Abstract:
Water supply distribution system modeling is a method of representing the real system, analyzing
and approximating the real water supply distribution system behavior and operating conditions
using computer softwares to solve short comings facing water utilities.
Some districts like Saris/Sar Sefer/ and some high elevation areas in Jimma Town are facing lack
of an access of potable water supply. As a result, the people living in these areas are travelling
more than a kilometer to fetch water from springs around Jimma Town, but there are no real
evidences which show the real causes of the problems; because there were no studies conducted
on the distribution system of Jimma Town. So to identify the main causes for the water shortage at
the mentioned areas, to assess the operating condition and hydraulic behavior of the distribution
system, to identify problems related to flow and pressure, to evaluate and improve the current
performance of the distribution system and to simulate the future condition of the system, it is
found crucial to prepare this hydraulic model for Jimma Town Water Supply distribution system.
The objective of this study is to model the entire water supply distribution network of Jimma Town
from the treatment plant Clear water well to the customers and to analyze and evaluate the
performance of the system under various physical and hydraulic conditions including fire flows.
The study does not include water quality aspects and energy analysis. The model is prepared using
the combination of waterGEMS, AutoCAD, waterCAD and GIS softwares. This study is conducted
with the aim of enabling JWSSE operators to ensure the safety of the distribution system without
wasting time and energy; because it is possible to manage the system simply on a computer using
the model once the WDN model is linked to GIS, water billing and other information management
systems of the utility. To prepare the model, different primary and secondary data were collected
and analyzed. Then after running the model for both steady state and EPS, low pressure values
around Gebrel Tank, high velocity and head loss through the gravity main, and low velocities
through most of the pipes were observed. Finally, it’s concluded that even though the main
problem of potable water shortage is pressure deficit, the main from the old treatment plant to
Gebrel Tank might be closed. Then solutions are suggested using different scenarios.
