Geospatial Analysis of Quality Indices of River Oba Water, Ogbomoso, Nigeria.

Abstract Many villages along the River Oba in Ogbomoso depend heavily on river water for crop irrigation, and water quality is important for maximum crop production. The River Oba water course in Ogbomoso was divided into four locations. River water samples were collected in three replicates from each of the designated locations during the dry and rainy seasons and analyzed for various quality parameters. The results indicated that the pH range was slightly acidic in the dry season but more alkaline during the rainy season. Calcium (Ca2+), magnesium (Mg2+), potassium (K+), sodium (Na+), bicarbonate (HCO3-), phosphate (PO3-P), electrical conductivity (EC), nitrate (NO3-N),sulphate (SO42-) and total dissolved solids (TDS) were within the recommended limits set for irrigation standard water, indicating that the river water in the designated locations were suitable for irrigation purposes. The water quality indicators, including SSP, RSC, KR, PI and SAR were all within safe limits for both seasons. Maps showing spatial variations of pH, electrical conductivity (EC), total dissolved solid (TDS), cations (Ca2+, Mg2+, Na+, and K+), anions (SO24−, NO3− -N, PO4−and HCO3−) were produced using geostatistics software. Overall, the findings suggest that the river Oba water in the four designated locations is suitable for irrigation purposes, and farmers in the areas can use it to grow their crops without adverse effects. However, continuous monitoring of water quality is vital to ensure that it remains within safe limits, and appropriate measures should be taken to address any issues that may occur.