Subsurface water flow detection by time-lapse reflection GPR data

2020 ◽  
Author(s):  
Hemin Yuan ◽  
Majken Caroline Looms Zibar ◽  
Lars Nielsen
Keyword(s):  
Water Flow ◽  
Ground Penetrating Radar ◽  
Water Injection ◽  
Time Lapse ◽  
Water Infiltration ◽  
Subsurface Water ◽  
Integrated Analysis ◽  
Injection Hole ◽  
Geological Conditions ◽  
Ground Penetrating

<p>Understanding subsurface water flow is important as it e.g. controls contaminant transport, has an impact on the amount of aquifer recharge, and can be used for storm water management purposes. However, there do not exist many methods that can observe the water flow in the field. Furthermore, the flow patterns can be very diverse due to the complex geological conditions, e.g. faults, fractures, and heterogeneous permeability of the subsurface formations. In order to map the subsurface water flow in a chalk formation, we performed a water injection experiment in the Rørdal Quarry, Northeast Denmark. A total water volume of 700 liters was injected via a 50 cm deep hole within 8 hours. Around the injection hole, we conducted time-lapse GPR measurements along 6 inlines and 6 crosslines. Seven measurements campaigns were performed over an eight-hour time period. We analyze the time-lapse GPR reflection sections in order to investigate the variations of the different measurements. Initially, we subtract the repeated measurements and baseline measurements, which shows that some survey lines have clear changes after water injection, while others only show very small or no changes. To verify the differences, we pick travel times of selected horizons in the time-lapse data and compare them (cf. Truss et al., 2007; Allroggen et al., 2015). This analysis highlights the travel time variations imposed by the injected water. Moreover, we perform correlation analysis of the measurements before and after water injection. The correlation coefficients show relatively small values on the lines that exhibit clear differences, further confirming the differences caused by the water infiltration. Initial integrated analysis of the different results shows that the water mainly flows towards the southeast from the injection hole. This is consistent with the orientation of the fracture system observed in the reflection GPR profiles, indicating that the water flow is primarily controlled by the fractures.</p><p> </p><p>[1] Truss, S., Grasmueck, M., Vega, S., and Viggiano, D. A. 2007, Imaging rainfall drainage within the Miami oolitic limestone using high-resolution time-lapse ground-penetrating radar, Water Recourses Research, 43, W03405.</p><p>[2] Allroggen, N., Schaik, N.V., and Tronicke, J. 2015, 4D ground-penetrating radar during a plot scale dye tracer experiment, Journal of Applied Geophysics, 118, 139-144.</p>

Ground-penetrating radar surveys for the detection of preferential flow into soils

2020 ◽  
Author(s):  
Simone Di Prima ◽  
Thierry Winiarski ◽  
Rafael Angulo-Jaramillo ◽  
Ryan D. Stewart ◽  
Mirko Castellini ◽  
...  
Keyword(s):  
Ground Penetrating Radar ◽  
Preferential Flow ◽  
Three Dimensional ◽  
Time Lapse ◽  
Water Infiltration ◽  
Single Ring ◽  
Before And After ◽  
Infiltration Tests ◽  
Ground Penetrating ◽  
Preferential Flows

<p>Preferential flow is more the rule than the exception, in particular during water infiltration experiments. In this study, we demonstrate the potential of GPR monitoring to detect preferential flows during water infiltration. We monitored time-lapse ground penetrating radar (GPR) surveys in the vicinity of single-ring infiltration experiments and created a three-dimensional (3D) representation of infiltrated water below the devices. For that purpose, radargrams were constructed from GPR transects conducted over two grids (1 m × 1 m) before and after the infiltration tests. The obtained signal was represented in 3D and a threshold was chosen to part the domain into wetted and non-wetted zones, allowing the determination of the infiltration bulb. That methodology was used to detect the infiltration below the devices and clearly pointed at nonuniform flows in correspondence with the heterogeneous soil structures. The protocol presented in this study represents a practical and valuable tool for detecting preferential flows at the scale of a single ring infiltration experiment.</p>

Detecting stemflow-induced preferential flow pathways through time-lapse ground-penetrating radar surveys

2021 ◽  
Author(s):  
Ludmila Roder ◽  
Simone Di Prima ◽  
Sergio Campus ◽  
Filippo Giadrossich ◽  
Ryan D. Stewart ◽  
...  
Keyword(s):  
Ground Penetrating Radar ◽  
Preferential Flow ◽  
Overland Flow ◽  
Root Systems ◽  
Time Lapse ◽  
Water Infiltration ◽  
Blue Dye ◽  
Horizontal Distance ◽  
Tree Trunk ◽  
Ground Penetrating

