Mapping of Agricultural Subsurface Drainage Systems Using a Frequency-Domain Ground Penetrating Radar and Evaluating Its Performance Using a Single-Frequency Multi-Receiver Electromagnetic Induction Instrument

Abstract

Subsurface drainage systems remove excess water from the soil profile thereby improving crop yields in poorly drained farmland. Knowledge of the position of the buried drain lines is important: 1) to improve understanding of leaching and offsite release of nutrients and pesticides, and 2) for the installation of a new set of drain lines between the old ones for enhanced soil water removal efficiency. Traditional methods of drainage mapping involve the use of tile probes and trenching equipment. While these can be effective, they are also time-consuming, labor-intensive, and invasive, thereby entailing an inherent risk of damaging the drainpipes. Non-invasive geophysical soil sensors provide a potential alternative solution. Previous research has focused on the use of time-domain ground penetrating radar (GPR), with variable success depending on local soil and hydrological conditions and the central frequency of the specific equipment employed. The objectives of this study were 1) to test the use of a stepped-frequency continuous wave (SFCW) 3D-GPR (GeoScope Mk IV 3D-Radar with DXG1820 antenna array) for subsurface drainage mapping, and 2) to evaluate the performance of a 3D-GPR with the use of a single-frequency multi-receiver electromagnetic induction (EMI) sensor (DUALEM) in-combination. The 3D-GPR system offers more flexibility for application to different (sub)surface conditions due to the coverage of wide frequency bandwidth. The EMI sensor simultaneously provides information about the apparent electrical conductivity (ECa) for different soil volumes, corresponding to different depths. This sensor combination was evaluated on twelve different study sites with various soil types with textures ranging from sand to clay till. While the 3-D GPR showed a high success rate in finding the drainpipes at five sites (sandy, sandy loam, loamy sand, and organic topsoils), the results at the other seven sites were less successful due to limited penetration depth (PD) of the 3D-GPR signal. The results suggest that the electrical conductivity estimates produced by the inversion of ECa data measured by the DUALEM sensor could be a useful proxy to explain the success achieved by the 3D-GPR in finding the drain lines. The high attenuation of electromagnetic waves in highly conductive media limiting the PD of the 3D-GPR can explain the findings obtained in this research.

Characterize Basin‐Scale Subsurface Using Rocket‐Triggered Lightning

“…Over the past decades, electrical magnetic (EM) surveys have been developed based on airborne, controlled‐source, or natural‐source methods (e.g., Magnetotellurics (MT) and Audio‐frequency MT (AMT)). They have been valuable tools for studying hydrogeological features such as wetlands (McLachlan et al., 2021), aquifers (Koganti et al., 2020; Korus, 2018), volcanoes and geothermal areas (Árnason et al., 2010), hydrocarbon reservoirs (He et al., 2010; Mansoori et al., 2016), ore deposits (Tuncer et al., 2006), salinity mapping (Cox et al., 2012), and fault systems (Tietze & Ritter, 2013). Generally, the artificial EM surveys are suitable for shallow depths and small areas, while the MT yields general locations of anomalies at depth with little detail.…”

Locating drainage tiles at a wetland restoration site within the Oak Openings region of Ohio, United States using UAV and land based geophysical techniques

“…In the absence of such maps, locating these drainage tiles by traditional probing using exible metal rod and excavations are tedious and destructive (Ruark et al, 2009). The use of non-invasive techniques including vegetation analysis (Tlapáková et al, 2015), aerial photographs, remote sensing (Williamson et al, 2019) and geophysical methods such as ground penetrating radar (Allred et al, 2004;Chow and Rees, 1989;Koganti et al, 2020) if applicable, provide a more e cient approach for locating the tiles. This study further evaluates the use of both unmanned aerial vehicle (UAV)-based visible and thermal infrared imaging and land-based ground penetrating radar for locating drainage tiles and mapping their network at a large eld scale within the Oak Openings Region of Northwestern Ohio.…”

“…Hence, the need to keep exploring the use of conventional ground-based geophysical techniques including magnetic gradiometry (Allred et al, 2004;Rogers et al, 2005) and ground penetrating radar (Chow and Rees, 1989). Ground penetrating radar (GPR) has been widely used to successfully locate drainage tiles and map their network relying on the contrast in the dielectric properties of the soil around the tile and that of the air, water or a combination of both within the tiles (Allred et al, 2005;Allred et al, 2004;Allred, 2013;Koganti et al, 2020;Wai-Lok Lai et al, 2018). Detecting drainange tiles using GPR is possible in a wide variety of soil types and properties with reported applications in ne and coarse loamy glacial till, sandy glacio uvial and clayey glaciomarine sediments (Allred et al, 2004;Chow and Rees, 1989).…”