Hydraulic transient occurrences occur because of planned or unexpected operating changes, such as pump shutdowns and quick valve closures. They induce an abrupt change in the equilibrium state of a pressurized water distribution system that can result in failure of pumps, system fatigue, pipe ruptures or bursts, and even unclean/dirty water ingress. Until recently, most water systems were planned and operated without taking into account the possible impact of hydraulic transients. However, as computer software technology has advanced, user-friendly transient flow analysis software is increasingly being utilized to model transient behavior in pipe networks and design preventative measures to appropriately protect the system from such threats. In this study, a transient analysis was performed on three distribution network zones that are found in the Rufael and St. Paul sub-branches that fed from the Gefersa water treatment plant transmission network branch via the Ras Hailu reservoir & pumping station site using the transient modeling software HAMMER. To determine systemâ€™s real transient behavior, a hydraulic model database depicting the real system dynamics was created & simulated using WaterGEMS software. It was then imported to HAMMER software and computational simulations for transient state were conducted for the worst-case pump trip/shutdown scenario considering that three pumps that were pumping water to their respective distribution zones through the three pumping pipelines were simultaneously shutoff due to a sudden power outage. The findings demonstrated that the rising portion of all the three pumping pipelines have been experiencing negative pressure waves which travel along the system, causing the pressure in the pipelines to fall rapidly, and creating low or negative pressures to the pumping pipelines as well as to their respective distribution zones. Similarly, at a certain time, the negative pressures at some pumping pipeline segments have been reduced to vapor pressure of the liquid, during which the water vaporizes and forms a vapor pocket that may cause cavitation and water column separation, which can cause catastrophic pipeline failures due to significant pressure surges caused by the vapor cavities collapsing. Therefore, to effectively protect the pumping pipelines, appropriate surge protection devices (double acting air valves and hydropneumatic tanks) were proposed, and initially, transient analysis was performed by installing air/vacuum valve in highly elevated areas where low and/or negative pressures were predicted and at some parts of the pumping pipelines where vapor cavities were found. The results showed that the presence of air/vacuum valves in these locations has successfully helped to reduce MSC. THESIS - [2021] rnrnthe cavities, but there were still negative pressures in the system. So the author decided to install hydropneumatic tanks/air chambers just downstream of the pump stations and found that the installation of a hydropneumatic tank was the best option to uplift the minimum pressure transient and reduce the maximum pressure transient in the system within acceptable limits. Even more so when the hydropneumatic tank is used in combination with air valves, it provides an adequate protection to the pumping system and reduce the potential damage to the pipeline.