<p>Research over the past several decades has shown that preferential flow is more the rule than the exception. However, our collective understanding of preferential flow processes has been limited by a lack of suitable methods to detect and visualize the initiation and evolution of non-uniform wetting at high spatial and temporal resolutions, particularly in real-world settings. In this study, we investigate water infiltration initiation by tree trunk and root systems. We carried out time-lapse ground penetrating radar (GPR) surveys in conjunction with a simulated stemflow event to provide evidence of root-induced preferential flow and generate a three-dimensional representation of the wetted zone.</p><p>We established a survey grid (3.5 m × 5 m, with a local slope of 10.3°), consisting of ten horizontal and thirteen vertical parallel survey lines with 0.5 m intervals between them. The horizontal lines were downslope-oriented. The grid was placed around a Quercus suber L. We collected a total of 46 (2 GPR surveys × 23 survey lines) radargrams using an IDS (Ingegneria Dei Sistemi S.p.A.) Ris Hi Mod v. 1.0 system with a 900-MHz antenna mounted on a GPR cart. Two grid GPR surveys were carried out before and after the artificial stemflow experiment. In the experiment, we applied 100 L of brilliant blue dye (E133) solution on the tree trunk. The stemflow volume of 100 L corresponded to 63.2 mm of incident precipitation, considering a crown projected area of 201 m<sup>2</sup> and a 1.3% conversion rate of rainfall to stemflow. Trench profiles were carefully excavated with hand tools to remove soil and detect both root location and size and areas of infiltration and preferential pathways on the soil profile.</p><p>The majority (84.4%) of artificially applied stemflow infiltrated into the soil, while the remaining 15.6% generated overland flow, which was collected by a small v-shaped plastic channel placed into a groove previously scraped on the downhill side of the tree. The 3D diagram clearly demarcated the dimension and shape of the wetted zone, thus providing evidence of root-induced preferential flow along coarse roots. The wetted zone extended downslope up to a horizontal distance of 3 m from the trunk and down to a depth of approximately 0.7 m. Put all together, this study shows the importance of accounting for plant and trees trunk and root systems when quantifying infiltration.</p>

On the usage of diffractions in ground-penetrating radar reflection data: Implications for time-lapse gas migration monitoring

Geophysics ◽  
2020 ◽  
Vol 85 (5) ◽  
pp. H83-H95
Author(s):  
Hemin Yuan ◽  
Majken C. Looms ◽  
Lars Nielsen
Keyword(s):  
Ground Penetrating Radar ◽  
Time Lapse ◽  
Flow Patterns ◽  
Water Infiltration ◽  
Small Scale ◽  
Essential Information ◽  
Surface Reflection ◽  
Imaging Approach ◽  
Diffraction Imaging ◽  
Ground Penetrating

Time-lapse ground-penetrating radar (GPR) measurements are used to image/monitor, for example, water infiltration, water table changes, and fluid/gas flow patterns. Although crosshole GPR is often preferred over surface-reflection GPR in such studies, its application is limited by the selected borehole geometry, which may be difficult to define in an optimal way, especially in experiments in which flow pathways are difficult to predict. Surface-reflection GPR data sets are generally faster to collect over relatively large areas and are therefore more efficient for covering the volume when a fast-moving tracer (e.g., gas) may infiltrate a heterogeneous subsurface medium. We have used a diffraction imaging approach on time-lapse surface-reflection GPR data to detect changes in radar wave velocity associated with gas (CO2) injected into a heterogeneous chalk succession. We initially test and evaluate the diffraction imaging approach on synthetic GPR data. Afterward, we apply the methodology to time-lapse GPR field data, and we evaluate the robustness of using information from diffractions in light of the obtained data quality. The synthetic tests indicate that diffractions provide essential information for delimiting the area affected by gas in the heterogeneous chalk section studied. Our field experiment shows that using the diffraction information alone allows for detection of gas-affected zones and, therefore, potential flow characteristics of gas movement. We infer that the CO2 flow patterns in our study most likely are determined by small-scale fractures rather than the porosity/permeability of the rock matrix. Moreover, the approach used may serve as an initial study for future more targeted experiments or for further detail-retrieving full-waveform inversion.

scholarly journals Quantitative high-resolution observations of soil water dynamics in a complicated architecture using time-lapse ground-penetrating radar

2015 ◽  
Vol 19 (3) ◽  
pp. 1125-1139 ◽  
Author(s):  
P. Klenk ◽  
S. Jaumann ◽  
K. Roth
Keyword(s):  
High Resolution ◽  
Water Content ◽  
Soil Water ◽  
Ground Penetrating Radar ◽  
Time Lapse ◽  
Test Site ◽  
Water Dynamics ◽  
Soil Water Dynamics ◽  
Capillary Fringe ◽  
Ground Penetrating

