THE INFLUENCE OF URBAN LAND USE ON THE WATER QUALITY OF OTAMIRI RIVER FOR MUNICIPAL SUPPLY

Abstract

Water quality levels of Otamiri River was studied to seek explanations for the variations of water quality indicators in the river and also tried to evaluate the influence of urban land use activities and season on the water quality and to examine the water quality of Otamiri River for agricultural and domestic uses. Water sampling and laboratory analyses were carried out using standard procedures to determine the concentrations of selected parameters in the sample. The data obtained ranged from 21.10 to 98.00µS/cm for Electrical Conductivity, 9.70 to 45.10mg/l for TDS, 5.60 to 20.80mg/l total hardness, 0.00 to 3.06mg/l NO3- , 0.15 to 6.50mg/l PO4, 0.00 to 12.63mg/l SO4 2- , and 14.48 to 32.96mg/l Cl- . Other results ranged from 12.03 to 19.26mg/l BOD5, TSS 40.50 to 1793.50mg/l, turbidity 7.86 to 96.40NTU and pH 6.48 to 6.90 at 29?C. The data clearly show that areas outside the influence of urban activities still maintain their pristine environmental conditions with water quality parameters falling within permissible limits. The water from these areas can sustain aquatic life and are safe for human consumption. However, the results further showed that the midstream area that receive wastes from urban land use activities was polluted with parameters such as NO3- , PO4- , Cl- , BOD5, TDS, and COD being higher than the permissible limit. This demonstrates the influence of urban land use on the water quality of Otamiri River.