Water quality in the Koga Irrigation Project, Ethiopia: A snapshot of general quality parameters

Abstract: The government of Ethiopia has initialized an investment in the agricultural sector in order to secure food production for a growing population. The Koga Irrigation and Water Management Project is a pilot project and hopes are that crop production will double. Water quality is an important factor to meet these expectations. The aim of this study is to assess the irrigation water’s biological and chemical quality by using locally available methods and compare the results with international water quality standards pertaining to agricultural use as well as human and animal consumption. The water was sampled and analyzed for biological, chemical and physical parameters. The most important parameters were thermotolerant coliforms, electrical conductivity and turbidity. The first part of the thesis was a literature study dealing with the Koga project and the water use in the area. The second part focuses on 17 water samples that were taken within an individual command area: irrigation canals, fish pond and drinking water well. The samples were then analyzed at the water quality and treatment lab at the University of Bahir Dar. The results were compared to guideline values for livestock, crop, fish and human use recommended by the World Health Organization (WHO). All water samples, including the drinking water from the groundwater well, were contaminated with thermotolerant coliforms and had a relatively high turbidity. Additionally, the irrigation water contained levels of boron which were higher than recommended for crop production. Electrical conductivity values were overall satisfactory. These results give only an idea of the overall water quality within the Koga Irrigation Project. More samples need to be taken in order to draw any concrete conclusions and provide any recommendations.