Abstract. High-resolution time-lapse ground-penetrating radar (GPR) observations of advancing and retreating water tables can yield a wealth of information about near-surface water content dynamics. In this study, we present and analyze a series of imbibition, drainage and infiltration experiments that have been carried out at our artificial ASSESS test site and observed with surface-based GPR. The test site features a complicated but known subsurface architecture constructed with three different kinds of sand. It allows the study of soil water dynamics with GPR under a wide range of different conditions. Here, we assess in particular (i) the feasibility of monitoring the dynamic shape of the capillary fringe reflection and (ii) the relative precision of monitoring soil water dynamics averaged over the whole vertical extent by evaluating the bottom reflection. The phenomenology of the GPR response of a dynamically changing capillary fringe is developed from a soil physical point of view. We then explain experimentally observed phenomena based on numerical simulations of both the water content dynamics and the expected GPR response.

scholarly journals Detecting infiltrated water and preferential flow pathways through time-lapse ground-penetrating radar surveys

2020 ◽  
Vol 726 ◽  
pp. 138511 ◽  
Author(s):  
Simone Di Prima ◽  
Thierry Winiarski ◽  
Rafael Angulo-Jaramillo ◽  
Ryan D. Stewart ◽  
Mirko Castellini ◽  
...  
Keyword(s):  
Ground Penetrating Radar ◽  
Preferential Flow ◽  
Time Lapse ◽  
Flow Pathways ◽  
Preferential Flow Pathways ◽  
Ground Penetrating

Application of Comprehensive Geological Exploration for Engineering Site Option

2011 ◽  
Vol 374-377 ◽  
pp. 2256-2260
Author(s):  
Sun Yong
Keyword(s):  
Ground Penetrating Radar ◽  
Geophysical Methods ◽  
High Density ◽  
Seismic Exploration ◽  
Accurate Analysis ◽  
Positive Role ◽  
Electrical Method ◽  
Study Results ◽  
Geological Conditions ◽  
Ground Penetrating

In the process of engineering prospective design and constructing, it is necessary to avoid the adverse impact of geological phenomena, such as fault, karst and landslide. Therefore, it’s important to choose a favorable project address by scientific and effective detection with engineering geological conditions. The main exploration method for geological conditions is the geophysical exploration, including: high density electrical method, ground penetrating Radar, seismic exploration method and so on. The discrimination result with a single geological method changes much, and it is difficult to make an accurate analysis of the geological conditions. So we should composite a variety of exploration methods. In this paper, it expounds the fundamental, the working method, data explanations of the high density electrical method and ground penetrating Radar firstly. And then it takes exploration of candidate sites of an aluminum waste disposal plant for example, the geological conditions of candidate sites are analyzed under the two geophysical methods. The study results of engineering site option have a positive role in guiding the work.

scholarly journals Preliminary results of the ground penetrating radar (GPR) prospection in the area of the prehistoric flint mine Borownia, southeastern Poland

2014 ◽  
Vol 31 (2) ◽  
pp. 123-132
Author(s):  
Radosław Mieszkowski ◽  
Fabian Welc ◽  
Janusz Budziszewski ◽  
Witold Migal ◽  
Anna Bąkowska
Keyword(s):  
Ground Penetrating Radar ◽  
Central Zone ◽  
Archaeological Site ◽  
Depth Range ◽  
Good Resolution ◽  
Underground Structures ◽  
Preliminary Results ◽  
Geological Conditions ◽  
Prehistoric Mining ◽  
Ground Penetrating

Abstract Preliminary results of GPR field prospection carried out in the area of the prehistoric mining field Borownia (Ćmielów, Ostrowiec Świętokrzyski District) are presented. This mining field forms a belt (30-50 m wide and 700 m long), starting from the valley edge of the Kamienna River southeastwards. Southeastern and western parts of the site have preserved the original post-exploitation relief. Geology of the Borownia mining field was examined and acquired radiograms revealed three distinct zones of anomaly concentrations. The central zone (B) is clearly a fragment of the prehistoric mining field, confirmed not only by the GPR sounding but also by archeological surveys. The other two zones have not yet been investigated in detail yet but their surface and archaeological examination may determine only whether their underground structures are natural or have been created by humans. Data obtained during the GPR prospection at the Borownia archaeological site confirmed usefulness of 100, 250 and 500 MHz antennas. The relatively large depth range and good resolution are due to favorable geological conditions.

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