The geology and groundwater condition of the area was studied with the aim of understanding their impact on the instability of the road in the study area. These include the petrology, geophysics and groundwater fluctuation (percentage in water table fluctuation). The methodology included geological field mapping, thin section preparation, resistivity and water table monitoring in dry and wet seasons. The study reveals that the road is underlain by schist, amphibolites and poorly fractured granite with quartz, biotite, hornblende and muscovite as the constituent minerals. The rocks have been altered through weathering to clayey minerals with resistivity values as low as 14 Ohm with the depth of weathering as high as 20 meter especially in the schist. The percentage of groundwater variation ranges between 154% and 2400% indicating medium to very high percentage of variation of groundwater fluctuation. These clay minerals absorb water and swell during the raining season and dry during the dry season. The result is the instability of the road pavement especially within the schist and where the elevation is lower. Proper design of the road and the provision of good drainage that will reduce the ingress of water are advised.

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This study examines the hydrochemical facies and groundwater flow patterns present in the crystalline basement aquifer of Minna in North Central Nigeria. Their aerial distribution was mapped and attempts to explain the controlling processes responsible for the various facies. Sixteen water samples were collected from wells and analyzed for various parameters including pH, total dissolved solids (TDS), electrical conductivity (Ec), K+, Na+, Ca+, Mg+, Cl-, HCO3-and SO4-using standard procedures of water analysis. The analytical results present the abundance of ions in the following order Na>Mg>Ca>K → Cl>SO4>HCO3. Chloride is the dominant anions found in the groundwater of the study area. Piper trilinear for the study area shows that there is a mixture of two types of water with variable concentrations of major ions. These are Na + K-Cl-SO4 water type and Ca + Mg-Cl-SO4 water types. This means that groundwater in the area is mainly made up of mixtures of the alkaline and alkaline earth metals and predominantly Cl-SO4-water type. Hydrochemical data analysis revealed four sources of solutes. The processes responsible for their enrichment include: chemical weathering, leaching of the overlying sediments, domestic activities, climatic condition and the flow pattern of the aquifer. The factors have contributed to the changes of the groundwater chemistry. Correlation analysis of the data set of hydrochemical constituents in the groundwater suggests that the aquifer is mainly controlled by TDS, Ec, pH, Na and chloride. There is positive strong correlation between Ec and TDS, TDS and Na, Ec and pH which indicates that there is strong evidence of anthropogenic activities on major ions present in the groundwater and weathering of sodium, potassium minerals in the study area. The groundwater flow trends dominantly N-S, NE-SW, NW-SE and somewhat E-W, which suggests that the groundwater in the study area is structurally controlled and the rocks were affected by the Pan-African Orogeny (600 ± 150Ma).