Classification of river water quality in Ogun and Ona River Basins, Nigeria using CCME framework: Implications for sustainable environmental management

AbstractThe limitation posed by the traditional comparison of water quality indicators with guide values or acceptable limits has necessitated the use of water quality indices. Most water quality indices depend on use of weighting factors which have the problem of subjectiveness. These limitations have been overcome by the Canadian Council of Ministers of the Environment (CCME) framework which estimates scope, frequency and amplitude of impairment to water quality status. The framework was used to create 3 Water Quality Indices (WQI) for Agricultural, Health and Environmental evaluation of water quality in the Ogun and Ona Basins which cover 8 rivers, with 27 gauging locations. 32 physical, chemical and microbiological water quality indicators were monitored over a 12-month period. The CCME scores showed that Health WQI ranged between 21 and 42 which rank all the rivers and locations as poor. Environmental WQI was 41–76 which ranks the basins between marginal and fair, while the Agricultural WQI was betwe...