Using Time-Lapse Resistivity Imaging Methods to Quantitatively Evaluate the Potential of Groundwater Reservoirs

Abstract

In this study, we attempt to establish an alternative method for estimating the groundwater levels and the specific yields of an unconfined aquifer for the evaluation of potential groundwater reservoirs. We first converted the inverted resistivity into the normalized water content. Then, we inverted the parameters of the Brooks-Corey model from the vertical profiles of the water content by assuming that the suction head was in proportion to the elevation regarding a predefined base level. Lastly, we estimated the groundwater level, the theoretical specific yield, and the specific yield capacity from the Brooks-Corey parameters at every survey site in the study area. The contour maps of the time-lapse groundwater levels show that the groundwater flows downstream, with a higher hydraulic gradient near the river channel than in the area away from the main channel. We conclude that the estimated maximum specific yield capacities are consistent with that derived from the pumping tests in the nearby observation well. Additionally, the specific yield capacities are only three quarters to two thirds of the theoretical specific yields derived from the difference between the residual and saturated water contents in the Brooks-Corey model. We conclude that the distribution pattern of the specific yields had been subjected to the distribution of natural river sediments in the Minzu Basin, since the modern channel was artificially modified. Although we had to make some simple assumptions for the estimations, the results show that the surface resistivity surveys provide reasonable estimations of the hydraulic parameters for a preliminary assessment in an area with few available wells.

Electrical resistivity imaging data for hydrogeological and geological hazard investigations in Taiwan

“…The primary focus of this work data was hydrogeological, land subsidence, and geological structural investigations such as aquifer characterization, groundwater level detection, groundwater recharge zone identification, hydraulic parameter estimation, clay layer identification, and fault detection [ [1] , [2] , [3] , [15] ]. The hydraulic parameter was estimated, and groundwater levels were monitored using time-lapse ERI measurement data from the Yilan, Minzu, Taichung, and Pingtung alluvial fans.…”

“… [1] for the Pingtung basin, Chang et al. [2] for the Minzu basin, and Jordi et al. [3] for the Taichung basin in order to estimate hydraulic parameters and characterize the aquifer systems.…”

Research on the Monitoring of Overlying Aquifer Water Richness in Coal Mining by the Time-Lapse Electrical Method

“…Compared with conventional geophysical methods, time-lapse methods like the resistivity method can obtain the dynamic characteristics of underground structures in the study area, and it is more convenient and cost-effective than the drilling method [4]. Therefore, combined with the sensitivity of the ERT method to hydrogeology, it has been effectively applied to assess the seasonal recharge characteristics of groundwater and potential underground reservoirs [17,22], monitor groundwater decline and aquifer rebound [23], and monitor the relationship between groundwater and surface water recharge and discharge [24], proving its feasibility in groundwater monitoring. However, despite the numerous practical applications mentioned above, the application used on the water richness of overlying strata in mining areas is very meaningful but there is not enough researches.…”