High-resolution investigation of the capillary transition zone and its influence on GPR signatures

Igel, Jan; Stadler, Sam; Günther, Thomas

doi:10.1109/icgpr.2016.7572603

Cited by 3 publications

(8 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Determining the depth to the groundwater table (DGWT) is crucial in water management because DGWT affects groundwater recharge, water supply to plants, and contaminant accumulation and transport (especially agrochemicals) [168,169]. Capillary fringe and the groundwater table fluctuate with seasonal variations, affecting agricultural water management, especially during the growing season.…”

Section: Groundwater Table and Capillary Fringe Reflectionmentioning

confidence: 99%

See 1 more Smart Citation

Ground-Penetrating Radar and Electromagnetic Induction: Challenges and Opportunities in Agriculture

et al. 2023

View full text Add to dashboard Cite

Information on the spatiotemporal variability of soil properties and states within the agricultural landscape is vital to identify management zones supporting precision agriculture (PA). Ground-penetrating radar (GPR) and electromagnetic induction (EMI) techniques have been applied to assess soil properties, states, processes, and their spatiotemporal variability. This paper reviews the fundamental operating principles of GPR and EMI, their applications in soil studies, advantages and disadvantages, and knowledge gaps leading to the identification of the difficulties in integrating these two techniques to complement each other in soil data studies. Compared to the traditional methods, GPR and EMI have advantages, such as the ability to take non-destructive repeated measurements, high resolution, being labor-saving, and having more extensive spatial coverage with geo-referenced data within agricultural landscapes. GPR has been widely used to estimate soil water content (SWC) and water dynamics, while EMI has broader applications such as estimating SWC, soil salinity, bulk density, etc. Additionally, GPR can map soil horizons, the groundwater table, and other anomalies. The prospects of GPR and EMI applications in soil studies need to focus on the potential integration of GPR and EMI to overcome the intrinsic limitations of each technique and enhance their applications to support PA. Future advancements in PA can be strengthened by estimating many soil properties, states, and hydrological processes simultaneously to delineate management zones and calculate optimal inputs in the agricultural landscape.

show abstract

Section: Groundwater Table and Capillary Fringe Reflectionmentioning

confidence: 99%

“…The soil above (i.e., unsaturated) and the soil below (i.e., saturated) the water table have different SWCs and thus have different ε r values [42,168,171,[174][175][176]. Therefore, due to the contrast in ε r at the interface, the water table can be identified in the radargrams [171,174,177].…”

Section: Groundwater Table and Capillary Fringe Reflectionmentioning

confidence: 99%

Ground-Penetrating Radar and Electromagnetic Induction: Challenges and Opportunities in Agriculture

et al. 2023

View full text Add to dashboard Cite

show abstract

“…Through knowledge of the waveguide's depth, velocities in each depth interval can be calculated and converted into permittivity values. The innovative technique applied here was developed by the Leibniz Institute for Applied Geophysics [56]. The velocity of the guided wave depends on the permittivity of the investigated deposits, which is strongly influenced by the water content.…”

Section: Gpr Downhole Profiling Using Guided Wavesmentioning

confidence: 99%

“…This technique was applied at the three locations of the corings (pink dots in Figure 1). An innovative way of measuring radar wave velocities at depth is the use of guided waves in a borehole [56], (Figure 2a). This method yields a continuous record of velocity with a regular downhole spacing of a few cm.…”

