This study assesses the impacts of recent climate changes on drought-affected areas and the occurrence of droughts during different cropping seasons of Nigeria using the standardized precipitation evapotranspiration index (SPEI). The crop growing seasons are considered because the droughts for those periods are more destructive to national agricultural production. The Mann–Kendall test and binary logistic regression were used to quantify the trends in drought-affected areas and the occurrence of crop droughts with different areal extents, respectively. Gauge-based gridded rainfall and temperature data for the period 1961–2010 with spatial resolutions of 0.5° were used. Results showed an increase in the areal extent of droughts during some of the cropping seasons. The occurrences of droughts, particularly moderate droughts with smaller areal extents, were found to increase for all of the seasons. The SPEI values calculated decreased mostly in the regions where rainfall was decreasing. That is, the recent changes in climate were responsible for the increase in the occurrences of droughts with smaller areal extents. These trends in climate indicate that the occurrence of larger areal extent droughts may happen more frequently in Nigeria in the future.

The hydrogeochemistry of aquifers in the western Sokoto basin was assessed. The objective of this study is to identify the impact of geological variability on groundwater hydrochemistry and the mechanisms controlling the hydrochemistry of aquifers. Univariate statistics (several samples ANOVA), Pearson’s (r), and multivariate statistics-hierarchical cluster analysis (HCA) and Factor analysis (FA) were used to interpret the hydrochemistry of aquifers. Subsequently, geochemical modeling was applied to assess the saturation index (SI) of rock minerals. Forty groundwater samples were collected from Gwandu (n = 20) and Illo (n = 20) formations. ANOVA results indicated that geological variability exerted a considerable impact on groundwater in Gwandu and Illo aquifers. It is characterized by a substantial amount of Ca²⁺, Mg²⁺, SO₄²⁻, HCO₃⁻, Na⁺, and K⁺. The hydrogeochemical facies indicated mixing conditions. FA and correlations analysis further revealed that groundwater received the noticeable influence of silicate weathering and dissolution of carbonates. There were significant differences in SI values for chrysotile, goethite, gypsum, H₂(g), H₂O(g), H₂S(g), illite, and sepiolite minerals between the two geologic environments. Positive SI values for gibbsite were noticed in eleven sampling locations, indicative of potential recharge zones. Likewise, all the sampling locations have positive values for K-feldspar and are supersaturated with mica, suggesting both discharge and transition zones. The HCA classified aquifers into three clusters based on their hydrogeochemical characteristics. Geochemical modeling, univariate, and multivariate analyses are user-friendly tools for hydrochemical analysis.

Groundwater resources benefits to human activity for developing country. Groundwater contamination is crucial, particularly due to the amount of leakage and spillage of hydrocarbon liquids such as light non-aqueous phase liquids (LNAPLs), resulting in contaminated the groundwater and unsafe for domestic and agriculture activities. Penetration of hydrocarbon liquids into groundwater can be seen through double-porosity soil. Therefore, this paper investigates the penetration of LNAPLs in double-porosity soil using computer modelling to calibrate and validate from physical experiment data. These computer modelling and physical experiment studies discuss the pattern and rate of LNAPL penetrations by employing PetraSim commercial software and digital image processing technique (DIPT) by using acrylic glass cylinder, mirror and Nikon D90 digital camera. The LNAPL volume of 70 ml and 150 ml were poured instantaneously onto the surface of soil sample for calibration and validation purposes. The penetration pattern in double-porosity were monitored and recorded using digital camera at pre-determine time intervals. The images were processed using Surfer software and Matlab routine to plot the LNAPL penetration pattern. PetraSim simulation was used to calibrate and validate the penetration of LNAPL through double-porosity soil with physical experiment data. As a result, the PetraSim results valid with the physical experiment results. The Nash-Sutcliffe efficiency results more than 0.50 with percentage of differences for calibration and validation are 1.34% and 5.47% between physical experiment and PetraSim simulation. As a conclusion, PetraSim simulation can be used for further investigation on LNAPL penetration through subsurface soil.