A three-dimensional seismic response analysis of an asphalt concrete face rockfill dam constructed on a thick overburden layer at the upper reservoir of a pumped-storage power station was conducted using the nonlinear finite element method. The study focused on evaluating the seismic safety of the dam body and the seepage control system. The results indicated that, under the design seismic load, the peak dynamic displacements of the dam body in the horizontal, vertical, and axial directions were 23.87 cm, 10.44 cm, and 26.13 cm, respectively, and the peak accelerations were 2.98 m/s$^2$, 2.01 m/s$^2$, and 2.98 m/s$^2$, respectively. The maximum permanent deformations in the same directions were 18.42 cm, -61.60 cm, and -5.61 cm/18.69 cm, with a settlement ratio of 0.37%. For the asphalt concrete face slab, the peak dynamic displacements in the horizontal, vertical, and axial directions were 23.87 cm, 9.42 cm, and 24.86 cm, respectively. The maximum and minimum principal strains of the face slab after the earthquake were 1.29% and -0.74%. The maximum principal tensile strains of the geomembrane at the reservoir bottom during and after the earthquake were -1.43% and -1.50%. Under the seismic check conditions, the dynamic responses of the dam body, face slab, and geomembrane increased. Comprehensive analysis of the results shows that the seismic response patterns of the dam are consistent with the general characteristics of rockfill dams on thick overburden layers. The dynamic response of the asphalt concrete face slab around the reservoir and the geomembrane at the reservoir bottom did not exceed their respective safety thresholds, indicating that the dam exhibits high seismic safety under seismic loading.

Rapid urbanization in Egbeagu Amansea of Nigeria poses a significant threat to the maintenance of groundwater quality, thus creating a requisite to support effective water management with comprehensive data. This study investigated the hydro-chemical characteristics of groundwater in Awka North, Anambra State. Samples of groundwater were collected from seven boreholes and a hand-dug well during the wet season. These samples were analyzed for physiochemical parameters, such as pH, electrical conductivity (EC), total dissolved solids, total hardness, major cations (Ca$^{2+}$, Mg$^{2+}$, Na$^{+}$, and K$^{+}$), and anions (HCO$_{3}^{-}$, Cl$^{-}$, SO$_{4}^{2-}$, and NO$_{3}^{-}$). The study employed standard hydro-chemical methods, such as Piper and the United States salinity (USSL) diagrams to characterize water types and determine the dominant hydro-chemical processes influencing groundwater chemistry. The results of the Piper trilinear diagram revealed that bicarbonate (HCO$_{3}^{-}$ + CO$_{3}^{2-}$) was the dominant anion, hence reflecting carbonate dissolution in the aquifer. Sodium adsorption ratio (SAR) values ranged from 0.53–0.674, thus classifying all samples in the low (S1) category and indicating minimal sodium hazard for soil. EC values spanned 44–130.6 $\mu$S/cm, placing samples in the low (C1) to medium (C2) categories. The study confirms that the groundwater in the study area is suitable for drinking and irrigation purposes.