Abstract:
Rural water supply systems that cover more than one village are becoming increasingly
common in the Amhara region, Ethiopia. Multi-village water supply schemes have the potential
to capture economies of scale and facilitate higher levels of service; they offer a feasible and
long-term solution to the acute water scarcity faced by many areas in the region. The Wodo Agari rural multi-village water supply scheme, which covers four kebeles of the Asagirt district,
has not reached the consumer tabs and experiences frequently burst pipes and failure of pressure
control devices. The objectives of this research were to evaluate the hydraulic performance of
rural multi-village water distribution systems with pressure control devices in the existing water
distribution system. Both primary and secondary data sources were used for the study. To
achieve this objective, the WaterGEMS model was used to examine the hydraulic performance
of the water distribution network. Additional statistical analysis was used to evaluate the current
hydraulic performance of the pressure break tank and compare the life cycle costs for the
different pressure control devices. The model simulation was run for the system's peak and lowdemand scenarios. Comparing representative samples of the distribution main’s pressure field
test with the model-simulated values showed a reasonable and small difference to calibrate the
model. Simulation results for maximum, minimum pressure and velocity for different scenarios
were used as a base tool to evaluate the hydraulic performance. The analysis result showed that
there were various problems in the system. which are over -sized pipes related to the currently
available existing source, 40% of the pipe length is in the velocity class below 0.6 m/s, 21% of
the junctions were below the allowable limit (15 to 70 mH2O) of pressure at peak hour demand,
and 27.65% of the junctions were above standard pressure during too low consumption
(minimum hour demand). According to the life cycle cost analysis, a pressure tank is more
expensive to build than a pressure reducer valve, but it has lower operational and maintenance
costs. High pressures in the existing system, caused by low levels of elevation relative to the
service reservoir and poor performance of pressure control devices, had been identified, and a
solution was established using pressure-reducing valves and the break pressure tank in the
system.
key words: Multi-village, Water distribution system, WaterGEMS Model, Hydraulic
performance, pressure control device, Wodo-Agari.