Section: Gpr Downhole Profiling Using Guided Wavesmentioning

confidence: 99%

Understanding Wetlands Stratigraphy: Geophysics and Soil Parameters for Investigating Ancient Basin Development at Lake Duvensee

et al. 2020

View full text Add to dashboard Cite

We present a case study of a bog showing how an integrated approach of multi-method geophysical sounding and local soil sampling can be used to identify, differentiate, and map organic sediments. Our study is based on ground-penetrating radar (GPR), electrical resistivity tomography (ERT) and shear-wave seismic (SH seismic) profiling applied to sediments of the former Lake Duvensee (northern Germany), nowadays a bog. This is a well-known locality for remains from the Mesolithic hunter-gatherers’ occupation that has been attracting archaeological and geoarchaeological research for100 years. The bog is embedded in low conductive glacial sand and is characterized by layers of different gyttja sediments (detritus and calcareous). The present study was conducted in order to identify the bog morphology and the thickness of the peat body and lake sediments, in order to understand the basin evolution. To validate the geophysical results, derived from surface measurements, drilling, soil analyses as well as borehole guided wave analysis of electromagnetic waves and Direct-Push (DP-EC) have been carried out and used for comparison. It turned out that each method can distinguish between sediments that differ in grain size, particularly between peat, lake sediments (gyttjas and mud) and basal glacial sand deposits. GPR is even able to separate between strongly and weakly decomposed peat layers, which is also clear considering resistivity variations in the ERT computation. From the association between geophysical properties and sediment analysis (e.g., water content and organic matter) different gyttjas were distinguished (coarse and fine) and seismic velocity was correlated to bulk density. Moreover, GPR and SH-wave seismics present different resolutions, confirming that the latter allows measurements, which are more focused on determining the extension of basal sand deposits, the depth of which is difficult to reach with GPR. Representative values of electrical resistivity, dielectric permittivity, and shear wave velocity have been determined for each sediment type and are therefore available to complete the investigation of wetland environments. Fine grained lake sediments were difficult to differentiate by the applied methods. This could be a result of high ionic concentration within the permanent groundwater body, partly masking the sediment properties.

show abstract

“…Secondly, oscillations of the reflected radar pulse due to the transition zone result in a series of bands representing the water table in the radar profile [4]. The top of the capillary fringe gives an earlier and more robust reflection than the actual water table [55,56]. The wetting front also has the same phase reflection as the water table [57].…”

Section: Gpr Theorymentioning

confidence: 99%

Distinguishing Capillary Fringe Reflection in a GPR Profile for Precise Water Table Depth Estimation in a Boreal Podzolic Soil Field

Illawathure

Cheema

Kavanagh

et al. 2020

Water

View full text Add to dashboard Cite

Relative permittivity and soil moisture are highly correlated; therefore, the top boundary of saturated soil gives strong reflections in ground-penetrating radar (GPR) profiles. Conventionally in shallow groundwater systems, the first dominant reflection comes from the capillary fringe, followed by the actual water table. The objective of this study was to calibrate and validate a site-specific relationship between GPR-estimated depth to the capillary fringe (DCF) and measured water table depth (WTDm). Common midpoint (CMP) GPR surveys were carried out in order to estimate the average radar velocity, and common offset (CO) surveys were carried out to map the water table variability in the 2017 and 2018 growing seasons. Also, GPR sampling volume geometry with radar velocities in different soil layers was considered to support the CMP estimations. The regression model (R2 = 0.9778) between DCF and WTDm, developed for the site in 2017, was validated using data from 2018. A regression analysis between DCF and WTDm for the two growing seasons suggested an average capillary height of 0.741 m (R2 = 0.911, n = 16), which is compatible with the existing literature under similar soil conditions. The described method should be further developed over several growing seasons to encompass wider water table variability.

show abstract

High-resolution investigation of the capillary transition zone and its influence on GPR signatures

Abstract: Index Terms

Cited by 3 publications

References 4 publications

Ground-Penetrating Radar and Electromagnetic Induction: Challenges and Opportunities in Agriculture

Ground-Penetrating Radar and Electromagnetic Induction: Challenges and Opportunities in Agriculture

Understanding Wetlands Stratigraphy: Geophysics and Soil Parameters for Investigating Ancient Basin Development at Lake Duvensee

Distinguishing Capillary Fringe Reflection in a GPR Profile for Precise Water Table Depth Estimation in a Boreal Podzolic Soil Field

Contact Info

Product

Resources

About