EZEILO, F. E.
OBA, K. M.
Department of Civil Engineering
Rivers State University of Science and Technology
Port Harcourt, Nigeria


Abstract
In this study, an attempt has been made to develop water quality index (WQI) for Orashi River using twelve water quality parameters: Temperature, Turbidity, pH, Total Dissolved Solids (TDS), Biochemical Oxygen Demand (BOD), Dissolved Oxygen (DO), Total hardness, Calcium hardness, Magnesium hardness, Iron (Fe), Faecal Coliform count, and Bacterial count, measured at five sampling stations along the river. The water quality index (WQI) was formulated by modifying the Canadian Council of Ministers of the Environment Water Quality Index (CCMEWQI). It was observed that the WQI for Orashi River varied from Marginal to Poor. The average WQI obtained was 48.5, while the WQI for the individual stations varied between 46.7 and 51.4. To validate the index, the above values obtained with the WQI were compared with aggregated sample values (raw values). The percentage error between observed WQI and predicted WQI was 2.8%. This variation is within tolerable limits, thereby attesting to the validity of the results. It was observed that the main cause of water quality impairment was due to lack of proper sanitation, unprotected river sites, anthropogenic activities and direct defecation into the stream by the residents. Recommendations for effective water quality management of Orashi River include, constant water quality monitoring, wastes discharged into the river to be treated and certified safe before disposal, improved watershed management to control or eliminate non-point source of pollution, and provision of conveniences to communities to prevent direct defecation into the river.


International Journal of Environmental Issues Vol.12 No. 1&2
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