Characterization of a fractured aquifer through potential geophysics and physicochemical parameters of groundwater samples

The heterogeneity of fractured and karstic aquifers is generally ignored, and not having an understanding of the hydrogeological evolution and functioning of these could potentially result in wrong water resource management practices. The geophysical methods are useful tools for hydrogeological investigations, helping in the detection of porosity and permeability zones in the subsoil that are important properties in the aquifer characterization. The combination of these with the measurement in situ of the physicochemical parameters of the groundwater can offer a detailed knowledge of the aquifer system. The study was conducted in the municipality of Tula, Tamaulipas, Mexico, where airborne geophysical data were analyzed. Then, 17 groundwater sampling points were established to measure physicochemical parameters (pH, Electric Conductivity and REDOX) and ionic concentration, to associate structures with zones of recharge, transport or storage of groundwater. It was found that the area with the greatest potential for groundwater recharge is located at the N and NW of the study area, with structures trending N–S and NE–SW, which favor the flow of groundwater to the convergence zone, located to the S of the study area. Also, near to the convergence zona, a fracture system with perpendicular direction to the groundwater flow acts as a barrier and divides the aquifer. Due to the chemistry characteristics of the groundwater, it was concluded that the main contribution of groundwater is through structures crossing evaporite rocks of the Guaxcama Formation.