Assessment of the performance of existed water distribution system: a case of Jimma Town, by using water GEMS V8i model

Abstract

Water is one of the prime requirements for life, and the Water supply systems are one of the most important and expensive core public infrastructures. In urban area of Ethiopia, water demand is increasing day to day due to urbanization. During operations of water supply systems in many towns of the Country, the common problems are pressure drops, Leakages, contamination and lack of a simple tool to accurately predict low and high pressure zones areas. Hence, the aim of this study is to assess the performance of the water supply system in terms of pressure and velocity variation using Water GEMS V8i software and to evaluate the amount of annual water loss in the system. Sample kebeles and sample population were selected to distribute questionnaires in order to collect information about current daily water supply amount and the level of customer satisfaction with current supply. And the distribution network data like; pipes data, junctions’ data, reservoirs data and other appurtenance elements of the network data were collected from Jimma Town Water Supply, Sanitation Service Enterprise(JTWSSSE) office. Based on the result of the study, the current average water supply coverage is found to be low (10 l/c/ dy).In Jimma town, the annual average water loss for the consecutive eleven years (2008 – 2018) is founded to be 39.14 % out of the total yearly production. This amount is 13,796,488 m 3 out of the total water production of 35,312,888 m3 in the last 11 years. This annual percent loss of water is more than the tolerable percent loss value of water for developing countries.The pressure and velocity distribution along the current distribution system is also found to be far from the recommended range. Water GEMS software was used to optimize the system by modifying and re-arranging the network elements for further improvement towards the pressure and velocity distribution and demand satisfaction. The result shows that, the system performance was increased ie. The number of junctions and pipes that have pressure and velocity in the recommended range was increased. Therefore, JWSSSE should modify and re arrange to improve the system according to the recommended modification in this study to maintain the system safe and customer satisfaction.