Abstract:
Due to ever increasing of population, there is a challenge on water delivery systems. As a result, expanding system service to meet their demand is essential. However, network expansion of water supply distribution systems is done without detail assessment on the impact of expansion on the existing systems. The objective of this paper was evaluating the impacts of network expansion on the hydraulic performance of water delivery systems in case of Debre Markos town water supply system. WaterGEMS software was applied to analyze the existing water distribution system. The analysis result showed that pressures at sample nodes are within the limit before the extension were made on the model, with a maximum pressure of not less than 35.87m water column. From all existing distribution network 25.83% of pipes had a velocity below and above the limits. But 74.17% of pipes fall between 0.6 and 2.2m/s. and While 68.97% of nodes are in the permissible pressure range of between 15m and maximum 70m
From model analysis, the coefficient of determination (R2) value was 0.93, it indicates that observed and simulated relation is acceptable. Then the additional pipe and demand expansion adopted for current settlements and future proposed expansion areas by made extensions from selected takeoff points. The system was checked for different expansion methods to find the system hydraulic property response regarding to pressure &velocity. The amount of network expansion analysis hydraulic property response was done from 10% to 80% of system demand expansion increment. Modeling result shows the area coverage having node pressure below 15m head varies from 30% to 80% after more than 50% network expansion done. These shows that the system service level drops as extent to which amount of network expansion increases. From this analysis, the current water supply distribution of Debre Markos town is not performed very well. Finally, before the expansion of the services from the initial designed systems, their impact should be assessed and for case of Debre markos further study should be done to enhance the hydraulic performance of the systems.
Keywords: Hydraulic Properties, WaterGEMS, Water loss, Water network expansion,