019

Abstract

Abstract. Multi-scale soil architectures in shallow subsurface are widespread in natural and anthropogenic depositional environments, and acquisition of the surface stratal structure and hydrological properties are essential in quantifying water cycling. Geophysical methods like ground-penetrating radar (GPR) can provide quantitative information like soil architecture and spatiotemporal soil water content distribution for the shallow layer. Concerning the informative multi-dimensional water flow in the surface layer with an undulating bottom at the plot scale, this study assesses the feasibility of efficiently estimating soil hydraulic properties using a few time-lapse multi-channel GPR observations, namely soil water storage and layer thickness of the surface layer, at reclamation land near an old river channel. We show that effective hydraulic properties of the surface layer can be obtained with a small number of time-lapse GPR measurements during a rainfall event. Additionally, we analyze the effect of some key factors controlling the informative lateral water redistribution on the results of the proposed approach using synthetic simulations.

Highlights

The exchanges of water and energy fluxes between the land surface and the atmosphere are strongly influenced by geomorphic features like landforms and soils (e.g., Corenblit et al, 2011)
We show that effective hydraulic properties of the surface layer can be obtained with a small number of time-lapse groundpenetrating radar (GPR) measurements during a rainfall event
This is mainly ascribed to the increasing intensity of lateral water redistribution, which results in a wider water dynamic range

Summary

Introduction

The exchanges of water and energy fluxes between the land surface and the atmosphere are strongly influenced by geomorphic features like landforms and soils (e.g., Corenblit et al, 2011). Soils in fluvial depositional environments exhibit a hierarchical stratal architecture at the scale of meters to hundreds of meters, and modeling subsurface water and mass transport is difficult due to large uncertainties in representation of the hydraulic properties (Huggenberger and Aigner, 1999). Apart from these natural depositional systems, land reclamation forms a surface layer overlying undulating landforms. Model predictions of water flow and nutrient transport in the surface layer are essential to agriculture It is challenging for the acquisition of such soil architecture information and soil hydraulic properties with the commonly used approaches using point measurements, as they are costly and time-consuming

Results

Discussion

Conclusion