PERFORMACE EVALUATION OF GIRJA TOWN WATER SUPPLY SYSTEM IN SIDAMA REGIONAL STATE, ETHIOPIA

Abstract

Increasing demand can be fulfilled by designing efficient water distribution networks based on advance computing systems include modern hydraulic modeling and designing software’s. The main objective of this study was to model the existing water distribution system and evaluating hydraulic performance of the system. For conducting this study, both primary and secondary data were collected and tools such as WaterGEMS and GPS were used. The total average per capita consumption of the Town in the year 2015 E.C was 10.15 l/c/d which showed lower performance compared to 50 l/c/d which is set by GTP-II of the country for category 4 town and 35653 m 3 /year of water is non-revenue (NRW) and the apparent losses and real losses of the town is 0.9% and 26.75% respectively. There is high gap between demand and supply in the town because the current (2015 E.C) and the future (2035 E.C) maximum daily water demand of the town was 767224.89 m 3 /year and 1172509 m 3 /year respectively and the current water production of the town was 128940 m 3 /year which only satisfies 19.6% of the current demand (2015 E.C) and 14.4% of the future demand in year 2035. Therefore, securing additional water supplies becomes an essential issue to meet the current and future water demand of the town. The hydraulic model result showed that 2.78% for pressure value (<10m), 76.39% for pressure value (10-70m) and 20.83% for pressure value (>70m) at peak consumption and the velocity of pipe flow showed that 91.3% (<0.6m/s), 8.7% the range of 0.6-2m/s at low consumption time. The performance of the model was evaluated using model evaluation statistics. The value of the coefficient of determination (R2 ) for pressure calibration was 0.98. Finally, the water quality was examined for biological, and physiochemical parameters, potential causes of water losses in the town water supply system were assessed, and improvement measures were proposed for existing water supply problems