ASSESSMENT OF WATER QUALITY OF MAJOR RIVERS IN GONDAR TOWN, ETHIOPIA

Abstract

Ethiopian highlands are highly populated by human habitation along the river banks. The protection of land and water is necessary for the survival of the human being. The purpose of this study is to evaluate the water quality of the major rivers in Gondar town. A total of ten water samples were collected along the rivers based on the accessibility and by covering domestic, agricultural and industrial areas. The rate of flow is very low and the samples were collected in the dry season. The samples were properly conserved and transferred to the Central Gondar Zone Water Quality and Pollution Control Laboratory for further analysis. The samples were analyzed for eight parameters such as temperature, power of hydrogen, electrical conductivity, total suspended solids, total dissolved solids, dissolved oxygen, phosphate and nitrate. Water quality was assessed by analyzing these parameters and the spatial distribution map was generated by open-source Quantum Geographical Information System (QGIS) software by Inverse Distance Weighted (IDW) interpolation method and correlation was made by using SPSS software. From this study the spatial distribution of water pollution was identified in the rivers, the maximum record of Temp, pH, EC, TSS, TDS, DO, PO4 and NO3 are 23oC, 8, 1958µS/cm, 16mg/l, 1156Ppm, 8mg/l, 62.3mg/l and 3.3mg/l respectively. The correlations matrix results, the strong positive correlation exists on EC, TDS, TSS and PO4 this indicates that pollutants are due to the discharge of domestic sewage, industrial effluents and agricultural fertilizers that lead to eutrophication process. From the multivariate statistical analyses study, it is understood that PO4, TDS, EC and TSS have strong factor loading which are the major parameters that control the water quality. The WQI estimated for the river water samples of the study area ranges from 105.73 to 2737.56. The water quality index shown that, the river waters fall under 60% in poor water class, 30% in unsuitable water class and 10% in very poor water class. The Shinta river is highly polluted and unsuitable when compared to the Keha, Dimaza and Angereb rivers. The mid and downstream areas of the Shinta river receives the main pollutant sources from wastewater discharged from the Dashen brewery factory and agricultural activities. The study recommends a need for sustainable management to prevent, control and reduce pollution in the study area