ASSESSMENT OF THE HYDRAULIC PERFORMANCE OF WATER DISTRIBUTION SYSTEM OF GIDOLE TOWN, SOUTHERN ETHIOPIA

Abstract

The main purpose of conducting this thesis paper was to evaluate the hydraulic performance of Gidole town's water supply distribution system in order to meet the demands of an ever-growing population by delivering water to all systems. The existing water distribution system in the town is a gravity system. To analyze the water distribution network, waterGEMS modeling was used, and the model result was computed with the standard allowable pressure and velocity values in the distribution system, and the configuration of the system was looped. The hydraulic model that was implemented in a water distribution network system includes 146 nodes and 208 pipes. The waterGEMS hydraulic model was calibrated (R2= 0.969) using measured and observed data at 10 randomly selected nodes out of 146 in the distribution system. The model calibration for selected nodes has good performance capacity in the current water distribution. The model simulation run was performed at peak hourly demand with 1.9 hourly factors and at low hourly demand with 0.25 hourly factors to evaluate the performance of the distribution system. From the analysis, at peak hour consumption, the pipes with the minimum velocity in the system are 58 (27.88%) of the total pipes, and pipes within the range of the Ethiopian standard are 117 pipes (56.73%), and at minimum hour consumption, it results in pipes with a minimum velocity of 149 (71.63%), and within the range of the standard, it was found that 27.88% of the pipes. It is also identified that at peak hour demand consumption, 85.62% of the nodes in the distribution have a pressure within the range, while 2.05% of the nodes in the distribution system have a maximum pressure head of more than 70 m and 12.33% of the nodes have a minimum pressure of less than 15 m. At minimum hour consumption, pressure distribution within the range of (15–70 m) is about 47.95%. From the detailed analysis, the estimated water demand of the town is 1,284.3 m3/day (48.4 l/c/d) and at the end of the design period of 2030, it would be 3,099.77 m3/day (66.03 l/c/d). The current water supply coverage for the town is 33.64%, and the average water loss is 75,434.11m3/year, which is 29.9% of the produced water lost in the system, which shows that it needs to be a matter of concern. The study's findings were suggested to the town's water supply project and institutional development offices for future modification and rehabilitation work.