Effects of Seasonal Variations on Groundwater Facies Classification in Otte, Southwestern Nigeria

Groundwater assumes different composition from place to place due to continuous interactions with earth materials and change in climatic condition. These factors place water bodies into different class of suitability for human consumption. This study evaluated effects of seasonal variation on chemical budget of groundwater samples from Otte, Southwestern Nigeria. This was with a view to determining the dominant ions and sources of pollutants. A total of 37 samples were collected for physicochemical analysis. Physical evaluation revealed that turbidity, color, electrical conductivity and PH are higher in order of degree pollution at the wet season than dry season. Hydrochemical analyses revealed ionic dominance in the order of Ca+2>Mg+2>Na+ and Cl->HCO-3>SO4-2for both seasons which is an indication of no change in seasonal effect. Also, CaHCO-3 is the major water facie while weathering of rock forming minerals is the predominant source of pollutants for both seasons. Thus, the study concluded that no significant variation in the chemical budget and mobilization of ions as a result of seasonal change. However physical parameters like color and turbidity show increase in the wet season while conductivity remain constant.