Electrical resistivity tomography monitoring of two managed aquifer recharge ponds in the alluvial aquifer of the Llobregat River (Barcelona, Spain)

Abstract

Over the past 20 years, there has been growing interest in the use of the subsurface for water storage using shallow ponds, where water is infiltrated to the subsurface and subsequently groundwater is recovered from pumping wells. This scheme is designed as a surface‐managed aquifer recharge. Llobregat artificial recharge ponds are managed aquifer recharge systems located in alluvial aquifers near Barcelona, with strong significance for water supply to the city. The recharge ponds have shown low infiltration rates since the beginning (e.g., Ca n'Albareda) and a significant decrease after some months (e.g., Sant Vicenç). Consequently, different methodologies were designed for monitoring the systems and evaluating the effectiveness of the selected areas and maintenance procedures. For this purpose, we combined the use of electrical resistivity tomography with standard hydrogeological methodologies, including water table monitoring from piezometers and infiltration tests. The combination of direct and indirect methods have allowed us to improve the diagnosis of the subsurface involved in the managed recharge system. The electrical resistivity tomography technique has shown to be a cost‐effective and high‐resolution tool, flexible and well adaptable for surveying at different scales without disturbing the recharge process. As a consequence, we demonstrate the usefulness of electrical resistivity tomography imaging to unveil hydrogeological heterogeneities and monitoring infiltration, the effect of clogging and clean‐up processes in surface‐managed aquifer recharge projects.

Review and Challenges in the Geophysical Mapping of Coal Mine Water Structure

“…In the field measurement, all electrodes must be placed on each measuring point in the observation section or plane, and then, the instrument automatically utilizes program-controlled electrode conversion device and a microcomputer engineering electrical measuring instrument, to realize rapid and multichannel automatic data acquisition, as shown in Figure 7. According to the arrangement of the electrodes, the high-density resistivity method can be divided into different devices, among which the most commonly used ones include Wenner (Wenner α, Wenner β, and Wenner γ), dipole-dipole, pole-dipole, and Wenner-Schlumberger devices [58][59][60] (Figure 8). Figure 9 shows an example of goaf detection using the high-density resistivity method.…”

Geophysical Characterization of Hydraulic Properties around a Managed Aquifer Recharge System over the Llobregat River Alluvial Aquifer (Barcelona Metropolitan Area)

“…A pilot excavation was placed in a pond sector to improve the system and two infiltration tests were carried out using the same procedure: one in the original surface (It 1 ) and the other over the excavated area (It 2 ). The two tests' results have already been used in previous research on monitoring of clogging process and maintenance actions outcomes [30].…”

“…Among others, geophysical measurements are often spatially exhaustive and can be acquired at relatively low cost, making them very useful for supplementing conventional measurements. Electrical resistivity tomography (ERT) and frequency domain electromagnetics (FDEM) are geophysical methods particularly useful for studies of hydrologic processes in the near-surface because of the high correlation between electrical conductivity and water saturation in the vadose zone [20][21][22][23][24][25][26][27], for surface MAR facilities monitoring [28][29][30] and for geological heterogeneities characterization in alluvial aquifers [31]. When geophysical measurements are used in an early phase of site investigations, they may provide useful input to the placement of new research boreholes or wells.…”

Controls on flood managed aquifer recharge through a heterogeneous vadose zone: hydrologic modeling at a site characterized with surface geophysics

“…However, the impact of sediment texture on recharge becomes even more complex within the vadose zone. As in the saturated zone, interconnected coarse-grained sediments can act as preferential recharge pathways during MAR, as revealed through time-lapse geophysical imaging of flood-MAR (Sendrós et al, 2020b). By contrast, MAR modeling reveals that, in some cases, these sediments actually inhibit flow as capillary barriers (Sallwey et al, 2018;Russo et al, 2022).…”