Variations in Water Quality among the Different Municipal Supply Sources of Gondar City, Ethiopia

Abstract

Gondar city is one of the highly populated cities in Ethiopia. Due to the recent rapid urbanization and the associated population growth, meeting the public demand for drinking water has become a critical challenge. To alleviate this problem, the city has started to use the different available sources including rivers, ground water and springs. The public however, has resentments on the poor quality of the supplied water and its frequently appeared bad taste. The objective of this study was, therefore, to determine the quality of water extracted from the different sources (Angereb reservoir, Angereb boreholes, Koladiba boreholes and springs), and to assess the water supply temporal variations. To achieve these objectives different physicochemical and biological water quality parameters were evaluated on a monthly basis for a year. Water supply from Koladiba boreholes was found to be significantly high in amount (p < 0.05) in Cl^- (122‒163 mg/L), F^- (0.74‒0.80 mg/L) and Ca (150‒193 mg/L) than water supply from the other sources. The high level of chloride requires its consideration during water chlorination treatment process. Water supply from Angereb reservoir was more turbid with higher concentrations of PO₄^3- (27.7‒47.7 mg/L) and SO₄^2- (31.1‒35.2 mg/L) as well as coliforms (18‒47 CFU per 100 mL). All of these water properties increased during the rainy seasons (June, July and August). This suggested that they originate mainly from surface run off water containing chemicals from the neighboring agricultural fields and urban domestic effluents. Hence, devising and implementing an effective management strategy to protect the reservoirs from the influence of the adjacent agricultural and urban residential areas is critical.