Physico-Chemical Water Quality Assessment of Gilgel Abay River in the Lake Tana Basin, Ethiopia

Abstract

The physico-chemical parameters such as PH, temperature, electrical conductivity, total dissolved solid, turbidity, total alkalinity, total hardness, ammonia, nitrate, nitrite, phosphate, sulphate, sulfide and iron were investigated to assess the various water quality parameters along the River course of Gilgel Abay River (GAR). The value of those parameters have been evaluated with respect to guidelines provided by World Health Organization(WHO), Ethiopian drinking water quality standards(EDWQS), Canadian Council of Minister for Environment(CCME) and European Community(EC) to indicate the pollution level of GAR. Overall compliance was 58.93%. From a total of 224 samples, 132 samples (58.93%) complied with WHO guidelines and EDWQS. Turbidity, followed by iron, phosphate and sulfide were the prime river water quality issues identified in GAR. Analysis of variance was used to examine the variations of water quality parameters between the dry and rainy seasons, and the variations along the river courses of Gilgel Abay (upper, middle and lower course). The majority of the parameters showed that there is a significant variation of the water quality parameters between the dry and rainy seasons. However, the variations along the river courses of GAR (upper, middle and lower course) were statistically insignificant. This implies that the GAR water quality is influenced by anthropogenic impacts from the upper course to the lower course of the River.

Keywords: Water Quality; Physico-chemical Parameters; Gilgel Abay River