Hydraulic Network Modeling and Upgrading of Legedadi Subsystem Water Supply
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Date
2012-03
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Addis Ababa University
Abstract
The thesis paper focused on the water supply network of Addis Ababa, capital city of
Ethiopia. The Addis Ababa water supply has three subsystems according to its principal
water supply sources. These are Akaki, Gefersa and Legedadi subsystem. The paper
considered the legedadi subsystem.
The main objective of this study is to improve the legedadi water supply distribution
service system and control its operation with the aid of computer analysis.
To analyze and improve the existing water distribution system, a model was developed
utilizing Water CAD software. The model can be used to solve ongoing problems,
analyze proposed operational changes, and prepare for unusual events. By comparing
model results with field operations, the operator can determine the cause of problems
in the system and formulate solutions that will work correctly the first time.
The model run was performed for different scenarios to analyze the system model, what
if conditions. These scenarios are at average day demand, FCV-66, FCV-71, FCV-72, and
FCV-73 set closed, FCV-73 set closed and firefighting flow.
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.
The model analysis result showed the different problems of the system. These are aged
pipes, oversized and undersized pipes, and high pressures.
The system has been modified using the design criteria of velocity and pressure. High
pressures in the existing system caused by customers at too low demand have been
identified and solution is established using pressure-reducing valves.
Finally, 10% of the total distribution mains are modified and 19.81% of the distribution
mains are old enough, replaced with newer one. These modifications improved the
performance of the system and saving 5,081m3/day amount of water leakage.
Hydraulic Network Modeling and Upgrading of Legedadi Subsystem Water supply
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Keywords
Subsystem Water Supply