Determination of Water Quality Index and Suitability of Three Major Dams in Ekiti State, Nigeria

Water Quality of Egbe, Ureje and Ero dams in Ekiti State was studied for a period of one year from November 2017 to October 2018. Twenty-four physicochemical parameters (temperature, conductivity, turbidity, pH, DO2, BOD, COD, alkalinity, turbidity, total dissolved solids, hardness, colour, phosphates, nitrates, nitrite, Cu, Pb, Mg, K, Mn, Fe, Na, Ca and Zn) were considered in the computation of Water Quality Index (WQI) based on Weighted Arithmetic Water Quality Index Method. ANOVA was used to evaluate the significant differences between water quality variables at the dams. T-test was used to show the variations of physico-chemical parame-ters and WQI between the two seasons. WQI in Egbe dam ranges from 118.00 - 164.67 (dry season) with a seasonal value of 145.69 and from 89.39 - 161.86 (rainy season) with a seasonal value of 120.59. In Ureje dam, WQI ranges from 101.88 - 164.76 (dry season) with seasonal value of 134.08 and from 96.61 - 138.36 (rainy season) with a seasonal value of 123.39 while in Ero, WQI ranges from 32.28 - 45.13 (dry season) with a seasonal value of 39.43 and from 52.12 - 106.22 (rainy season) with a seasonal value of 81.84. WQI of Egbe dam and Ureje dam during the dry and rainy seasons indicated poor water quality that is unfit for drinking while in Ero dam, the WQI during the dry season indicated good quality water while during the rainy season, the water in the dam was polluted. Our findings highlighted the deterioration of the dams due to anthropogenic activities and urbanization. There is an urgent need for proper management measures and suitable tools to restore the water quality of these dams. The formulas used to calculate the WQIs are easy to use thus providing a valuable tool for the accurate monitoring of water pollution in water bodies.